Gmt400 to gmt800 brake upgrade Has anyone upgraded to the 3. After installing, bled the brakes and it is terribly squishy, worse than before. you have a ton of options. I have read a lot about upgrading to the GMT800 master cylinder along with calipers, rotors and wheel cylinders from a dual rear wheel application. GMT800 Brake upgrade different control arms for a 6. Aug 20, 2015 · My old K1500 had a gmt800 Tahoe MC, gmt800 single piston rear disks and 8 lug front calipers and that was by far the best K1500 brakes I’ve ever driven My K3500 is getting the Lugnut4x4 rear disk conversion with JB7 calipers so I’m curious to hear feedback on the negatives of that setup Jan 6, 2022 · Single Caliper Disc Brake Adapter for 1988-1998 Chevrolet ½ ton, 10 bolt rear endThese Billet Aluminum Single Caliper Disc Brake Adapters are the perfect place to start when converting your 1988 - 1998 GM 10 bolt vehicle from drum brakes to disc brakes. May 13, 2014 · I did the GMT800 front, Russell braided lines all around, GMT800 master up front (make sure it is the 34mm bore from a ~2002 Silverado). 15" diamter piston, and dual rear wheeled trucks used a 3. Now, you can find the older style 14 bolt FF under the CUCV trucks. 125, so the bigger bore has lower line pressure but higher volume of fluid moving, to me it feels like there's less take up in the pedal, the science says you should have to hit the pedal harder in Sep 15, 2013 · Didn't seem to be much interest here. Lift knuckles/spindles do not exist for GMT400 as they do for GMT800+, there are funky add-on pieces to sort of make a lift knuckles out of the We would like to show you a description here but the site won’t allow us. Brakes are fantastic! A Motive Power bleeder works well for getting all the air out. I also noted that the attachment bolt and bracket for the brake line is different than the GMT-400. Replace your pads with good pads. I didn't modify the proportioning valve as the instructions said that they "advise" you to and didn't state that it is "required". Jan 28, 2019 · I finished my brake upgrade on my 88 GMC K2500 6 lug (7200lbs). 4l. I also thought I read that the 99-00 Z71 Tahoe used the 2500 3/4 ton front caliper. 5" shoes from the 10,00 Nov 25, 2019 · So, you have a GMT 400 truck, but the brakes are somewhat crummy You have some options. Locking Differentials; Oct 18, 2016 · I'm a firm believer in replacing brake parts by rpo code. The spring perches and shock mounts are also in the wrong place. Brake pedal is really soft after changing fluid and replacing front pads and rebuilding the rear drums. Along with a set of fresh tires just recently, and she stops real good now. My wife likes the newer and bubblier GMT800 truck better, however I am a little upset about the 450+ mile range due to the smaller 33. Their brake calipers and brackets are also smaller. The Pedal came from a 96 C3500. Feb 29, 2020 · Upgrade to the bigger single bore HD2500/3500 GMT400 MC for a bolt in solution that would give the same results. May 30, 2010 · I've never had any issues or complaints on my GMT800 2006 SIerra Denali brakes, even when towing my RV or loaded car hauler. Fluid of course. 5" wide rear shoes and the other uses 3. The heavy duty 2500 was an 8 lug 8600 gvw that was completely different (frames, brakes, springs and stuff). Just checking to see if someone has done it before. Once he pulls off the drums he will swap out the complete disc setup. Dangerous lack of brake power. slowburb; Feb 19, 2025; Full Custom Suspension Jan 12, 2021 · So since I no longer have my 95 c1500. Brake drag has to be minimized to meet CAFE requirements, and to be competitive with "official" EPA fuel-economy estimates. Thread starter Gibson; What is the difference between GMT800 upper control arms and GMT400? It seems that if the lower control arms are compatible Jan 11, 2022 · The T1XX factory option "big" brakes w/13. that would be my recomendation. GMT800 Brake upgrade different Jun 21, 2013 · For the rear, only the 14bsf of of another OBS is a direct swap. you can swap dual piston 800 burb brakes, 900 brakes. Nov 24, 2020 · The GMT800 master cylinder firms up the pedal because it has more piston area than a GMT400 master cylinder. 75 or OEM 6×5. WHICH "new calipers"? Low-drag? 4. people are using metric s10 calipres or eldorado was the first swap. For those with 6 lug wheels, you DO Jan 28, 2019 · the srw 1 ton piston is 3. You'll need the Ford/3 prong attachment part # 1107 for the 2002 Silverado master Nov 23, 2014 · This is something I also have been doing a lot of research on, and have both a GMT400 complete subframe and a GMT800 subframe Im trying to compare and see what and how to swap over a few pieces. There is a sticky thread here on this. So far, what I have come up with, is that the GMT800 spindle is shorter than the spindle you are using. There are some pretty good options for GMT800 and GMT900 trucks that would be awesome on a GMT400. It seems easy enough to go hydroboost to hydroboost other than swapping the mounting plate from the GMT400 hydroboost over. GM designed the 03 and up astro awd knuckle to bolt in place of the gmt400 knuckle on the astro and use the newer style brakes and hubs. Now to the back! REAR KIT: This new brake kit will work with ’88-’98 rearends, and it does NOT require machining to the axle or rotors because we use a true truck rotor. Aug 9, 2015 · My nosing around reveals that the track width for a GMT400 is in the 63. The hubs were different but the OBS axles fit the NBS hubs perfectly. The most expensive part was the rear axle spacers to adapt the GMT800 disc brake backing plates. I originally paid $200 or so for the whole shebang. Most of what I found is half ton upgrades from vacuum boost This spring, I installed a Dana 70S rear axle from a Chevy Express van into my GMT400 K2500 Suburban. to the top of the spindle and using the gmt400 tie rod or purchasing an adapter to use the gmt800 tie rod. Would be intersting to know if the GMT-800 3500 DRW had even larger Pistons in their calipers. As soon as he sees the third brake light he jumps out of the back, holds on to the tailgate and slows me down Fred Flintstone style. 1999 k2500 crew cab 7. Solutions Aug 13, 2021 · Has anyone tried the brake upgrade using the 2019 and up rotors and four piston calipers? Found this video on it. Check out my other Tahoe videos!https://www. Check into the late Astro van setup, I know the late 6 lug AWD used GMT800 stuff, I wouldn't be too surprised if the 2wd also swapped over to the dual piston caliper setup. This caliper has an integrated parking brake but will function without it hooked up. IT'S MAGIC! I DISCOVERED A MAGIC UPGRADE!. Even the NBS brake hoses fit the OBS brake lines perfect. Or you could swap to gmt400 shock mounts but that's just more effort than it's worth Jul 21, 2020 · I have been working on a budget "big brake" upgrade for my 93 Burb, consisting of the new 2019+ Silverado 13. My plan is to do a rear disc upgrade from Little Shop MFG (www. Aug 2, 2024 · I have read a bunch of threads about using the GMT800 master and other similar upgrades but am still unclear on the benefit and what it takes to make the swap. some rpo's are better than others and if you get into swapping brake parts just because they fit, could actually impair the brakes due to mismatched master cylinders with mismatched brake cylinders or calipers. Will I be able to put that axle in place of the axle Jan 2, 2019 · I have owned both GMT400 K1500 with 6" lift and 35s and my current GMT800 K1500 3" body lift and 37s. any update May 6, 2025 · Want to get the full potential out of your GMT 400 Truck? At Auto Accessories Garage we have all the top name brand accessories at rock bottom prices. Anything else and you will have to move spring perches, shock mounts, and find adaptions/conversions for the brakes and U joint/yoke. I went to the NAPA parts store for fresh calipers and rotors and made another huge discovery. I have front calipers with the 2. The brakes should be the 11 5/32" drums on the back. If you search the part numbers, you can get the calipers for 400 each and 70 bucks each for the rotors. I had to modify my brake pedal to make up for the shorter pushrod, drill a new hole in the firewall and fab up some brake lines. Best thing I've done the Apr 29, 2023 · Anyhow I noticed it looks like AAM or whoever beefed up the cases on the GMT800 IFS a fair bit. (7200lbs). It eventually self clearances and shuts up, but I'm not a huge fan of it. I bought that MC but had to use a proportional valve from an older 3rd gen truck with disc/drum. Thanks in advance. GM offerred these from the factory on TAHOES sold for police and fire department use, and will work with your stock rotors. I Looking to upgrade my brakes. My front brakes were SHOT and yesterday I replaced the rotors and pads with a set from Powerstop (K1990-36). I did upgrade to the 2008 tahoe calipers and rotors. I don't need it to stop on a dime, just need it better than what it is now. If his feet get too much traction he hops up and down to keep me from spinning out. As I said I know the 8k weight ball joint and the 7k ball joint are different. Aug 9, 2015 · Correct me if I'm wrong here. But you can just grind the shock bushing flat with the shock body and it works just fine. Not bad for 15" rotors and 6 piston brembos around $1000 for everything. The front ends on the 2wd 2500 non HD are coil sprung like the 1500 2wd but with 8 lug. The video I've watched on this just said use the k2500 upper control arm and ream the knuckle for the GMT400 ball joint. This brake kit will work with any disc brake drop spindle, such as McGaughys, Street Edge, BellTech, etc. Once I went to the GMT800 disc/disc setup, the rear discs stopped after 15-20% pedal travel. 663. Are the rear brakes properly adjusted? Does the park brake work, and do you use it frequently? 5. Enjoy! Nov 22, 2024 · My '88 had JB3 brakes--the worst power-assisted brakes ever installed on a GMT400. From an earlier post: "My vehicle is a 97 K1500. E36 M3 I've spent more fixing broken stuff than a major brake upgrade on the GMT400 would have cost. littleshopmfg. Aug 12, 2020 · I'm going to upgrade my master cylinder and brake booster since they're both questionable. If you have a mish-mash, go fully GMT400 or GMT800. Oct 13, 2016 · I've done some searching but most of what I see is for 1500 Vac to hydroboost. Apr 19, 2013 · The only modification needed for these knuckles is reaming out the upper balljoint hole to fit the GMT400 upper balljoint. 6" rotor. Dec 24, 2009 · GMT 400 Hydroboost swap. 5 14 shared the same 4 bolt flange. The firm pedal is nice, but you are decreasing your brake system effectiveness in the process. Sep 30, 2019 · I've heard from many of the GMT-400 owners on this site that the power stop upgrade has been amazing on their platforms. I had to buy parts anyways so I went with a set of 2010+ GMT900 Calipers, pads, rotors and brake hoses to upgrade to the 13" rotors instead of 12". Do pads and tabs need to come off the GMT400 axle being replaced? Or are the GMT800 bits being removed suitable? Jan 5, 2010 · I believe the PPV tahoe brakes are the same as that performance brake system but with uncoated calipers. 5 lug patterns. That’s when I found out it is an obsolete part now. Hell Brembo even has a 6 piston caliper / 16" (16"!!!) front rotor option for GMT900's but it's $2K+ and requires 20"/22" wheels (and not all will fit) and that's just for front brakes Apr 21, 2019 · Short answer, no. On the later models it was built into the abs unit but the earlier ones mounted beside the master cylinder. May 7, 2025 · Yes the diesel and the big block are the same. I installed a GMT400 ring on the GMT800 booster. All connections are tight and all 4 corners bled. I’m definitely doing those. If anyone knows about a stock 2WD dual piston upgrade let me know. Grabbed a mc out of 2001 Tahoe with vacuum booster. The usual trick that everyone tells you is to use the 3. Mar 19, 2024 · Be prepared to find all sorts of other issues as you take the suspension apart--PS pump, PS gear, rusted frame at the PS gear, brakes including metal tubes and rubber hoses, ABS, disgustingly contaminated brake fluid that needs to be flushed using a scan tool to chatter the ABS solenoid valves, ancient front or rear differential lube, leaking Jul 11, 2023 · The front brakes are tied together with a T, and the rear brakes have a wilwood adjustable proportioning valve. It looks like it’s based off a 4WD Astro van. 5" range where the GMT800 is around 65" so the rack shouldnt be too wide. Nov 17, 2015 · 1500 (6200? Gvw) and Light duty 2500 (7200? Gvw) were the same 6 lug but the gvw were different. The Hydroboost came from a 2005 z71 Suburban (GMT800). The reason why I am doing so is because I am going from torsion bars to coilovers for comfort and a better ride quality! I also want to make the bolky lower control arm to a more sleek and Sep 27, 2010 · Did any GMT400s come with disc brakes in the rear? Is the GMT800 axle exactly the same as the GMT400 (except for the disc braked versions) ? I like my disc brakes on all 4 corners Feb 25, 2025 · A couple of my favorites: 2500HD gauge cluster (for transmission temp gauge) and the "big brake" upgrade. Thank you for pointing that out, I was not aware. 94" diameter piston in the front calipers, 8 lug single rear wheeled trucks used a 3. so if someone wants to upgrade the brakes you need all of the parts for that Apr 26, 2022 · A126-2 Rear Disc Brake Conversion w/ Built In Parking Brake - Red: 88-99 Chevy 1/2 ton truck, 2 wheel drive - Red Get up to 30% more braking power, by installing an SSBC-USA rear disc brake conversion kit. I could simply swap out with another gmt400 master but was curious is I could keep the gmt400 hydrobooster and upgrade the master from a gmt800. gmt400. Best way to get better rear brakes is to grab a 14-bolt 9. I anticipate have to cut off the stamped steel LCAs from the torsion because nothing would remove them the last time I was in there doing ball joints. Feb 23, 2023 · yea. 7L. My truck stops amazing, has a fully functioning stock parking brake setup, everything is GM and it was pretty cheap to do all of it. Jan 3, 2016 · So since it’s possible to upgrade the gmt400 to gmt800 - is it also possible to just use the gmt800 spindles and tie rods with gmt900 13 inch rotors and calipers (instead of the smaller gmt800 parts) since the gmt800/900 is a bolt on swap for the gmt800 trucks ? Jul 3, 2022 · Hi I am new to the forum. I am asking $125 shipped in the lower 48, I am located in Saginaw mi. Mar 1, 2012 · The cherry on top is the hydroboost with HD master cylinder, truck will lock the 33s down hard since merely adding HB. About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright Aug 9, 2019 · If you have GMT800 brakes, you want the GMT800 master cylinder. com adapter plate, the modified brake pedal and the GMT800 master cylinder as a package deal, this fits 94+ trucks. I am selling the manualbrakes. It’s been difficult trying to find any info on this though, I mainly just find info about aftermarket brackets that are available. Mar 26, 2011 · There is a shiny new master cylinder from a 2005 Silverado hooked up to my booster. Latest: wilburou812; 12 minutes ago; Axles + Brakes. The drum brake hardware is often overlooked, and kits for Chevy trucks are reasonably priced. I had read a bit about folks upgrading to a GMT800 brake setup but haven't been able to find anything definitive in my google research. 5" SF into GMT800 half ton. The factory gear ratios for teh rear are the same as the fronts. Anyhow, I did the GMT800 front knuckle/ brake "upgrade" along with the GMT800 master cylinder. theres a place called cunninham making a caliper bracket that uses stock k1500 front calipers. Pull both rods from both units and swap the '400 rod into the '800 HB unit. 5L??? I like the EBC yellow stuff brake pads for up front and semi metallic shoes out back. May 5, 2018 · Axles + Brakes . That "dead spot" that I know these trucks are famous for is gone. Now on to the front brakes. 1 brake fluid. Recently discovered my master cylinder in leaking in the front. I plan to snag some AWD 6 lug Astro knuckles to run GMT800 rotors and calipers myself. Just got around to doing the brake lines from the abs out before this winter. Now, the brake pedal is without question firmer. Maybe if I wanted to deal with bleeding the brakes again I'll go ahead and do that. if you mount the 800 suspension on that truck, you want to terminate the brake line near where it would be for Jan 14, 2018 · I see GMT800 brakes for sale in the forum, what's the ball joint story? Confused about brake upgrades for 93 K1500. I was reading about brake upgrades online. I was Apr 21, 2019 · Short answer, no. Without 4 wheel discs, big rotors, and 2 piston calipers, I believe this is doable. That upgrade also must use the thicker dually rotor. I got new shoes and drums and adjusted everything properly out back. I also had to use 08 tahoe front CV shafts. Yes the pedal is a bit spongy but it stops great. Sep 23, 2018 · So in my research on the NBS front brake upgrade for our trucks, I've noticed a couple things I wouldn't mind getting a clear question to, I've seen tons of stuff for half tons, but with FSC being gone I can't find much on this swap for K2500/K3500s. Dec 2, 2009 · The tierod stud hole was the same on both, just had to turn the tierod 180-degrees. My goal with this project was to upgrade the brakes on a 1999 k1500 suburban to roughly 70-80% of the GMT800 (NBS) duramax. 0L on my 99 K2500/5. Looks like a big improvement over the stock setup. Reply Reactions: bigdogYJ , ORVietVet , dreid13 and 1 other person May 30, 2017 · Then the axle will be wider (WMS to WMS) than the GMT400 has. The brakes still need to stop the vehicle without excess pedal travel. The front brake upgrade was noticeable. . Those should be adequate if in good condition. com/playlist?list=PLTy67ig2sA9PKGBXWephfDa5Y11SdZutcParts linked below!Complete Budget Friendly Kit:https Dec 2, 2015 · If this actually works this will be an awesome upgrade to get some real brakes with a wheel pattern that hasn't gone the way of the dinosaur lol. 2000 suburban package on my 89 GMT400 Nov 22, 2020 · Found a pretty significant leak on the hydroboost unit in my '99 3/4 ton Suburban yesterday. I've had my share of GMT400's but this one needs a brake overhaul. You will receive a template and instructions on modifying your spindle, which requires cutting of the caliper "ears" and drilling and tapping for the caliper mounting bracket. I bought a 98 Suburban K2500 7. 5-inch drop spindle for GMT400 GM C/K 1500 2WD truck and SUV models features an OEM style GMT800 sealed hub conversion in dual 5×5, 5×4. Mainly the GMT800 MC firming up the pedal was the difference I felt. 5 full float all factory disk brake with internal parking brake from what I have seen. There are 2 things you need. It is worth it to upgrade the master? What else needs to change? May 24, 2020 · It took about 65-75% of the brake pedal travel to get the rear wheels to stop in 1st gear idling. I picked up a GMT800 hydro master cylinder for it because of threads like this and it wouldn't fit the 400 booster. I upgraded the rear axle and rear brakes a couple of years before upgrading the front brakes, master, and booster. I think I read that you can improve the braking by putting in the booster from a 2500 or 3500 and haven't been able to track down where I read it to get the specs on it. The brakes on these trucks suck. 1 and diesels had the 11. I’ve got a k1500 with very squishy brakes. Dec 10, 2015 · Not sure on that one. 285" diamter piston. The problem in doing the gmt800 and 900 swap is the lower control arms and balljoints. Perhaps Oct 24, 2022 · I’ve wondered whether the GMT800 DRW factory disc system from 2001+ could be retrofitted to the GMT400. the one im saying to be important to make sure it is done is the brake hose on the gmt400. 25 is probably not a QTU; so functionally the GMT400 and GMT800 should work the sameIF (big IF) they'll mount to the booster correctly, and connect to the brake tubes, and don't interfere with anything else. Really been happy with the swap. The popular affordable options seem to be steel lines and a gmt800 master cylinder swap. Sent from my Nintendo 64 Jan 19, 2021 · When you get REAL rear brakes, you may not need to upgrade the fronts, except to assure that the caliper pistons aren't sticking, and the caliper floats properly on it's pins. May 16, 2020 · Changing out the lower control arms from stamped/welded steel to forged is on my to do list. The forged LCA go on and off easily. 5" semi-float axle from a 6-lug 2500. The only difference Dec 5, 2017 · I'm in the process of finishing the the 800 dual piston brake upgrade. 1988-1999 gmt400 obs ; 1999-2006 gmt800 nbs; 2007-2014 gmt900 nnbs; trek 2025; dodge ram front axle; you can installl your factory gmt800 brake rotor, and hub Mar 7, 2017 · I hired a gorilla to hang out in the back of my truck. autoaccessoriesgarage. Dec 15, 2021 · I am using this as a template for anyone who wants to do a gmt400 suspension conversion to a gmt800. Bought to tow a small travel trailer (4500lbs loaded) dual axle. I started doing some research on the GMT800 MC upgrade. Were I to repeat the brake upgrade process on another GMT400, I'd just start with the HB and likely be done at that point. How many "old hoses" in the rear? Do the rear brakes bleed nicely, good volume of fluid out the This brake kit will work with any disc brake drop spindle, such as McGaughys, Street Edge, BellTech, etc. This idea came from my research which showed that the new trucks use a huge rotor but share the 6x5. Mar 2, 2010 · I have a friend if mine that has an axle that was under a GMT800 or NBS truck. Oct 30, 2015 · Like the title says, I want to upgrade the brakes on my project 2000 Tahoe Z71 (OBS obviously). 3. Beyond that I’m not sure, but I think it is possible to put GMT800 spindles on which gets you only slightly bigger rotors. Recently did the nbs master cylinder upgrade. If you go into them, look closely at the condition of the shoes,wheel cylinders and hardware parts. Aug 18, 2013 · My 2003 2500HD crewcab Duramax weighs in at ~4 tons and thanks to hydroboost (and much better rotors and calipers) , it will stop on a dime. Jan 3, 2016 · The GMT-400 to GMT-800 front brake/knuckle conversion is no more different than when I took my ex-girlfriend's '68 Cutlass Convertible and converted it from straight hydraulic drums all around to power front disc brakes 3 years before any aftermarket kit was available, by going to parts yards to scrounge find an A-Body donor for the correct Mar 29, 2016 · I know it’s been gone over thousands of times, but I’m trying to get a clear picture of what I need to do the upgrade. Try looking up a proportioning valve. Electric brakes. For the 3/4 ton/1-ton trucks, the 99-00 Jan 10, 2025 · now the photo I posted, which is pictured with a speed sensor wire ON TOP and the brake hose snakes behind and it goes off to the right, yes. 15" drw is 3. 285" i don't think much gain if any came from the drw pads over srw but they are a bit thicker and designed different. GMT800 rear axle swap, or convert 1999 14 bolt to discs? GMT400 9. The Modular Truck spindles are also ABS-ready for ’95-’98 factory equipped trucks. I was going to just do the GMT800 upgrade, but it's much easier to get the rear drum master cylinder for the gmt900. My truck is a 2000 k2500 8600gvw. 0 had a 10. This is also referred to as the GMT400 to GMT800 MC swap. Aug 7, 2019 · I just watched this guy swap GMT 800 front brakes into his K2500 suburban. The new master cylinder part number is as follows if you don't get one from a junk yard. 88-98 GMT400 Conversion Kits; 01-10 GMT800 Conversion Kits; Disc Brake Conversion; Disc Brake Conversion Brake Lines; AAM 11. Here is the predicament I’m in: The brake pedal is firmer but the truck doesn’t want to stop. Aug 20, 2015 · The brakes on my 89 K1500 are terrible to the point I do not want to put a trailer behind it. Jun 11, 2020 · If your truck isn’t a dually, you can easily upgrade to the dually calipers which have a slightly larger piston. Aug 26, 2017 · 1994 Chevy full-size blazer (5. There are two brake packages for the 2500 (3/4 ton), one uses 2. The one place I'd like to upgrade is the brakes. com Sep 21, 2013 · Got bored yesterday and found and installed the new MC. The lower control arm ball joint specifically is not oriented correctly to allow attachment to the later style knuckles. Jun 22, 2016 #64 Oct 22, 2015 · I have a 2000 Z71 Tahoe that I am looking to upgrade the brakes on. Thread starter DRAGGIN95; front brake upgrade for 1997 k3500. Your swap would be similar I just bought a 99 K1500 suburban JB6 brake package. I cover the most common GMT400 brake upgrades. Jul 20, 2013 · I've seen where people will use the lift knuckles for a gmt800 2500hd with the gmt400 k1500 lift kit that way its easier to convert to 8lug up front and then you have 2500hd brakes instead of gmt800 1500 brakes, doubt its just a bolt up swap but I've seen a few of them so it shouldn't be to bad other than the cost of all that. Anybody know of kits that give it a little more stopping power that aren't crazy expensive? Aug 16, 2012 · Also if you have a 88-94 truck, you can swap out the wiper arms off of a 95-98 GMT400. I have a 1989 K3500 SRW. 15" and pads from a K2500 8 lug (8600lbs) Had to grind the front outer pads just like Nitro Junkie posted on one of the pervious pages. 5" Rear Axle. 5" rear shoes but the same drum. I have a fairly new GMT400-style master on my truck. Click or call 800. I want to measure a 800 vacuum master to see if it would fit in the 400 hydrobooster. 1570 to learn more! www. "I" would not bother with a GMT800 master cylinder. Jun 14, 2020 · Looks like the dual piston caliper upgrade for 4WD works for possibly 4WD only. I have not made any upgrades to my brakes because they are fine and not in need of replacement, but when they are, I will upgrade everything I can. The vacuum booster remains behind. 15 calipers from the 8 lug (8600lbs) calipers. I absolutely loved the 42. The most popular GMT400 brake upgrades include: GMT400 rear disc brake conversion; GMT800 brakes on GMT400; GMT 400 brake master cylinder upgrade; GMT 400 big brake kit; GMT400 front brake upgrade; GMT 400 brake Nov 18, 2017 · However it had seized in that position. But thought I’d. Donor truck was a 2003 2500hd. Of course wheel selection gets to be pretty important as many have found the "rib" on the OEM caliper rubs against the inner face of some of the earlier factory wheels - the rib can be ground off, but that's Jan 3, 2016 · But seriously, I believe that the 7° is the upper taper and 10° is the lower ball joint taper and is done because the diameters of the shafts of the new parts are larger. The appearance isn't the upgrade part here, but the performance. The braking feels different, but I also swapped in a 14 bolt semi floating rear axle with bigger drums at the same time. First thing Make sure all the little things are set up properly. Jul 19, 2020 · Those are the only QTU master cylinders for GMT400 that I'm aware of. Everything I've read either talks about rotating the tie rod. Sent from my SM-G900W8 using Tapatalk May 14, 2016 Feb 18, 2022 · I am running coilovers and switching to rack and pinion and have also found that the cvs from a 09-13 silverado are 1 15/16" longer per side than the 88-98 gmt400 or gmt800. that being said, i am gonna run the high-articulation cv axles from napa for the 2009-2013 silvy, and i am building new upper and lower control arms that are 2" wider per Jul 15, 2021 · I just bought my first truck, 1998 GMC c1500. There are many GMT400 upgrades centered around the brakes. 7. 4l Automatic off a buddy to haul the family and pull the camper with. Dec 11, 2018 · I decided to try the brake upgrade that Lawrence Tolman was showing on his Youtube channel. The ABS wires plugged right in,too. I started with the rear and removed all the Jul 15, 2011 · It possibly could, but I have a GMT400 hydroboost sitting on the shelf to install in my truck. I assumed the GMT400 MC didn't have a big enough piston to get enough brake pressure to the rear discs. 5gallon fuel tank and 650+ mile range the GMT400 had. Feb 19, 2019 · 88-98 6 lug disc brake upgrade The 1988 - 1998 GMT400 Chevy & GMC Pickups Message Board I swapped to GMT800 knuckles on my 3/4 ton. Looks like the hydroboost is still the best bang for your buck along with ceramic brakes. There is a really great thread on here about upgrading brakes on 3/4 ton GMT400's, but unfortunately won't work for me. 2. Mar 17, 2022 · They have in my opinion the best type of Parking brake set up, (Drum inside the disc, GMT800 rear discs are the same). The pedal feels way better. You can then use 8 lug GMT800 lower controls arms, brake calipers, and rotors and 99-07 GMT800 half ton 4x4 brake hoses. It was not a bolt on installation. Aug 23, 2020 · If you're towing, you need this item. If you're feeling really froggy, research brake system math, get the specs for each part in the brake system, build a spreadsheet, and buy the parts you want that don't throw the numbers out of spec. Bled the ABS unit and bled the system from the furthest to closest point. If not, maybe I'll just roll the dice, Amazon will return anything. I also found newer style case halfs that said they fit the gmt400 and gmt800 years. Unless someone has something to add that I haven't already learned, I'm going to conquer it this weekend. The 1. I’m now looking into the master Brake booster upgrade? It's time to replace the booster in my '88 k1500 5. Aug 6, 2010 · The above (plus GMT800 master cylinder) will get you Astro/GMT800 brakes on a 2WD. 94 diameter piston. Mar 16, 2022 · I did the GMT800 master cylinder upgrade and it helped the brakes and I could have done a bunch of other upgrades to the brakes a lot cheaper than the GMT900 cost. 'Course, if they'd used the proper fully-functional QTU master, the brakes would have worked even better. I had read on some other forums that the brake master cylinder from a 2000 Silverado was the right upgrade for our trucks, the gmt800 1500 master bore is 1. Dec 29, 2010 · Here is a 2007 disc brake 14FF in my 88V2500. Aug 21, 2021 · *No need for this*. I honestly didn't realize it was that difficult. 6 lug trucks used a 2. Aug 6, 2010 · I just watched this guy swap GMT 800 front brakes into his K2500 suburban. I also thoroughly bled the system with my Motive power bleeder and I am quite certain I got all the air out. DRAGGIN95; Sep 6, 2012 front brake upgrade for 1997 k3500. The Dana 70 comes with massive rear disc brakes, but I Feb 16, 2012 · How to swap out the squishy brake pedal for a firm brake pedal. I got a set of knuckles and lower control arms from a 1999 Silverado 2500 and a complete rear axle from a 2002 Silverado 2500HD. Going to do the master cylinder with an aftermarket residual pressure valve this spring. Jul 3, 2019 · They have a wealth of info on this subject. I am selling the last little bit of parts. youtube. I may decide to do this to my K3500 beater, LOL. I have a 88 GMC K2500 with 6 lug wheels. The OBS trucks are known for a horrible squishy brake pedal. Aug 15, 2018 · Brake Upgrade. Oddly, on RockAuto, I find disparities in the specs. 5" bolt pattern and 78mm center bore diameter as the OBS K1500 rotors. Jan 16, 2021 · Vehicles with larger master cylinder bores tend to have more-powerful brake boosters to compensate for the lack of hydraulic advantage. Lift knuckles/spindles do not exist for GMT400 as they do for GMT800+, there are funky add-on pieces to sort of make a lift knuckles out of the Apr 19, 2021 · The above (plus GMT800 master cylinder) will get you Astro/GMT800 brakes on a 2WD. Nice thing about the bigger bore is that it reduces pedal travel, and it's my own personal suspicion that the crappy ass 1500 brakes are due to the pedal overcentering which stalls forward travel of the MC pushrod. Never tried it and haven’t owned a 4wd OBS or newer Chevy truck. your cross car depth is what youll need to be concerned about to Apr 10, 2019 · Yes my original post was based on the fact that 90-02 awd astro vans used the exact same knuckle as 1500 4wd gmt400 trucks. Between quick take-up systems, drum versus disc proportioning valves, and the liability of grinding on brake components to get them to fit, there's way too many Apr 6, 2015 · I can't seem to find a thread with relatable information. This also results in less clamping force at the brakes. 5" rotor/4 piston caliper have been adapted to GMT900's and GMT800's already with minimal work. 10 bolt and9. I found a thread where a guy installed 99-02 GMT800 1/2 ton front brakes and reamed the knuckles to fit over the GMT400 ball joints. Nov 5, 2013 · I'll post some pics later, as everyone knows, on the two wheel drive GMT400's they have a rotor with a packable bearing. My question is this - does anyone know of an easy brake upgrade Aug 25, 2020 · To finish off the front, simply fasten the new brakes lines and bleed the brakes. -NBS 1500 series master cylinder (buy the corresponding master cylinder for your truck, 1/2 ton=1/2ton, 3/4ton= 3/4ton)-AGS BLF 26C brake line adapter (I got mine at autozone)-DOT 3 brake fluid Nov 24, 2020 · Folks have a defective QTU master cylinder, they "upgrade" to a fully-functional non-QTU master from a newer vehicle, and the brakes improve. Jun 7, 2023 · The push rod on the the GMT800 is a different length than the GMT 400, I had to do a custom length one for my truck. I swapped the booster, master cylinder, lines, and p/s pump. Was going to bleed again. Them being single piston calipers, does not really make them inferor to the gmt800 rears, but might come into play when finding a suitable master cylinder. 5 gallon fuel tank. Anyway, I was thinking about upgrading the calipers as well. I use Powerstop z36 brake pads. bought with upgraded brakes, 4 wheel disc , from a gmt800. I also switched to DOT 5. Works only on HD rotor drop spindles. Depending on how you've plumbed in your new MC, you may have made it impossible for your rear brakes to work correctly with your current setup. Apr 21, 2020 · J/K I understand the attraction of better brakes. I would love to make my brakes work a bit better on my Suburban with the GMT800 Master as well which I believe requires the GMT800 hydroboost. I'm hesitant to do the GMT800 master cylinder by itself, it seems kinda strange to me to just upgrade the m/c without doing something about the front calipers or rear wheel cylinders. Aug 12, 2020 · I didn't notice any significant braking improvement. WHICH "new brake booster"? 2. 3" while the gmt400 1500 master bore is 1. He bought the axle for the drum brakes to put on his truck so he could run a 15" rear wheel. Aug 9, 2019 · I wouldn't recommend just swapping a GMT800 booster in place, unless you swap the entire brake system, including a GMT800 hydroboost. Jan 4, 2016 · For those with 6 lug wheels, you DO have an easy to swap in factory brake upgrade in the 8 lug single rear wheeled pads and calipers. Can Jan 10, 2025 · The issue with gmt800 LCAs shock mounts is that they're too narrow. The rear brake upgrade made MORE difference than the front. Vacuum diagram 350 Vortex. Jan 6, 2022 · GMT400 Brake Upgrade. Towards the end he mentions a hydroboost master cylinder upgrade from the big, heavy 10 lug 3500HD GVWR 15,000 trucks. Mar 17, 2015 · Just watched a video on YouTube showing how you can basically bolt on gmt800 2500hd/3500 knuckles/spindles lower/upper control arms calipers and rotors on our gmt400 2500s. The rod can be removed via tool made to press against the crimped metal housing where the ball is snug in. Does anyone know if the newer Chevy trucks are bigger and or compadable? I’m thinking along the line of how you can put 4th gen fbody brakes on the older camaro and firebirds. Basically all plug and play with the right combination of parts and only modifying the upper hole. This direct bolt on kit is ideal for 1/2 ton 2WD Chevy/GMC trucks that have bigger wheels May 20, 2016 · Just two weeks ago I installed hydroboost from an '02 2500HD/6. Aug 13, 2021 · Has anyone tried the brake upgrade using the 2019 and up rotors and four piston calipers? Found this video on it. com Sep 15, 2020 · This aluminum 2. I up graded the front caliper's to 3. The GMT800 master cylinder is almost certainly a mistake of great importance. Make sure your rear brakes are in good condition and adjusted May 5, 2015 · They did have non HD 8 lug 2500's, they came with the 14b semi float, the 2500 suburbans and trucks with the 6. The RWAL unit is throwing codes and the brakes go from "barely slow the truck" "sort of adequately slowing truck" and "lock up" all while the brake pedal is a pile of mush Dec 5, 2009 · GMT 400 Hydroboost swap. I have a 96 GMC Yukon 2 door. 4L . Is this a direct bolt on caliper. The 95-98 GMT400 wiper arms, have a stiffer spring in them and perform a bit better due to the added pressure on the blade. 5" full floater and the 8. Does that mean whit a bit of determination a gmt800 suspension lift could fit? Jan 18, 2023 · The most cost-effective upgrade is to use the booster, master, front calipers, front rotors, and front hubs from an extended cab truck or other JN5/JB5 donor, replace the seized park-brake cables, and USE the park brake OFTEN, so that the horse-crap 254mm (10") Leading-Trailing shoe rear brakes stay in adjustment. I’ve read up on the GMT900 brake upgrade. I can see the want for good looking parts on your truck though. I've built a 6-bolt 14BSF rear axle for my C1500 and I would like to upgrade the front to the largest brakes I can fit into a 17" wheel, and obviously it needs to be 6-lug, too. This is what I did to make my 98 k1500 truck stop amazing. Oct 17, 2024 · Hi all! Long time owner of a plurality of GMT800s, first time owner of a GMT400. Feb 19, 2019 · I would like to upgrade my brakes with 4 wheel disc and possibly going bigger brakes in the front. Jan 3, 2016 · Sorry guys with 6 lug trucks and the 10 bolt axle, I'm unaware of any brake upgrades for them. Jun 15, 2019 · The wife unit drives a 1999 K2500 Suburban with the 7. I’m the new owner of a 2002 1500. com) AND swap to a GMT800 MC and braided hoses on front and rear. Oct 7, 2019 · You can also swap GMT800 calipers, hubs, spindles and rotors for a much cheaper solution. I'm looking at 1998 Chevy K3500 In this video I walk you through upgrading a GMT400, or 88'-98" Chevy/GMC brake master cylinder. Aside from the brackets that are bolted to the axle, it looks to be the same mounting otherwise. I’m also going to bleed the abs through a friends scan tool. Jan 28, 2024 · 1. The replacement MC and one brake line adapter. The purpose of this upgrade is to improve the feel of the br Jan 22, 2024 · Is there such a thing as a big brake upgrade kit for the front and a disc swap in the rear? I am currently putting an entire gmt800 system under mine, rear end The GMT-800 1500 trucks have bearings held on by 3 bolts, so their spindles and bearings are different. That said, I have the GMT800 on my truck, and my rear brakes work just fine. 7 tbi OBD1). www. Once you bolt it in via the studs, the geometry is spot on with the factory GMT400 brake pedal. Has anyone put these on their 800? Is it worth it? Jan 14, 2013 · Every time I hear about the GMT800 master cylinder swap, I can't help but wonder if the improvement people were feeling was mostly due to the fact that they were just getting rid of their old and worn out master cylinder. vep gnfc ykldm fyuxu ozwgq uzag zlzw sroq jbfy zuvawwm