Will the Gmt900 booster and master cylinder work on gmt400?

[Sinister Silverado]

Sorry if this has already been asked, or if I'm overthinking it and the rear disc master cylinder works fine. It seems to, a lot of guys on here are doing it.
I'm going to upgrade my master cylinder and brake booster since they're both questionable. I was going to just do the GMT800 upgrade, but it's much easier to get the rear drum master cylinder for the gmt900.
Just checking to see if someone has done it before. If not, maybe I'll just roll the dice, Amazon will return anything.
Thanks in advance.
Oh, it's going on a 1996 scsb 2wd if that makes a difference.

 

[MrPink]

no on both accounts, the GMT800 master will be perfectly fine with rear drums. Just make sure you follow the proper bleeding procedure for the ABS(aka connect the scan tool to it).

 

[Sinister Silverado]

Perfect. Thanks for the info.

 

[Ruff Idol]

Trust me, you will NOT be disappointed with the GMT800 upgrade. I did the master on my 92, along with reman ACDelco calipers and redid the rear drums - WOW can you stop on a dime now. You won't get race-car response from the drums but the pedal is nice and hard and it feels safer than any of the 3 vehicles I've owned so far.

 

[MrPink]

Or you can be like me... And delete the booster, ABS, and do a NBS(Gmt800) swap.

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[Sinister Silverado]

Thanks for the input guys. I do hate the abs, and have threatened to remove it. Due to time constraints, I'm doing the swap with the new booster. I do think I went a little far with the booster though. It wasn't painted, so I shot it with sem hot rod black.
The next brake upgrade is going to be late model Durango four wheel disc. I want to keep the truck 5x5. I've done a lot of research on it, and it seems very possible with a little help from my buddy's cnc. I realized there's probably easier ways of doing it, I like the size of the rotors, and the factory parking brake set up. I have a t-56 in the truck, so I'd really like to keep the parking brake.
Thanks again for all the help. I've been lurking around here for years, and usually I find everything with the search function. Being forced into big city traffic this weekend prompted me to fix the brakes fast.

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[hot_rod4]

Can you please update on the Durango rear end? Looks like it might be a good option. Looking at pics online, obliviously going to have to strip all the coil spring stuff off and weld perches and shock mounts but the one thing that was concerning was the pinion offset.

 

[L31MaxExpress]

NBS master was dangerous to me. Zero panic stop at all, pedal firm as a mesquite stump in the ground. I swapped it for hydroboost and a 1-ton master cylinder.

 

[Sinister Silverado]

I'm just going to put the brakes on the 8.5". I'm going to ditch the leaf springs and go with a coil over 4 link set up with air bags when I "tow". It's been a while since I thought about doing it. I'll have to go over my notes. It seems like it needs a spacer/adapter made to correct the difference on spacing for the axels.

I'm finding out that I'm not liking the nbs master cylinder swap. It's a firm pedal on bad brakes. Oh well, it was worth a try. Putting new rotors pads and wheel bearings on it next week. I can really tell the rotors are warped now.

 

[Schurkey]

The stupid "NBS" master cylinder "upgrade" is a disaster if the truck has Low-Drag front calipers. (JN/JB3, 5, 6 brakes. JB/JD7 and bigger don't have low-drag calipers.)

Low-drag calipers require a three-chamber master cylinder; also known as a "Quick Take-Up" master cylinder. A big-bore master cylinder is no proper substitute for the huge third chamber coupled to normal-sized primary and secondary chambers, allowing appropriate hydraulic advantage when the booster dies.




Doing ANYTHING to an 8.5" ring-gear axle is a waste of time, money, effort, and enthusiasm. Don't get me started on the 254mm (10") leading-trailing shoe drum brakes.