ShawnG
ShawnG PowerDork
6/15/19 6:11 p.m.

The wife unit drives a 1999 K2500 Suburban with the 7.4L 

The brakes on these trucks suck. 

There are two brake packages for the 2500 (3/4 ton), one uses 2.5" wide rear shoes and the other uses 3.5" rear shoes but the same drum. The usual trick that everyone tells you is to use the 3.5" shoes from the 10,000lb package truck even if you only have the 8,600lb capacity.

Our sub is already the 10,000lb rated HD model and already has the biggest stock brakes I could stuff in it.

So, off to the internets I go and find SSBC makes an upgrade kit for around $2,000. No thanks, I don't want stuff I can't buy at a local parts store.

Next is a kit to convert to the GMT800 3/4 ton spindles and brakes. Again around $2,000.

So I start digging and find that the 1999 Sierra 3500 DRW trucks used the same spindles as the 2500 but with thicker rotors and larger caliper pistons. 86mm diameter vs the 80mm 2500 calipers.

2500 rotors are 1.30" thick vs the 3500 rotor at 1.47" but more meat in the middle with less fin thickness. 20lbs vs 24lbs so more thermal mass.

Made the swap to the 3500 brakes today and it made a huge difference. Less pedal effort and faster stops. Should help with the rotor warping issues too.

Floating Doc
Floating Doc SuperDork
6/15/19 6:53 p.m.

I'm glad to see this. I wonder if the modification will work with my 88 C2500.

ShawnG
ShawnG PowerDork
6/15/19 7:45 p.m.

Had a quick look on Rockauto, the '88 C2500 calipers are the same as the 1999 K2500 calipers I took off so you should be able to make the swap.

Rotors might be a different story with the 2wd rotors but even if you can't get a thicker, heavier rotor, the larger pistons in the calipers should make a big difference.

Run_Away
Run_Away Dork
6/15/19 9:33 p.m.

Crud, was hoping for 6 lug/1500 upgrades.

SkinnyG
SkinnyG UltraDork
6/15/19 10:38 p.m.

I thought I had links to offer, but they are all 6-bolt.

D52 calipers?

 

ShawnG
ShawnG PowerDork
6/15/19 10:52 p.m.

In reply to SkinnyG :

Much bigger than those. 

Maybe the 1500's got D52 calipers, not sure.

 

SkinnyG
SkinnyG UltraDork
6/15/19 11:39 p.m.

99-02 Silverado Master has smaller pistons, and improves brake feel considerably.

(Googling this right now anyway, as I'll be running GMT400 spindles and brakes on my '61 Apache)

SkinnyG
SkinnyG UltraDork
6/15/19 11:40 p.m.
stylngle2003
stylngle2003 Reader
1/23/20 7:58 a.m.
SkinnyG said:

99-02 Silverado Master has smaller pistons, and improves brake feel considerably.

(Googling this right now anyway, as I'll be running GMT400 spindles and brakes on my '61 Apache)

Yes, did the "NBS" master cylinder swap on our '96 Tahoe 2wd and it made a huge difference in pedal feel.  Also did 2500 calipers at the same time (80mm, i believe).  You need one brake line fitting adapter for the NBS master to work with the older trucks.  The boosters and ABS systems can also contribute to crummy pedal feel.

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