96 burban calipers upgrade

[racnredneck]

I have a 1996 k1500 suburban.. and yes the mushy brakes, stops well, but.....want better .....
I read about the gmt800 master, bought one for a 2001 c1500 with the front port adaptor, installed, very firm pedal, but no stopping power at all... supposed to be better I read... now also reading that a k2500 caliper with the gmt800 master will ok well,. also read that a factory 1996 2500 master has no step bore and will firm up pedal feel too...????
down the road planning on 9.5" 14 bolt semi - float rear axle upgrade and will give me 13" brakes in the rear... but still using 8.5" tone 11" brakes for now. so what is gospel???

 

[michael hurd]

If a line was folded over and crimped off, you would have a fantastic stiff pedal, but zero braking. The proportioning valve may be shuttled, blocking flow to one end or the other of the vehicle. Can you lock the brakes, or does one end lock faster than the other?

Does the ABS engage? Is it hooked up?

Depending on what the rotors and pads look like, you may require replacement.

Did you bleed the ABS with a tech2 scantool after replacing the master?

 

[tinfoil_hat]

i think the calipers you want will be off the 1-ton, not the 3/4.

 

[michael hurd]

i think the calipers you want will be off the 1-ton, not the 3/4.

Sure, if you want 30% more pedal travel for the same action as the 1/2 ton calipers.

 

[michael hurd]

I posted this before, just a cut and paste of what I had typed previously when I did the math.

"Yes, 8600 GVW 3/4 ton calipers ( and 1 ton as well ) will physically bolt in place of the 1/2 ton calipers.

They also require more fluid volume to move the pad the same amount, meaning the brake pedal will move farther for the same amount of pad travel towards the rotor.


Is this what you are after?


Taking the pedal ratio out of the equation ( hydroboost and vacuum boost have different pedal arm / pivot ratios and M/C bore sizes )

If the master cylinder bore is 1.125" and the piston is moved one inch, you will displace 0.994 cubic inches of fluid.

0.994 cubic inches of fluid will move a 2.9527" half ton caliper piston ( 6.847 sq in ) 0.145"
0.994 cubic inches of fluid will move a 3.1496" 3/4 ton 8600 GVW caliper piston ( 7.79 sq in ) 0.127"
0.994 cubic inches of fluid will move a 3.3858" 1 ton DRW caliper piston ( 9.003 sq in ) 0.110"

Working backwards, if you have a 1.125 inch bore, and you need to move a 3.3858" 1 ton caliper the same amount as the 1/2 ton caliper piston... 145/110=1.31~ 31%more.


I wouldn't want 31% more pedal travel before the pads hit the rotors.


As far as swapping the master cylinder goes...... I wouldn't.

Deleting ABS, sure, as long as you are aware, in the event of a motor vehicle collision, as the owner of the vehicle with a 'modified' braking system, having willfully or 'recklessly' deleted safety equipment, you may be the recipient of a lawsuit, should someone else be injured or killed.

Do what you like, if you want to swap parts, no one will stop you. Just remember there may be consequences.

The proportioning valve ( factory ) may be shuttled one way or the other, giving you so-so brakes as well."

http://www.rockauto.com/en/moreinfo.php?pk=1571946&cc=1303647&jsn=1502

http://www.aa1car.com/library/abs_kelseyhayes.htm

http://www.etoolcart.com/proportioning-valve-depressor-otc7853.aspx

 

[michael hurd]

What is gospel? Take it to someone with a pressure bleeder and a tech2 scan tool to perform a ABS module bleed procedure if you want the brakes to work properly.

 

[tinfoil_hat]

Interesting that we have stickies at the top of this forum recommending both the master swap and the caliper swap. This might be one of those lipstick on a pig scenarios.

 

[Black_cirrus]

People around here are often trying to upgrade there vehicle, thus this forum is an outlet for idea sharing and the stickies address common questions. Some people feel that stock is the best way out of fear IMO. I'm not one of them and don't often interact with them but the 31% number is misleading the DRW calipers are for thicker rotors and larger thicker pads also so I doubt they would be put on a 6 lug truck even by accident 14% is the better number. I've done so much math to decide what route I would go if/when I do something. That said I'd be far more afraid of fault from poorly maintained brakes then brake changes. I'm a mechanic and car nut and as much as I know of cars I wouldn't think that I could identify the difference of calipers without measuring them or having them side by side and 99.9999999999% of the accident investigations won't even look for that. And lastly people spec 1 ton srw calipers because 3/4 ton could be either caliper.

 

[shovelbill]

the brakes sucked from GM....and they spent LOTS of money on R&D.....don't you think if this was a viable option for better brakes that General Motors would have done it?

one think i haven't investigated is the police package Tahoe's....usually cop cars have/had upgraded braking systems....i'd check EVERY single part number for THAT system and go from there. maybe they used the J7B setup on the 1/2 ton trucks.

me? i'm converting to complete and proper J6B from J5B on my '98 RCSB, which includes the 14 bolt semi-floater and the CORRECT comp valve.....every part of the SYSTEM will be new too....that is a an upgrade for a 1/2 ton in my opinion, the same setup on the 6 lug light duty 2500......i've also replaced my warped rotors with the EBC dimpled and slotted rotors, i'm using their green pads also, a good setup with a difference that i immediately felt......my brakes were bled correctly too.

 

[shovelbill]

here's something to read:
http://67-72chevytrucks.com/vboard/showthread.php?t=586972