1 ton calipers on a 88-91 truck with LD brakes

[arrg]

I have a 1988 C1500 RCSB. The early year GMT-400's in this configuration come with the JB3 brake option. The JB3 brakes have 1.03" thick rotors unlike all the other brake options that have 1.28" thick rotors. Rotor diameters are the same. JB3 also comes with tiny 2.5" piston front calipers vs the 2.95" front calipers of the JB5/6 or the 3.15" calipers on the JB7. I'd like to put the JB7 calipers on my tiny little rotors for more stopping power. The 0.25" difference in rotor thickness is well within the wear thickness of a new set of pads. Is there any reason why this wouldn't work?

 

[454cid]

Off hand that does not sound like a good idea. 1/4" is a lot. I would think you could easily upgrade to the later C1500 brakes, but I don't know what's involved. You might even be able to run 8-lug stuff on a 2wd since I think the control arms are the same, but that's changing a whole system, not just throwing on different calipers.... and you'd have to run the 8-lug rims.

I'm running DRW front brakes on my SRW 1-ton, but I used the calipers, pads and rotors. It's something GM did themselves for the extended cabs and vans.

You might look into doing a GMT-800 brake swap... again you're looking at more than just calipers.

 

[arrg]

It all fits. It's all bolted together out in my garage. I just thought I'd get some more opinions on this before I finish bleeding it and go try it out. If someone has tried this before and it didn't work, I'd like to find that out before I go for a test drive.

 

[454cid]

It all fits. It's all bolted together out in my garage. I just thought I'd get some more opinions on this before I finish bleeding it and go try it out. If someone has tried this before and it didn't work, I'd like to find that out before I go for a test drive.

Trying it out, and it working long term are two different things. The piston will be out further than normal, and when the pads start to wear, it'll likely pop out, and you'll have no brakes.

 

[arrg]

Trying it out, and it working long term are two different things. The piston will be out further than normal, and when the pads start to wear, it'll likely pop out, and you'll have no brakes.

If I tried to run the pads down to the wear indicator, I think that is exactly what would happen.

 

[Untraceable79]

I have a 1990 K1500 with the JB3 brakes. I have changed the master cylinder to a 2001 1/2 ton and 1990 K3500 calipers with stock style pads. The truck has never had stoping powre like it does now.

 

[arrg]

I have a 1990 K1500 with the JB3 brakes. I have changed the master cylinder to a 2001 1/2 ton and 1990 K3500 calipers with stock style pads. The truck has never had stoping powre like it does now.

This is the same setup I'm putting together on mine right now. I put the NBS master cylinder on first and had a rock hard pedal with no stopping power at all because of the tiny 2.5" calipers. Initial impressions with the new setup are much better. Great stopping power with moderate pedal pressure.

 

[rojas84]

If you feel the extra 1/4 inch is extending the caliper out too far you can swap to 96+ spindle and rotor

Sent from my SM-G920T using Tapatalk

 

[arrg]

If you feel the extra 1/4 inch is extending the caliper out too far you can swap to 96+ spindle and rotor

Sent from my SM-G920T using Tapatalk

True. I could swap to the bigger spindles and get the bigger rotors, but I have a Belltech lowering kit sitting in a box that I'd like to put on soon and it has the small spindles.

 

[arrg]

On a different note, I tried out my new pressure bleeder for the first time yesterday. Man, I've been bleeding brakes the hard way all these years.