Rear brake issue

[sahls01gmc]

Just replaced the pads and rotors on the rear, and I think the calipers have some issues. When I was collapsing the caliper, it was rather difficult to do so. Now, it was also 15 degrees outside when I did this, so I figured the cold weather had something to do with the viscosity of the brake fluid. The truck drives like normal, however the rear brakes were insanely hot after a 40 minute drive yesterday. I immediately smelled the hot brakes when I got out of the truck. Just in comparison, I threw some snow on the rear rotors and the reaction was similar to putting frozen food into the fryer! The front brakes just slowly melted the snow, no insane heat.

 

I have replaced the front calipers and master cylinder over the past year, so do you think it is time for the rears? Or are there any other scenarios I should look into?

[Jsdirt]

Sounds like it's time for some new calipers. I've seen that happen to every truck, large and small, of that era. They hang up after slapping some new pads in there. Guess it's got a crappy designed piston or seals.

[sahls01gmc]

That's what I figured. It was quite the struggle collapsing the calipers, and I imagine almost 300,000 miles is enough to do that. Which is reason why the front ones have been replaced.... The truck still rolls in neutral if on a hill, but I think it's definitely hung up somewhere.

 

Thanks!

[00Silverado4x4]

How were the caliper slide pins? They may need to be cleaned/lubed. Also could try to bleed the rear brakes.

[Jsdirt]

Yeah that's a big one too up north here. Every brake job I do where the last place to touch them was a chain auto-repair shop (Midas, etc.), the pins are always BONE dry ....

 

You can always tell without even taking them apart by the diagonally-worn brake pads.

 

 

 

WOW Sahls you got your money's worth out of those! I haven't seen a set up here make it much past 100k miles. Less if they ever sit idle ....

[sahls01gmc]

Yeah, got about 250,000 out of the front calipers and master cylinder.

 

The slide pins weren't bad actually. NOT bone dry, but needed some more lube....typical for what I've seen. On one of the calipers, one piston was easy to collapse, the other was a PITA to collapse.

 

 

Hard to beat Rockauto.....$140 shipped to the door, then I get $50 back when I send in my cores!

 

 

I'll try to bleed all of the fluid out that I can as well.

[Doug_Scott]

What usually happens over lots of miles and time is that the brake fluid becomes contaminated with water, and that creates a sludge that seems to gather in piston bores on either wheel cylinders or calipers. If you have the knowledge, replacing the seals and pistons(if they are pitted from rust) is pretty easy to do. Hard part is getting the piston out if you don't already know the easy ways.

 

Pushing the piston back into the caliper just pushed a lot of the crap what was in the piston bore of the caliper. I used to open the bleeder when pushing pistons back, that would vent the crap, and showing that to the customer usually meant rebuilding the calipers. The smell you had may have been more from some of the stuff they coat rotors in for storage. You likely only cleaned the braking surface, and left the stuff on the rest of the rotors.