Rear Brakes Smoking *solved (stuck slides)

[kwalsh]

This afternoon I serviced the rear brakes on my CC. new NAPA rear rotors (old rotors turned 1x before) & new NAPA Sure Stop pads.

Issue #1: passenger side: parking brake drum shoes were covered in a thin layer of grease. Found grease on dirth shield bottom (5:00 - 7:00).

I am assuming the rear axle seal has blown? How in the heck do I fix?

Before I removed the rotor I smelled that 'grease' smell & thought is was odd. After rotor was removed I saw axle with treads.

Issue #2 - during test drive after installation of new rotors & pads.
Driver side: I saw smoke after 1 mile drive through neighborhood. I drove 25pmh & then hit brakes, drove 30 mph then hit brakes, drove to 40mph, drove to 45 mp...done this plenty of times before on all of the family vehicles for the past 15+ years....just another test drive. but this one was different.

I've never seen brakes smoking like this after a normal ride. Therefore I assume the rear caliper is slow, sticking & time for a rebuild at 140k miles. Yes?

Does the CC have a proportioning valve?

[HenryJ]

You will need to pull the rear cover, center pin and c-clip to remove the axle for seal replacement. Did you clean and lube the caliper slide pins? Those are prone to seizing.

[kwalsh]

Thanks HenryJ. No I did not clean & lube the slide pins.

[killian96ss]

Yes, definitely lube those slide pins, and make sure you only use synthetic high temp grease designed specifically for brake caliper slide pins! Do not use chassis grease or any other type of grease. Anti seize compound can also be used if you cant find the special high temp grease. Make sure your e-brake cable is not over adjusted. As the e-brake pads wear down, the cable can be adjusted to make sure the brakes hold properly when engaged, but the cable needs to be backed of when new pads are put on or you will burn them up real fast. I believe there is a write up somewhere on this site for properly adjusting the e-brake.

Steve

[kwalsh]

Pulled the brakes apart to grease the slide pins. From what I gather the rear caliper slide pins are attached to the disc brake caliper mounting bracket and this pin has small rubber boot on it. Yes?

Steve, Thanks for the info. I plan on using high temp drum brake grease.

[green02crew]

Yes the caliper slides into two pieces and should be lubed liberally. There is a little rubber boot that acts like an accordion attached to it. These dry and become stiff. If you cannot pull or compress this rubber boot, the caliper is seized more than likely. An exchange for a Napa rebuild is not much when you give them a core. I used to use never seize but it seems to dry out in the extreme conditions of the brakes. A true brake grease is needed. I too have had brakes smoke. My rear axles seals have leaked onto the rotors when gone. That smoked. Also, after putting new brakes on then stressing them before the pads were fully seated.

[kwalsh]

One of the slide pins was frozen. After soaking with solvent I could not move the pin. Eventually I located a caliper mounting bracket at an auto parts store. Installed new bracket, new pins, rubber boots & lubricated with high temp grease. Both left & rear side caliper slide pins slide.
Problem Solved.

Thank you HenryJ, Steve & green02crew for the help.

[green02crew]

I hope you get many miles out of those new brakes!

[killian96ss]

And the lesson learned here is, make sure you clean & lube all 8 caliper slide pins at least every other oil change if not every time. Hey GM, why is this maintenance not mentioned in the owners manual?

Steve

[kwalsh]

So I was a bit quick on the draw...

The brakes started to smell again & get really hot after routine driving.

I am assuming/taking a stab at this theory...the excessive heat, caused by the locked up caliper, affected the brake fluid?
I decided to bleed the brakes and while doing this I saw a pocket of air leave the drain line.

Did the brake fluid boil?

[HenryJ]

Fixed that leaky axle seal yet?

[kwalsh]

couldn't do the right side axle seal until I got my hands on something to pull the axle out & remove the castle nut. that will be tonight's or tomorrow night's project.

Should I do both left & right side axle seals? I figure I should.

[killian96ss]

Should I do both left & right side axle seals? I figure I should.

Yes, do both of them since you will have everything apart anyway! Before you install each seal, clean the inside of each housing end with brake cleaner, then apply a small amout of oil resistant silicone to the outside of each seal before tapping them into place. This will prevent oil seepage around the outside of each seal.

Steve

[HenryJ]

couldn't do the right side axle seal until I got my hands on something to pull the axle out & remove the castle nut.

The axle will slide out by hand once the C-clip is removed.
What castle nut?

Should I do both left & right side axle seals?

Yes. You are only one c-clip away from doing both.
Check the axles for pitting too. Bad axles could be the reason that the seals went. If that is the case , you need new or good used axles and bearings too.

[kwalsh]

I assumed there was a castle nut that would need to be removed, similar to the front. If there isn't then that will make life easier.

[HenryJ]

Nope. You get to partially disassemble the rear differential

[kwalsh]

Okay, so I'm still having an issue with the left rear brake. It is getting hot, not smoking, but something is not right.

So I am wondering if there is a swollen brake hose...they deteriorate inside and swell up, causing the caliper to hold pressure and not able to return after pedal application.. but return/release pressure is residual, so the hose acts as a one-way valve due to the interior swell/restriction....

I found this posting on a google search:
"Here is a simple diagnostics trick to iso the problem:

Jack the suspect wheel off ground and apply the brake pedal as hard as you can...now get out and try to hand turn the wheel... if NO , open that bleeder..if the wheel then turns freely, you have a swollen hose...if it does not, you have a frozen caliper [ or e -brake bind]

Simple.............opening the bleeder will release any line pressure to the caliper, so you then know the hose is shot...but if you release pressure w/open bleeder and the caliper is stll holding that wheel, it is not line pressure that is the cause b/c there is no line pressure w/bleeder open.."

I'm going to jack the truck up when I get home from work & find out what is going on.

[HenryJ]

Worth a try.

I would suspect a seized emergency brake cable. If the caliper moves. make sure that the e-brake shoe is not dragging. A kinked or corroded cable can cause the shoe to drag. The mechanism that applies the brake might also be stuck. Pull the drum to check all that out.

[roadrunner]

Another cause can be a seized/partially seized caliper piston. Buddy of mine just had this experience. Reman caliper--problem solved. I've experienced the collapsed hose thing in the past on another vehicle.

[kwalsh]

Caliper is no good.
E-brake is good, no dragging there.

Lesson learned here is that I should have inspected the caliper closer when I was changing the slider pins.

[roadrunner]

Glad you found your problem!!

[green02crew]

They really can seize up quite easily. I have had rear pistons seize on both sides. One was a recent rebuild and was replaced for nothing. While doing axle seals, toss in some bearings while you're there. Its already apart and you're at them, might as well change them to save time later as they are a cheap item.

[HenryJ]

... While doing axle seals, toss in some bearings while you're there.

Have you changed yours? They can be a real PITA. If they are good , I leave them. If they are loose or I question their condition after lots of miles, then yes, I'd change them. I would not relish the job though. I try to avoid it if I can.

[kwalsh]

Yes, they were a major PITA. I had to ask a friend for help & get the truck up onto his lift. Before I attempted to pull everything apart I read the service manual & decided to give him a call. It was a little more than I expected, but with over 140k miles I decided to change them. While I was at it I also replaced the dust/dirt shields since they were falling apart.

Thank you all for your support & guidance on this repair. This is by far the best automotive forum ever.

Regards,
Kevin

[green02crew]

I did do mine. I tapped a screwdriver in between the race and axle tube to deform them as they have a thin wall and then simply pulled them out using that same screwdriver as they were now loose. The new ones I tapped in with a large socket and hammer.