SOMETHING just failed on my left rear wheel

[AirmanPika]

So I was driving home today when I noticed more shaking than I was used to. It got progressively worse, especially at lower speeds. Eventually the car was hard to drive and was shaking back and forth when I got it to my apartment. When I stopped to turn into my complex I noticed smoke from the left rear wheel well and then some clunking when I started moving again. All I can guess is either the brake or ebrake jammed up. My ebrake has never worked to be honest. Either way I saw some extra scoring on the disc compared to what I usually see so I think its brake related. Now I just gotta wait for the area to cool off so I can take the wheel off to get a better look. I guess this might be my excuse to do the brakes now.

[jawn101]

So I was driving home today when I noticed more shaking than I was used to. It got progressively worse, especially at lower speeds. Eventually the car was hard to drive and was shaking back and forth when I got it to my apartment. When I stopped to turn into my complex I noticed smoke from the left rear wheel well and then some clunking when I started moving again. All I can guess is either the brake or ebrake jammed up. My ebrake has never worked to be honest. Either way I saw some extra scoring on the disc compared to what I usually see so I think its brake related. Now I just gotta wait for the area to cool off so I can take the wheel off to get a better look. I guess this might be my excuse to do the brakes now.

Yikes. Let us know what you find. Could it have been a wheel bearing?

[AirmanPika]

Well I'm not sure if this is a symptom of the heat or cause of the issue but there is brake fluid dripping from the inner portion of the caliper when I depress the brakes. Could that cause the brakes to seize up and cause an issue like this?

[Bitsyncmaster]

I just had a brake seize in my Malibu. You could not touch the wheel for hours afterwards. I know the smell of overheated brakes from a lot of driving in the mountains.

My problem turned out to be moisture in the brake fluid just got to hot that day (104 deg air temp) and it boiled and clamped the brake.

If your fluid has not been changed for many years that may just be your problem. A stuck caliper is also common on cars that have sat a long time not being use.

[AirmanPika]

Well I'd say a stuck caliper is likely. I rechecked the thing because I forgot to check for bearing symptoms but there were none. No play and spins smoothly (now that its cooled off). Looking at the disc, I find the following...

1236712368123691237012371

Obviously the car sat quite a while, but it made it from Ohio just fine. This just suddenly decided to happen on the way home from work today. Fluid is old and prolly needs replaced. Its coming out brown. Not sure if its just mixing with dirt from the rotor or is truly brown from the line. Of course since this caliper is leaking, I prolly need to rebuild it too. Might as well do the others at this point.

[Bitsyncmaster]

Discolored fluid would be from age. It is clear when new. Definitely you want to flush. Just bleed about 6 oz. from each caliper bleed nipple.

Just remember to keep the reservoir filled.

[Citizen]

I vote stuck caliper. Could be a broken retracktion spring?

At first when you described shaking back & forth that got progressively worse, my first thought was a broken TAB. Glad you made it home safe!

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[AirmanPika]

I think I'm gonna go ahead and install new brakes, rebuild the calipers, and replace the fluid. Should I also change out the discs?

[Bitsyncmaster]

I think I'm gonna go ahead and install new brakes, rebuild the calipers, and replace the fluid. Should I also change out the discs?

They looked not flat so you need to "sand" them flat or replace them. I use 40 grit sand paper on a flat surface and just press the high side of the pad when hand sanding them over the paper.

[Citizen]

I think I'm gonna go ahead and install new brakes, rebuild the calipers, and replace the fluid. Should I also change out the discs?

Do everything you said, yes, but probably no need to change out the discs, but definitely have them turned.

Thomas

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[AirmanPika]

Thanks. I'm just glad this happened now and a couple miles from my house. I can only imagine the headaches if this had happened 200 miles into my trip back to DC.

[David T]

Before you get all excited about this I would jack the car up and remove the wheel. My guess is the 4 lugnuts are loose. A stuck caliper would not cause shaking. It would just lock up the rear wheel making it difficult to move the car. You may still have problems with your brakes too.
David Teitelbaum

[AirmanPika]

Before you get all excited about this I would jack the car up and remove the wheel. My guess is the 4 lugnuts are loose. A stuck caliper would not cause shaking. It would just lock up the rear wheel making it difficult to move the car. You may still have problems with your brakes too.
David Teitelbaum

How else would I have taken pics of the rotor? :)

Lug nuts were tight when I took off the wheel.

[DMCMW Dave]

Do everything you said, yes, but probably no need to change out the discs, but definitely have them turned.

Thomas

...

Measure the thickness. New they are 1/2 inch think (0.500). If they are close to the discard thickness (0.460) you can't resurface them, at least not safely although I've seen some pretty thin discs come in here.

How thick were the pads? if they were completely gone you might have had a piston come so far out you lost brake fluid although that isn't supposed to happen.

[DeLorean]

classic symptoms of a stuck caliper. The piston binds, and the pads stick "on" - typically either a replacement caliper or simply a new seal kit for the caliper will fix the issue.

[stevedmc]

Before you get all excited about this I would jack the car up and remove the wheel. My guess is the 4 lugnuts are loose. A stuck caliper would not cause shaking. It would just lock up the rear wheel making it difficult to move the car. You may still have problems with your brakes too.
David Teitelbaum




How else would I have taken pics of the rotor? :)

Lug nuts were tight when I took off the wheel.

:TrainWreck:

[AirmanPika]

Measure the thickness. New they are 1/2 inch think (0.500). If they are close to the discard thickness (0.460) you can't resurface them, at least not safely although I've seen some pretty thin discs come in here.

How thick were the pads? if they were completely gone you might have had a piston come so far out you lost brake fluid although that isn't supposed to happen.

Pads still seem decent but prolly original to the car so I want to swap regardless. I'm gonna get a reader to double check the disc thickness tomorrow. Definitely not something I can eyeball. Now I wish I could just figure out why my ebrakes never have worked. I've done all sorts of adjustments and even replaced the pads with no luck so far.

[WelmoedJ]

Pads still seem decent but prolly original to the car so I want to swap regardless. I'm gonna get a reader to double check the disc thickness tomorrow. Definitely not something I can eyeball. Now I wish I could just figure out why my ebrakes never have worked. I've done all sorts of adjustments and even replaced the pads with no luck so far.

When I got my D the e-brakes didn't work as well as they should.
Reading about e-brakes made me feel these on our cars are not the best kind available at the time.

However since you're going to rebuild the calipers, you may want to tale the e-brakes apart, clean and re-assemble.
After I did some work on my e-brakes they work as intended, though it's possible to drive away with the e-brakes ON, without noticing much of a difference.
While parked, they hold firm, also on a slope.

The adjustment "screw" is not the only way to get them to work reliably.
I also used the cable adjustment to mate the e-brake's left and right hand side operation (important for best effect, as you know).

[Bitsyncmaster]

They looked not flat so you need to "sand" them flat or replace them. I use 40 grit sand paper on a flat surface and just press the high side of the pad when hand sanding them over the paper.

This comment was to reuse the pads. Your rotors look like they need some work. The over heating may have made them not run true. I would get them turned.

[David T]

You should not have the rotors cut unless necessary. Many shops do it automatically. You need a dial indicator and a caliper or micrometer. If you have no runnout and you are not under .460 just break the glaze with a 3" disc sander on an electric drill. If you had bad clunking and the lugnuts were not loose the next possibilities are the rear bearing and the C/V joints. If you overheated the pads they should be changed. You must change in sets, ie, both rears and/or both fronts. If the rotor got really hot you should rebuild the caliper because the seal inside is probably damaged from the heat.
David Teitelbaum

[AirmanPika]

Well I finally got the brakes in so I started tearing down the stuck caliper. I measured the disc and it measures .49 to .5 in spots so I think thickness I am good. Just gotta get it turned now since the surface is all messed up. Of course now I'm dealing with a different stuck...I can't get the bolts apart on the caliper to split it. I was able to remove the pistons in the meantime and they seem to be good and smooth. Its just hard to get inside the caliper to clean it out and replace the o ring/seals

[David T]

The bolts holding the caliper together are very tight. It takes a lot of force to undo them. You haven't mentioned anything that would account for the clunking. If you have one caliper that got stuck you should rebuild all 4. How badly corroded are the pistons? Were they leaking? If they are corroded they should be replaced.
David Teitelbaum

[AirmanPika]

Yea I am doing all 4 wheels. I just have to do it one at a time because I have limited facilities (my garage has a half disassembled land rover in it). The pistons are fine actually. No corrosion or pitting that I can see once cleaning em off. I'm guessing the interior of the caliper should be the same but I'll be able to get a better look once I get these things apart. Its been slow cleaning as the old rubber turned solid and I've been using a fine steel wool pad to prevent scratching. I think the clunk was just my pad unsticking from the disc when it first happened since I was at a stop at the time. The thing was leaking but I think thats because the rubber seals melted from the heat. Now I just need to figure out how to get good leverage on the caliper. I may just put it back on the car so that it has a solid mount and then try to loosen the bolts.

12705

[David T]

This is not making sense yet. Typically the calipers (the pistons actually) get stuck because they corrode from bad brake fluid. The corrosion also cause the seals to leak. Inspect the pistons carefully, if the plating came off they are no good. You can clean them up with steel wool. The inside of the caliper is not all that important, the piston should slide easily in and out without the seals. The area between the groove and the top of the bore is the most important, if it is very rusty it could cause the piston to stick. This can happen because the dust boot allowed water to get to the inside of the caliper and rusted the piston in place. Usually all you need to do is clean up the inner bore with a brake hone.
David Teitelbaum

[AirmanPika]

heh well I wasn't as lucky on what I thought was the "good" side. Seems one of the pistons seized up a long time ago. Lots of rust and took quite a bit to get the piston out. It was stuck part of the way out and had rusted up heavily on the exposed part. Wasn't much left of the pad on that side either. Kinda makes me wonder if it was ever working...and scares me as to how bad my brakes must have been all this time. Taking the discs to get turned tomorrow on base. $10 a pop at the auto hobby shop. At least its being fixed now. God knows what the fronts will be like.

[David T]

Try not to let the shop take too much off the rotors and you do not have to take equal amounts off of each one or even on both sides, only what you must to clean up the surface and true up the rotors. If you do one caliper at a time you cannot flush and bleed the system until they are all done. Figure on dong the master cylinder also and you should also do the clutch master and slave. If the brakes are messed up chances are the fluid in the clutch system rotted it too. With stuck pistons you will find the car will tend to pull to one side and your gas mileage will be low. If the pistons are corroded you cannot clean them up, the pitting will ruin the seals and they will leak.
David Teitelbaum

[AirmanPika]

OK so I'm putting the calipers back together but I'm not 100% certain I have the dust boot back on right. My old ones were so deteriorated I couldn't tell their proper orientation. I don't feel like the boot is well seated in the grove on the piston itself too well. Is the very edge of the boot supposed to slip under the top edge of the piston groove? Did I even install it right?

12764

[DMCMW Dave]

Did I even install it right?



Looks good.

[AirmanPika]

Looks good.

OK cool thanks.

[AirmanPika]

Almost there...just gotta finish reworking the ebrake and I can move to the other caliper for rebuild.

12765

[AirmanPika]

Well I just noticed there is a lot of movement of the rotor when turning the wheel hub. It literally wobbles between the two new brake pads and then jams against one at a point unless I force it hard. Guess I just need to get new rotors. Prolly will be best if I just replace both rear ones. I could chance it, but with this motion and the fact that I'd have to tear everything apart again if I am right I'd rather just do it while everything is mostly apart.

[WelmoedJ]

It's always wise to replace them as a pair (on the same axle).
However if the rear ones are so bad (warped), how about the front ones?

[AirmanPika]

It's always wise to replace them as a pair (on the same axle).
However if the rear ones are so bad (warped), how about the front ones?

Well that's the issue at hand...I can't see the fronts since I can only work on the rear brakes at this time. I decided to get rotors for the fronts and rears just to be safe since my rear brakes were in such bad shape. My only concern now is if my front pistons are in good or bad shape. Decided to just see what we have before I go and order those too. I've only had one bad piston so far.

[WelmoedJ]

Well that's the issue at hand...I can't see the fronts since I can only work on the rear brakes at this time.

What do you mean by this? Not being able to raise the car's front and rear one after another?
Not enough axle stands?

I only have two (heavy, 6 tons) axle stands.
Use them to raise the front.
Then raise the rear and use big logs to support the rear jack points.
Very solid and safe way to raise the car some 24".
Works like a charm.

All wheels of saves a lot of time.
Bleeding the brakes takes less time (using a pressure bleeder like the one of Motive: http://www.motiveproducts.com/) than raising the car :)

BTW: If the rear calipers are in a bad shape, suspect the front ones will be even worse.
If the fluid is dark, there's a lot of "dirt" in it.
Clean out your fluid reservoir too and consider doing a brake main cylinder overhaul (if possible) or replacement (the best solution).
You only want to go in there more than once in a short period of time.



Hope this will give you ideas on how to proceed.

[Doogie]

Well I just noticed there is a lot of movement of the rotor when turning the wheel hub. It literally wobbles between the two new brake pads and then jams against one at a point unless I force it hard. Guess I just need to get new rotors. .



I missed something. You had the rotors turned as evident in the "Almost done" pic. Assuming a properly equipped shop and a competant machinist, your rotors should be true as the ever will be now. So why the wobble? Could it be what the rotor is mounted to is wobbling? Not the rotor? I'm thinking the wheel bearing is bad?