I've only gone about 35k since the last rear brake job, but I did it again since I found dust on my rear-right rim, the rotor gets hot when touched, and when I peeked through the rim I could see the pads were thinner than they should be.

As the car continues to age, simpler jobs seem to get more complicated. This time I used premium Bendix pads because I didn't want to deal with the outrageous OEM price increase that recently took place.

The left side was as expected, pads about 25% worn in 35k. But the right side was about 50%.

With my tool I had no problem compressing the piston. But this time the rubber boot was twisting along with the piston. but only on the right (possible issue that caused corrosion?).

Tip#1 Don't worry, get the piston where you want it, you can gently work the boot back into the proper position afterwards, it wont tear or anything.

I don't think the slide pins were the culprits as I thought, as both pads were overworn evenly. I put everything back together but decided to check with the rim off--as I applied the brakes, with the motor running, and yanked the parking brake several times, the piston did not make any contact with the inside brake pad!!!

Tip#2 On an older car (mine is 8 yrs. and 125k), possibly the work should be checked with the rim off--after applying the brakes, you should see that the caliper no longer slides with freeplay (because the piston was compressed when you took the caliper off, when you reinstall it slides easily), and that you can't turn the wheel/hub with the parking brake applied (I could!). Then, when brake is released, wheel should be free to spin again. This action would show that the caliper is functioning properly.

So I undid everything again, and went through this process several times--pull the lever on the caliper manually like the parking brake cable would, use the tool to compress again, and repeat a total of 3X. I had to fix the rubber boot again, but when I reassembled this time, the caliper seemed to be working normally. If I hadn't checked, I would have reassembled and not known that I had no brakes in the rear-right (apparently there would be no warning lamps just because the piston is stuck, maybe someday). This is just a factor with an old vehicle, I doubt that would happen at the first brake job.

Probably that caliper is on the blink, but I bet it's good for a while. These are just some thoughts about working on the brakes yourself. Also, one tip that doesn't get mentioned all the time

Tip #3 line up the notches on the piston at 12, 3, 6, 9 o'clock--that needs to be in the approximate vincinity due to the knub on the pad backing....

Now I'm a believer in at least verifying that after the rear brake job, the wheel cannot be turned with parking brake on, and it can turn freely when off. Checking that will also show you a dragging as well. ...

 

Here's a tip, exercise the calipers at each brake job to keep them working smoothly. I always put a few drops of brake fluid around and under the dust seal to lube up the piston and the external seals. Then after compressing the piston I give my brake pedal one full shot to the floor while the caliper is still off the car. That will extend the rear piston out pretty far, not far enough to push it completely out. Then I compress it again, repeat a second time. This assures the seals and the piston get a nice sweep alone it's full travel and brake fluid will lube up external seals and keep them from drying out. I do the same with the front calipers, takes 2-1/2 strokes of the pedal to get the piston out a good amount.

I've done that process on every car I've ever owned and I've never had a caliper go bad on me. It's also very important to keep your brake fluid clean by flushing it with every brake job. Brake fluid is hydroscopic by nature and absorbs moisture. That distroys your brake components from the inside out, slowly over time. Another reason why most calipers fail, they rust up internally, which seizes the piston and other moving parts.

Simple maintenance and fluid changes is all thats needed to make them last the life span of the vehicle.

 

well 35 k is a normal interval to change rears. fact that one side is more worn than other, likely indicates u have a siezed caliper (commom on rears). as far as touching it it should be hot, but ir ur actual rim is hot that confirms the siezed claliper.

u can get new ones form any auto store about $80-90 each. or rebuild them urself: http://bmwe32.masscom.net/sean750/ca...akeCaliper.htm

changing both sides is recomended.

 

Very insightful information. I would have never thought do extend the caliper piston and lube it up. I plan on doing this at my next brake job (in a couple of weeks)

 

DAMMIT. I just did my brakes and did not even think of this. Great post, Jeff.

 

what kind lubrication should be used for the slide pins? my right rear pads slighty rub on my rotors at slow speeds. i'm thinking the slide pins are not lubricated enough.

 

Silicone paste works quite well. I try to avoid anti seize on the slide pins though due to it getting gummy over time.

 

OEM OEM OEM OEM OEM OEM!!! :attention

Well, I've done 4 brake jobs, 2 front, 2 rear, and as you see I went with premium Bendix this time in the rear because I boycotted the price increase on the OEM. Well, I've never had any squeal whatsoever before (last 3 jobs were OEM), and now I do...yippeeee!!! I've seen the arguments how with OEM there was extensive research in general to avoid any noise from the brakes. When I looked at the overall quality as well of the Bendix, which were about $10 cheaper than OEM, it seemed to be not as good. So even though I didn't follow my own advice, I strongly advise people to stick with OEM.

Also, on the grease, Advance Auto sold me 2 packs of grease for $1 each. I didn't use them, as when I reassembled the calipers, I made sure there was that freeplay before the piston pushed out. Also, before reassembling the caliper, I pulled the pins out, pushed them back in, and then slid them back and forth. I think it may be unnecessary to add more grease and I've seen people say it can actually cause suction? if too much....

Hopefully those of us who have done these brakes can have others benefit from what we've learned.