brake caliper piston rubber seal - PeachParts Mercedes-Benz Forum

RKreutzer · #1 12-08-2003, 02:11 PM

Hi everybody,

When I took my caliper off to look at the parking brake, the rubber around the piston was wavery and broken. Can this be repaired by replacing just the rubber seal on both sides and how do I do it? Take off the caliper and try to poke it off? I don't have compressed air. Is there a chance to get this seal off and on without having the piston to come out? I could use the brakes to bring them out, but one might be stuck.
Any proposals from somebody who has been there?
Thank you very much.

Reinhard Kreutzer

haasman · #2 12-08-2003, 02:20 PM

In a one word answer: Yes.

What you are looking at is the dust boot, for lack of better description. These are sold along with the internal brake pistons seal.

This site (FastLane Parts) sells them together as a kit for your car, #N1050-40226. For both sides (depending on the brand of caliper you have) they list as:

Caliper Repair Kit ATE (Teves) Retail: $30.00 FastLane Price: $12.73

I would not use compressed air or anything else. I would try to use a pick or other tool to remove it. Leave the piston as is, just inspect carefully to make sure it is not scored, has corrosion or any other damage. The dust boot is there to keep road dust, moisture and general crap off of the brake caliper piston. It only works well and lives along time when it is kept ultra clean and dirt free. (These are your brakes, after all!)

Make sure the the entire edge of the caliper is very clean (including under the dust boot) and then coat them lightly with a silicone spray on both sides for long-term protection, let dry, then reinstall.

The key is to get the dust boot over the the edge of the caliper without tearing it. If I were going to use a tool, it would be one that has very rounded edges so that the new rubber does not get torn or cut.

Haasman

RKreutzer · #3 12-08-2003, 02:31 PM

Thanks Haasman,

can I get away with only doing the outside or do I need to do the inside seal too?
And is it possible to do this without compressed air?

Thanks again

Reinhard Kreutzer

haasman · #4 12-08-2003, 02:44 PM

The key here is safety, first and foremost-

You car car is a 1987 model, 16 years old.

If your caliper is not leaking and all that you want to do is to replace the torn dust boot/seal, then you do not need to use compressed air and take the piston out.

It is your determination whether the piston and its seal are in good condition: No scoring, rust or damage, not to mention leaks or any other reason that your brakes would not perform properly.

Please understand, I feel very cautious about advising people on safety items.

If you have any concerns or don't feel you can perfrom this repair yourself, safely, have a professional do it for you.

Haasman

ctaylor738 · #5 12-08-2003, 02:56 PM

I would be concerned about getting dirt and dust in th bores.

Check these guys out for rebuilt calipers-very good value:

www.********.com

I had a good experience with them and posted it on the Vintage board.

RKreutzer · #6 12-08-2003, 07:45 PM

Thank you guys,

I am also concerned about safety and never had to deal with a caliper seal. As luck would have it, the local MB dealer had the kit that Haasman mentioned on hand. I have a good relationship with the parts guys and one of them offered to put it on for me if they couldn't get a mechanic to do it for me this afternoon.
So I took the caliper to them and paid the $32 incl. taxes for the kit and he installed it for me. He wouldn't even let me pay him for the labor.
I put it back on after cleaning the parking brakes and then bled the system. My short test drive this evening indicates no trouble so far.
But I know now I have to deal with the other 3 calipers too, as that rubber is just as old although not torn.

Thanks again

Reinhard

haasman · #7 12-08-2003, 11:08 PM

Reinhard

Good job! Nice when it all goes well.

Haasman

Ken300D · #8 12-09-2003, 07:11 AM

That sorta looks like heat damage to the old rubber boot.

If so, that could be caused by a jammed caliper piston. I had one do that on the 1987 300D and ended up with new Lucas calipers from FastLane. They were nice.

So, did you have any burning brake smell? When my caliper started locking I would get burning brake smell and some grabbing when the pads got hot.

I think you should probably monitor that caliper condition when you have the chance. Keep an eye on the pads and the new dust boot.

Ken300D

RKreutzer · #9 12-09-2003, 10:47 AM

Thanks Ken300D,

About 2 weeks ago I replaced the front rotors, brake pads and the 4 brake hoses with stainless steel ones. I noticed at that time that the rubber seal on this caliper was a bit wavery as if the piston had turned a bit, but it was still intact. I put some rubber spray on it and thought it would be ok. I also used some of that blue anti-squeal paste on the back of the pads. I believe that blue stuff is like glue and I probably used too much of it. The glue stuck to the already weak rubber and when I took the pads out this time, the rubber broke as it was pulled along with the pads. The moral: Don't use that blue stuff and don't use too much of any paste anyway...

I did not smell any burnt brakes before, but I keep an eye on all the four wheels. I touch the wheels now when I get out of the car to feel their temp. until I am certain nothing is sticking. I will do the remaining 3 calipers pretty soon. From Haasman's description and others (I did a search yesterday evening) it doesn't seem too difficult a job once you have the c-clamps and the seals etc. It was the unexpected that threw me off.

Thanks again for everybody's help

Reinhard