Splitting Brake Calipers? - Page 2 - PeachParts Mercedes-Benz Forum

warmblood58 · #16 03-16-2010, 02:26 PM

Quote:

Originally Posted by Diesel911

I did this about 3-4 weeks ago and there is also another thread from about that time.
It would be best if you had a new square crossection O-ring.

If you look colsely at the area by the O-ring you will see a blue hazy area around it. That is blue Loctite. I guy I worked for taught me that. I works to seal tight fitting surfaces also.

Find the torque for the bolts by looking at the head of the bolt and doing an internet search for the torque.
I found the previous thread:
http://www.peachparts.com/shopforum/showthread.php?t=271499

How can it be that you can rebuild a complete Engine but it is forbidden to take apart your Brake Calipers?
The Rebuilders have to take the Calipers apart to replace the square crossection O-ring.

Very helpful, thank you! Source for square crossection o-ring? Many thanks!

rrgrassi · #17 03-16-2010, 02:32 PM

Quote:

Originally Posted by dropnosky

If not, you can replace the O-ring from about any hardware or automotive store in the world.

As long as the o-ring is rated for contact w/brake fluid. A normal rubber o-ring will swell up and break apart with brake fluid contact.

leathermang · #18 03-16-2010, 03:18 PM

Quote:

Originally Posted by warmblood58

I am tempted to split the caliper for my own education.

Go for it and post the pictures to this thread...

Diesel911 · #19 03-16-2010, 05:46 PM

Just for the record. In the last 2 months I resealded the Mercedes Front Calipers and the Rear Calipers on my Volvo; both have ATE Calipers.
And, I resealed the Rear Mecedes Calipers sometime way past the last 2 months.

On all of them I split the Calipers and none of them have been leaking.

My Wife drives the Mercedes when I am not working on it.

Diesel911 · #20 03-16-2010, 05:57 PM

Quote:

Originally Posted by warmblood58

Very helpful, thank you! Source for square crossection o-ring? Many thanks!

I suppose NAPA would have some they could match up if you bring an origional one in.
However, I did not replace the O-rings so I cannot give a specific source.

Working on my own cars; I have never replaced that Square O-ring (this is since the 1970s) when I have split the Calipers with the exception of 1 time when I actually lost one of the O-rings.
And, in that case I had I picked a fat round cross section O-ring and used that (where I used to work we had a big box of O-rings left over from other jobs).

So far the above has always worked for me. If the Calipers had leaked I would have pulled them of and gone looking for the correct O-rings.

leathermang · #21 03-16-2010, 06:19 PM

Quote:

Originally Posted by dropnosky

Much harder is pulling the piston out, and replacing the square cut seal. A caliper piston removal tool really helps in that circumstance, and rust makes it pretty difficult. Several times I had to give up and ended up getting a new caliper.

Remember, the FSM says do not split them...

but the trick if all else fails it to mount them very securely and protect the distance from the caliper the piston can travel... ( or ricochet )
and use air power into the bleeder hole....

Very dangerous if you do not do it correctly !!!!!!!!

Carpenterman · #22 03-16-2010, 07:30 PM

I just replaced my master cylinder and the brakes are now fine. I did nothing to the booster other than to make sure there was no fluid in it. I know there is some controversy whether a sinking pedal is the MC or the booster, but in my case a new master cylinder solved the problem.

Diesel911 · #23 03-16-2010, 11:48 PM

Quote:

Originally Posted by leathermang

Remember, the FSM says do not split them...

but the trick if all else fails it to mount them very securely and protect the distance from the caliper the piston can travel... ( or ricochet )
and use air power into the bleeder hole....

Very dangerous if you do not do it correctly !!!!!!!!

I cannot argue with the quote from the FSM.

It is just that Rebuilt Calipers bought at a Auto Parts store are taken apart by someone; and someone puts them back together and they sell them.
So I do not see why I cannot be that someone.

leathermang · #24 03-16-2010, 11:52 PM

Those that are rebuilt and are then available for you to buy are the ones which were not warped or out of specs so far they could not be fixed properly...
The assumption that because it can be done by a person on their OWN brakes automatically due to being a simple concept ignores the fact that many not rebuildable ones were discarded and not available for resale......

warmblood58 · #25 03-17-2010, 02:57 AM

Quote:

Originally Posted by Carpenterman

I just replaced my master cylinder and the brakes are now fine. I did nothing to the booster other than to make sure there was no fluid in it. I know there is some controversy whether a sinking pedal is the MC or the booster, but in my case a new master cylinder solved the problem.

and this is relevent how to this topic? We are talking brake calipers man -

Carpenterman · #26 03-17-2010, 09:23 AM

I posted in post #11 about my decision to not split the calipers and my experience in rebuilding them. I had a problem with the MC and thought people would be interested in the resolution.

If you are not interested, put me on ignore.

Diesel911 · #27 03-17-2010, 11:00 AM

Quote:

Originally Posted by Carpenterman

I posted in post #11 about my decision to not split the calipers and my experience in rebuilding them. I had a problem with the MC and thought people would be interested in the resolution.

If you are not interested, put me on ignore.

Don't know about others but I was interested.

My own experience on the forum is that I read about problems members have and their solutions.

And, guess what I have had some of those problems myself at a later date and was better able to deal with them because of what I read.

The accumulation and volume of info from members is important.

Diesel911 · #28 07-04-2013, 12:03 PM

O-rings for use in Brake Fluid: Auto brake fluids require the use of EPDM
(ethylene propylene) O-rings.

I had trouble finding the Torque for the grade 12.9 Metric bolts Brake Caliper Bolts that hold the caliper together.
I only found the Torque for the Socket/Allen Head Bolts of that grade but I don't see why that torque would not work for the Hex Head Bolts.
http://www.cncexpo.com/MetricBoltTorque.aspx

Stretch · #29 07-04-2013, 12:46 PM

Information for where to get the O-rings is here

http://www.peachparts.com/shopforum/general-information/295769-ate-caliper-half-o-ring-source.html

.

Packard Don · #30 07-30-2014, 03:04 AM

I know this is an old post but I am just now resolving the same problem on our 1972 Mercedes 280SEL 4.5, which had stuck calipers from lack of use even though the car itself is in beautiful condition and still owned by the original family. It turns out that to not disassemble the caliper halves is an Internet myth and indeed it is important to disassemble any caliper to properly re-plate (yellow zinc, then paint any color you want over the plating) and restore it.

It is correct that the seals are not available through Mercedes but they are available through industrial sources as they are rather basic Ethylene-propylene (EPDM) square cross section o-rings. I am still trying to determine the exact size but they are something like 9.5mm OD; 4.75mm ID and are about 1.5mm thick. That’s about 3/8” OD; 3/16” ID and 1/16” thick. Since my own have been crushed inside the calipers since 1971 or 1972, I imagine the thickness should be a bit more.

I hope this help and if I learn more I'll post it.