230 SL rear brake problem - help required!

[mille]

Hi,

I just found that brake fluid is running out of the rear left drum brake on our 230 SL. When I removed the drum it became evident that the brake cylinder is leaking and the brake linings have been soaked in brake fluid. We will need to replace the brake cylinder and probably the brake linings too. As seen from attached photos it looks like the brake cylinder piston rods are not pushing the brake shoes in a straight line and I wonder if the rear brake shoes have been placed & assembled correctly- wonder if the springs are situated correctly. As our Haynes "Mercedes-Benz 230,250 & 280" repair manual does not cover rear drum brakes, I don't have any references, and we therefore rely on help from you knowledgeable guys out there. I also need to know if we have to replace the brake linings on both rear brakes - it looks like the linings are almost new and the linings at the right brake are dry and fine.

Thank you for any assistance.

Cheers

Finn

230 SL 1964 Euro 4-speed manual silver metallic/black leather interior

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[ja17]

Hello Finn,

Observe the bottom pivot of the brake shoe. The shoe which goes on first must off-set to the outside. The two shoes may have been installed on their pivot incorrectly.

You may just need a rebuild kit in the cylinder. Inspect the bore closely after cleaning it up. Seal kits are inexpensive. If the brake cylinder is pitted inside you will need to replace the cylinder.

Do both sides, the other is probably not far behind. Get in the practice of changing the brake fluid every two or three year to help keep moisture from accumulating in the brake fluid.

As much I can see the rest looks ok. Brake shoes can be re-lined with good results these days.

You may want to clean up the shoes with a solvent like "brake clean" and lightly sand the surface of the lining. The shoes will probably be fine. However the risk is that the brake fluid soaked shoes may have compromised the bond of the adhesive holding the lining on the metal shoe.


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Joe Alexander
Blacklick, Ohio

[mille]

Hi Joe,

Thank you very much for your detailed advise. I will look further at the brakes probably next week-end and follow your advise. I think I will go for two new cylinders rather than mess with rebuild kits (did that before when I was a student and had to run my cars on a shoe string :-) and if it's pitted the malady will turn up again. May try and reuse the linings, but you are right it's possible to get them redone.

Cheers

/Finn

[bpossel]

Hi Finn,

This picture may help?
Bob

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bpossel
Memphis, TN.
1971 280SL
1997 E320

[Benz Dr.]

I always keep relined brakes shoes in stock as I also do a lot of 190SL work which is all drum brakes. I change fluid every year because I live in a high humidity climate - you should too. If you have any brake fluid on the brake lining replace them. The fluid will migrate back out of the friction material and the brakes will never work right. I would also replace the rear brake hose on each side if the metal ends appear rusty or if they've been on the car for over 10 ten years. The brake drums should be checked for out of round on a brake lathe.
Rear shoes are $30.00 each with a core return.

Dan Caron's
 SL Barn
benzbarn@ebtech.net
 slbarn.mbz.org
  1 877 661 6061

[mille]

Thank you Dan and bpossel for all your guidance and hints. I found a local brake shop who can reline the brake shoes and the wheel cylinders can be bought from SLS Hamburg in Germany:- www.sls-hh-catalogue.de -which I have used before and which I can recommend. They do speak English too.

Cheers

/Finn