Rear brake adjustment

[jpsenft]

I had the brake hoses replaced, emergency brake adjusted,  and the brake system flushed on my 230SL by an independent Mercedes specialist.

Since then, I get a loud "metallic grinding" from the left rear wheel for about the first 10 feet when moving.   The noise stops, but wheel does get significantly hotter than the other three.  As the shop is two hours away, I want to try to see if I can find something stuck or misadjusted in the brake myself...

1.  How can I easily get the brake drum off?
2.  Is the brake adjustment like other drum brakes...ie, a star wheel to adjust?  From inside or outside of drum?
3.  Is there any adjustment of the emergency brake at the rear wheel, or is it at the lever?

[merrill]

1. How can I easily get the brake drum off? - remove rear wheel, pull drum off.  you may need to loosen the pads - see  below


2. Is the brake adjustment like other drum brakes...ie, a star wheel to adjust? From inside or outside of drum? - you do not have star wheels but 2 large nuts on the back of the dust shield.  these turn the circular adjusters.  one way tightens the pad the other loosens. you have one for each pad.  

what I usually do is jack one rear wheel, support car of course, dis engage the e brake, turn wheel,  then turn in one adjuster till the wheel does not turn, loosen till it turns .  do the other the same way.  then go to the other side.


3. Is there any adjustment of the emergency brake at the rear wheel, or is it at the lever? - the adjustment is at the lever,

good luck
matt

[graphic66]

There are two slotted screws that hold on the brake drum. Take those out, you sometimes need some impact to get them loose. You will find two threaded holes in the drums, screw the screws into those to pull the drum off. I like to use some hex headed bolts to pull the drum as not to buggar up the slotted screws. Loosen the adjusters first before pulling the drum. Be very careful with the drums, they are very, very expensive. There are places now that reline the drums now though. You may have a brake pad come delaminated from the shoe. The shoes are bonded, not riveted.

[graphic66]

Forgot, in your owners manual are step by step brake adjusting directions with pictures.

[Largeowner]

From your symptoms it sounds like a dragging brake.  The brakes are not adjusted like an American car. On the 230SL the brakes can be adjusted with the wheel on.  At the rear of the wheel are two adjustment bolts. Loosten both until the wheel can spin freely by hand. Then re-tighten each until there is some light resistance felt when you hand spin the wheel. That's it!

The 230 manual (green book) has step by step instructions how to do this.

Large

[jpsenft]

An update....first, thank you for the suggestions and tutorial.  I have the rear jacked up, emergency brake released, and the wheel still takes all my strength to turn.  I have backed off the two adjustment bolts following the owners manual (actually tried with both ways) and the wheel remains extremely tight.   I can see the brake pads thru the little inspecttion holes, and each brake appears to have about 3/16 of pad material, but they are up tight against the drum ( no matter which way the adjustment bolt is turned).   I tried to bleed the brake (release any pressure) but no pressure noted.  I can manually pull the emergency brake line and feel the spring tension and release.   I still can not get the drum off (probably because the brake linings are firmly pressed to the inside of the drum. I note that the adjustment bolts appear to have about 3/4 to 1 revolution "lock to
lock".  Does that appear correct?  Any other ideas?
Thanks,

[graphic66]

Sounds like the cable going into the rear brake to actuate the parking brake is siezed. Put lots of penetrant on the cable and ends and bend it, wiggle it, beat on it, pull on it, and anything you can do to shake it up and free it. Again, be careful with that drum, don't drive it until its fixed.If it needs turning, find someone experienced and ask to watch while it's done. Sometimes a rookie will grind to much or to quick or both. Just clean it up, taking the minimum amount of meatal off. New drums are over $2000.00 each.

[Largeowner]

JP,

The brake adjustment points are directional...they tighten (and loosen) in opposite directions.  

Large

[jpsenft]

To close the thread on this....managed to get the car to a neighborhood Mercedes specialist (walking distance!!) and they found a seized rear cylinder.  Had both replaced and the car is back to normal.  Thanks for all the assistance in troubleshooting.