1988 300SEL - sticky brake calipers
 

My '88 300SEL has been mostly setting around since May of 2017 when my mother bought a brand new car and gave the old beast back to me. I have only started it every 1-2 weeks and let it run and move about the driveway for about 10-15 minutes a week. I obviously was not moving it enough al all of the brake calipers are now very sticky, especially the front. I can barely turn the front tires by hand if I raise the front tires off of the ground. I have driven it up and down the driveway a few times, does not seem to be helping. :( I have read that the old MB's tend to get sticky brakes if they set around.

With that said, what should I do first? Replace the brake calipers and brake hoses, or one or the other, or? I have way too many cars, but want to get this one back on the road.

Thanks.

Open a bleeder screw, if fluid surges out and the brakes free it is likely hoses. If no release or fluid it's calipers.
Good luck!!!

I've encountered brakes on a 123 sticking because the pads were binding in the calipers. Removing, cleaning and lubing the pads fixed it.

Good luck!!!

One of the calipers on my SDL was binding after a long period of sitting. Pressing the pistons back into the caliper and exercising them again solved the problem and hasn't reoccurred.

Thanks for the information! I will try that as soon as possible to see if that will solve the problem.

Sugar Bear - does it matter which bleeder screw is opened?

Rears are easiest to fix. I would turn the rotors and toss in fresh pads, flush the system.

Once the brakes are unstuck, take that car for a full power run down the freeway. Mine can hit ~122mph before it gets to the 6400rpm redline. :eek:



Did those electronic modules I mailed you for the 300SEL work out? :):):)

You may elect to do some of the things already mentioned or buy a rebuild kit.

From personal experience, I would advise against buying rebuilt ATE from O'Reilly. Half the time they have the left caliper in a right caliper box or vice versa. Same holds true for their Bendix. They do sell rebuilt ATE/Bendix, but do a terrible job coating the main body of the caliper. Rust sets in fast.

Open either front, if only that caliper frees then it is likely that hose. If both free from only one bleeder then the master probably is not relieving pressure which would be very unlikely unless it is the wrong master or master pushrod length.

My guess is that either the caliper pistons are sticking or the pads are sticking in the calipers. R&R the pads clean and lube the sliding surfaces. Push the pistons back and see if any are binding or frozen.

How does the brake fluid look? Fresh, old or worse?

Good luck!!!

Thanks for all of the replies. I have had to put this on a back burner for a bit - hope to get back to it soon. Fluid is fairly new, clean. All of the brakes seem to be sticking pretty badly. Going to try to work on it again within the next couple of weeks - using some of the tips above mentioned.