Picking up 300SDL with dragging rear brake, what parts should I take? - PeachParts Mercedes-Benz Forum

86Gray300SDL · #1 01-19-2007, 06:33 PM

I am getting an 86 300 SDL from my sister. It is 350 miles from my home and has a dragging left rear brake. I drove it at Thanksgiving and it ran well but after a few miles the brakes began to howl. After returning to their home, I felt all the wheels and only the left rear was warm. After searching on this site, I am thinking the brake hose might be the problem. The car (186K w/original head) has always been garaged, originally from Memphis, it spent time in St Louis, and one winter in Chicago, but now resides in Birmingham.

I am going to get it in a few weeks and will only have one day to fix the brake drag because I have to be in Atlanta by Sunday afternoon. I plan to purchase a set of brake hoses before going. Is the brake hose the most likely cause of this type drag or should I go with a caliper also? I think the parking brake is mechanical so if it is sticking I should be able to free it up. If I check the brake after sitting for a few weeks without pressing the pedal, should I expect it to be free if the hose is bad?

Also, there is an 87 300SDL at a local salvage yard. Would the left rear caliper off the 87 fit the 86? What other parts off this 87 should I grab for future use?

The only other thing wrong with this MB is the transmission fluid leaking which I suspect to be the cooling lines.

Thanks,

Carl

Brian Carlton · #2 01-19-2007, 06:37 PM

You really can't be sure it's a brake hose. In fact, odds are decent that one of the pistons is hung in the rear calipers.

So, bringing a caliper and a brake hose will surely guarantee your success.

The '87 is identical to the '86.

stcbenz83 · #3 01-19-2007, 07:32 PM

arnt u suppose to replace calipers in sets?

Hatterasguy · #4 01-19-2007, 07:39 PM

Quote:

Originally Posted by stcbenz83

arnt u suppose to replace calipers in sets?

Yeah, but just to get it home you do what you have to.

The discs are probably shot as well. Order a set of those, a pair of rebuilt calipers, and a pair of rear brake lines. Then you should be in good shape for a long time.

86Gray300SDL · #5 01-19-2007, 08:31 PM

Thanks for all your replies. Is there any reason why I should not consider to rebuild the original calipers or the ones from the salvage yard?

Carl

mobetta · #6 01-19-2007, 08:37 PM

Isn't there a possibility that its just the parking brake shoes? if so, remove them.

JimmyL · #7 01-19-2007, 08:39 PM

Quote:

Originally Posted by 86Gray300SDL

Thanks for all your replies. Is there any reason why I should not consider to rebuild the original calipers or the ones from the salvage yard?

Carl

First off, there is the possibility of the salvage yard caliper being sticky also. Brake caliper and hoses are mission critical, and it simply is not a good idea to "roll the dice".
Also, rebuilt calipers, from O'Reilly's for example, aren't a whole lot more than a rebuild kit. Some calipers aren't rebuildable due to piston wear or rust.
Congrats on the car...

Brian Carlton · #8 01-19-2007, 10:11 PM

Quote:

Originally Posted by 86Gray300SDL

Thanks for all your replies. Is there any reason why I should not consider to rebuild the original calipers or the ones from the salvage yard?

Carl

Depends on you skill level and your time. The pistons are tricky to remove and reinstall. The rears are not too bad because they don't have the heat shields. I've done them both ways. Getting a rebuilt from a supplier is a whole lot easier.

captainmonk · #9 01-20-2007, 01:46 AM

some jobs just arent worth doing junk yard calipers have been sitting undoubtably sticking also Hoses are the least likely scenario in my mind

86Gray300SDL · #10 02-12-2007, 10:42 PM

Well, I picked up a Bendix and a ATE left rear caliper at the salvage yard last week. Both checked out with good boots and easy out with slight air pressure and easy push back. Fluid that came out looked good also. So with these and some new hoses, I went to Birmingham on Saturday and found that the left rear caliper was the original and the piston boots were really bad shape. The outside pad was significantly thinner than the inside and appeared to have been overheated. The caliper had the Mercedes emblem and appeared similar to the Bendix and used the clips to retain the pins but the pins were too short to use with the Bendix caliper I had brought. Fortunately the one I brought also had pads and hardware. It also looked like the parking shoes were a little tight and were dragging slightly. The rotor looked to be a replacement and I guess they did not adjust the parking brake shoes when it was installed. Anyway, I checked out all the fluids, fuses, etc.., cranked it up on Sunday morning and headed off toward Atlanta with my son following me. Ran pretty good. After some meetings here in Atlanta I will drive to Charlotte on Wednesday. I think it needs new motor mounts, oil and transmission fluid lines, and a new antenna. Of course I need to check out all the brake calipers but they seem to be working very good for now. My son did comment that it was smoking out the tailpipe as we drove along at 70mph. I could not see it. His windshield did have black soot on it? Would this be normal to see a little smoke while following a 603?

t walgamuth · #11 02-12-2007, 11:05 PM

yep. especially at night. the headlights light it up really well.

good score!

tom w

Hatterasguy · #12 02-12-2007, 11:09 PM

Quote:

Originally Posted by 86Gray300SDL

My son did comment that it was smoking out the tailpipe as we drove along at 70mph. I could not see it. His windshield did have black soot on it? Would this be normal to see a little smoke while following a 603?

No, only during hard acceleration.

POS · #13 02-13-2007, 08:38 AM

If the issue is a dying master cylinder, then taking a caliper won't solve your problem at all. The MC has individual lines that run to each corner, when it starts to fail, one rear caliper will lock up, then the other rear caliper will lock up. In other words, you replace that one "bad" caliper, and when you get going, it's highly possible it, or the other rear one, will lock up again.