Parking brake woes, 300SDL

[cmac2012]

The emergency brake only half worked the first few years I had this car. I sat it for long periods while it was waiting work.

It's running really well now and I have found myself in spots parking on something of a hill where I really wanted that parking brake.

I replaced rear drum brake shoes plenty of times on other rigs back in the day, but never got into one of those tiny drum brakes on a rear rotor. I bought Kent's special tool and DIY video. Worth the purchase price.

At one point, he recommended having an assistant work the pedal while you watched the mechanism at the back in action. I had no helper nearby so I propped up my cell phone and in a cardboard box and took a video. The passenger side seemed to work better than the driver side, but I eventually decided it was OK. Now I'm not so sure.

The rotors were in bad shape, Pick and Pull had a 1990 420SEL, the rear rotors were both nice on that one. While I was at it, I looked at the little activator cam and the cable, the last part of the cable going down to the E brake. I tried to take it out, but oh my God, it would be a challenge.

I got it all together back today and it was a serious letdown. First time out they didn't work at all. I took the wheels off and dialed each adjusting gear quite a bit. They had been so tight to fit over the drum, I didn't think it would need adjusting, but it did.

Even then it did not grab well. So I found an adjusting bolt for the cable tension and got it pretty tight. It still doesn't work well and the pedal pressure feels abnormal. I'm afraid I'm going to break something before too long if I use it like this.

This is just a little bit daunting. New cables are available, but oh my God putting that in will be one hell of a job. Cap'n Ahab had his Moby Dick, I sometimes fear a Waterloo moment on an old car - the job you can't quite do and can't justify spending two grand to have done.

[bigpanda16]

These cables are known to stretch, my old 300sdl would have the brake indicator on after release unless I pulled up the pedal with the top of my foot while driving.
I’d recommend jacking up the rear, placing the car in neutral and pulling the rear wheels off. There are holes in the face of the rotor hat that you can hit the adjusters through.
Tighten them up until you feel resistance and then back them off a tiny bit.
There is also one other place of adjustment, but it’s not really recommended to use, at the rear of the driveshaft tunnel where the single pedal cable transfers to the rear left and right cables.
Good luck

[oldsinner111]

I lubed up silding surfaces, I had adjusted cable and drivers rear would smoke after stopping lube worked.

[cmac2012]

Originally Posted by bigpanda16

These cables are known to stretch, my old 300sdl would have the brake indicator on after release unless I pulled up the pedal with the top of my foot while driving.
I’d recommend jacking up the rear, placing the car in neutral and pulling the rear wheels off. There are holes in the face of the rotor hat that you can hit the adjusters through.
Tighten them up until you feel resistance and then back them off a tiny bit.
There is also one other place of adjustment, but it’s not really recommended to use, at the rear of the driveshaft tunnel where the single pedal cable transfers to the rear left and right cables.
Good luck

I appreciate the help, but I did all of that. I tightened the little wheel with a screwdriver on both sides until it was hard to turn the wheel. I think something is faulty in the part that applies to pressure to push the shoes out. I tightened up the nut in the tunnel you're talking about, but I loosened it a little bit again. I was pushing so hard I was afraid I was going to break something. It's not a happy mystery, not easy parts to work on. You sure realize how nice a good parking brake's is when you don't have one.