1987 300TDT Caliper Paritially Seized? - PeachParts Mercedes-Benz Forum

jonbobshinigin · #1 10-11-2011, 01:22 PM

Well...after swapping out my control arms and being very excited about no longer wearing the outer edge of my tires...after a day I hear a scraping noise from back right when braking. Home is a minute away so I make it home with little braking. I check out the back right caliper and the outer brake pad is down to metal, while the inner pad is fine.

Context: 3-4 years ago and 30-35k miles ago I changed all rotors to crossdrilled zimmerman rotors, and akebono ceramic pads. Brake hoses were not touched. No problems until last July when I had a soft pedal and fluid loss. Turned out to be the passenger rear caliper was leaking. I replaced it with a reman unit from online vendor and purchased a Motive pressure bleeder at the same time. It worked great and I had no problems. I also replaced the two rear brake hoses at the same time and flushed thoroughly with the Super Blue fluid.

Having few options, I went to parts store and got some rear pads and pulled tire off and inspected. Outer pad is down to metal and ate in to rotor a bit, I spread pistons out and replaced pad so I did not eat my rotor. The outer one was very difficult and went in very slowly under a lot of pressure. The inner one went in as usual. I put the pads on and have been driving minimally. Most of the time when I stop I check out the varying temps this wheel is hotter than the others, but sometimes only marginally so.

All of my rotors until this looks great and I still have quite a bit of pad life left.

Why is the same caliper giving problems? (last time it leaked not seized and I believe the caliper was original at 175k or so)

I have a new one on ordered at a local parts place but am I likely to see the issue again?

Air&Road · #2 10-11-2011, 01:50 PM

It could be hydraulic lock. With safety glasses on crack open the hose and see if fluid spurts out. If it does and the caliper frees, then replace the hose. It would be a good time to replace all hoses, since they are cheap and you will have to bleed the system anyway.

Hope this helps.
Larry

jonbobshinigin · #3 10-11-2011, 01:54 PM

Well, I just replaced the rear hoses one year ago...and all other brakes are working just fine. I am just dragging the back right around a bit. If it is in fact hydrolocked, would that cause both pistons to have issues?

ah-kay · #4 10-11-2011, 02:18 PM

I have the same problem with my daughter's 300D in Santa Cruz. Charlie in Santa Cruz is helping her. It happens when the car has been driven for a while, 10-20 miles then the R/R caliper will seize. The caliper had been changed 2 times with a good PNP one then a rebuilt one but to no avail. The brake hose had also been changed.

We now suspect is the Master cylinder. We have ordered the parts but it is not installed yet. So the jury is still out. It is worth your while to take a look at it.

An article on brake binding.

Brake Parts for Cars

jonbobshinigin · #5 10-11-2011, 02:28 PM

That is not the news I wanted to hear! Haha

Once again, I am curious as to why it is only one side of the caliper.

barry123400 · #6 10-11-2011, 06:00 PM

Piston is only seriously dragging on the one side. Poor quality rebuild perhaps. The fact it is not dragging on both sides of the caliper proves it is the caliper.

I guess the caliper could be jammed on its slides as well but highly unlikely.