HELP! W126 Brake Questions

[jcantor]

On my very short drive into work this morning, the brakes on my '87 560SEL went from a little spongy to almost nothing. The fluid reservoir is empty and I can smell the fluid so obviously there is a leak somewhere. I'm going to take the car in to have someone else deal with the issue since its below 20 deg out there and only getting colder.

I'm assuming that this is probably just a blown seal or a rusted steel line but I wanted to know if there are any common failure points on these cars that I should be aware of when I get to the shop. Are there any pitfalls or areas where shops have a tendency to make errors - intentional or otherwise - on these systems? Is there something with the ABS system that could be part of the issue?

Thanks
jlc

[stevebfl]

A leak is where you find it. It is not likely to be involved with the ABS as all the connections are steel. More likely a rubber seal or hose: calipers, master cylinder, reservoir grommets, etc.

[jcantor]

Steve,

Thanks for the quick reply. I strongly suspect that you are correct. Normally, I'd go home now, crawl under the car, find the leak and deal with it from there but given the cold weather, I'm going to find out about the leak from the mechanic which, depending on where it is may be somewhat questionable.

jlc

[euronatura]

Where ever you find the leak and then repair it. Keep in mind that if the master cylinder went dry you should also change it or the seals within the master cylinder since the seals will no longer be realiable.

Iggy

[Q]

With air getting into the master cylinder, isn't he going to have the MC bench bled? If true, I think it woud be prudent to just replace it as a preventative maintenance item.

[SCOTTFISH]

I just had calipers go out on both my 89 300se and my 90 420sel over the Christmas holiday. My 300se just started puddling in the garage and was leaking slowly. My 420's brakes was working fine one time and I got back in to drive back home and the brakes were very spongy and almost not there. I check the tank and it was almost all gone. I made it home and then the next day took it to my mechanic and sur enough the caliper on the passenger front wheel was bad. I had it replaced and it ran me about $150 with an excellent condition used caliper. I had the 300se replaced, but the fluid had soaked the pads enough that I had to put new pads and while there the mechanic noticed that the rear rotors (where the caliper was bad) were under the specs for replacement so I had them replaced as well. That job ran me about $350 total. I understand that calipers are a weak spot in these cars once they age a little bit. I would bet 99% chance it is one of your calipers. Check the inside of the wheels and you can tell if fluid is leaking out and running down. Good luck in the repair.

[jcantor]

Ding, Ding, Ding...the prize goes to Scott Fish!

The leak was at BOTH front calipers, something the tech said he had only seen happen once in 15 years. It certainly surprised me that both would fail at exactly the same time.

Total for two calipers, pads, and rotor resurfacing (including all labor) is around $390. The parts were about $240 which matches up well with what I researched online.

Thanks again for everyone's input.

jlc