So I bought a 1973 220D and the rear end squeaked sometimes. I had the master cylinder replaced because it seemed to be leaking and the booster was filled with fluid. New master and brakes seemed fine.
Then a few weeks later I was driving on the freeway and had to slow suddenly (Los Angeles traffic) and the pedal went to the floor. Pumped it and it worked.
This came and went and then I noticed one day when I was checking my new hucaps that the back wheel was hot. Went to the mechanic and he said the rear caliper was seized. Had the rear brake lines repaced, the rotors, and the calipers.
Got in the car to drive home and was told to be careful????? There was no (hardly any) pressure at the pedal. The mechanic told me they bled the lines as much as they could and I should drive it a while and if it didnt fix itself they would bleed the lines again.
Well I drove home and it didnt get better so I parked it in the driveway until I had time to take it back to the mechanic.
When I took it back they bled the brakes again and they didn't seem any better so he said he would power bleed them. They still had verry little pedal pressure. Then he said my master cylinder was bad.
The pedal had good pressure before the rear brakes were replaced so why would it be bad now???? Does that sound right? The master only had about 500 miles on it.
The brakes work but there seems to be very little pressure at the pedal. Also sometimes when I park in the driveway it seems like the brakes are on (dosn't roll in neutral) Should I replace the master again or ???? What do you think???
Thanks for the advice

Are ye doin any of this work yerself - or subcontracting it? Reason I'm asking is that if the same shop did yer MC now says it's shot then I'd throw a brick threw their window if it was me. And what DOT rated fluid was the system flushed with? Never heard of unseizing calipres by power flushing em.

I think maybe that shop does not know what its doing.

The brakes on a 220d are very simple and durable. Nothing mysterious about them at all.

It could be something as simple as a bad flexible hose. The master if needed should be under warranty, right?

Tom W

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

I bought the master $145 and had it installed by a friend about 7 months ago. I hardly drive this car but would like to start using it as a daily driver.
I had the brakes done at a shop that is highly recomended on this forum, MR MB in Tarzana. New metal lines (thats what was on it before), new calipers, new roters. If the master is bad would it have had pressure at the pedal before the brake job and then hardly any now? And now somtimes feel like the brakes are on when I back into the driveway and try to coast?
I am afraid to drive the car for fear of messing up the new brakes if the new calipers are dragging.

oh yea 3 of my door locks dont lock, is it related???????

I think the rubber brake hoses should be replaced too.

You mentioned that the booster was full of brake fluid. You may have to replace it, as the fluid will deteriorate the booster.

Another possibility is that they didn't bench bleed the master cylinder. Power bleeding will correct that, but the MC needs to be level, which means the back has to be jacked up fairly high.

__________________
Chad
2006 Nissan Pathfinder LE
1998 Acura 3.0 CL
OBK#44
"Pleasure in the job puts perfection in the work." - Aristotle (384-322 B.C.)

SOLD
1985 300TD - Red Dragon
1986 300SDL - Coda
1991 - 300TE
1995 - E320
1985 300CD - Gladys

my car has metal brake lines not rubber. not sure if it is because it is from Belgium or if is because it is an ambulance. my 240d and my 300tdt both have rubber lines.

How are the metal lines connected to the calipers then? How can you steer your car without breaking the brake lines?

__________________
Chad
2006 Nissan Pathfinder LE
1998 Acura 3.0 CL
OBK#44
"Pleasure in the job puts perfection in the work." - Aristotle (384-322 B.C.)

SOLD
1985 300TD - Red Dragon
1986 300SDL - Coda
1991 - 300TE
1995 - E320
1985 300CD - Gladys

Sorry, metal in the rear rubber in the front. I had the REAR brakes done.

Was the MC installed dry? I'd be tempted to slightly crack open each connection to see if they bleed under pressure with pedal depressed. Shoulda been bench bled with an eye dropper before installation. Another question is whether or not your friend installed a new O-ring where the MC meets the booster. Some master cyls include the O-ring others do not.

Then I would ask the installer if they did a bench bleed prior to installing the master cylinder.

Also check your fluid reservoir and make sure it has enough fluid. They may have been sucking air while bleeding from an underfilled reservoir.

I don't know if yours is the same as a w123, but the compartment for the rear calipers to get fluid from is hidden from plain view. The compartment for the front calipers can be full while the rear is almost empty.

__________________
Chad
2006 Nissan Pathfinder LE
1998 Acura 3.0 CL
OBK#44
"Pleasure in the job puts perfection in the work." - Aristotle (384-322 B.C.)

SOLD
1985 300TD - Red Dragon
1986 300SDL - Coda
1991 - 300TE
1995 - E320
1985 300CD - Gladys

came with the o-ring.
would a bad master cause the calipers to drag sometimes?

Yes.

__________________
Chad
2006 Nissan Pathfinder LE
1998 Acura 3.0 CL
OBK#44
"Pleasure in the job puts perfection in the work." - Aristotle (384-322 B.C.)

SOLD
1985 300TD - Red Dragon
1986 300SDL - Coda
1991 - 300TE
1995 - E320
1985 300CD - Gladys

didnt bench bleed but had the system flushed and bled later. The pedal had pressure before the rear brakes were replaced.

would air in the lines cause the calipers to drag?