Master Cylinder "Going Bad"......Maybe?????

reesestewww · reesestewww's Garage

Or, is a master cylinder one of those items that either work or don¡¦t work? I¡¦m NOT having great stopping power in my 88 930. I¡¦m not getting near the stopping power that my 88 Carrera has. I have removed the brake pads and looked at the rotors. They both look in good shape, all though I have NOT measured them with a micrometer. I have bleed the brakes using a power bleeder, purchased from pelican ƒº.

Any thoughts? Could this be a master cylinder? Any other trouble shooting techniques I can do to determine if it is a master cylinder?

Thanks for the advice¡K..

R

reesestewww · reesestewww's Garage

I’m doing some searching around the forum and see a lot of talk about a “soft brake pedal”. I would not describe this situation as a “soft pedal”. It’s more like I hit the brakes and the car doesn’t want to stop. I can press harder and harder. The pedal never gets to the floor. The harder I press the more it stops, but its not stopping much.

I drove the Carrera tonight for the first time in a few weeks and locked up the brakes. Not used to that stopping power. Hhhhmmmm???

dean · 07-11-2003, 06:50 PM

I would look at the powerbooster. I think the way a master fails is the fluid leaks past the seals. If you hold the pedal down firmly the pedal will sink to the floor if the cyl is bad. Also check the calipers and hoses but I don't that that is your problem either.

reesestewww · reesestewww's Garage

bump

CARRERIC · 04-15-2004, 11:51 AM

Hey R,

I have the same problem with my 75 911 Carrera. I am considering the problem to be the master cylinder as well. I have new rotors and Hawk pads and new fluid ATE super blue. Same as you I do not have squishy pedal. Was it your MC?

Eric

Bill Verburg · Bill Verburg's Garage

As Dean said, when they leak they leak into the booster can.

Also check for vacuum leaks.

The pads aren't contaminated or glazed?

CARRERIC · 04-15-2004, 12:56 PM

I don't have power assist brakes. No leaks that I could see.

Bill Verburg · Bill Verburg's Garage

Non boosted cars leak into the footwell box.

They can also leak internally.

CARRERIC · 04-15-2004, 01:07 PM

Thanks Bill, checked I haven't any leaks . The pedal is not suishy just a little hard and the car does not seem to stop well. Car does not pull so I don't think it's the calipers.

Bill Verburg · Bill Verburg's Garage

A fhard pedal is good

Check for pad contamination or glaze. Check to be sure that they are an appropriate temperature range.