Hello to all of you from a new member and glad to be part of this community! As a recent owner of a 1999 996 cabrio, I have a problem: since I bought the car one month ago it seemed to me that the range of the brake pedal was too long...and it increased more and more so that I drove the car to the assistance, where they told me that there was no air along the brake line, so they stated problem was the master cylinder. A complete repair kit ( http://pages.ebay.com/link/?nav=item...obalID=EBAY-IT ) was ordered and installed but, despite of that, after few kilometers again happened the brake pedal increased his range so that now to stop the car (even going slowly), I have to push the pedal completely to the bottom :-(. Pumping the pedal doesnt work that much: always the pedal goes down! Any ideas about the origin of the problem? Maybe the brake lines? Or what else?

 

Has the brake booster been inspected?

Here's a DIY on Pelican:

http://www.pelicanparts.com/techarti...eplacement.htm

 

Nice question. I don' think so. But I thought that a failure in brake booster action should result in a "harder" pedal, not in a "smoother" one. Or not?

 

You're right - don't know why that didn't register in my mind before I posted.

Have you bled the system?

 

Yes, system was bled before and after the master cilynder repair.

 

I have the 99 cab. If this was happening to mine I would check the bleeding procedure yet again. Brake fluid is cheap enough. Keep an eye on the brake reservoir where you keep topping up the system when bleeding. Rear right then left, front right then left. Inspect all brake lines for damage and/or brake fluid leak. While I was in there I would be checking rotors and pads and calipers for any fluid seepage. Also around each nipple and master cylinder. Apart from that I wouldn't know what to suggest. Good luck.

 

Bleed it again.

 

What level is the fluid in the reservoir when this happens? Does it need to have fluid added?
You might be pulling it back to the engine through a bad booster.

 

you say that for a few miles it was okay after the master cylinder rebuild. ssssoooo this tells me IF you have no air after bleeding again and IF all your pads are wearing evenly and IF you are not losing fluid and IF a brake line isnt expanding like a balloon the rebuild did not take [imho] .now you could go back to the shop [they charged you] and tell them its not right and have them warranty the repair but IF they [the shop recommended rebuilding a brake part that is 15 years old] i would seek another repair shop

 

Level in the reservoir is Max! I agree to repeat the bleeding procedure checking all lines and connection. If I would see nothing strange and this shouldn't work, I think only chance could be a bad brake booster! Or an uncorrect master cylinder repair.

 

I seem to remember reading someplace that the secondary (ABS) circuit needs to be bled in the event that large amounts of air are introduced into the system, as in the event of a master cylinder replacement. Something about soft pedal or excessive pedal travel even after bleeding the brakes using the normal method.

I may have seen this in one of the threads related to brake bleeding with a Durametric. You might want to do some Google searches on ABS bleeding or bleeding with a Durametric.

 

Thank you KoB, at last the cause was identified just in the ABS unit: there was a oil leakage. Do you think bleeding with Durametric has to be performed immediately after the regular one or also after few days (I have to wait the reopening of a store repair in Milan....actually in vacation )?

 

don't be afraid to bump if you're stranded on vacation