View single post by Mark Rosenbaum
 Posted: 06-20-2007 03:39 pm
PM Quote Reply Full Topic
Mark Rosenbaum

Joined: 03-12-2005
Location: Kingman, Arizona USA
Posts: 532
Joel wrote: Ok, so they worked fine for a day or so.  I gave them more of a workout today and the pedal is almost to the floor and no more lock up.  I'm thinking bleed them again.  But maybe there's a problem w/ the vacuum?  I'll bleed and check again.

I replaced all the lines and the front calipers (and front pads).  For 2 days or so they seemed to be MUCH better.  I could actually lock them up.  Now, no go. 

In addition to the other suggestions provided, this could be caused by either a defective master cylinder front brake piston seal, or a leaking tipping valve (also part of the master cylinder).  If the former, you can rebuild or replace the master cylinder (and yes, even new ones can fail, though it's rare).  If the latter, tiny particles in your brake fluid are preventing the tipping valve from sealing, thus preventing your front brakes from being activated, and the cure is to bleed the brakes with copious amounts of new fluid in the hope of flushing away the debris.  If the problem is intermittent, it's almost certainly the tipping valve.

Attachment: Master cyl cross section.jpg (Downloaded 44 times)