Date:         Tue, 17 Aug 2010 12:04:44 -0700
Reply-To:     Sheilah Rogers <sheilah@SHEILAH.ORG>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Sheilah Rogers <sheilah@SHEILAH.ORG>
Subject:      brake question
Content-Type: text/plain; charset=us-ascii

Howdy Folks, 

I'm wondering if I can bother the list's hive mind for some answers (that I already could not find via the search tool)? 

Basically something went weird with my brakes and my mechanic cannot reproduce the problem. 

So I was driving in ~80F weather, up and down a not so steep road but some curves, about 30 minutes of said road was unpaved, van warmed up of course. Brakes no problem. (not sure if weather matters but there it is.) I drove about 45minutes total here.

Then I got on the highway for another 45 minutes-ish. When I went to slow down a bit, it was like my brake peddle wasn't responding with its normal sort of push-back and instead, the brake pedal just dropped with no brake functionality about 80% to the floor before it engaged. Once engaged, I could slow the van down but of course I then had the pedal to the medal just to slow down a bit. 

Being on a quiet highway I kept going, figured I'd pull over in a bigger town and at least I can stop the van. But after 30minutes, the brake resumed normal so I just continued driving to my mechanic's. 

The next day he could not reproduce the problem, after warming up the van, driving on hills, 30minutes or so. He says 50% chance it's the master cylinder. But he's not sure (???) what else it would be since the brake fluid seems fine. 

Anything else that should be ruled out or should I just have the master cylinder replaced and hope it doesn't give out (50% chance?!) the next time I'm driving on presumably worse mountain roads. I don't feel safe or comfortable with this plan. 

Does anyone want to weigh in at all?
Mucho thanks appreciated. 

Sheilah

1986 Westy water-cooled vanagon: Vanna White.