Help Support

Hydro brake mystery

Post in this forum for topics relating to suspension, steering, and brakes

Moderators: ron, bfons, GRNSHRK

Post Reply
User avatar
Bigcoupe Contributor
Posts: 27
Joined: Wed Apr 30, 2008 7:30 pm
Location: Dordrecht, Netherlands

Hydro brake mystery

Post by ZesCoupe » Mon Jun 11, 2018 2:00 pm

Hi All,

Read loads of posts here and other forums but still can't find anything to answer my brake problem. It doesn't fit with the usual symptoms.

The shark hadn't run for some time and I replaced all the front brake lines a couple of weeks ago. The garage that did the obligatory test to be able to get it back on the road refreshed the fluid and bled it with their special apparatus. Pedal felt fine but then yesterday an enormous squeal started while driving on the highway at about 120 kmh. Convinced this was the PS pump but it disappeared after a while. Later after the car had been standing for a while I found suddenly that I had a hard pedal, but the brakes worked although needing a lot of effort. The brake warning light (exclamation mark) was also flashing so I limped it home and did the accumulator check. Fluid level pumped up OK but needed extreme force on the pedal where there was very little travel. After that starting the engine didn't lower the fluid to where it should be, so I presume the accumulator was not refilled. The level is still at the top of the reservoir.

Today I took it all apart. Pump itself looked OK, no obvious damage inside and the seals where OK. The accumulator had no leaks and I could feel the membrane with a plastic rod about a centimeter or so below the opening. I assume it's intact, it was replaced a few years ago. As for the regulator, I saw no leaks when removing the return pipe connection (as read somewhere) but apart from that......

So the question is where could the fault lie? Accumulator, regulator, pump? Any help apreciated.

"If a job's worth doing, it's worth doing well" My Dad (1921-1995)

1986 635CSi

Post Reply

Who is online

Users browsing this forum: No registered users and 3 guests