Hey all, Lately I've been experiencing what I think might be my brake servo taking a dump.... Pedal feels completely normal when first applied when slowing down, however if I lift off then re-apply pressure, it gets very hard, like there is no vacuum assist. Unless I give the engine some throttle in-between brake applications, the pedal gets hard, as mentioned. I guess I might just have a vac leak, but it seems like this is the notorious booster going south. Ideas? Cheers, Aaron '82 GTSi
.....okay so no bites. Tell me then, anyone, what ARE the symptoms of a failing brake servo? Cheers, Aaron '82 GTSi
Mine only gets rock hard at certain times, leading me to think there may only be a vacuum leak. I haven't dug into it yet but is there a vac line that feeds the booster? Cheers, Aaron '82 GTSi
time permitting I would go ahead and replace all the lines anyway. It's a cheap fix apposed to a $225 rebuild plus the labor of putting it back in.
The check valve has a metal ball that seats against another steel insert. Sometimes after sitting, moisture and corrosion interferes with free movement of the ball, however most of the failures I've seen are hard pedal at first (because it sticks) and then a boosted pedal after it comes loose. I would look for a collapsing hose between the engine bay and the booster. The hose is NOT generic. It has extra reinforcement to prevent collapsing internally and causing the problem you describe. It actually has an FMVSS number on it for the US cars. The failure mode of the booster itself is the hard pedal and an accompanying "hissing" sound of a vacuum leak through the compromised rubber membrane in the booster itself. More noise when you press the pedal and displace the membrane. -Peter (BTDT)
