Re: treadle vac brakes

Posted by HH56 On 2012/5/22 17:35:30

There is a large spring inside the vacuum section which is supposed to keep the pedal up.

With engine off, pedal will move down a little before getting hard but should return all the way back when you take your foot off. Do you feel the spring pushing the pedal back up? If so, but not with engine running then the vacuum section needs checking. There are some rubber valves which may have deteriorated.

If no return in either condition, the spring may have broken, retaining clip might have moved out of position causing a bind, or the piston may be gummed from dry or improper lube or brake fluid.

A known issue is brake fluid might have leaked past the piston shaft seal and congealed in the vacuum section. There is a gasket issue which can allow the fluid to be drawn into the vacuum side instead of returning to reservoir in case of a leak.