i2on1n

Hello,

My 1987 f150 started hissing on the brake pedal, exactly from the booster, when I remove the vacuum line that goes into the engine the hissing stops, either way my truck stops well, so it is a vacuum issue, I have seen that there is a check valve on the connection for the hose outside the booster this could cause the hissing? Any ideas? Thanks in advance for any ideas or feedback!

Best Regards,

fltdriver

You have a leak somewhere in the booster or the large vac line, you just need to track it down and fix it. You may be able to just patch it if it's on the booster (if not just grabbing one from a junk yard) but you should replace the line if it's the problem (super cheap).

i2on1n

I have found it, it one of the rubber seals inside the booster, and actually the pedal comes back, but it is easier to push since there is no resistance from the vacuum, do you know how to fix this rubber seals? or I have no option but to get a new booster? Thanks in advance for any feedback.

fltdriver

RTV silicone could be a temp fix since the system only puts out about 17-22hg of vacuum, but I would try to track down some new seals, don't even know if they sell just the seals or not. Someone else might be able to chime in on that.

Crownman

It's your brakes man. Just buy a new brake booster.

Chris_1

iTrader: (1)

Gotta agree with that. Sometimes you only get 1 chance to stop.