My brake pedal does not like to come back up all the way
Posted by AR15sAndShitV2@reddit | projectcar | View on Reddit | 5 comments
I’ve got a 1970 Oldsmobile Cutlass that I’ve been dumping a lot of money into restoring into a fun driver. I’ve worked out almost every kink but my last major one is the braking. When I push down on my brake pedal, I have no problem stopping. But letting off of the pedal is the problem. It’ll come back up 90% of the way, but the brake lights will still be engaged, and have a very small amount of grab. I’ve just been using my foot and tucking it back under the brake to lift it back up which fixes it, but I’d like to fix it.
I’ve went through and completely flushed, and bled the brakes.
-Checked my front discs for warping and pads for wear (they look like new)
-Pulled the back drums off, hit it all with some brake clean, and re assembled(looked good aswell)
-Checked my Vaccum at the brake booster and it did have Vaccum
What else should I do or check?
Foreverwite@reddit
You may have done this when you checked vacuum but the check valve on the brake booster can have issues. Quick and easy to check, air should only travel in one direction on the valve.
When you pump the brakes rapidly does it get stiff and return to its position easier?
AR15sAndShitV2@reddit (OP)
It does get stiffer, but it does not return to its fully out position, it goes back about 90%. Eventually it’ll pop back out without me manually pushing it back out
Expensive-Steak-5511@reddit
It’s your master cylinder / booster, one or the other. Just buy a new set up (about $400)
Glum_Introduction755@reddit
I suspect your booster. There's a big spring inside it that can break if it's old. There's also the rubber diaphragm inside. If that leaks it can cause wonky behavior. It's also possible that the check valve is leaking. If you can blow through both sides of the check valve it's no good.
Start the car and pump the brakes a few times, then shut it off. Wait a few seconds and pump them again. If the diaphragm isn't leaking it'll hold enough vacuum for a couple more pumps, if it's leaking or if the check valve is bad the pedal will get hard almost immediately.
BKEDDIE82@reddit
Have you checked the master cylinder? The brake pedal spring?