My Camaro sat for about a month. I got in it and the pedal went right to the floor but pumping it could get a pedal built up.

What I've done so far:

1. Put in & bleed a rebuilt master cylinder from NAPA:
When I bench bled it they didn't have the tubes that go back up into the reservoir. Instead they had plugs that screwed into the ports and told you to just push it until the air stopped coming. I followed the directions and bled down the lines in order.

Result: Brake pedal still goes to floor and can be pumped up



3. Bleed master cylinder on car (some air does come out) and bleed lines down again in order.

Result: Pedal pumps up but slowly goes to the floor. It seems to hold a pedal much better at a lower RPM than a higher RPM. With the car off the pedal does to the floor but does offer some resistance.




So where am I? Do I have air trapped somewhere? It would have to be in the master or possibly the proportioning valve. Could my booster be bad?

 

Long Island,NY

Yes, I would think that you do from the proportioning valve out.

Possibly so, but more likely it is a much more simple problem like contaminated brake fluid. That stuff absorbs moisture and sometimes it is inadvertantly mixed with differing DOT fluids.

I'd spend some time bleeding and then more bleeding to get all the old stuff out, then I'd bleed them again. If it's drum rears,then I'd make sure those shoes are adjusted out to the drums.