I was taking my old 2.0l 1990 Sunbird out for a drive before it's e-test and I hammered on the brakes a few times as it's been sitting for 2 years.
I just wanted to test them.
At one point I was braking really hard and then I hear a 'poooffffff' (like air releasing?) and the pedal went to the floor.. lost all brake pressure. Pumping them did nothing.
I limped it back to the garage as the last 3cm of pedal travel did work, but barely. It appears maybe one drum still worked but nothing else.
No loss in brake fluid.. what happened? I'm assuming it must be master cylinder related?
Any help is appreciated, thanks.
Steve
Blew the diaphram in the brake booster?
Ya I was thinking the same thing... sounds vacuum related, or the vacuum line going to the booster came off????
Interesting.... I do have a vacuum leak. Enough that the EGR gets no vacuum. Haven't found that yet. I would hope that we would have seen if a hose blew off but perhaps not.
Not sure bout the sunbirds but there should be a check valve going into the booster
Check that the valve is working correctly and that the rubber seal is in good shape. If it isnt either of those you could have blown the brake booster diaphram, they get weak from sitting not moving/being used and etc... i think brake fluid can also leak into the booster from the MC as well.
With it sitting so long I would pull all 4 wheels and check your slide pins for dried grease and check the drums and clean just as a preventive.I would check out your booster as stated and just start simple by replacing the vacumm lines one at time just with the shear age of the car lines crack and leak.I did all my lines couple years ago on my 2.0 cav and very worth while and cheap to do.Just a thought
can be malfunction of the abs unit
abs unit commonly will cause pedal dive all the way to the floor when they malfunction
but usually returns pretty much immediately though
usually
ive driven many different models of 90s gm cars and had this happen to me while driving them
the ABS pedal dive malfunction that is
-96 cavalier 2.2 auto 143k miles
Thanks for all the suggestions.
It sounds like consensus is the brake booster diaphragm.
I will update this post once we figure it out.
