Brake help please

[LCBC]

So my brake warning light comes on if the pedal is pressed in a sequence, rev the engine it goes off. I checked the vacuum seemed ok, replaced the master cylinder, same problem. I have bled the brakes a number of times (did have some air) same problem. I cant figure it out? The pedal goes stiff when the warning light comes on, I’m starting to suspect i may have a faulty booster. I've tried unplugging the switch from the reservoir (thinking its was a faulty switch) but the light still came on. Could it be the vacuum pump or vacuum storage tank? Can anyone offer some insight?

1985 - 3B BJ60

 

[crushers]

do a vacumm test at the alternator...

 

[UpsideDown]

So my brake warning light Could it be the vacuum pump or vacuum storage tank? Can anyone offer some insight?

1985 - 3B BJ60

Yes, and yes... there is a check valve in the pump, if it leaks the storage tank can fill with oil.

But check to see if the vacuum pump is working first. It's not uncommon for the splined shaft that drives the pump to strip, leaving the pump with no drive (and no vacuum).

If you press the pedal many times in a row, the vacuum reservoir/pump can't keep up with the useage and will take some time to build up vacuum again. That does not constitute a problem, it's normal.

 

[LCBC]

I took the vacuum pump off the alternator, it looked ok. What kind of readings should i be getting from the vacuum?

 

[Tapage]

I'm not sure about how much vacc from the vacc pump you need to get, but before you remove it, if you flace your finger at vacc tube, you need to feel the vacc.

It's in must of cases easy rebuild and cheap .. other cases you loos vacc in the brake booster.

 

[jfc]

When you took the vacuum pump off were the alternator shaft splines stripped?

 

[LCBC]

No the splines were'nt stripped and i could feel vacuum which was pretty strong. So ????? and the vacuum line going into the booster seemed ok.

 

[Tapage]

No the splines were'nt stripped and i could feel vacuum which was pretty strong. So ????? and the vacuum line going into the booster seemed ok.

you are loosing vac from your booster .. my best bet.

 

[LCBC]

seems to be working fine today??? i dunno, gonna have to check the booster i guess

 

[bj70alex]

Do you have clutch booster?