Power brakes gone...

[STIFFLER]

Hey guys.. after I fixed my electrical gremlins with what I thought was regulator/alternator (Alternator was taken off).. My power brakes seem to be non existent..did I hook up a wrong hose somewhere? Everything looks good and I think I put everything back the way it was.. but I must have done something wrong..

Oh ya this is on a 83 bj42..
thanks

 

[jake2far]

Start up the engine, pull off a vacuum line from the pump and see if you have any vacuum at the pump, if you do put the hose back on and pull the vacuum hose at the booster, check to see if you have vacuum at the booster, if you do then you probably have a bad booster, if you don't track the line back to see where you lost the vacuum at. If you don't have vacuum coming from the pump, you stated you had the alternator worked on, then take the alternator off and inspect the pump. Check to see if all the ports on the pump have been hooked up it should have 2 lines? If you left one off then you would have a lose of vacuum. Not sure about the last part as I have a 1985 3B engine you may only have one line but look at the fitting and you can see how many ports there are.
Good luck,

Jim

 

[STIFFLER]

Did what you said. And I have vacuum at the pump and booster.. Intereting thing is when I pump the brakes a few times I must be losing vacuum because the brake light will come on for about 10 seconds then go off.. So it must be the booster?

 

[crazybushman]

I'm not sure that you should rule out the booster just yet. You do have vacuum at the booster but by feeling with your finger you really don't know how much, it could be sucking in somewhere else as well and you'd still feel vacuum at the booster. Have a good look at your lines and clamps, the rubber lines are probably 26 years old and could have cracked when you were pulling the alternator off.

Cheers!
Tyler

 

[jake2far]

Did what you said. And I have vacuum at the pump and booster.. Intereting thing is when I pump the brakes a few times I must be losing vacuum because the brake light will come on for about 10 seconds then go off.. So it must be the booster?

The booster will lose vacuum if you pump it several times because each time you pump the brake pedal it vents the booster so you will run out of vacuum at idle setting off the light, what you need to know now is what level of vacuum you have at the pump, at the booster, I believe the minumum vacuum is 15 inches of mercury and the max is near 22 inches.
It sounds like you either have low vacuum from the pump or a leak somewhere in the system. Get a hand pump for a brake bleeder and hookit up to the pump the gauge will show how much the pump will produce from there you can check the system and also apply vacuum to the system to find out if you have any leaks.

Jim

 

[dieseldad]

The booster will lose vacuum if you pump it several times because each time you pump the brake pedal it vents the booster so you will run out of vacuum at idle setting off the light, what you need to know now is what level of vacuum you have at the pump, at the booster, I believe the minumum vacuum is 15 inches of mercury and the max is near 22 inches.
It sounds like you either have low vacuum from the pump or a leak somewhere in the system. Get a hand pump for a brake bleeder and hookit up to the pump the gauge will show how much the pump will produce from there you can check the system and also apply vacuum to the system to find out if you have any leaks.

Jim

Have you checked the vacuum tank? ( drivers side on the frame rail ) My rusted out so I had to replace it. West coast salty winter roads suck. Although since you just replaced the alt that would be the place to start looking.
Cheers
Andrew