Hard pedal

[Ole BlackBetty]

Make brake pedal suddenly became very hard to push and brake light comes on. I think it might be the brake booster, anyone else have any opinions? Vacuum pump seems to be working, i pulled the vacuum line from the booster and it forms a suction on my thumb.

 

[sassyrel]

Make brake pedal suddenly became very hard to push and brake light comes on. I think it might be the brake booster, anyone else have any opinions? Vacuum pump seems to be working, i pulled the vacuum line from the booster and it forms a suction on my thumb.

you need to measure HOW much vacuum. sounds like its really weak....

 

[Ole BlackBetty]

What should the vacuum be using a vacuum gauge?

 

[lotzagoodstuff]

What should the vacuum be using a vacuum gauge?

Should be about 21 inches of hg at sea level. Just for fun, unhook the line going to your booster, and carefully (in a safe environment) test your brakes. If they seem the same I'd say you probably have a bad booster, they are fairly prone to failure, but then again so are the vacuum pumps.

I'm willing to bet on the vacuum booster, anybody like to take some action on the vacuum pump?

Good luck

 

[snicklas]

Does it "woosh" when you step on the brakes? If so, that is almost definitely a bad booster as the diaphragm has split, and when you step on the brake and move the diaphragm, it leaks...

How about the HVAC? Do the vents change with the selector? The doors in the HVAC box are operated by vacuum. If they don't change, or only come from the defroster vents, no matter where the selector is, you may have either a huge vacuum leak, or the pump has failed.

So a "quick and dirty" synopsis: "Woosh" = Booster, No HAVC selection = Leak or Pump

 

[lotzagoodstuff]

Does it "woosh" when you step on the brakes? If so, that is almost definitely a bad booster as the diaphragm has split, and when you step on the brake and move the diaphragm, it leaks...

How about the HVAC? Do the vents change with the selector? The doors in the HVAC box are operated by vacuum. If they don't change, or only come from the defroster vents, no matter where the selector is, you may have either a huge vacuum leak, or the pump has failed.

So a "quick and dirty" synopsis: "Woosh" = Booster, No HAVC selection = Leak or Pump

^That's a great "no tools needed" diagnosis. You definitely paid attention in class Snicklas

 

[Ole BlackBetty]

No woosh when brakes are applied and hvac works fine in all modes. Using the thumb suck-o-meter, the vacum lines pulls an eighth inch bulb onto a 52 year old well callused thumb at idle. Havent had a chance to hook it to a regular vacuum gauge yet.

 

[snicklas]

^That's a great "no tools needed" diagnosis. You definitely paid attention in class Snicklas

I've had a booster or 2 fail on me over the years........ and a master or 2.... I would rather the booster go.... at least the brakes still work........

 

[dizdak]

had same thing happen on mine, but the a/c would only blow out the defrost vents, turned out to be the vaccum pump..but seeing as you checked that i would start at the booster and go from there..