Almost crashed into the garage
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From: Westfield, MA
Almost crashed into the garage
I have a new problem now that the temps are dipping down in the 20's. I drove the truck to work yesterday and several times I had no power brakes. Scarred the poo out of me the first time it did it. Then last night I almost crashed into the garage. This summer I changed the vac pump, master cylinder, calipers, pads and front brake hoses. It is obviously a vac problem but what? I still have normal heater function. Are the boosters known to have problems? I never have been able to lock up the brakes, but from what I am reading that is fairly normal. I don't really want to replace the booster if that is what it is because I'd like to convert over to hydra boost brakes, just don't have the time or money to do that right now. I'm I barking up the right tree in thinking its the booster leaking vac internally? The big vac line coming off the pump looks ok. Maybe I should replace it first just to rule out the cheap and easy fix.
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From: Peterborough, Ontario
Sounds like either your booster or your vacuum pump is toasted. If the heater will still change functions (defrost to vent for example) then you have at least some vacuum, as it is vacuum assisted to switch it. Losing that was what clued me into my vacuum pump being toasted a few years ago.
The boosters will also go, in my case I didn't realize the master cylinder had leaked into the booster chamber, so when I changed the master, everything seemed good for a while, until the booster died. They aren't hard to replace, biggest issue is the contortions you have to go through to undo the clip under the dash for the pedal linkage.
The boosters will also go, in my case I didn't realize the master cylinder had leaked into the booster chamber, so when I changed the master, everything seemed good for a while, until the booster died. They aren't hard to replace, biggest issue is the contortions you have to go through to undo the clip under the dash for the pedal linkage.
Lead Driver
Joined: Dec 2006
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From: So. Jersey
For a quick test pull the rubber hose off at the pump and see if the pump will suck your finger to the port (with the engine running of course)
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From: Westfield, MA
Ok, I hooked up a vac guage and the pump is pulling 24 in. at the booster. All the lines appear to be in good condition. Hooking up at the booster and pulling 24 in. seems to tell me that the pump and plumbing to the booster is in good condition. Am I right? What should these pumps be pulling?
Post Fiend
Joined: Nov 2003
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From: Nutter Fort, WV
Now if you press the brakes, how low does it go?
And how long to recover?
24" of vacuum is fine.
You also might want to pull one of the block off caps on the vacuum tree and check various positions on the heater control to make sure you don't have a vacuum leak in one of the heater control lines.
And how long to recover?
24" of vacuum is fine.
You also might want to pull one of the block off caps on the vacuum tree and check various positions on the heater control to make sure you don't have a vacuum leak in one of the heater control lines.
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From: Westfield, MA
Baby went back to sleep so I went out and did a few more tests real quick. With guage plumbed into the vac manifold operating the heater controls had no effect on vacuum. Stayed steady as a rock. Pressed brake with moderate pressure and vacuum went to about 7 in. recovered to about 15 in and stayed steady. Released brake, vac went to 5 in. and took almost 40 seconds to recover back to 24 in. If I press the bake real hard the vacuum will drop to about 10 and recover up to about 20 and stay steady. Turned truck off and vacuum only dropped about an inch in three minutes. Pressed brake with truck off and vac dropped to 10, when released vac went to zero.
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