2nd Gen Non-Engine/Transmission Loss of vaccum for brakes

[Tcolesanti]

My father has a '95 2500 4x4, being in the northeast he plows snow every winter. While plowing there is quite a bit of stop and go. After repeated on and off with the brakes the pedal gets real hard and travels further than normal. Basically the truck runs out of vaccum to power the brakes. Has anyone else had this problem? Corrective action? Has anyone added a vaccum tank to store vaccum?

 

[Reb.B]

add the vacuum tank or change the power steering pump and go to hydroboost brakes

 

[Jammar9082]

I made a vacuum tank out of 6 inch schedule 40 Plastic Pipe. It is about 18 inches long with two caps glued on and a hose fitting tapped and screwed into the cap and pipe. It is mounted on the left frame rail with a couple of support arms bolted through existing frame holes.



The tank has been used in the mountains of the west with no loss of vacuum.

 

[jelag]

Jammar has a good point..... but your almost talking about a set of pads that are overheated from execessive use and your getting brake fade... once this starts the pedal feels like its getting hard... . and there are no brakes... . Do you have a good quality set of pads on the front... .



I've been where your at... . but its from fade... .



Also... take a vacuum meter and place it in the circuit... . you should always have 26-27" of vacuum... . as these pumps age they don't come up to full volumn and vacuum... . I've taken some and sprayed some WD 40 through the pump with the vacuum booster disconnected..... and that's helped for a while... .



When you have brake application..... check the gauge again... . any leak in the booster will allow the gauge to go to zero and you'll have problems.....



hope this has helped...



JIM

 

[Tcolesanti]

Its more or less a gradual drop in vaccum at speeds of 5 mph and lower. When he's in a tight area plowing snow, he goes forward, backward alot in a short amount of time with the engine idling. So I'm figuring the vaccum pump can't keep up with the booster. Sound good?? Comments???

 

[Joe G.]

That is normal for a '95 ('94 and '96 too). Well known problem with vacuum boosters on these trucks. It's definitly not brake fade. The vacuum is not keeping up with the demand at low RPM. Mine does it too. That's the reason for the switch to a hydraulic brake booster in '97.



You can install an extra vacuum tank, but there is a draw back. It will still run out of vacuum after a while. The tank just delays that happening. Then it takes longer to build the vacuum back up. I just let it idle a while before continueing when that happens. Or you can just put up with the hard pedal.