I have a 92 2wd 5 speed and the power brakes get hard some times ,,,,does this mean the vacuum pump is going bad or is there something else i should check????.....I luv this truck ..........

 

What do you mean get hard. Where is the peadle?

 

It is very rare for the vacuum pump to fail, or make less vacuum. Usually, the only fault it will cause is an oil leak. Sounds to me like you may have a vacuum leak somewhere in the system though. Test it with a vacuum gauge. Tee it into the system, usually up by the booster inlet somewhere. Read your vacuum at idle. Now remove the big vac. hose right at the vacuum pump and measure vacuum right at the pump, at idle, with the rest of the system disconnected. Your two readings shouldn't be more than 1 inch of vacuum apart, and both should be over 18 inches of vacuum. The brake booster is a common place for a leak. You can use a piece of hose held to your ear, and move the other end of the hose slowly around the seam of the booster to detect the hiss of a leak.

 

I had the same problem not too long ago. Do the vacuum test like torquefan suggests and pay real close attention to the brake booster. Mine leaked real bad only when I stepped on the brake peddle.

 

Take a good look at all the lines for cracks. I've seen moisture get in through cracks, puddle and freeze, causing a low vacuum situation.

 

the peddle gets real hard to push like it does in a car with power brakes when the engine dies ..
cool ,,,i will try those things this weekend and get back to you ,,,,,,,,,,should I have someone work the brake peddle while I listen through the hose ,with the engine running ????
thanks