Haven't posted anything here for awhile, but today I was almost home from work and my vacuum pump went out (I think) lost power steering and power brakes. Took it over to a friend of mines shop, hope to work on it this week. Anyone else had this happen? I was thinking too myself that I was glad it didn't happen in a bunch of traffic, I might have just plowed the guy in front of me. Seems like there should be a safety or something so that you wouldn't have an accident. I can deal with no PS but no power brakes makes big truck hard to stop!

 

Power steering pump failure. The power steering fluid charges a brake booster as well as assists steering.

Sudden failure like that is often a hung up relief piston which is behind the pressure fitting on the back of the pump. You can get it out without pulling it by taking off the pressure line and then the nut under it comes out. The relief piston is under it and is spring loaded.

If you had this happen once it's more likely to happen again. I'd consider draining the system and refilling and dropping in a magnet into the reservoir (preferably "rare earth" neodynium) to catch any ferrous wear particles.

Burping all the air out of the system will take a few shut downs. It can be a pain to purge at first.

Could need a new PS pump.

 

I would assume your power steering pump would be the culprit rather than the vacuum pump. It provides hydraulic pressure for both the power steering and hydroboost brake booster.

 

Thanks guys, you are exactly right, did some tests and power steering pump was the culprit. I am replacing the power steering pump and the vacuum pump. Both are originals anyway and truck has 215,000 miles on it. I figure I can't go wrong with replacing both. Sounds like a common problem, talked to someone I know that had the exact same issue. I am assuming most of you have had the same experience?

 

I haven't seen too many power steering pumps fail on 2nd gens, but it can happen. As far as vacuum pumps, there is nothing that ever fails in there besides the seal and o-rings leaking oil. If you want to save some money, you can get a relatively cheap seal kit and just reseal your vacuum pump while it's out instead of replacing it. That's up to you.

 

Actually, I ended up replacing the vacuum pump mainly because the 2 of the ears that mount the pump were broken. Working well now with both pumps replaced, expensive fix but glad to be done with it. I did notice a few weeks ago, that the truck seemed to have more blow-by than normal, I am sure now that the vacuum pump had alot to do with that.

 

Might have a vacuum leak. The vacuum is created by ejecting into the air into the crank case. If you have a leak, it will constantly pump air into the case.