PSV

Ok, I seem to have continual problems with my vacuum system. I bought my truck last year with 189k miles on it and came to find out no one had ever brought the truck in for the vacuum check valve recall.

I had some items such as the cruise control unit replaced under warranty, but I still feel like there is a vacuum leak somewhere in the system.

Could someone please explain or at least verify how good of a vacuum each part of the system should hold? I can isolate each component, but I don't know what type of vacuum I should expect. For example, if I test vacuum back to the pump should it hold? or if I test vacuum to the brake booster? Transmission (there is a vent of some type in that circuit).

Ultimately I know I can get parts replaced by the dealer if I push them hard enough, but at this point they are insistant my vacuum pump is bad and won't work on anything else till they replace it. Note that I rebuilt the pump myself and it seems to be much better.

Sorry for the long-winded post, but I need some expert help and I couldn't find a similar post on expected test results for each circuit. I do have a hand vacuum pump with gauge I can use to work on the system.


Thanks for the help!!!


Oh, I currently have a 1996 4x4 extended cab with an 8 ft bed. 47RE auto transmission with apparently the low gearing option.

infidel

About all I can tell you is my trucks will hold vacuum for days without starting the engine.
Friend was having vacuum problems and we used my hand vacuum pump with gauge isolating different parts of the system till we found it. His problem was an internal leak on his Pac exhaust brake actuator.
A hand pump is about the only way to hear a leak, engine is too loud. They don't cost much, often sold as brake bleeders.

PSV

Sorry for such a delayed response, but thanks for the reply infidel. I was having a tough time finding data on the vacuum system. Sounds like it should be pretty leak free and airtight for at least 1/2 hr.

I think I have found a sympathetic dealership (hah, is there really such a thing?) and I will try to work them over to replace certain parts in the next couple of days. Thanks again.