My front end will not lock into 4x4 so i found out that i have no vacuum in the vacuum lines running to the front end.So where do i check for the other lines to c what the problem is? Also i know on gas trucks that if there is a vacuum leak then it will affect some other things. So if i have a vacuum leak near my engine would it affect my engine at all such as the idle, because when i put it in gear it drops down almost enough to die. Any help woud be appreciated so thank you all very much.


mitch@jc

 

vacuum pump is located between the timing gear cover and the power steering pump. not sure if it's used for brakes on a '97 or not (you should be able to see if there's a vacuum hose going to brake booster behind the master brake cylinder), but vacuum should operate the air duct controls for the heating and a/c system (you should be able to hear the duct doors open and close). vacuum should NOT affect engine performance like it would a gasser. what is your idle rpm set to in neutral or park?

 

hydraboost on the 97's.

 

mitch,

The vacuum pump is just in front of the power steering pump (drivers side front of engine). There is one vacuum line coming off the vacuum pump. Start there and check the vacuum at each “T”. There are not that many branches in the line.

I had a vacuum failure due to oil in the lines. The check valve on the side of the vacuum pump failed and allowed oil into the lines. I was able to check the vacuum harness with a MityVac from Harbor Freight. The vacuum line runs up under the rubber cowl on the top of the firewall. I was able to isolate my failure to behind the firewall and then to the defrost/floor actuator.

Hope this helps.

T-Bone