Engine/Transmission (1994 - 1998) Vacuum Leak

[RAMnDART]

I need some help in locating a vacuum leak that is preventing my vacuum actuator from engaing 4 wheel drive. I have ordered a manual actuator to get around the 4 wheel drive problem, not the problem I have is that the ari direction on the dash,(A/C, heat, vent, etc... ) will not direct the air to any place exept for the defroster. What I am asking is if someone knows how I can find the vacuum leak so I can replace the hose. I know there is supposed to be a 90 degree bend in the hose down by the ABS sensor and that is sometimes the likely culpret but I have yet to dig into it. Thank You for any and all help.



#@$%!

 

[Skydiver]

Vacuum leaks can be very hard to find. A good friend who is a mechanic told me about a smoke machine that applies a low pressure to the system to identify the leak. Don't know much about it at this time. He also said that one person could blow cigg. smoke into the tubing while another person searched. Doesn't sound like fun.

I once worked on an old 1981 Mercedes 300d for 2 days trying to find a leak. Never found it.

Good Luck

 

[hsmith]

Check the cruise vacuum supply beneath the driver's side battery. May be broken. Put a gauge in the supply line going inside the truck. Should have 26" and hold when engine is shut off. Also check the vacuum hoses for oil contamination from the pump. If oil is present, you may have to do repairs beneath the dash, servos, etc.

 

[wcjp]

On my 96', the largest vacuum leak was at the transfer case. The vacuum lines became brittle and cracked. I cut them back, used some extension to reattach to the TC. Do one line at a time. All other vacuum connections I used very small zip ties to make sure all connections were tight.