2002 E450 A/C Vacuum Loss

j-d wrote:
FIXED!

I bought a spherical vacuum canister (looks like the Acme anti-Roadrunner bomb ordered by Wiley Coyote) and a two-port vacuum check valve (both in Dorman products HELP line) from local Advance Auto Parts. O'Reilly, NAPA, Amazon all have equivalents.

Found a spot underhood behind the air filter assembly. I could get to the area by removing the filter housing and element ONLY. No need to pull anything else. There were two brackets hanging down. Nothing attached, holes ready for 1/4" bolts. Mounted one end to one bracket and made a strapping iron strip to reach the other end.

This pic shows the canister installed, behind the filter


Here's the connection to the vacuum line from the intake manifold, along with the new check valve. Intake manifold line is RED. All the rest of vacuum source to the controls are BLACK. One line out of the valve goes to the Canister, the other to the bypass line I ran into the cockpit


SO!!! Verify Source Vacuum First! Anybody needing help, send'em to me.

I too had this same problem and researched several fixes. All fixes pointed to the check valve and/or vacuum canister, the question is how to deal with it. One person, after abandoning the entire check valve and vacuum chamber simply ran a new vacuum line from the engine area to the line coming out of the evaporator area (have to cut the black line there to splice new line into it) but they didn't use a new check valve or vacuum chamber. I tried this just to verify that the problem was in the check valve and/or reservoir and it was and, my vents work with no check valve or reservoir installed but long-term it needs to be there. So down to two other methods, yours and one other. The "one other method" told you to jack up the rig, remove the wheel and saw into the sidewall to access the valve and replace it and the reservoir. A lot of work and more dangerous, all to access a valve that is better left right where it is and simply abandon it (as you did) and install a new valve and reservoir in the engine compartment area instead. I have yet to get the valve but will order it in a few days. For now I am relieved that I know what the problem is and that your fix works. Great post you did!

BTW: mine is also a 2002 (truck chassis is 2001) E450. What are the part numbers you used that I should be looking for?