No vacuum football

I am working on a friends xj (91 4.0 auto) and noticed that the heat is only coming out of the defroster. Now before the search police get me I now that it is a vacuum leak causing this problem, but my question is this: Will it ever work without the little football thing or should he get one of those first before we try and find the leak? Thanx Digger

If you plug all the leaks and have no vacuum reservoir, it should work most of the time, but it will tend to flop back to defrost when engine vacuum goes low, such as climbing hills. Kind of annoying. But you can at least test the system by blocking off the line to the reservoir, and see how that affects things.

e.t.a. If this is a 91, does it have a vacuum disconnect front axle? If so, you definitely want a working and leak free reservoir, or it will also pop out of 4wd at inopportune times.

No on front axle, it has been updated to a 99 dana 30. Where is the best place to hook up a vacuum pump to try and find the leak?

mine works ok without the football air tank. i broke mine when messing with my front bumper. I just took it off and plugged the line with a bolt.. I havent had any advers affects yet. I have been running it half a year now like that. it doesnt switch to defrost or anything. stays on what i set it on.


Edit- also i have a 92 so no axle disco.

thederrick106 said:

mine works ok without the football air tank. i broke mine when messing with my front bumper. I just took it off and plugged the line with a bolt.. I havent had any advers affects yet. I have been running it half a year now like that. it doesnt switch to defrost or anything. stays on what i set it on.
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Same here on my 96. Digger, If he needs the vac. ball I have 2(large & small) just pay shipping. JIM.