Help!
My 97 XJ seems to have a vacuum leak. The cruise control doesn't work (the lights work fine but nothing happens) and the air vents are stuck on defrost. A jeep mechanic had a quick look and said that there was vacuum at the bottle but I didn't have time (or money) for him to check it out further.

I've bought a vacuum gauge,where should I start?
Thank you from a very non mechanic
Morat

 

Start by checking the vacuum ball like you mechanic said. It may have a crack in it or a loose hose. Then fallow all the vacuum lines to the fire wall.

 

No need for a gauge really. Here's a diagram of the lines.

 

I'm so useless I can't even find the reservoire WITH the diagrams
My Jeep seems to have lots of extra plastic for the foglights which gets in the way and I'm scared to break it.

I think I've found the line that goes to the vacuum ball, but it's covered in some sort of ribbed plastic conduit so it's very hard to spot any wear/breaks. Unless that plastic IS the line, in which case I can't see any leaks. I guess I'll find a way of generating some smoke for a test. Would that be the way ahead?

 

Look harder for the ball, or just get another one and install it in the engine bay.

 

Make sure check valves are working properly.

 

The illustration below (and in a previous post) shows the vacuum reservoir bottle with the right hand front bumper end cap removed. Of course you don't want to go through the drill of removing the end cap to see the reservoir - and you don't have to. Refer to the illustration.

Use a flashlight and a mirror (if requird).

Lay on your back with your face just aft of the right end cap. Pull back the right wheel well liner (in pic) enough to look up and see the reservoir and the plastic tube that connects to it. You can see the tube connection clear enough to determine if it has broken off or is loose. You may have to use the mirror to see more of the reservoir to see if it's cracked/broken.

 

Morat,

Here's a thread you can read through - same subject. And you've been here before.

https://www.cherokeeforum.com/f2/no-...-vents-176621/

 

Morat,

Since you're from England, can we just call you Moor Rat.

 

My leak, which caused the same issues was the tiny vacuum line that goes into the firewall next to the rubber heater core lines from the water pump got disconnected.


The smoke idea might work... any friends that smoke?

 

I'll be taking smoking up again myself if I don't get this fixed soon!
Thanks for all the help guys, I'll get on and try it all out.

 

just some input: when i bought my 96 i had both of the same issues.

mine was missing the vacuum ball entirely and had an open hose there, and was also leaking from a cracked rubber piece that connects the furthest back line to the intake manifold