Engine/Transmission (1994 - 1998) Vacume pump leak

[JKure]

Quick question about the vacume pump on my 98 12v. I noticed it was knocking and that my heater workes than dosent. And also noticed that you can here a small ticking sound at the fuel tank and it not a exhaust leak. any ideas? Could it be the vacume pump or some thing else? thanks

 

[CumminsPower98]

I'm not sure about the vacuum pump knocking as I have not heard of them failing much other then leaking oil between the vacuum pump and p/s pump. Are you sure the vacuum pump is making noise and it's not something else? You might have a vacuum leak some place that's causing the HVAC control problems. My cousin's vacuum pump broke three gear teeth off for no visible reason, which made quite a racket but I have never heard of this any other time. The ticking sound you hear back at the tank is from the fuel lift pump transmitting it's sound down the steel fuel lines, which is normal.