Jake Brake stopped working - Vacuum pump problem?

[drdemocracy2000]

I've been searching the forums for a few hours but so far no luck.

My Jake Brake just stopped working. The light comes on, but that's it. I disconnected the line from the vacuum pump, and while I felt a very subtle pulsating sensation, I didn't feel any suction.

For comparison, I checked the suction from the pump on my Dad's 2000 cummins, and it was very strong which makes me think my vacuum pump may be my problem.

The thing is, everything else in my truck works just fine, and if the vacuum pump went out I would expect I would notice problems elsewhere.

Any thoughts?

[drdemocracy2000]

Turns out it was a fairly easy fix. Apparently it's pretty common for the vacuum pumps on these Jake Brakes to go out, and when they do it is normally the diaphragm that fails. On ebay it will cost you about $370 for a new pump, but only $160 for a diaphragm replacement kit, which is what I purchased.

Simply loosen the serpentine belt off the pump, remove the 3 nuts holding it, and pull off the pump.

Then take off the 4 bolts holding the diaphragm on, and check inside the lower unit. There should be oil in the reservoir which you can change (standard engine oil will suffice, and it should be filled to about 3/4 of the way). Make sure you spin the wheel around to see that the cam operates correctly. Basically unless it looks burnt inside it should be fine.

Then replace the diaphragm with the new one and put it back on.

Hope someone else can find this useful

[06speed]

Awesome. Thanks. Shoulda taken some pics. I read about these going out somewhat often, and wonder when mine will go. (knock on wood, hasn't yet)

What brand were the parts? Same as the pump or generic?