I'm new to the site, and have a question.
I have a 2003 Dodge Ram with 5.9 Cummins, to which I installed a jake brake, back a few months.
My Jake problem is that I turn on the switch and it may or may not work. If it doesn't work, I can help the linkage with my finger, and it comes on, so it seems to me that there is a vaccum problem, or perhaps a diaphragm problem. I checked all the hoses and the solenoid, and it all works well. I don't know how the diaphragm assembly works inside, but the can has a little dent on the outside, that happened during shipment to me. I can't imagine that that would be the issue. When I first installed it, it worked fine. Now, suddenly, it doesn't. Thanks for any ideas...

 

Ticomalo, you need to put a vacuum gage in the supply line to the cylinder on the brake. Then activate the switch, see how much vacuum is being applied to the cylinder. If your vacuum is low, it will not be able to overcome the return spring force within the cylinder. If your geting full vacuum about 28" to 29" (depending on your altitude) your right it will be the dent in the cylinder. If you need a replacement cylinder, good luck, maybe someone here can help you locate a replacement, Jacobs customer support sucks. If your vacuum supply is low, ceck all your clamps for leaks, failing that check for vacuum right at the pump, if it's low there and you need a new vacuum pump, your really in trouble.

 

I hope you are wrong about how bad Jacobs is . . . . Hopefully it was just the local shop you dealt with!! (Ours is great so if you ever need anything, just ask!)

 

Hey, I really want to thank you for the info. I'm going to try that. It does seem that altitude is an issue, though. When I get to the top of the mountain, it stops working for sure...Also, no Jacobs cust. service in Costa Rica! I'll let you know how it works out, when I get a little time to work on it

 

Hey, I don't know if it would help, but if I can be of assistance through my local Cummins shop with this (Or anything for that matter) just ask! I would be glad to help out. The local guys are tops and I have wholesale accounts set up with the 'big three' for that matter. (I can't remember if I have one with Cummins. If not, that will be no big deal to get it set up!)