Engine/Transmission (1994 - 1998) Jacobs E-brake question

[blackholehunter]

I've been lurking on here for about a year now and just recently got a subscription to the TDR. I try to answer my questions with search but, this one I cannot. I recently picked up a 1996 Dodge 3500 2wd. It has the Jacobs exhaust brake on it but, it does not work. I found their instructions/troubleshooting guide online and tested everything and pinpointed the problem to be the solenoid. Sometimes it works and sometimes it doesn't. When it does work it will actuate the e-brake but, not enough to do anything worthwhile. I did check all electrical per Jacobs instructions so, i am positive that is not the problem. I tried to take the solenoid apart (it has a snap ring on its top) but, I could not take the "cap" off of it without ruining it. Is there anyway to disassemble or, do I need to pick up a new one? I called Cummins and they want $232 for one. Would there be someplace else that would have a better price on it? Any help is appreciated!



Scott

 

[Steve Campbell]

Welcome aboard......

I don't own a Jacobs e-brake. Is this the vacuum solenoid or is it an electrical one. If the latter, could you take it to an auto parts or truck parts distributor and match it up to something similar? If the former... . perhaps somone like Grainger would have something similar. There are some pretty good heads on this site who will probably have an already "been there, done that" answer for you.

 

[GAmes]

Did you call Cummins NW or a truck place that services Cummins engines? If it was Cummins NW you will probably have to bite the bullet and pay the $232. Look at it this way, that is still 1/3 of the cost of a new one. Before doing that remove the actuator rod and make sure the butterfly is free. It could be carboned up and binding. Also remove each vacuum line, one at a time, starting at the pump and check with a vacuum gage. There may be a leak somewhere. One other thing I just remembered. I had to replace the relay that is mounted next to the solenoid a few months ago because sometimes it worked, sometimes not. It was a little pricey, but way less than $232. One other thing to check is the microswitch mounted on the engine. It may be slid too far forward and is not being fully depressed at all times.



Hope this helps.



Gary

 

[blackholehunter]

Originally posted by GAmes

Did you call Cummins NW or a truck place that services Cummins engines? If it was Cummins NW you will probably have to bite the bullet and pay the $232. Look at it this way, that is still 1/3 of the cost of a new one. Before doing that remove the actuator rod and make sure the butterfly is free. It could be carboned up and binding. Also remove each vacuum line, one at a time, starting at the pump and check with a vacuum gage. There may be a leak somewhere. One other thing I just remembered. I had to replace the relay that is mounted next to the solenoid a few months ago because sometimes it worked, sometimes not. It was a little pricey, but way less than $232. One other thing to check is the microswitch mounted on the engine. It may be slid too far forward and is not being fully depressed at all times.



Hope this helps.



Gary

Thanks for the help guys. Yes, it was Cummins NW I got the quote from. The valve at the brake will move but, only for 2-3 seconds. The solenoid (cycles). Under the hood I can hear it click on. Then, the actuator moves and closes the butterfly. Next, I'll hear another click from the solenoid and the butterfly will open back up. I forgot to mention vacuum was fine. 25in. When the solenoid would work it would show 25in on the outlet as well. I didn't check the relay. I will have to do that. As far as the microswitch according to their test it was working. When the e-brake switch was turned on both wires from the throttle switch had power to them.



Scott

 

[blackholehunter]

Re: Welcome aboard......

Originally posted by Steve Campbell

I don't own a Jacobs e-brake. Is this the vacuum solenoid or is it an electrical one. If the latter, could you take it to an auto parts or truck parts distributor and match it up to something similar? If the former... . perhaps somone like Grainger would have something similar. There are some pretty good heads on this site who will probably have an already "been there, done that" answer for you.

That is what I was hoping for as well. I read in my searches about someone with either a pac brake or a US gear brake and they where trying to find a replacement without having to buy one from the maker. When the weather turns around out here, I might take it off and see what I can locate! Thanks!



Scott

 

[GAmes]

Originally posted by blackholehunter

As far as the microswitch according to their test it was working. When the e-brake switch was turned on both wires from the throttle switch had power to them.



Scott

Guess I wasn't very clear. If the microswitch on the engine isn't positioned correctly the relay will click on and off (don't ask how I know and why I now have a spare microswitch ) It must be fully depressed with the throttle at idle or it will not work correctly. When my relay quit there was no click, so if the microswitch is adjusted correctly I'm guessing the solenoid releases when it gets warm. Have you tried giving it direct current from another source?

 

[blackholehunter]

Originally posted by GAmes

Guess I wasn't very clear. If the microswitch on the engine isn't positioned correctly the relay will click on and off (don't ask how I know and why I now have a spare microswitch ) It must be fully depressed with the throttle at idle or it will not work correctly. When my relay quit there was no click, so if the microswitch is adjusted correctly I'm guessing the solenoid releases when it gets warm. Have you tried giving it direct current from another source?

No problem. While out an about today, I came to the realization that it isn't or shouldn't be the relay or switch. When the solenoid would cycle both wires at the microswitch would show power neither would go off or on as it cycled. Same with the two wires at the solenoid itself. Before, i go buying anything I will try to give direct power and see what happens.

 

[Bob V]

Does it have the micro switch under the hood on the injector pump or on the throttle in the cab? They had a lot of problems with the switch on the pump. If you do need a new valve I can help you locate one for a lot less

Bob V

 

[Howard Durand]

Connect an ammeter in the line between the switch and the solenoid. If you still have voltage but the amps drop off when it clicks, you may have a bad solenoid or, quite possibly, a bad ground connection.

Find where the green wire emerges from the wiring harness and check it's attachment to ground.

 

[Slow Six]

I had this e brake on my 94. I had two relays go bad. Before they quit completely, brake operation was intermittent. I took a bad relay apart and found that moisture had gotten into the relay and the parts inside eventually corroded and the relay would not work. I put a new relay in a weather proof box from an electrician and rerouted the wiring into the box. This solved the problem and te brake performed perfectly for several years until I sold the truck. It is still working for the new owner.

 

[blackholehunter]

Originally posted by Howard Durand

Connect an ammeter in the line between the switch and the solenoid. If you still have voltage but the amps drop off when it clicks, you may have a bad solenoid or, quite possibly, a bad ground connection.

Find where the green wire emerges from the wiring harness and check it's attachment to ground.

I will check that. I haven't tried to find the ground on the harness , I will check that as well.



Scott

 

[Howard Durand]

Scott



If your setup is wired the same as mine, you will find the green solenoid ground wire fastened to the passenger side fender at the same place that the passenger side battery is grounded to the body.