Seized Exhaust Brake and didn't know it!

[evotech]

Just thought that I should share this story. I bought my 1998 HR Endeavor about a year ago. I had never driven or owned a class A coach before. When I engaged the exhaust brake it would slow somewhat, but nothing too dramatic. Fast forward to this week. I am preparing for a cross country trip with the family and going over every nut and bolt. I decide to take a good look at the Jacob Exhaust brake. Well, The butterfly valve was completely seized open and was not working at all. All that I really felt was the transmission downshifting. After a night of soaking in PB blaster and many hours with a hammer and other instruments of destruction, it finally freed up enough to start working it. I worked it back and fourth for hours with ATF fluid, PB blaster, motor oil ect...until it was totally back to normal. A quick test ride confirmed that it was finally functioning and boy what a difference.

[wa8yxm]

I drive a workhorse.. As you may be aware there is a problem with Siezed Calipers on some Workhorse models...

Though I'm sorry to hear of your problem

IT is always refreshing to read of a brake issue that is NOT the Bosch calipers on my Workhorse

Glad you found and fixed it.

[mahon1993]

I think the book recomends lubing the exhaust brake with silcone[sp] lube. You don't really want any kind of petrolium[sp] baised lube. It can get sticky.
Greg

[walt2137]

Try Lowes part # 65880 or #93615 it is a non petroleum base lube will work as good as Pac Brake lube, that was the part # a few yrs back.

[WindsorDave]

Go to post number 4 in this thread and click on the link to see where to lube the exhaust brake mechanism.

Jacobs eBrake exhaust brake maintenance

FWIW

[LeeB]

Quote:

Originally Posted by DiplomatDave Go to post number 4 in this thread and click on the link to see where to lube the exhaust brake mechanism. Jacobs eBrake exhaust brake maintenance FWIW

My Dad told me the stupid question is the one that does not get asked...So here goes....

Where is the exhaust brake? Physically?

I have a 330 Cummins....

[mahon1993]

It is usually mounted right after the turbo in the exhaust pipe. Usually a cast iron valve assembly with a air operated cylinder on it. When activated the air cylinder closes the valve. The valve is kind of like a chimney damper on old wood stoves.
Greg

[kketterling]

I also have to ask a dumb question. How did you know the butterfly valve was stuck. Did you observe it while driving the coach and activating the exhaust brake? I'm thinking that's the only way I would be able to tell and could probably do this via an inspection hole in the bedroom over the motor. Of course Chris would be driving and I'd be observing the valve action. Even though I have the Cat I'm assuming I have the same basic setup. As new as the coach is I doubt I have a problem but every time I read about issues fellow Rv'ers have I've got to check mine out to see it's working.

[WindsorDave]

Quote:

Originally Posted by LeeB My Dad told me the stupid question is the one that does not get asked...So here goes.... Where is the exhaust brake? Physically? I have a 330 Cummins....

I think your coach is very similar to mine. When you lift the bed and raise the engine cover, the exhaust brake will be near the top of the engine on the driver's side.

[LeeB]

Quote:

Originally Posted by DiplomatDave I think your coach is very similar to mine. When you lift the bed and raise the engine cover, the exhaust brake will be near the top of the engine on the driver's side.

Thanks I will have to check it next time I am in there.... These are the types of things it's nice to know ahead of time. You never know.

[walt2137]

Quote:

Originally Posted by kketterling I also have to ask a dumb question. How did you know the butterfly valve was stuck. Did you observe it while driving the coach and activating the exhaust brake? I'm thinking that's the only way I would be able to tell and could probably do this via an inspection hole in the bedroom over the motor. Of course Chris would be driving and I'd be observing the valve action. Even though I have the Cat I'm assuming I have the same basic setup. As new as the coach is I doubt I have a problem but every time I read about issues fellow Rv'ers have I've got to check mine out to see it's working.

Yes you could have a look at the exhaust brake going down the road but you should be able to move it with pair of pliers or wrench, you can also unplug the mac valve and put 12v from a out side source (with the air up) and cycle it, good idea to lube it while you are working it.

[evotech]

Quote:

Originally Posted by walt2137 Yes you could have a look at the exhaust brake going down the road but you should be able to move it with pair of pliers or wrench, you can also unplug the mac valve and put 12v from a out side source (with the air up) and cycle it, good idea to lube it while you are working it.

Believe it or not there is a procedure for testing a Jacob exhaust brake without going down the road or taking the air cylinder off. Shift the transmission into neutral and activate the switch with the engine running. I don't think that this would work with a Pac brake.

[walt2137]

Quote:

Originally Posted by evotech Believe it or not there is a procedure for testing a Jacob exhaust brake without going down the road or taking the air cylinder off. Shift the transmission into neutral and activate the switch with the engine running. I don't think that this would work with a Pac brake.

Evotec I dont know what coach you have but the Monaco coaches will not activate the Pacbrake below about 10 mph, I did not say to take the air cylinder off, I guess I didnt explain my self clear enough what I do is unhook the power line 12 V(to keep from back feeding the computer) I leave the ground hooked to the Mac valve that activates the air cylender that closes & opens the pacbrake I hook 12v from a out source, starter or where ever to a push button type starter switch and with the air pressure up I cycle the pacbrake with the push button switch.

[BigSkyBob]

I do my PRXB the same way Walt does. Just be sure to open the circuit from the exhaust brake solenoid to the ECM before hooking 12 VDC to the positive side of the solenoid. I don't know if feedback would be a problem but why take the chance.