PacBraKE

wolfe10 wrote:
Mike,

There are several relays involved in activating the exhaust brake. I would start by checking for good voltage at them. If so, I would buy one extra relay and start swapping the new one for the existing ones.

I will take your advice and change out the relays. I'll post what happens, hopefully the problem will go away. Thanks for you help!

Mike

Idea is OK, but, be sure to disconnect the wire from solenoid going forward before applying 12 VDC positive.

Without a lot of research into the effects, you do not want to back- feed the relays/transmission ECM.

sjholt wrote:
I ran a wire from 12 Volts to a switch and to the PacBrake solenoid so I could test the PacBrake operation any time I was in the engine compartment.
You might think about doing that.

Great idea thank you.

I ran a wire from 12 Volts to a switch and to the PacBrake solenoid so I could test the PacBrake operation any time I was in the engine compartment.
You might think about doing that.

I have my Pac brake back on and still not sure it's working properly. I still have 1-3 lbs of turbo boost when I apply the brakes, it does shift down and I took the air line off the ram and jammed some paper towel into the hose and took it for a drive and it blew the paper out of the hose. I guess the next step with have somebody watch it while I drive it.:@

Mike,

There are several relays involved in activating the exhaust brake. I would start by checking for good voltage at them. If so, I would buy one extra relay and start swapping the new one for the existing ones.

Here's another problem that may be related to this topic. I have verified that the air and exhaust brake electrically function normally. We have a 1992 Monaco Dynasty with an 8.3 Cummins and an Allison 3060 transmission. The trans does not display the 6 to 2 when the exhaust brake switch is activated. I have been through the system including: making sure the throttle switch is active and functioning, changed the relay in the trans control module.

After cleaning all the wires at the transmission the problem has changed. Now, the trans downshift from 6 to 2 readout and the brake does activate after a delay when the MH is first on the road. As I continue to drive the delay from turning on the switch gets longer, maybe 45 seconds or more.

Is it possible that connecting to an Allison control module computer can diagnose this issue?

After I posted my response, Brett, I finally figured that was probably what happened. Sorry 'bout that.

Ed

eheading wrote:
Brett, didn't you say the same thing I said, except maybe a little more detailed???? Duh, or were you answering the original poster's question, not responding to my response?

ED,

Sorry, I was not clearer. The OP was incorrect. You were correct.

tinkerer wrote:
Thanks for all of the advice, just some more information as to why the PacBrake set up. I bought this coach in 2008 but it was a left over model that sat in San Diego for a year after being driven from Indiana. I am thinking the people who drove it from the factory might not have used the engine brake. I am thinking that was the main cause plus the lack of lubrication. I tried to buy the PacBrake lubricant locally at Freighliner or my local parts store didn't have it. It's available on E-bay;)

The Pac Brake stuff is made by Super Lube. Super Lube is available at Ace Hardware.