NE frmhnd

The brake won't stay shut off. Boss had to unhook it the other day, hauling cattle down the road and it cut in. Gets used regularly.

Also has an issue with the T/C sometimes not locking. Has the BD lock-up controller as well.

Any ideas?

torquefan

I have installed several BD exhaust brakes that used vacuum from the truck's existing vacuum pump to control the brake operation. The only maintenance issue I found with them was that the brake's spool valve would get gummed up with soot and cause erratic brake operation. Very simple fix; just follow the vacuum hoses to locate the spool valve. One end of the spool valve has a little cover plate held on by two small screws. Remove the screws and the plate, and be prepared to catch a very small spring and a small plastic collar. Now you can pull out the valve from the valve body. It may be sticky enough to require pliers to remove, but after it's out just clean it and its bore with WD-40 until it moves freely in its bore. Put it back together and you should be in business.

carl48

I think you have the air operated bd. if you do it is probably the wire from the relay to the ecm or from the ecm to the switch has the insulation rubbed off and touching ground. the wire loom used did not take heat very well.

NE frmhnd

It's the vacuum operated brake. I'll pass this on to our mekanik.