2nd Gen Non-Engine/Transmission Wiring Problem???

[Teacher]

Those of you with Pacbrakes may be able to help me with this problem.

I have a Pacbrake, DTT smart controller and cruise control.

The ABS light and the brake lights stay on. The Pacbrake engages but does not disengage when the throttle is applied. My cruise control does not work.

We thought the problem was the wires from the smartcontroller were shorting out because they were tightly shoved in with other wires through the firewall grommet. They did show some "charring" but not all the way through the wires. We replaced the "charred" wires and rerouted the harness through another firewall location.

When I engage the Pacbrake, it goes on and stays "stuck" until I flip the switch off, but it does not react right away. I have to wait about 15 seconds for it to disengage.

Where to trouble shoot???????

Thanks for your help.

 

[jelag]

I can help you with part of this... . on top of the engine is a solenoid that controls the vacuum going to the exhaust brake..... disconnect the exhaust brake from the solenoid on the brake side of the solenoid... .

Now move the brake butterfly... . if the brake is stiff, it needs to be taken apart, (remove brake from truck) clean and lube the swivels where the butterfly pivots... . there is a special lube for this... . any oil, or grease will not work... the lube is a special high temperate lube... . see your pacbrake distributor for this... re-install once this is moving freely... Do not remove the shaft from the housing or the butterfly from the shaft... . the brake has been calibrated and this relationship should NOT change.....

Apply some air to the cylinder... 20 to 30 psi will work. . if any air leaks out of the back side of the cylinder, or around the shaft, replace it... .

Now take apart the solenoid and clean it, by removing it from the truck, and taking it apart. . there are small parts in this solenoid, don't loose them... clean all these parts and lube with Vaseline before assembly.....

Take a couple of oz's of oil... . start your truck and let the vacuum pump on your truck suck up a little bit of this oil... we suggest that you put a rag around the outlet on the pump to catch the excess after you lube the pump...

Put it all back together... and put a vacuum gauge in the circuit between the solenoid and the vacuum pump... . start the truck, if you don't have at least 25" of vac on the gauge at idle check belt tension, and if the tension is good replace the pump... . its bad... and will also contribute to problems with your brakes... .

If you have further questions either email me directly or call our 800. 445. 4696 and speak to Jack or Paul 7:30-5:00 M-F on the west coast for additional help...

 

[Teacher]

Jim,

Thank you very much for your prompt reply. I will try that and see how it goes; even if it doesn't solve the total problem, it sounds like a good thing to do anyway. Will let you know how it goes.

Jim

 

[Teacher]

Jelag,

Thought I'd get back to you about previous problem: ABS and Brake lights on, no cruise control and pacbrake not working.

The culprit was the plastic vacuum hose that goes from the firewall to the diaphram under the battery holder. It was brittle and cracked. We must have bumped it when we took the battery and holder off. It was divine providence for sure! Lots of good things happened as a result of that problem.

Thanks again for your advise on the Pacbrake. I was glad it wasn't the problem.

Jim