Hi Guys,

Put an ATS transmission controller and a vacuum style Pacbrake on my truck this weekend. Tranny controller works great. Pacbrake doesn't seem to make much difference whether it's on or off. I would think the exhaust would sound a little different when it's on, but it doesn't. I didn't hook the ATS controller up to the Pacbrake yet, since I didn't want to complicate things if something went wrong ... Anyway, I've got current to the solenoid when the throttle is released and none when it's depressed, so the electrical appears good. The other easy thing was checking that the hoses coming from the solenoid were correct per the diagram. When I check the vacuum cylinder, specifically the rod that moves in and out of it, I see it move between 1/4 and 3/8 of an inch when comparing the on .vs. off position. Anybody out there running this style Pacbrake tell me how far it should be moving when it does work? Any tips on how to diagnose this problem?

 

Have you checked the vacuum connections?

 

push the button on top of the solenoid, that should activate the brake. if that does not work, you may have to take the solenoid apart, it sounds almost like the piston in there is hanging partway.

I could be wrong on this, it may be a matter of adjustment at the bellcrank end, but I have not seen any that were out of adjustment right from the factory. that little solenoid can be a bugger though.

There is a cleaning procedure, and I think you can find it on the pacbrake website. There used to be a link to it from PDR's website too

 

does the ats controller handle tc lock up?

brett

 

I've checked the vacuum hoses - each runs from the proper port on the solenoid to the pump and the to the two correct ports on the vacuum cylinder. No noticable leaks. Didn't know about that button on top of the solenoid, thanks, I'll give that a shot. And, yeah, the ATS controller handles TC lock up. With the stock VB it'll lock it up at 18mph or higher, depending on setting.

 

When I push the reset button on top of the solenoid the brake activates, just as if I turned on the switch in the cab - I get the same effect, which is the rod that from the vacuum cylinder moves 1/4 to 3/8 of an inch. I don't hear a difference in the exhaust and it doesn't seem to have much effect. How far does that rod need to travel to open/close the butterfly valve?

 

im probabaly missing something, but if its not locking your tc, you wont really get any benefits from it yet. when you activate it at idle, what are your egts? does it have an engine warm up feature? its not going to sound like a big rig jake either...just in case you didnt know. basically its more of a big air leak type of sound on the outside...in the cab its not to bad

my advice would be to finish the install, but hooking it up to the controller and giving it a try.

brett

 

So, I learned something 'bout the PacBrake. Talking with the guys at ATS, they recommended removing the small rod that connects the vacuum rod to the butterfly valve arm. Doing that, I was able to tell the butterfly was moving freely in the brake. When hit the reset button on the solenoid, the vacuum rod (disconnected from the butterfly) moved a good two inches, so vacuum looked good, too. Bottom line is that the vacuum cylinder needs to pivot a bit in both directions to accomodate the arc off the butterfly valve arm. Dumb me didn't know this. So when I bent the trans dip stick tube to clear the Pacbrake, I didn't leave enough room for the cylinder to move. Their docs say the trans dip stick tube touching the PacBrake can cause it to stick closed. Well, it can cause it to stick open even if it doesn't touch.
Now that it's working by itself, and the ATS Co-Pilot is working well too, I'll hookup 'em together and be done with it.

Thanks for your suggestions, guys.