Coming home from a short trip this morning, my PacBrake decided it didn't want to release. I had to pull the pin and open it by hand. Trying to pry the linkage back down shows that it feels "springy." Checking it out, I see a little valve with one tube leading in, and 2 leading out to the brake. Is this a vacuum controlled system ?? Never had to work on it before. I find that even pulling the wire at the valve doesn't release it, and tapping on that valve didn't help either. Before I go getting hysterical about all this, can anyone confirm what my problem is ?? Thanks a lot.

Lar.

 

Not one response........?? I called Pac Brake and talked to a very pleasant fella in Vancouver, B.C., Canada, eh ??, who diagnosed my problem - sticking vacuum control valve - and what to do about it - take it off the truck, carefully take it apart, clean it with alcohol, and re-assemble it DRY, then re-install. He said to take it slow and easy and it should be straight forward. I'm impressed and pleased.

Lar.

 

I had a similar problem with mine...

It was the electric control valve that was sticking. But I had the easy part of going in under warranty to get it replaced.

 

I had the same thing with mine. I have to clean the solenoid in mine about twice a year. Cold weather seems to make it a little slow to respond.

 

By chance Barry...

What did you use to clean your with? I know someday down the road I will have to clean mine and keep it functional...

 

I have had good luck using basic rubbing alcohol to clean the solenoid valve. Any cleaner that does not leave a residue is good.

As far as the solenoid valve, something else to watch for, is that brass filter, especially on the trucks with the crankcase breather bottle. a little oil vapour under the hood can goa long way to clogging that little filter. some brakleen and compressed air will clean it out though.

This is an ongoing issue, and try it in colder weather, like -50C. I am pretty sure there is a better plan, that I am working on currently to solve the solenoid valve issue. As well, I have thought of an assist spring for shutting the brake off, should it not want to fully release on the mechanical end.

I have found that if the brake sticks on, there is no need to remove the pin from the linkage, just put a glove on, and give the end of the rod a shove back into the canister, it will go. Also, every 6 months or so, more if you are idling a lot, take the pin out, and rotated the bellcrank all the way around on the butterfly valve. this will help to clear any carbon build up around the butterfly, which can also cause a sticking problem.

 

I used Electro-clean.