Pacbrake no workie

[george]

My Pacbrake stopped working all of a sudden, the compressor comes on but the Pacbrake isn't engaging. Any idea where the problem is?

 

[Doubleclutch]

George- compressor? Mine ran on vacuum... . check the shuttle valve which ports vacuum to the piston... if vacuum. If you're running pressure, ya got me!

Greg

 

[george]

Well it looks like a compressor to me, mounted under the hood. Normally when it's working right I shut it off and it sounds like disengaging an air brake. The unit is mounted on the exhaust just past the cat.

 

[SRadke]

Sounds like you've got an air activated inline brake? Based on their reputation I'd guess the solenoid to be at fault but be sure the hose is still connected to the cylinder and isn't leaking. You could also disconnect the line and put pressure to the cylinder to see if it will activate manually.



-Scott

 

[Doubleclutch]

Well, suck or blow, if the butterfly valve doesn't move, it doesn't matter. Follow the lines back from the compressor to the solenoid valve. Most of these valves have a button you can press to push the shuttle to the "release" port (if the brake sticks in the on position). Two lines usually go to the brake from this valve. The usual cause of a exhaust brake not working is this valve getting gumbed up and needing cleaning. There have been articles written in the TDR mag and also posted on this forum about cleaning procedures, all easy if you catch the small parts that jump out when you remove the four screws holding the top of the valve together. If this doesn't do the trick, I'd look at a throttle switch or the pump to make sure it was doing it's job.

Greg

PS a vacuum pump and a compressor do the same thing in reverse. Mr Radke, was I asleep at the switch THAT long????

 

[SRadke]

Mr Radke, was I asleep at the switch THAT long????

You lost me there.

 

[Doubleclutch]

Started a reply to George and your message popped up in between. I didn't know that both brakes were offered, but then again, my 4. 5 has an air Pacbrake, and my buddie's 05 has a vacuum Jake. Good idea on the manual apply on a pressure brake.

Greg

 

[SRadke]

Ah, I'm with you. By the posting times I couldn't see how that was what you meant



They did make both styles however everything for the third gens from Pac is air activated as well as most of their inline stuff because they're designed for larger busses, motorhomes, etc where they usually have air compressors to use as an activation source.



-Scott

 

[george]

Found the problem with my pacbrake, one of the air lines has a hole in it and is leaking. The hole was caused by rubbing or being burned on the lower intake hose (near lower radiator hose)it looks like the hose was melted. I didn't think that intake got that hot?

 

[SRadke]

If you're pushing more than stock fuel through a stock charger the intake can get quite warm. Glad you found your trouble.

 

[george]

Yeah I'm a little bit beyond stock, that explains that.



I'm glad I found it too, Thanks

 

[Doubleclutch]

Thanks for posting the find. Lots of times WE never learn from what you do.

Greg

 

[RMachida]

I had the same problem just yesterday. I had the line running under the upper radiator hose and it was occasionally touching a pulley.

 

[george]

One more question, should there be any air leaking at the compressor? I heard a little air leaking and sprayed the area with soapy water and found it leaking at a brass bolt that's on the side towards the top of the compressor. I tightened it and the leak slowed a lot but didn't completely stop. Next I took the bolt completely out and put some nylon tape on it and it seems to have stopped. I haven't driven the truck since I did this, just wondering if I did anything wrong.

 

[RMachida]

The "brass bolt" is a plug so it shouldn't be leaking.