I have a 1994 L9000. It developed an air leak and a friend helped track it down to broken off fitting on what I think is a relay valve but not positive. Found we could kind of thread a bolt in the broken part to stop the constant air leak. The hose going to it was left unconnected but the brakes seem to work fine. I'm only using the truck on my own property at relatively low speeds. Can someone more experienced identify the valve/component and how important it is for my application? The broken connection is on the other side and is fed with a larger air hose.
R12 pilot valve. Kinda really important.
Might be an anti-compounding line? Follow it and see where it goes?
A little closer pic of detail would help, and a closer pic of said broken fitting.
It's a larger hose inlet that broke. I forgot to look at the broken part but I recall it was a male thread coming out of the valve that broke. All the pics. I've looked at of R12 valves have female threads on all ports unless they aren't showing all of them. I'll try to get a pic. in the next few days. The brakes appear to be working fine. I thought it a little odd the valve leaked and not the hose. The truck is also equipped with trailer air so I was wondering if maybe the relay valve is more for a trailer?
Hmmm. Would it happen to just be the exhaust port leaking?
I was kind of wondering the same thing but it's a large hose and a constant leak that won't let the truck build pressure. If it is an exhaust port though, would it go to another valve or something so it isn't a constant leak? Edit: I just remembered why I needed help to locate the leak. It would only leak with the brake pedal depressed but would deplete the air in the system pretty quick.
Well maybe something on this couple pages would help: Also thought I'd add the page where you can do a search for literature from Bendix: https://b2bendix.com/US/en/USD/documentLibrary
Sorry for the confusion. My link is for a trailer relay valve, R12P. The link above, R12-R14 is the correct one for that valve.
standard issue R12 horizontal ports. there is a R12 vertical also.
A picture of the suspect hose would sure help solve the mystery Welder Dave.
I think I'll be going out tomorrow and will get a couple more pics.
I went out today and took a better look at it. The R12 valve is fine. What broke was the bulk head fitting going through the cross member. The hose goes from the R12 to another valve on top of the diff. There is an identical valve on top of the other diff. fed from the port on the R12 beside the one that was blocked off. Should be a simple repair. It is the larger braided hose in the 1st. pic. that connects to another hose that goes to a valve like in the 2nd. pic.
Now it makes sense.
The hose on the left in the 2nd pic. is the one that went to the bulkhead fitting that was blocked off. Looks like steel bulkhead fittings aren't very common but brass is OK for air lines.