923A2 not building any air

[twisted60]

Need help, I've found plenty of issues where air builds up to +/- 60psi but in my case it does not build up any pressure. I can service the tanks from an external source, I do not hear any air leaking, truck drives normal with each application of brakes bleeding down the air as normal but no air going back into tanks.

Going by what I've found on other posts, I'm lead to the PPV. Does this sound correct ?

Any other hint or direction is welcome.

 

[Andyrv6av8r]

Is your compressor producing any air? Did you check the expello valve in the bottom of the air dryer, as in, stuck open?

 

[big block 88]

I would be checking the compressor line for preseure. Take it off and see if she is pushing air.

 

[twisted60]

With the truck running I crawled under and there was no air coming out of the expello valve.

I have not disconnected any lines from compressor yet, that will be tomorrows mission weather permitting. Also will pressurize tanks tomorrow and recheck for air leaks.

Started driving and building pressure as normal, then I noticed the air was bleeding down and not recharging so I pulled over and checked for leaks, none heard, bleed tanks and started truck up again but no air building. Got a tow truck to hook up and charge my tanks to 120 psi so I could limp home, pulled in driveway with just over 60 psi remaining.

 

[98G]

Water in the air lines condensed and filled your compressor, acting like pressurized air on the unloader...

 

[twisted60]

Oh I hope not, unless it is serviceable and not requiring a new compressor. I'll try to dig in more tomorrow and see if compressor is blowing air. I assume I'll just need to disconnect at output line from compressor.

 

[98G]

It's fixable. Just blow the water out.

I suspect it may be time for a new air dryer.

 

[98G]

The output line will be hot if it's supplying pressurized air. No need to disconnect. My guess is that it is not hot.

Disconnect the unloader line from the governor to the compressor. My guess is that when you do this, you'll find water.

I haven't done this hands on on the A2s, but I have done it on A0/A1. It's going to be practically identical on the A2.

 

[twisted60]

I did notice a little moisture around the expello valve last week but no moisture came out when i drain tanks.

I do have a rebuild kit for the dryer, it is on my list of things to do, guess it just got bumped up to top.

Thanks

 

[twisted60]

How long before the output line gets hot ?

 

[twisted60]

Problem solved ? Not sure what I did to get her working again but here is what I did.
1) Disconnected the line from Gov to un loader, it was dry. Reconnected line.
2) Disconnected the out put line from compressor, it was making air (pulses) Reconnected line.
3) Followed the line to the Air Dryer,disconnected at input side of air dryer, started truck it was making air (pulses) Reconnected line.
4) Disconnected the out put line from air dryer, started truck there was a steady flow of air coming out. Reconnected line.
So far all looked good, next step was to pull the PPV but I thought I'd try starting the truck and see if anything had changed, well I started her and watched the air building like normal. So I crawled under and waited for the expello to pop, when it did it looked like a spray of mist, so that is leading me to do a rebuild on the air dryer.

Took her for a drive and all was well.

Thanks to all who offered assistance/guidance/ideas.