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wvabeer · 05-14-2022, 10:51 AM

I have rebuilt the air drier, replaced the governor and checked all the air lines. I'm down to the compressor unloader. Has anyone replaced/repaired one? 1999 dutch star Spartan 8.3 isc.

Ray,IN · 05-14-2022, 01:11 PM

The obvious question is, have you closely inspected the compressed air system for leaks?

wvabeer · 05-23-2022, 04:26 AM

I guess this isn't a common problem or not that big of a deal.

Ray,IN · 05-23-2022, 02:26 PM

Quite the contrary; it may be very serious.
I ask again, have you tested the compressed air system for leaks? That answer comes before throwing money at the problem.
If you determine there are no/very small air leaks, next are the one-way check valves in the system.
The unloader merely turns the compressor on/off-so to speak.

wvabeer · 05-24-2022, 06:48 AM

There are no leaks between the reserve tank, dryer, governor and compressor. I kinda of figured that should have been obvious from my original post.

wvabeer · 05-24-2022, 11:16 AM

Quote:

Originally Posted by Ray,IN

Quite the contrary; it may be very serious.
I ask again, have you tested the compressed air system for leaks? That answer comes before throwing money at the problem.
If you determine there are no/very small air leaks, next are the one-way check valves in the system.
The unloader merely turns the compressor on/off-so to speak.

I was thinking the unloader diaphragm may be leaking.It is hard to get to. After thinking some more, I may have a problem with the air dryer checks. The air suspension leaks slightly but it takes all night to lower, not enough to cause my problem. When I rebuilt the air dryer I found the check for the supply loaded with crap. It may have happened again.

Ray,IN · 05-30-2022, 03:02 PM

Yes if there was a lot of gunk in the assembly and lines from lack of maintenance before you, it might have stuck a one-way valve open again.
The Spartan chassis air brake test helps identify such things as stuck open valves. Maybe even on a different chassis.

flyboy013 · 06-03-2022, 07:50 PM

I had similar symptoms with my air dryer. Ended up that the purge valve was leaking. I had to put some paper under it (think Pom Pom) to see that it was leaking there.

wvabeer · 06-11-2022, 04:10 AM

The turbo valve seal broke off inside the air dryer. I replaced that valve 6-7 months ago. Oh well this made me go thru and find a few small leaks that without it I'd never looked for. All works great now.