Air Dryer Purging Air Every 15 Sec

[Bengy88]

(09-23-2023 )JHeavy_Hauler Wrote:  I am having similar issuse on a coronado!
When at idle it goes off every 30 sec. When excelerating, it increases to 10 sec. Also when the purge valve cycles, for about 3-5 sec it sounds like it is "farting",(best way to describe

First thing to check if you have a dd platform engine is pull your discharge hose off the compressor, it can be a complete bitch depending on the year, then take every section off between your compressor and dryer. I bet at least one line and a couple couplings is carbon packed. These trucks/engines are horrible about this shi#t.

[Bengy88]

(09-20-2023 )GunRunner Wrote:  I did some digging and it’s possible that K057542 is a part number for the assembly, mount and all. It looks like K093427 is the air dryer that comes in that assembly. If that’s the case, the only think left that it could likely be is the compressor. I guess I’ll need to decide if I get a rebuild kit for the head or a new compressor.

You can supply air to the unloader valves in the compressor to see if it stops pumping. If it stops then I would say the compressor isn’t your issue. Regulate 90-120ish psi of shop air or truck air to the unloader port on the compressor and see if it stops building

[DVT873]

Is that a Bendix AD-IP ? Thats what it looks like. It looks like your lines are wrong. Below is a link to Bendix. You can get manuals there. Their plumbing pictures could be better. Pay attention to the differences between a Holset compressor and everything else.
First page of the installation directions also shows differences between what they are calling hard seat and soft seat, whatever the hell that is. I noticed that the elbows have black paint on them and the nuts and lines don't. Somebody probaly yanked the old dryer off and didn't pay ant attention to the lines. Which is so dam stupid especially today when everybody has a camera in their pocket. The lines probably had paint on them also.

Once you get the lines sorted out you may still have your origional issue. It is most likely a leak. Take the big line off at the compressor and get fittings so you can connect an airline in from shore. Release the park brakes (chock a wheel) and listen for a leak. Guys say, I don't have a leak my gauges aren't dropping. There are three air reservoirs on any truck. The "wet" reservoir and the primary and secondary. The "wet" reservoir doesn't have a gauge. That is the reservoir that connects to the compressor and dryer.

Somebody mentioned that the lines might be plugged with soot. Or even the reservoir cuttin way down on volume. I think I read about that on here years ago. Came up in a post crash investigation. Below is a link to Bendix. Their phone support used to be the best in the industry. In the last year or so it has really gone downhill. They are hard to get ahold of and it seems a few of the old guys are gone. Below is a link to their site. Click on the manuals tab. Good luck

https://b2bendix.com/MX/en/MXN/Products/.../p/5003424

[GunRunner]

It is the AD-IP air dryer. I called Bendix because I am still learning about all of this and they weren't much help. The shop put an aftermarket governor on and charged me $223. Bendix strongly suggested putting a Bendix governor on and I got one from Freightliner for $106 and was able to get the plumbing diagram for the air dryer since Bendix said Freightliner plumbs their stuff differently than what they would do.

(09-24-2023 )DVT873 Wrote:  Is that a Bendix AD-IP ? Thats what it looks like. It looks like your lines are wrong. Below is a link to Bendix. You can get manuals there. Their plumbing pictures could be better. Pay attention to the differences between a Holset compressor and everything else.
First page of the installation directions also shows differences between what they are calling hard seat and soft seat, whatever the hell that is. I noticed that the elbows have black paint on them and the nuts and lines don't. Somebody probaly yanked the old dryer off and didn't pay ant attention to the lines. Which is so dam stupid especially today when everybody has a camera in their pocket. The lines probably had paint on them also.

Once you get the lines sorted out you may still have your origional issue. It is most likely a leak. Take the big line off at the compressor and get fittings so you can connect an airline in from shore. Release the park brakes (chock a wheel) and listen for a leak. Guys say, I don't have a leak my gauges aren't dropping. There are three air reservoirs on any truck. The "wet" reservoir and the primary and secondary. The "wet" reservoir doesn't have a gauge. That is the reservoir that connects to the compressor and dryer.

Somebody mentioned that the lines might be plugged with soot. Or even the reservoir cuttin way down on volume. I think I read about that on here years ago. Came up in a post crash investigation. Below is a link to Bendix. Their phone support used to be the best in the industry. In the last year or so it has really gone downhill. They are hard to get ahold of and it seems a few of the old guys are gone. Below is a link to their site. Click on the manuals tab. Good luck

https://b2bendix.com/MX/en/MXN/Products/.../p/5003424

[GunRunner]

So I blew air through the 1/4" line going to the compressor for the unloader valve and heard it stop pumping. I then heard large amounts of air escaping from the back of the compressor through what appeared to be a weep hole. I'm guessing the head gasket blew so I just went ahead and replaced the air compressor since I was able to get one at Fleet Pride and use a 25% off coupon. Got it swapped out and everything is back to normal. Thanks for everyone's input and suggestions and patience while helping me diagnose this. I guess I won't be going back to that shop, they had the truck for 1.5 weeks and said it needed a new compressor because it was likely the unloader valve but never told me how they diagnosed it to come to that conclusion. I'd rather do all the work myself anyways, I only had them do the air dryer initially because it was in for resealing the power divider and they said the air dryer was leaking during a DOT annual inspection.