Air Dryer Purging Air Every 15 Sec

[GunRunner]

I don’t disagree, they are starting to frustrate me. I can get my way around an engine but I’ve got a lot to learn with an air system. If they don’t have it fixed, I’ll get it tomorrow and post some pictures for advice, direction and self education. Thanks guys![/b]

(09-17-2023 )Bengy88 Wrote:  Unless it’s some weird shi#t like JMBT had goin on If a shop can’t figure that out in an hour or less you need a new shop buddy. And that’s giving them a little time to play with. Most of the time it’s as Rawze said the governor is plumbed wrong….. or an air line is broken. Depending on how your governor mounts there is usually 2 air lines. For example a D2 governor will have 3 sets of ports, 3 will be labeled res, 3 will be unl, and one port is exhaust…. Never block the exhaust port. The “unl” port will go to the air compressor head and to the air dryer signal, the “res” goes to a main air supply. It’s literally that simple…. If the governor is plumbed correctly and the “unl” line to the compressor doesn’t have a leak but it’s still purging every 15 seconds then your unloader valves are most likely stuck in your compressor and when the governor sends the signals the compressor isn’t unloading so the air dryer is purging every time signal is sent.

[GunRunner]

I got the truck back and here are some photos of how everything is hooked up.
-The 1/4” black line is going from the air dryer to the “res” port on the governor
-The 1/4” blue line is going from the “unl” port on the governor to the control port on the air dryer which has a T Block and the 1/4” line from the T Block goes to the air compressor
-The large black braided line goes from the supply port on the air dryer to the head of the compressor
-The larger (maybe 3/8” line) goes from the delivery port of the air dryer to the wet tank I believe

Does this look correct? My next step is to see if the unloaded valve is sticking by spraying some oil into the tube that feeds into the head of the compressor.

[GunRunner]

Here is a video of what it is doing.

https://youtu.be/izsex-PTtD4?feature=shared

[JMBT]

Interesting… is it possible the new governor is bad?? About every 3rd new part I get for anything is bad… also if it is an adjustable governor.. unscrew the black cap on the end and there will be a set screw to adjust the pressure, work it back and forth a few times then set it to what you want your working pressure to be. If it is somehow stuck internally maybe that would free things up. I run 135psi

[GunRunner]

The governor that the shop put on it was an off brand governor, probably Chinese. I just went to Freightliner and bought the Bendix governor that it calls for, which is not adjustable and set at 130 psi. Still the same issue but now it is purging about every 25 seconds. I pulled the tube off the manifold and disconnected the supply line at the compressor and administered several healthy doses of 3 in 1 oil in case the unloader was stuck. I did that two separate times to no avail. The only other thing that I noticed is the part number stamped on the body of the air dryer is K093427. When I was at Freightliner, they said the schematic called for K057542. I’m going to try and call Bendix tomorrow to see what the difference is between the two and if that could cause my issue.

[GunRunner]

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.

[ktblogistics]

on picture numer 3 exhaust port is visible but there is something black in it
mostly it is just open straight from box

also on volvo engine you can use shop air on 1.4inch line that goes to air compressor and see if it holds air

tried this on cummins and air escapes fro safety valve on compressor head
do not know if its good or bad but had same situation before with purging every 30sec
unresolved :(

[GunRunner]

I think the black plug you are referring to was screwed into the exhaust port. I removed it last night thinking that was going to fix it and it didn’t. The plug appeared to be one way with a little rubber flapper. The new Bendix governor that I put on today has the exhaust port wide open.

(09-20-2023 )ktblogistics Wrote:  on picture numer 3 exhaust port is visible but there is something black in it
mostly it is just open straight from box

also on volvo engine you can use shop air on 1.4inch line that goes to air compressor and see if it holds air

tried this on cummins and air escapes fro safety valve on compressor head
do not know if its good or bad but had same situation before with purging every 30sec
unresolved :(

[JHeavy_Hauler]

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