Community Forums

Stonefish · 05-12-2022, 02:48 AM

The more I dive into our new to us coach, the more I find I either want to change or find a potential issue as I did yesterday. I was changing out all the stop, tail, turn, reverse bulbs out to LED, easy enough job, after finishing up and before buttoning things up I had the DW sit in the coach and operate all the functions pertaining to the lights, all good, I then wanted her to see the difference from the old and when I applied the brakes both front and rear low air alarms came on. Thinking just low on air from applying the brakes a half dozen times I started up the coach and let the air build up, shut it down, and went back to button up the lights and could hear a slight, but definite hiss of air. Checked all visible air lines and dump ball valves with soapy water, nothing.
I put the coach in travel mode, shut off the engine and could hear absolutely no leak. Leveled the coach back out, leak was back. I realize that is very little to go on, but just curious if anyone has experienced that scenario? The leak is most audible from the engine compartment, but that is not saying crawling under the coach that the leak would be louder, because I have not been under it. Compressor bleeding off? (because nothing when in travel mode, and pressured up?)

Thanks,
Stone

Ray,IN · 05-12-2022, 09:00 AM

How long since the air dryer unit has been serviced? For a part-time use MH it should be serviced every 3-4 years. Daily use, like semi-tractor, annually.
What happens is, the internal valves get oil/water mixture gunk on them and become sticky. If the desiccant filter gets full of oil it cannot separate water and oil out of the compressed air, which contaminates the entire compressed air system, most importantly possibly affecting braking ability.

sbeers · 05-22-2022, 01:12 PM

I would check the 6 packs next. There should be 3, one for each axle. Also see if the front or rear drops when the air is leaking, to help narrow down the area.

Stonefish · 05-23-2022, 03:23 AM

Quote:

Originally Posted by Ray,IN

How long since the air dryer unit has been serviced? For a part-time use MH it should be serviced every 3-4 years. Daily use, like semi-tractor, annually.
What happens is, the internal valves get oil/water mixture gunk on them and become sticky. If the desiccant filter gets full of oil it cannot separate water and oil out of the compressed air, which contaminates the entire compressed air system, most importantly possibly affecting braking ability.

I'm completely leaning towards the air dryer...thanks. Now if I can get my eyes on it for ID purposes.

funjnt · 05-23-2022, 05:36 AM

Air dryer would have air pressure at all times. The air dryer receives air supply from the compressor and then it goes to the tanks. This removes the moisture straight from the source. I would drive coach up on some 6x6 (safety first) as these coaches ride low. Then activate the leveling system to manual so it isn't trying to level on the blocks. This will bypass the coach ride height valves and apply pressure to the leveling system. This should give you your air leak back. Try to isolate it this way. And yes there are the 6 pack of valves and some axles have one or two depending on location.

a250gpguy · 05-23-2022, 11:16 AM

Quote:

Originally Posted by sbeers

I would check the 6 packs next. There should be 3, one for each axle. Also see if the front or rear drops when the air is leaking, to help narrow down the area.

I too am leaning towards the 6 pack solenoids.

When we were stranded last year with the PTO break I also had this condition that the OP was describing. Over a short time our coach would become unlevel towards the rear of the coach especially requiring frequent relevelling of the coach.

This spring we replaced ALL of the 6 pack solenoids on the coach and although we have some different behavior than before that doesnt seem to affect the coach negatively, we no longer have the leak down condition the OP describes. The coach holds air and it's level for days on end...the autocycle compressor also now only runs very infrequently.

YMMV
Chris and Nadia
CC Magna #6503

a250gpguy · 05-28-2022, 02:17 AM

Any updates OP?

Stonefish · 05-28-2022, 04:33 PM

Yes, just yesterday as a matter of fact. I found that a stainless braided air line from governor to air dryer that ran parallel with a return hydraulic line with a hose clamp had rubbed a hole in line. Very small hole that I could run my finger over and hear a difference in air pressure, also air dryer purged while I was spraying soapy water on lines and blew water everywhere, not good, aaannnddd fitting on rear of compressor was leaking, so now I have my work lined out for me. Local Cat dealer can make a new braided line,local fleet pride store has the ADIP dryer assembly in stock, and I believe by tightening the fitting on the back of compressor solved that issue. Lot of cussing involved, but what to ya do.

Stone

a250gpguy · 05-30-2022, 12:01 AM

Quote:

Originally Posted by Stonefish

Yes, just yesterday as a matter of fact. I found that a stainless braided air line from governor to air dryer that ran parallel with a return hydraulic line with a hose clamp had rubbed a hole in line. Very small hole that I could run my finger over and hear a difference in air pressure, also air dryer purged while I was spraying soapy water on lines and blew water everywhere, not good, aaannnddd fitting on rear of compressor was leaking, so now I have my work lined out for me. Local Cat dealer can make a new braided line,local fleet pride store has the ADIP dryer assembly in stock, and I believe by tightening the fitting on the back of compressor solved that issue. Lot of cussing involved, but what to ya do.

Stone

I asked a rather shady lady once how she walked all night in super tall heels....her response was classic:

"I just keep putting one foot in front of the other baby"....

Seems these oldie but goodie coaches are like that...

Ch