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Topic: Ride Height Valve or D2? (Read 722 times) previous topic - next topic

Ride Height Valve or D2?

1st.......would it be unusual for the compressor to run up to cut out pressure of 110 and then decrease to cut in of 90 within 3 miles continuously? It takes about 5 minutes to air up from 30 lbs. I find no noticeable leaks while leveled, engine off, although it has always leaked down in a few days. This has not changed. I'm looking at either the D2 governor or a height valve leak while driving. Any other suggestions? The air dryer is only a few years old.

Re: Ride Height Valve or D2?

Reply #1 –
What you describe is not like any d-2 failures I have had. It is kicking in and kicking out correctly. It must be an air leak that is only there with ignition on. Have you tried to leave the ignition on and see if you can hear any leaks? Thinking step cyl. or step cover cyl. or as you say ride height system.

Re: Ride Height Valve or D2?

Reply #2 –
Check for air leaks with wheel chocks and spring brakes off, could be a bad brake can diaphragm.

Re: Ride Height Valve or D2?

Reply #3 –
You might try building air then shutting the motor off, chock the wheels release the parking brake with the key on and see what you hear. Could be a parking brake pancake ( can) leaking also. Be leaving the key on the hwh thinks is going down the road.

Re: Ride Height Valve or D2?

Reply #4 –
Bruce hit on what I have had happen on the truck cranes. The diaphragm to release the spring brake was blown.

Re: Ride Height Valve or D2?

Reply #5 –
Quote from: craneman –
Bruce hit on what I have had happen on the truck cranes. The diaphragm to release the spring brake was blown.
Would this not cause the parking brake fail? It works fine. I will, however, go over the brake system. Just waiting for everyone in the park to wake up to run the engine.

Re: Ride Height Valve or D2?

Reply #6 –
Parking brake works when air pressure is removed( when you pull the button) then the spring applies the brake. The air pressure holds the brake in the off position, until the leak where to get big enough that the compressor can't keep up. One othe thing if you have a air tank drain check and make sure it didn't get bumped partially open. . I've had that happen.

Re: Ride Height Valve or D2?

Reply #7 –
Update: Thanks Bruce. I knew that. But it turns out to be the right rear height valve. The conundrum.........with 110 lbs of air there was no hissing from the valve, BUT, when I applied the "raise rear" button to go underneath I could hear the distinct leak. Thing is.....it only leaked for the time it took me to walk to the rear then stopped and I'm assuming the right rear dropped to ride height. So I'm not sure if it would be the valve or a solenoid. Anybody know how to isolate them for test?

Re: Ride Height Valve or D2?

Reply #8 –
Quote from: Twig –
So I'm not sure if it would be the valve or a solenoid. Anybody know how to isolate them for test?

Maybe swap the solenoid on the 6 pack with one of the others?

Re: Ride Height Valve or D2?

Reply #9 –
Update #2. Problem possibly solved. Removed the pass side ride height valve. Found that the cover was missing and looked as if the thingy that makes the piston go up and down would not turn so I'm buying a new one and save this for a spare once cleaned up. Check your ride height valve covers people. And thanks Bruce and Craneman. I got to check my brake system at the same time. I'm in Matzatlan and it's CARNAVAL time so I won't know the results of the cut in/out situation 8)  ^.^d  for a month when I leave.

Re: Ride Height Valve or D2?

Reply #10 –
Quote from: Twig –
Update #2. Problem possibly solved. Removed the pass side ride height valve. Found that the cover was missing and looked as if the thingy that makes the piston go up and down would not turn so I'm buying a new one and save this for a spare once cleaned up. Check your ride height valve covers people. And thanks Bruce and Craneman. I got to check my brake system at the same time. I'm in Matzatlan and it's CARNAVAL time so I won't know the results of the cut in/out situation 8)  ^.^d  for a month when I leave.

I had the same issue last year near Pittsburgh......lost the front Level valve......scary stuff on the side of the road....Police diverted traffic for 2 hours to get around me..

Re: Ride Height Valve or D2?

Reply #11 –
Just replaced all three of my covers. Found new ones on the net. Old were starting to crack but not letting dirt in yet!

Re: Ride Height Valve or D2?

Reply #12 –
Twig,I would consider redoing the air drier for good measure if it's been,a few years.

Re: Ride Height Valve or D2?

Reply #13 –
When my front ride height valve, got it replaced.  Then had the others replaced as they were all original.  Went through the whole system also, replaced some leaking check valves and had the air dryer serviced- it had been about 18 months since the last service.

Coach ran great on our last cross country run and the new owner has a good air system on the coach that should last a long time.

Be safe and cya down the road........................ ^.^d

Re: Ride Height Valve or D2?

Reply #14 –
Quote from: Hans&Marjet –
I had the same issue last year near Pittsburgh......lost the front Level valve......scary stuff on the side of the road....Police diverted traffic for 2 hours to get around me..

... everyone should know the workaround losing a leveling valve. Manually leveling and pulling the 7.5 amp travel height  fuse in hwh box, back on the road in the matter of minutes.

Re: Ride Height Valve or D2?

Reply #15 –
Quote from: John44 –
Twig,I would consider redoing the air drier for good measure if it's been,a few years.
With 20K miles on it? Not a chance. I put it on brand spanking new. The original lasted 20 years. They were built for the trucking industry which drive about 125K a year.
 

Re: Ride Height Valve or D2?

Reply #16 –
Quote from: Twig –
With 20K miles on it? Not a chance. I put it on brand spanking new. The original lasted 20 years. They were built for the trucking industry which drive about 125K a year.

Another Haldex air dryer failure

One of several topics that outline what can happen if you don't maintain the air dryer...

By re-doing, one means changing out the guts periodically to make sure you don't end up with desiccant everywhere.