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Another ride height troubleshooting question.

Yahoo Message Number: 63566
I know that we have cussed and discussed this topic many time over the past 8 years and now I have another.
On our way south on I-74 from the Escapades our front end started to bound violently up and down without any notice. Any time I got above 50 MPH it started to bounce again. I'm sure the pneumatic ride height (RH) system is at fault but upon close visual inspection of the RH valve, hoses, linkage I cannot see any evidence of a problem. I have used the HWH system to elevate the front end as high as it will go to allow me to crawl under to take a look. This indicates that the air bags are holding pressure and that the leveling system is OK (maybe). I have not taken anything apart yet for fear that I will allow the front end to fall on me. I know they come down fast when the valve is opened and I really don't need any broken bones.
My suspension system has one RH valve at the rear of the wishbone front suspension. The valve actuator is operated by a steel channel arm U-bolted vertically to the sway bar rod. When the chassis moves up and down this arm swings forward and backward and linkage from the RH valve to this arm makes the RH valve open and close. since this arm is anchored to the sway bar by only one U-bolt I'm wondering if maybe a stone or other debris on the road could have jumped up and hit the bottom end of the arm and knocked it backward. Only a few degrees of movement of this arm would have a big effect on the RH adjustment.
Can any of you guys offer advice on how to troubleshoot this issue to determine the cause and the remedy? TIA

Larry

2000 Allure 30485

Re: Another ride height troubleshooting question.

Reply #1 –
Yahoo Message Number: 63587

Larry,

This is mostly guesswork but here goes.
When our ride height valve failed it would either drop the coach all the way down or raise it to the stops - nothing in between could be held. At the top most position the coach would bounce over the slightest road defect to the point the front wheels would leave the pavement on things like bridge expansion joints.
It sounds like the RHCV might have failed and is moving to extreme ends of adjustment rapidly. If the interior valving of the controller is directing air to raise or lower the coach and can't stop before reaching the extreme that would do it. I don't know if a valve can fail that way that would do it.
You have HWH ride correct? I had it on an Intrigue and it reacts much faster than the RHCV so it might be an HWH problem. You say the change is violent, I don't think the RHCV can act that fast. Not sure the HWH can either but it is quicker.
Another possibility - in a recent Motrohome magazine tech reply plus an experience we had with our engine, fuel supply problems can cause rapid loss and gain of power. It will make the coach feel like it is jumping up and down. John Davis while at Buddy Gregg for CC drove our coach and had never experienced anything like it. It was hard to believe it was the engine but it was. The facf this happens above 50 might be a clue. I am not exaggerating, the coach actually felt like it bouncing up and down even though the cause was at the rear it affected the whole coach.

Shutting on and off 1,000 ft lbs of torque can get your attention.

Bob (rthandren@...)
'05 Inspire 51178

Re: Another ride height troubleshooting question.

Reply #2 –
Yahoo Message Number: 63606
Thanks for the response Bob.

When we stopped for inspection the front suspension was completely in the down position. We were only about 20 miles from home so I decided to bring the rig home even with the front end all the way down. I knew I would have to be very cautious about turns and the front tires hitting the wheel wells. We made it just fine.
I have posted a few pictures of the RHCV here in the Photos section in the Barefoot Beatnik album. As you can see, the arm that is attached to the anti-sway bar is not vertical. I have a strong suspicion that this has something to do with the problem. I also know that these RH control valves take severe punishment under normal driving conditions and that they are prone to failure.

I'm going to dig into it more tomorrow.

Re: Another ride height troubleshooting question.

Reply #3 –
Yahoo Message Number: 63616
I doubt the ride height valves are the issue. First, they have no idea of what speed the coach is moving, second, due to the dampening orifices in the valves they cannot change height very fast. If the ride height valve adjustment was moved by a rock it would stay off, not vary. The issue is more likely a result of the road, tires, etc than the ride height valve(s). Does the coach exhibit this on other roads, or was it a one time happening?

Mikee

Re: Another ride height troubleshooting question.

Reply #4 –
Yahoo Message Number: 63623

Looking at the pictures and assuming you are in 'travel' mode.
1) The most obvious thing is the ride valve has failed.
2) A possibility (though remote) is the solenoid valve that controls the air flow between 'travel' and 'HWH leveling' could have failed. When in 'level' mode the ride valves are isolated from the air bags.
If you can raise the coach in 'level' mode and then switch to travel and the bags deflated then I would think the ride valve is shot. It has lost it's ability to 'see' the position arm.

Dave

aka Billy Byte (trusty hound)
2000 Allure #30443

Re: Another ride height troubleshooting question.

Reply #5 –
Yahoo Message Number: 63624
Your ride height valve is shot. There is a very small plastic pin on the inside that shears off making the valve useless. It is a very poor design in my opinion.
I think you did something really dumb here by inflating the bags and crawling under the coach with a failed component involved. Something could have happened and you would be stuck under there possibly killed.

Don

'02 Intrigue #11427
'02 Intrigue #11427

Re: Another ride height troubleshooting question.

Reply #6 –
Yahoo Message Number: 63629
Mikee - I'm sorry if I gave the impression that I thought the valve was causing the bounding or porpoising. I'm sure the front air bags had totally collapsed and I was bouncing off the bumpers inside the airbags. What I guess I should have said is that I think the bouncing was an indirect result of the valve failure.
The local NAPA store will have a new valve for me in the morning and I can give it a try tomorrow.
The specification for my front end ride height is 9.0" bag height. I think I will adjust my bags to about 9.5" to see if I can eliminate or reduce the bottoming-out effect on big bumps. I'll let you guys know of my success or failure.

Larry

2000 Allure 30485

Re: Another ride height troubleshooting question.

Reply #7 –
Yahoo Message Number: 63641
Larry:

I am not certain if your problem has started as a result of replacing the ride height valve, removal and replacement of the same valve, or just failure as some have reasonably indicated..............but When installing these little jewels one must rember that they are handed.
I learned the hard way. The coach would rise to the top and not adjust.
After working with HWH I learned my error and was told the coach could have dropped under some cercumstances with my incorrect handing.

It is covered by the instructions that come with the new valve. one advise given to me by HWH, if you are working the rear do both not just one.
Hope this is of some value.

James M. Green "Rollingghetto" 119,000+ miles 2000 intrigue 11021
 

Re: Another ride height troubleshooting question.

Reply #8 –
Yahoo Message Number: 63660
Well the new valve is in place(NAPA #KN27000 $100.00), the air bag height is adjusted to 9.5" and everything seems to be working perfectly. The ride is smooth and level. I'll have to wait until I get into some serious bumps or RR tracks to see if the new setting of 9.5" does anything to reduce the bottoming out issue.
The replacement valve from Haldex (the original valve is no longer manufactured) is a simple bolt-on replacement which is fairly simple to do. The new valve has a plastic body opposed to the cast aluminum original. It is a metric size and the original 3/8" mounting bolts must be replaced with M8x2.25" bolts. And, of course, I had to drive all over creation to find a hardware store and pay an outrageous price for two stinking metric bolts and nuts. The original 3/8" bolts will not fit through the mounting holes in the new valve. Bummer!
The final ride height adjustment is very simple to accomplish by loosening the U-bolt on the ride height actuator arm and tapping on it to either raise or lower the coach.
I guess all is well that ends well :-) Thanks everyone. Now it's time to hold our breath until the next thing breaks down.

Larry

2000 Allure 30485