[Gem930]

Pic with part number.

[cwl1979]

Might I ask what prompted this air bag investigation? From the for sale post on this site they were recently replaced by the previous owner.

[Gem930]

Oops….. here it is

[Gem930]

Not sure why the pic won’t post but the part number is Goodyear  1R11.066.  

To answer the last question …. I was trying to get the ride height correct after replacing the left side rear height control valve.

[cwl1979]

Not sure why the pic won’t post but the part number is Goodyear  1R11.066.  

To answer the last question …. I was trying to get the ride height correct after replacing the left side rear height control valve.

Ah, Ok, in that case then yes 11.75 is all your going to get out of those airbags. They are almost 1 inch shorter than the Firestone equivalent.

[Gem930]

so does that mean I should set the ride height closer to 11 inches so that there is less air in the bags and perhaps a better ride quality?

Thx for the information, by the way! 

[email protected]

[cwl1979]

Ride quality is actually determined by a combination of shocks, air bags, HCV. Setting the rod height to only have 11 inches of clearance might feel softer but its actually more damaging to components. Same as setting it to high. I only say this as i was an auto transport driver and we had 2 trucks custom built for Alaska use. A lot of engineering goes into setting ride height. Ride height also plays a major role in determining drive line angles. Getting U joints into a bind in some cases. Other times wearing a pinion gear or seal far faster than they should. If you're really looking for a more rapid reaction from the suspension and airbags there are ways. First i would determine the type of HCV you have, standard action or rapid? Because these systems use 4 bags per axle and 2 on the tag you can install quick relief valves in line as well. What these do is... when a tire hits a bump it flexes the airbag bellows and sends the pressurized air (typically) into the next airbag. The quick relief allows this air to be discharged from the system instead. Resulting in a smoother ride feel. Newell uses "ping" tanks to accomplish basically the same thing. Rapid response HCV is also necessary for either of these designs to work properly. The link is the HCV that almost all Alaskan commercial trucks have installed. https://daytonairsuspension.com/products...e-50860014

By replacing the 2 HCV's on the drive axle and the 1 on the steer axle in combination with the Newell ping tank system would be the way i would go. They do require 3/8ths air line as well, they move a ton of air quickly.

From the previous owner they mention upgraded shocks already. Road kings are nice.

[Gem930]

Thank you for the reply. 

I have road king shocks and felt the ride was great, particularly compared to my last two coaches.  The issue arised when the left rear HCV failed.  I replaced it and when I was trying to set the height to 12” realized I could not get it above 11.75.  I disconnected the rod that connects the HCV to the axle and held it up by hand for quite a while.  11.75 was max height it would do.  Ok then a previous  poster stated the new Goodyear bags (1R11.066) were and inch shorter than the original Firestone bags and 11.75 was all I was going to get.  I’m fine with that , but was concerned running them max out to get to 11.75 might degrade ride quality.   NOW…. Just to further complicate the issue I ran the engine at fast idle and held the “raise “ button on the HWH for a while so I could get under the coach to purge tanks of water.  Interesting enough I was able to get just over 13” of height?????? After draining the tanks I dumped all the air, hit travel mode and now I’m at just over 12”???? Hmmmmmm!?!?  I’m going to take it for a ride and let it bounce around a bit and settle and then hit travel mode and remeasure.

[Richard]

Greg,

I am sorry for my late reply. Your leak rate, although excessive is not a blown seal. With a blown seal you can not build enough pressure to flush the potty.

I was going to suggest that you try the all raise button. I am glad you did because that eliminates the air bags and seized suspension as culprits.

You have isolated the problem to one of two areas. The first is the HCV, the second may be a stuck travel solenoid.

As Carl said Newell used ping tanks which add air volume to the spring system but slow down the response time. Also, some HCVs have slower response than others. I use the king of the road valves from Dayton which have a very slow response but tight tolerance.

Here is a trick that will save you many trial and error headaches. Because the HCVs have some freeplay or hysterisis in them you can get varying ride heights. The best technique when measuring ride height is to lower the coach below travel height and then put the coach in travel mode and let it raise to travel. You will get consistent results doing this. If you raise the coach to gain access, and put it in travel to check ride height you will get inconsistent results.

[Gem930]

Well I found one leak.  The Parker valve that was installed to switch between the vacuum pump to suck the slide seal down and inflate it had a piece of Teflon tape jammed in it and was leaking pressure into the vacuum pump.  Enough that it actually blew the pump apart.  Still muddling through all this….. I’ll report back!