[superbirds]

1975 Newell - Ride Rite rear air spring - Normal pressure

I need to back up a little to explain this. When I picked up this coach I noticed the air pressure on the dash showed around 90 psi after running for several minutes. I found a line that came from under the dash connected to the brake switch "parking plunger" that was leaking or regulating I'm not sure. I found a new one and replaced it now the line maybe a waste pressure release port. Currently it is not leaking or regulating and the line pressure is running around 120-128 psi. I replaced the unit with the same number, also looks identical.
This has caused the rear of the coach to sit higher then it originally did. Looks a little too high to me. 
I can adjust the regulator on the engine mounted belt drive compressor, however it doesn't go much lower then 120 psi. 

This has Firestone air springs quantity = 4.  Two on each side front and rear or the axle mounts. The front suspension is standard leaf springs no air springs. I also plan on inspecting the rear bars/arms the rear air springs and shocks attach to. My thinking was to get it cribbed up with wood blocks and 20 ton jack stands then get up close and personal with the rear axle and air springs.

This coach also does not have a leveling system when parked. They may have used ramps or wood to level it, not sure. I did run across someone selling a hydraulic 4 shock/strut system. Looking underneath I'm not sure how you'd mount it. My crazy idea was to use the rear air springs with a aux 12v air pump. 

I suspect I either need to adjust or replace a pressure regulator for the rear air springs. I've done some searching online, but really have not found anything that gives a range for this setup. I've not called Newell yet. since it's such an old unit, I thought I'd ask here first to see if anyone has any thoughts.

Thanks in advance.

[pairodice]

I would call Newell FIRST... I have been surprise a few times when I talked to the guy that built our coach! This sounds like a leveling valve but not sure which system your coach has - I would assume they are similar... As I recall Newell said the coach should ride about 8 (I think) inches from the bottom of the coach just behind the rear wheels. I don’t think it will hurt anything to be too tall but call them in the morning just to be sure... remember they are closed on Fridays!
Would love to see pictures inside your coach! Hopefully it still has the original orange and brown shag carpeting! :-)

[superbirds]

My coach originally had the red shag. I found it under a number of things - not sure if I still have any laying around I'll look

Here's the discovery from calling Newell

I spoke to one of the Service Managers at the factory. One of the other people on the phone said the guy's around there that worked on these old coaches are pretty much all gone. The Shop Manager really knew quite a bit though.

I've always noticed the left rear side of my coach was lower then the right side. I've thought there was an issue with the suspension level or maybe a part going bad - it turns out they were setup that way by design to account for driving on crowned roads. From what he said it was a late 1970's early 1980's thing. That revelation makes me feel better and is one less thing I need to dig into "unless something turns up under closer inspection".

For my question on the suspension / brake air pressure acceptable range, his thoughts were it should be somewhere between 70psi and 95psi. One this unit both of the systems run at the same pressure. "unless I find a regulator" He thought for this type of rear suspension it was more for height adjustment and to cushion the ride. For my coach I'm going to have to look a little closer at the belt driver compressor's pressure regulator. Once I have that fixed or I may just add a regulator to it with a gauge. Or maybe a regulator to the height adjustment. We'll see how that shakes out. 
The compressor seems to be a pretty standard model so I should be able to find some specifications online. It's also an opportunity to do a little service on it also. Filter - oil - fix the busted weld on the bracket. Shouldn't be too bad other then getting all the parts pulled together.

I also asked about the leveling and my idea of adding a couple Firestone air springs and brackets to the front with an auxiliary compressor. No joy on that idea, oh well looks like I'm back to the plastic bricks and an on-board level system. He suggested the HWH Hydraulic 4 shock/strut system. I had a line on one a while back. Looks like I'll need to look into that again.

He had some good information on leveling the body, I guess the front springs of this era coach are pretty rigid. No surprise since there's at least 6-8 per side. It is one heavy front axle and spring setup. Also a little bouncy when you walk around. That surprised me a little since the springs are so massive. It must just be the right balance. The front and rear height is controlled by the adjust on the height control valves. "Yeah I know - you can call me captain obvious" One per side with the rod attaching to the rear axle. Once I get the pressure where i want it - it may just be perfect - ok, that's probably not realistic - here's hoping.

Anyway good info all around. Thanks very much for the suggestion.
Hope no one fulls asleep reading this - I do tend to prattle on and on.

[HoosierDaddy]

Our 1978 Newell had a similar suspension. It had “BigFoot” hydraulic levelers on each corner. They would lift the coach off the ground.

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Big Foot company is just south of you on 131 at RT.12

[Richard]

I do not have a working knowledge of your coach so take this for what its worth. I am confused a bit by your post. You speak of adjusting pressure in the air bags and also of ride height control valves. Forgive me, but it aint both. If you do have air bags and you do have height contol valves then the hcv automatically adjusts the pressure in the bag to acheive the ride height. All of that assumes you have enough pressure to raise the system. You adjust the ride height by adjusting the distance from the axle to horizontal arm on the hcv.

So before I go down the wrong rabbit hole. Do you have air bags? Do you have height control valves?

[superbirds]

Yes it does have air bags and height valves - after thinking about the pressure affecting the height - you're right that just doesn't make sense if the height control valves are working and adjusted.
If I understand there function, they are a simple centering valve with 3 settings - release - neutral - pressure - determined by the arm attached to the axle. The overall system air pressure should make no difference as long as the valves are working.

Thanks Richard for getting me on the right path. I'm in way too many rabbit holes.

[Richard]

Cool!

The one watchout, and there seems to be a rash of it this year, is that the rear aair bags on the later coaches require about 110 or more psi to “float” the coach so if your overall system pressure is too low then even though the hcv is calling for more pressure the valve cannot deliver what is not there