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Topic: Air Suspension Pressure regulator (Read 4186 times) previous topic - next topic

Re: Air Suspension Pressure regulator

Reply #25 –
oldguy
hot water bypass only on non aquahot coaches. it diverts engine
heated water to dash or can route it through hot water tank for
over the road hot water.

Re: Air Suspension Pressure regulator

Reply #26 –
Front air bags support less weight than the rear air bags. Could this be the reason for the front air pressure regulator?

Re: Air Suspension Pressure regulator

Reply #27 –
It does not affect the ride height, just the leveling function. I turned it up a little yesterday and for the first time the 12" safety tubes go in the front without me having to tilt the coach to get the right front tubes in.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Air Suspension Pressure regulator

Reply #28 –
Craneman, thinking about it some more, I guess if you increase air pressure it will only effect how fast either end goes up until some valve shuts off the air source.
In level mode air in is controlled by the raise solenoid valve that is controlled by the level sensor and HWH computer, or manual raise buttons.
In travel I think the air goes into the airbag through the open travel solenoid and ride height control valve which will shut of air flow at travel height.
So I guess you just need enough air pressure to lift the coach at any weight up to travel height. More pressure with just make it happen faster.
John Duld
1995 U320C SE 40'

Re: Air Suspension Pressure regulator

Reply #29 –
No, the added pressure raises the bag to the max extend, not ride height. This is only in the manual raise function to put the safety stands in. It has nothing to do with ride height that air is supplied by the ride height valve only.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Air Suspension Pressure regulator

Reply #30 –
so before this thread fades away, are we all in agreement that the
only function of the pressure regulator under discussion is so that
both ends of the coach rise to ride height at the same speed, and it's
removal will cause no harm?

Re: Air Suspension Pressure regulator

Reply #31 –
Wayne,
I'm looking at the HWH repair manual for the 600 series system.
Page MP75.4510 dated 25 July '97 is the schematic i'm looking at.
It looks like front brake tank pressure goes to the ride height c/v for the front and rear brake tank pressure goes to the rear ride height c/v's.
Looks like regulated pressure only goes to the front level system raise solenoids.
So, to me it appears removing the regulator will only effect how fast the front airbags will inflate in the level mode(both in automatic level and with the manual raise buttons) and have no effect on travel mode.
Take a look at the schematic to confirm that.
So if i'm reading the schematic right, why would anyone care how fast the front goes up in the level mode?
John Duld
1995 U320C SE 40'

Re: Air Suspension Pressure regulator

Reply #32 –
Quote from: John Duld –
Wayne,
I'm looking at the HWH repair manual for the 600 series system.
Page MP75.4510 dated 25 July '97 is the schematic i'm looking at.
It looks like front brake tank pressure goes to the ride height c/v for the front and rear brake tank pressure goes to the rear ride height c/v's.
Looks like regulated pressure only goes to the front level system raise solenoids.
So, to me it appears removing the regulator will only effect how fast the front airbags will inflate in the level mode(both in automatic level and with the manual raise buttons) and have no effect on travel height inflation speed.
Take a look at the schematic to confirm that.
It not only affects the speed it also affects how much inflation is in the bag. When I added 5 psi. my front bags extended farther than they did before. I don't know if having 120 psi would cause any damage as the bag would be really extended.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Air Suspension Pressure regulator

Reply #33 –
Quote from: craneman –
It not only affects the speed it also affects how much inflation is in the bag. When I added 5 psi. my front bags extended farther than they did before. I don't know if having 120 psi would cause any damage as the bag would be really extended.

To be clear, this is when leveling/manually adjusting, as the RIDE HEIGHT VALVES determine air to the bags when in travel mode.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Air Suspension Pressure regulator

Reply #34 –
Quote from: craneman –
It not only affects the speed it also affects how much inflation is in the bag. When I added 5 psi. my front bags extended farther than they did before. I don't know if having 120 psi would cause any damage as the bag would be really extended.
I don't see how increasing the air pressure to the front bags could cause any damage.  The same exact bags are used front and rear.  The rear bag pressure is unregulated, and regularly sees full system pressure.

The bags can only extend so far.  If they can be fully extended with 60 PSI pressure, then they aren't going to extend any further with 120 PSI pressure.

I personally agree with Wayne's statement (above).  However, I hesitate to flat out declare that removing the regulator is a good idea.  I'll let somebody else try it first, and wait for the report on what happens.

1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Air Suspension Pressure regulator

Reply #35 –
My front bags were not fully extended with 65 psi. I raised it to 70 psi. and gained one inch which let my 12" stands go in without having to tilt the coach each time to get the front right stand in. I don't think this is as much a psi. rating for the bags, but a stretch limiting issue. The weight on the rear probably stops the bags from extending to the stretch limit while the front weight needs less pressure to keep from overextending. The gauge was put there for something and my guess is as good as any other explanation. The speed was never an issue in my opinion.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Air Suspension Pressure regulator

Reply #36 –
When I use the "RAISE" function to jack our coach up so I can insert the 12" safety stands, the coach is as high as it can get.  There are mechanical limits to how high the coach can go, and how much the bags can extend.  My bags, front and rear, are all extended to their limits when the coach is fully raised.  The rear bags reach this limit with full system air pressure of around 120 PSI.  The front bags reach this limit with 60 PSI.

On my coach, the front bags will fully extend up against the mechanical limits with the regulator set at 60 PSI.  The front bags would not be "stretched" any further at 120 PSI than they are at 60 PSI.

I don't know why the regulator is there, but like I said, I'm not willing to remove it...for exactly that reason.

1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Air Suspension Pressure regulator

Reply #37 –
Ok Chuck,
If there is an up structural limit(stop) then the only other thing is how much pressure is to much. If the rear bags can take 120 psi then why wouldn't the front ones handle that also?
With less weight on the front wouldn't it just push up harder on that up limit? Still only 120 psi  in the bag. 
At normal travel height when you hit a hard bump that bottoms out the suspension I wonder what that compressed air bag pressure is then?
My coach had that regulator and if it failed I probably would have replaced it just because that's the way it was built.

John Duld
1995 U320C SE 40'