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Topic: Ride Height Adjustment and Air brake pressures. (Read 644 times) previous topic - next topic

Ride Height Adjustment and Air brake pressures.

I have a two part question here, and I apologize if these should be in 2 different topics.

1. I have read tons on adjusting the ride height and looked at everything from the Beam topics to scrolling through the Forum on this. Maybe I missed it but nowhere that I can find does it state which clamp (upper in red, lower in yellow) requires loosing to adjust the ride height. Is it a combination of the 2 or just one...if so which one?  Also do you adjust the ride height with it in travel (flat surface of course) with the engine running?  About the front adjustment now. It is near impossible to crawl under my coach to adjust the front ride height unless I use blocks. I do not think you are to block up your coach to adjust ride height...Am I  correct?
2. When I start my engine and let the air brakes "come to life" they start at about 50-60 and the air "popoff" when the back is at 128  and the front is about 122. It takes about 3 minutes at fast idle to get to that point. First off, is that time frame ok for getting to proper brake pressure and secondly is it ok that they are not PERFECTLY aligned on pressure indications?
Peter    Alberta Canada
'98 U320 40'  Build 5359 M11 450 HP, Aqua hot, Blu Ox

Re: Ride Height Adjustment and Air brake pressures.

Reply #1 –
I do my adjustments using the bottom one but I don't think it makes any
difference. The difference in the air pressure could be the gages and the
time it gets to pressure is fine.
Peter and Frieda Morin
1999 36ft. U320 Foretravel
Build # 5436
1998 Suzuki Sidekick Sport

Re: Ride Height Adjustment and Air brake pressures.

Reply #2 –
dicksop
the only way I know to adjust the front ride height is to
block the coach up and adjust by trial and error, unless
you can get it over a pit.

Re: Ride Height Adjustment and Air brake pressures.

Reply #3 –
Thanks for the info. So I do these adjustments with the engine running?  And does anyone have the issues that I do about crawling under the front of the coach to do the front ride height?  Unless the coach is raised there are issues with getting under it to adjust
Peter    Alberta Canada
'98 U320 40'  Build 5359 M11 450 HP, Aqua hot, Blu Ox

Re: Ride Height Adjustment and Air brake pressures.

Reply #4 –
 I replied before I saw your answer Wayne  So I block the coach then adjust then take the blocks off the coach  return the coach to travel then check and repeat if it needs more adjustment?  Seems like a pita
Peter    Alberta Canada
'98 U320 40'  Build 5359 M11 450 HP, Aqua hot, Blu Ox

Re: Ride Height Adjustment and Air brake pressures.

Reply #5 –
dicksop
it is a pita, but don't go under coach without blocking.
but at least the back ones are easy, no blocking required

Re: Ride Height Adjustment and Air brake pressures.

Reply #6 –
Wayne,

Just to clarify - the engine doesn't need to be running while you are adjusting the linkage.  Just needs to be running to check to see if your adjustment had the desired effect.

Check ride height, start engine, raise coach, insert blocks, shut off engine (if you wish), make linkage adjustment, start engine, remove blocks, check ride height.  Rinse and repeat.  Yes - pita.

Getting squashed under the coach - BIGGER PITA.

When the air dryer "pops off" (compressor unloads) - at that instant - your entire air system is at the same identical pressure.  If, at that moment, your gauges read slightly different then as stated above it is a error in the gauges.

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: Ride Height Adjustment and Air brake pressures.

Reply #7 –
Quote from: Chuck & Jeannie –
Wayne,

Just to clarify - the engine doesn't need to be running while you are adjusting the linkage.  Just needs to be running to check to see if your adjustment had the desired effect.

Check ride height, start engine, raise coach, insert blocks, shut off engine (if you wish), make linkage adjustment, start engine, remove blocks, check ride height.  Rinse and repeat.  Yes - pita.

Getting squashed under the coach - BIGGER PITA.

When the air dryer "pops off" (compressor unloads) - at that instant - your entire air system is at the same identical pressure.  If, at that moment, your gauges read slightly different then as stated above it is a error in the gauges.




Only thing I will add to this excellent description  is that there is another way to safely do the front-- you can drive the front up on boards (I use 2X12's stacked one on top of the other).  That gives ME safety room.  Let all the air out before going under to verify that YOU would have room. Yes, a little better if you adjust the fronts by this method to be on a very slight slope down in front, so that when the front is on boards you are back to level.
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: Ride Height Adjustment and Air brake pressures.

Reply #8 –
Best place to set ride height is in a FLAT surface parking lot. Coach doesn't need to be level, but that's a plus, just needs to be flat. ie : all wheels on the same plane as if you were going down the highway, level or not. 😎
Justin & Cathy Byrd
1995 U280 "Old Faithful"
36' Build #4673
C8.3 Cummins
Allison MD3060R 6 speed - retarder
Powertech 10KW  4cyl Kubota

Re: Ride Height Adjustment and Air brake pressures.

Reply #9 –
I don't mean to hijack this thread, but I've been struggling with this ride-height concept. There are 4 air bags in the front of the coach, 2 left and 2 right. The measurement of all four bags is different.
On either side of the coach, the bags in front of the wheel do not measure the same as the bags behind the wheel. Is this normal, and which should I be using?
Also, the measurement(s) on the driver side of the coach are never the same as those on the passenger side. One side is often an inch higher than the other. What causes this, and how do you deal with this when there is only one ride-height adjustment?
1998 U295 36' No slides
Towing 2018 Jeep Wrangler
Previous rigs:
  1995 26' Fleetwood Flair
  1998 34' Fleetwood Bounder
  1997 40' Bluebird BMC
  1999 24' Winnebago Minnie Class C

Re: Ride Height Adjustment and Air brake pressures.

Reply #10 –
Quote from: Dan & Annie –
...the measurement(s) on the driver side of the coach are never the same as those on the passenger side. One side is often an inch higher than the other...how do you deal with this when there is only one ride-height adjustment?
Actually, there are three ride height adjustments.  Two in back - one in front.

You deal with one side higher than the other by adjusting the rear ride height valves. Either raise the low corner or lower the high corner - whichever is required to make both side close to the desired ride height.

The front adjustment must cover both corners, so it is sometimes a compromise.  Get it as close as you can, and move on to more pressing matters.

Proper Travel Height for a 1997 U295

Ride Height Adjustment

Ride height

Ride height valve ??








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"