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Ride Height Question


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I just finished adjusting my rear ride height valves because my coach was leaning a bit. After a few adjustments with dumping air and bringing it back to travel height I have it sitting level but I have some discrepancies amongst the air spring dimensions. I realize the target dimension is 9” and I’m not sure how much variation to this number is normal. Here are my current dims.  Not sure what adjustments I could make to get them closer to target.  How much variation to nominal is to be expected?

        Front of coach

  9 1/8”.               9 1/4”

  9 1/2”.               9 1/4”

 

  8 1/2”               9 3/4”

  8 1/2”               9 1/4”

         Rear of coach

 

Thanks for your input  

 

 

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1 hour ago, Chargerman said:

I just finished adjusting my rear ride height valves because my coach was leaning a bit. After a few adjustments with dumping air and bringing it back to travel height I have it sitting level but I have some discrepancies amongst the air spring dimensions. I realize the target dimension is 9” and I’m not sure how much variation to this number is normal. Here are my current dims.  Not sure what adjustments I could make to get them closer to target.  How much variation to nominal is to be expected?

        Front of coach

  9 1/8”.               9 1/4”

  9 1/2”.               9 1/4”

 

  8 1/2”               9 3/4”

  8 1/2”               9 1/4”

         Rear of coach

 

Thanks for your input  

 

 

Are you looking at the ride height measurements or the “dimensions” of the bags/springs?  I think the goal is to get the height correct,not dimensions, using the measuring procedure your manufacture recommends.  Those numbers (front and back) are manufacturers recommended and usually the distance between the top and lower bag plate.

Edited by David White
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2 minutes ago, David White said:

Are you looking at the ride height measurements or the “dimensions” of the bags/springs?  I think the goal is to get the height correct,not dimensions, using the measuring procedure your manufacture recommends.  Those numbers (front and back) are manufacturers recommended and usually the distance between the top and lower bag plate.

Those dims listed are the air spring dims. plate to plate. As mentioned I wondering how much variance from the nominal are to be expected and if my current dims are satisfactory and normal. 

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Yes, that is what I did. Don’t have an issue with that. Thanks for your reply but my questions in my original post remain. 

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I think the big variations you have are not good. As ChuckB said, the adjustments are in 1/8” increments. So apparently that was not done since you’ve ended up with big differences, mainly on the rear.

Edited by David White
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But if I adjust it to increase the 8 1/2” on the left rear it seems like it will increase the dims on the front left.  Do you know how close yours are?

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Mine are within 1/4”, but my front and rear are the same height.  I don’t have # in front of me at this time, but I think it is 9 5/16” on the ‘05 Windsor.  That differs within models. I see one file on this site says yours is 9”.

I think you’ll have to do that and just keep cross setting (left rear to right front, etc) in small increments till you get it close. This means you’ll need to keep playing with front and back. 

Mine has the Firestone Intelliride leveling/ride system, so I make changes with a computer hooked to the cpu.

 

Edited by David White
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11 hours ago, Chargerman said:

I just finished adjusting my rear ride height valves because my coach was leaning a bit. After a few adjustments with dumping air and bringing it back to travel height I have it sitting level but I have some discrepancies amongst the air spring dimensions. I realize the target dimension is 9” and I’m not sure how much variation to this number is normal. Here are my current dims.  Not sure what adjustments I could make to get them closer to target.  How much variation to nominal is to be expected?

        Front of coach

  9 1/8”.               9 1/4”

  9 1/2”.               9 1/4”

  8 1/2”               9 3/4”

  8 1/2”               9 1/4”

         Rear of coach

Thanks for your input 

The rear is the most important adjustment as it will affect the front more than the front affects the rear.  The ride height valves are not extremely accurate and can vary a little.  I find I get better results by driving it to see where it ends up.  I adjust the rear based on the airbag in front of the drives and don't bother checking the other rear bags.  I adjust the front based on which one is easier to measure and ignore the other.  You aren't building a timepiece.

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Thank you Jim   I will follow your suggestions. I did see that the valves are not accurate. I have not touched the front yet. I will adjust the left rear again and take a ride between adjustments 

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When I want to check the accuracy of my ride height I drive over to a location in a parking lot where I have measured how level it actually is and park the coach. Then using my trusty tape measure, I measure from the pavement to the bottom of the belt-line at the center of each four wheel wells, steering and drive axles.

If they are drastically different then the coach goes over to Josam's in Orlando for them to set the ride height correctly.

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Chargerman, do you have one height control valve in the front that controls both sides and two valves in the rear that control either side? I need to adjust mine as I believe I have 9"s in the front and 8"s in the rear. I have one valve in the front so I am not real sure why you have different numbers on the bags in the front. I don't think increasing the rear will effect the front much at all. Based on the geometry and mathematics a slight change over such a long distance on fulcrum points will be tough to notice. I think the biggest thing to consider is the engine/trans to driveshaft and driveshaft to differential angle. U-joints, input shafts and pinion gears all get worked a little hard if those angles are not as they should be. I am in the same boat as you with regards to what is the acceptable tolerances. Is 9" +/- 1/4" within range or is the the 9" a hard number with no +/- acceptable?? My biggest challenge is going to be finding a level spot to work on it. 

 

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Rob

  I do have three ride height valves also. I have not touched the front one yet. I will adjust the left rear one again and focus on the two springs in front of the rear axle as far as rear measurement. Once I have them closer I am also going to check measurements from the belt line to the ground at different points. Lastly I will check the front on both sides and split the difference side to side to get a 9” nominal. 
  I’ve come to think that the variation that I have over all of the Springs is due to manufacturing variation in the many components and sub assemblies within the complex Roadmaster chassis. 

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Nevada Bob hit the nail square on it's head.  The procedure and sequence is very important to adjusting the ride height correctly.  "I think the biggest thing to consider is the engine/trans to driveshaft and driveshaft to differential angle. U-joints, input shafts and pinion gears all get worked a little hard if those angles are not as they should be. I am in the same boat as you with regards to what is the acceptable tolerances. Is 9" +/- 1/4" within range or is the the 9" a hard number with no +/- acceptable??"

I had Josam's adjust my 2004 Windsor.  The first thing they did was to drive the coach onto their adjustment ramp very slow locking the brake peddle to stop the coach.  They then drove the coach to the end of the ramp, stop, put the coach in reverse, let the coach ease backward, and locking the coach brake to a sudden stop.  They repeated that procedure.  That way all components are working freely, not in a bind on the level ramp.  The tech showed me the measurements.  They were spot on.  After that I never had a problem with ride height.  

The tech recommended having the universal joints greased every 3 thousand miles.  He reminded me that there are 2 fitting on each universal joint.  Make sure you see fresh grease coming out of each cup.  If you drop the end of a drive shaft that faces the front of the coach, you will need to have a very thick wallet to cover the damage.

Chuck B 2004 Windsor

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The front ride height valve controls front height of both air springs.  They are plumbed together.  I have to question how you coach can be level is the springs heights are not correct.  If the pavement you are sitting on is indeed level, then the only variable between the level pavement and you coach is the springs.  If they are set correctly, then the coach has to follow.  If one is an inch off, then that side of the coach has to be an inch higher or lower than the pavement which is level.  Now Monaco may set the spring dimensions differently between the front and rear in consideration of design characteristics (steering alignment, drive shaft angle, etc.) 

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The front also has no way to adjust for weight distribution ahead of the drive axle. We assume that the frame is always perfectly straight and there's no flexing which there still is no matter how rigid we like to think it is.

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Rarely is a surface perfectly level or even flat. I would not worry about your fronts being slightly more than 9”… I raised mine to an average of 10” to give the front cap a little more clearance.

You want the rear 2 ride height to be the same… makes no difference if the surface is level. I increased my rears to 10” after cracking the oil pan. 1” is not going to hurt the U joints or the airbags that have 8” of movement…9” is the mid point. 

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2 minutes ago, Ivylog said:

Rarely is a surface perfectly level or even flat. I would not worry about your fronts being slightly more than 9”… I raised mine to an average of 10” to give the front cap a little more clearance.

You want the rear 2 ride height to be the same… makes no difference if the surface is level. I increased my rears to 10” after cracking the oil pan. 1” is not going to hurt the U joints or the airbags that have 8” of movement…9” is the mid point. 

Why do you eat it makes no difference if the surface is level?   Are you saying that weight shifting from one side to the other has no effect on the air bags?  

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Yep, makes no difference. Ride height valve only knows how far it is to the axle and supplies whatever psi it takes to keep the same distance regardless of the weight.

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Posted (edited)

So I followed Jims (Hypoxia) suggestion. Fired up the coach and took it for a short drive. Back in the garage and measured all of the springs again. I am pleasantly surprised that I did not have to touch a valve and all of the springs are within 1/4” of 9” except one on the front the is 9 1/2”. It nice to be on the right side of luck sometimes as I’m usually on the other side. Lesson learned, drive it after any ride height adjustment and then remeasure.

Thanks Jim and everyone who responded!

Edited by Chargerman
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Ivylog is right.   

First off, you will NEVER find a level slab of concrete or asphalt that you could measure within a half inch over this distance.
The l/r tilt of the coach is ENTIRELY controlled by the rear bags, the front just follows the rear as the front bags are all plumbed together, and controlled by one centrally located ride height valve.  This is done to prevent extreme twisting forces on the chassis.  It's basically like a tricycle.

The most accurate way to adjust, is to get on a REASONABLY LEVEL slab, and set the rear bag dimensions to be as equal and close to the desired height as possible.  Generally within 1/4 " is probably as good as you'll get, as the ride height valve likely won't repeat any closer than that anyway.

Then go to the front bags and set the valve so that the average between left and right equals the desired ride height.

The dynamics of these things is not severely affected by cross weights as a car is, and minimizing chassis stress is much more important.

This is also why you never dump the air to the bump stops before lowering your jacks.  The inevitable uneven pavement WILL put huge stress on your chassis, often cracking windshields or affecting slide operation.

 

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