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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: Lin on October 28, 2012, 09:55:45 AM

Title: Leveling System Pics for Feedback
Post by: Lin on October 28, 2012, 09:55:45 AM
At the risk of inviting ridicule and derision, I am posting a couple of pictures in the hope that feedback may save me from some seriously dangerous issue I have overlooked.

Obviously, this is the leveling valve side.  The cable is 3/16" and seems strong enough to remain rigid.  It has about 2.5+ inches of travel up and down. This is the front.  The rear ones are soon to follow.

This is the control side. A small bolt attached to the end of the cable slips into a hole in the flat piece above to secure it in the neutral position for travel.  The bolt will get a wing nut.  This is located in a small cabinet in the left side of the entry stairs where the door closing cylinder used to be.

Title: Re: Leveling System Pics for Feedback
Post by: TomC on October 28, 2012, 10:12:27 AM
It is a novel idea for leveling. My first impression is that the tremendous up and down movement on the suspension will cause the cable to either kink or move while in motion.  Not my vote as to the best way of doing this.

Sean has a similar way of leveling his bus.  But he uses electric actuators that are the screw type-so the vibration of the road does not affect the height.  Then, just a flick of the up or down switch and he is level. You may want to explore changing to electric actuators instead of your cable system.  Good Luck, TomC

Title: Re: Leveling System Pics for Feedback
Post by: chessie4905 on October 28, 2012, 11:17:50 AM
Unless I'm seeing it wrong, you need to clamp the cable at the same location as the valve itself. Otherwise, the body movement will move the lever, which you only want to move with the cable??

Title: Re: Leveling System Pics for Feedback
Post by: Lin on October 28, 2012, 11:55:36 AM
Tom, I guess there is a question of whether the cable is strong enough, but it does seem that the lever does not take much force.  Although I would like to have come up with the idea, I got it from one of Bob G's posts.  I have not seen a picture of how he did it, but since he said he used a hinge somewhere, it must be a bit different.  There are cables that have the open cable encased in steel, which would make it a lot stronger though.

Chessie, The body movement does move the level, but the valves have a delay so they will not respond unless the lever position change is maintained as in added/reduced passenger load in the buses original use.  By changing the distance between the attachment point and the lever the idea is to "fool" the system into raising of lowering the cabin.  It could be done as you say using the valve to directly raise/lower the cabin since the original leveling system does not have much purpose in our use.  The only issue there is returning to the neutral position for travel.  In this method, adjusting the cable to the desired length returns the coach to its ride height.  If the cable raised/lowered the coach directly, it would require measuring or some other method to get back to the travel position.  Am I understanding correctly?

Title: Re: Leveling System Pics for Feedback
Post by: robertglines1 on October 28, 2012, 12:07:13 PM
They were and were Morris cables I used to move the steel rods attached to leveling valves. I moved the hinge with the Morris cables. Not saying what you have won't work. The way I put tension on the control lever was using Teflon washers and squishing them for friction.   One thing I did discover when you turn a corner there is allot of pressure on your leveling valve rods.  Good luck Bob

Title: Re: Leveling System Pics for Feedback
Post by: gus on October 28, 2012, 01:40:23 PM
When I was going to do this to my 4104 I was going to do it the same way Chessie says to eliminate all the movement problems. There really is no need for a conversion to have automatic leveling anyway.

Having it attached to the body will also allow pulling on the cable to raise and pushing to lower, more logical than the way it is now.

Keep in mind that the original system does not level the bus, it only keeps the suspension equidistant at all times with varying loads.

I have the same thought as Tom, it appears that the cable will kink after a lot of movement both up and down and sideways.

It does eliminate the manual leveling of the bus every time you drive it. However, after you level the bus for parking you have to redo it anyway.

I'm anxious to see how this works.

Title: Re: Leveling System Pics for Feedback
Post by: Lin on October 28, 2012, 04:28:08 PM
Thanks for the input.

Bob- I looked up Morris cables and they appear to be the same as those they call Morse type.  The steel jacket they show on some would certainly be stronger than what I have.  These were bought dirt cheap from a surplus outlet so there is little investment in the experiment.  If the only problem turns out to be the cable rigidity, I can replace them.  Unfortunately, I just can't seem to picture what you did exactly.  I don't know if the setup is different for a Prevost, but I did not see where a hinge would be go on this one.  Of course, I could be missing quite a few things.  How thick is the cable that you use?

Gus- I have no loyalty to the original height control system.  The only issue is an easy return to road ride height when it is time to get underway.  Some here have chucked the original system and have valves and controls to manually inflate/deflate the air bags as needed for ride and leveling.  They know the pressure that gives them the correct ride height, so they set the bags to that pressure and are ready to roll.  As mentioned, this is the same problem with just hooking the cable directly to the lever although that would greatly reduce stress to the cable.  It will be easy to raise or lower the coach, but finding the correct ride height for the road would be a nuisance unless I am missing some simple way of doing it.  With this system, one just has to return the control end of the cable to the set neutral position and lock it in place to have the lever attachment duplicate the original linkage length and return the coach to the preset road height.

Sean uses linear actuators, which is a great idea.  Again the issue is returning to the correct ride height to travel.  He has a clever electronic way of sensing when the actuators return to that position.  It might not be terribly complex, but it is definitely not something I know much about and would have to learn a bit before approaching.

Thanks again 

Title: Re: Leveling System Pics for Feedback
Post by: Dave5Cs on October 28, 2012, 06:14:19 PM
Lin, you have the air going to the air bags. If you put an air line from each air bag to  out going side of a good air regulator with a gauge and a small 1/4' or 3/8 " depending on what size hose you use, Ball valve handle on the other end of the regulator. Then hook another hose to that and the other end to an air supply that isn't regulated like from the accessory tank in the tool compartment up front under the driver area.

Now the in line which will go to all 4 ball valves and all 4 regulators will always be getting air, but will only go through the regulator that you want to fill said air bag and it will tell you how much air is in the air bag that you opened the handle for. If you want to let it out you should either get a regulator with a side release or put a t in each line ahead of the regulator on the fill side with another ball valve so you can release air when needed. Make sense?


Title: Re: Leveling System Pics for Feedback
Post by: Lin on October 28, 2012, 09:29:31 PM
Dave- I have seen gauge/valve combos that would be good for that type of system.  It is a good and reasonable simple way to go.  

At this point, I am having serious doubts whether what I have done will hold up.  The mention of stressing on the link while cornering is a definite issue if it would bend or move the tube holding the cable.  I will take it for a ride this week and see what happens.  I am just waiting for a new height control valve for the front since this project exposed that one as bad.  If the front seems to hold up, I'll install the rear cables.

Title: Re: Leveling System Pics for Feedback
Post by: gus on October 29, 2012, 07:55:23 AM

I like your system since it is so simple and sure hope it works.

Keep us posted.

Title: Re: Leveling System Pics for Feedback
Post by: robertglines1 on October 29, 2012, 11:07:14 AM
All we are doing is lyeing to the anchor point or length of the control arm on the leveling valve.  Need friction on your adjustment lever or it will slip.  Lock nut and or teflon washer.   Bob.   I used pressure guages and valves on my Mci then the cables on the 89 and now have level low on the 98.  If it is to much trouble will go back to the cables and levers. I have no pictures any more. sorry. Bob

Title: Re: Leveling System Pics for Feedback
Post by: Lin on October 29, 2012, 01:59:52 PM
Bob, I have it so the control side bolts in place for travel.  Are you saying that it will slip when parked and leveled?  I did not plan on that, but if that is what you are saying, we'll have to do something.

Just an update-- We went out for a ride up into Joshua Tree Park today.  It was about 40 miles round trip.  Aside from the nice windy roads in the park (which seems to me the perfect roads for a bus), the dirt road from our house to the highway is a mile of washboard each way, which I would guess is a good workout for the cable.  Now I am not saying that this is a definitive test, but there is no noticeable difference in the cable.  I feel good enough to go and finish the job and monitor it for signs of impending failure as we go. It will take several hundred miles to develop confidence.

I do think the concept is fine may but have to upgrade to cables with the steel ends.

Title: Re: Leveling System Pics for Feedback
Post by: robertglines1 on October 29, 2012, 02:24:58 PM
Sometimes the simple things are best.  I did have to keep after the adjusting levers but you might have a better design.  Welcome to the other side! That will never work!!!  I just put three slides in a bus--will never work!  Bob