Next brilliant idea??? Hydraulic ram bumpstops?

daddyoften · November 16, 2015, 07:22:13 AM

First off, thank you all very much for the information on converting to stainless hinges and gas shocks. I'm sure that will be the way I'll go once I can start working on the bus.

My next brilliant idea is

What about using small hydraulic rams in the area of the bump stops. Either as replacements of or next to the bump stops. My idea is to use these rams only for leveling while parked. Then retract them out of the way or back to the proper measurement for the bump stops. The reason for this idea is I know that area of the bus can withstand the weight of the bus and this could also double as jacks to raise the bus up to more safely work underneath it without worrying about loosing the air in the air bags. I am familiar enough with hydraulics and would use pilot operated check valves as holding valves to hold them in the down (bus up) position. Anybody else think of this already? Pro's, Con's? Just forget it?? LOL

Thanks,
Eric

MB LeMirage · November 16, 2015, 07:45:47 AM

Good question. I have been thinking of the same sort of thing. Using 3 or 4 20 ton cylinders.
Ryan.

bevans6 · November 16, 2015, 10:52:52 AM

Most buses use a "tripod" suspension - two leveling systems control each side of the rear (or front) independently, and one leveling system controls both sides of the other end, usually the front, together. The reason is to prevent "racking" of the bus, putting twisting loads into the chassis. This can range from a non-issue to breaking windows. If you use three - two in the back and one in front - there is no strong point in the chassis to pick up the front load, so it would be hard to use three, but easy to use four. One possibility that comes to mind is to use load cells or sensors to measure the weight on the four "feet" and equalize to create equal pressure on the chassis. You could do that with something as simple as a pressure sensor.

Brian

daddyoften · November 16, 2015, 12:51:52 PM

Brian,
I thought of that. It's simple to just run two cylinders in the front with a "t" hooking the two together. This would allow as one goes down due to the rear tilting the bus it would transfer fluid to the other side and vise-versa. Just the same as the air bags do.
Eric

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kyle4501 · November 16, 2015, 02:43:41 PM

Good idea, the implementation will be interesting.
Is there room for the cylinder above the bump stop? Not on mine - unless I cut a big hole in the structure. Then there may be an issue of the cylinder sticking thru the floor . . . .

daddyoften · November 16, 2015, 04:45:03 PM

That's the part I haven't had time to look at. But hey why be so picky? Lol

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Jim Eh. · November 16, 2015, 05:32:16 PM

If you can go into the cavity above the bumpstop could you weld on a nut to mount a cylinder like this? (inverted of course)

This installation would be positive clearance when fully retracted and you could even screw on a rubber bumpstop onto the end of the cylinder.

kyle4501 · November 17, 2015, 02:13:00 AM

For what it is worth, that cylinder with a 8-1/4" stroke has a 12-3/4" retracted height, has a 3-3/8" body diameter.
Don't forget about access for the hydraulic line to the cylinder.

All that said, it is a very compact cylinder & has a better chance of fitting in the limited space.

Cheapest I found was over $800 each.

Dang, ain't nothing cheap about a bus conversion - except maybe, the owner . . . .

eagle19952 · November 17, 2015, 03:18:05 AM

ebay has chinese portapower cylinders in your price range
http://www.ebay.com/itm/261520653207?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

daddyoften · November 17, 2015, 04:55:17 AM

Thank you all for your input so far. I will fall back on the air bag leveling if this hydraulic idea flops. I work on cranes on a daily bases and they use hydraulics for almost everything and modern holding valves are very reliable.

I guess when I have time I'll crawl underneath my bus and see if there even is physical room for my idea. I know there are people in here who know the underside of their bus like the back of their hands. I have the time and knowledge to do the hydraulics, I just don't know if is feasible to apply it to a leveling system in the area of the air bags/bump stop, where there already is sufficient supports to raise and lower the "coach" part.
Again, thank you and keep the ideas a coming ;-)
Eric

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Darkspeed · November 17, 2015, 05:08:01 AM

I do not know if yours is similar but here is a shot of my 4106.

Bumpstop mount is plate steel in a terminated ibeam configuration welded to a box section above it -which is hollow

The chain is something I added to limit the travel of my suspension when I deploy my hydraulic legs as it lifts the tires off the ground.

Without the chain it is possible to hyper extend the suspension doing damage to the shocks.

You could go to either side of the center webb of the i beam and cut a simi circle out of the lower terminating plate and weld in a saddle mount for a hydraulic cylinder. If it was a tall one you could even recess the top of the cylinder into the box section above. -but it would be a lot of work vs. additional valves on your air bags.

You only have a bout 6" of travel to play with before you start damaging your shocks if you are pushing down.

luvrbus · November 17, 2015, 11:05:59 AM

We used sleeved air bags on a 4106 they were 2-1/2" collapsed and would extended out to 8-1/4" cost us 50 bucks each. He didn't won't the leveling system on his air ride system for some reason, they have worked good for 10 years with a small 12v compressor for supply

oltrunt · November 17, 2015, 02:54:09 PM

I use the chepo Chinese port o power rams to level my little bus. They work just fine but don't have enough stroke to make much sense if you want a lot of lift. I use a port- o-power hand pump with an external oil supply and a four gang valve system. If you use the bump stops you probably would have enough stroke but you would still have to live with the rock and roll left in the tires which I would find as annoying as a not level bus. Jack

TomC · November 19, 2015, 03:49:16 AM

Personally-I wouldn't go the hydraulic route-far too powerful. I have an air suspension leveling system and love it. It is good for about 3 days when my bus will settle down again. One of the great things with the air suspension leveling is if you park on a highly crowned road, you can quickly level the bus. When I stay for longer than 3 days (which isn't often) I'll use leveling blocks under the tires and then deflate the air bags all the way down. Besides-the lowered bus looks cool.
I use three sets of air solenoids-one in the front and one in the back. At each location, one solenoid to cut off air supply from the automatic leveling valve, then one for adding and one for exhausting air from the air bags. Your smart-you can figure it out. Good Luck, TomC

kyle4501 · November 19, 2015, 03:10:43 PM

Quote from: TomC on November 19, 2015, 03:49:16 AM
Personally-I wouldn't go the hydraulic route-far too powerful.

If you size the cylinders & fluid pressure correctly, they will have the same power as the air bags.

I like the adjustable bump stop idea. Sounds like it will be firmer than the air bags, with only the tires touching the ground.
I'm getting too lazy to bother with leveling blocks - pushing a switch is more my style.