| Author |
Message |
Jim Shepherd (Rv_safetyman)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 13, 2005 - 12:21 pm: | |
I am asking this question for two reasons: my own application, and also for an article I am gathering information for so that I can submit it to George Myers’ publication.
Here is the background. I fabricated my own jack leveling system, using cylinders from Northern tool and a valve body from a surplus company in Lincoln. For the pump, I used a 110 volt unit that I had available (they run about $400 new). Indeed, I had two of these units and fried one due to a bonehead plumbing circuit design that I plumbed for the first try. My cylinders are two way, and I am now paranoid that the pump will fail when the jacks are in the down position and I will not have an easy way to retract them.
Early stages of the system, along with documentation of the parts I have used are shown on my project page listed below.
So, I am wondering how practical it would be to plumb the power steering pump on the engine to operate the system - either as an emergency pump, or as the main supply pump.
As I see it, there would need to be a “T” in both the supply and pressure lines along with valves for each line. The “T” in the supply line would be needed in order to change from the PS supply tank (small) to the jack supply system (5-10 gallons). I think each line in the supply would need its own valve. For the pressure line, I think the only valve needed would be in the jack line so that the jack valve would not see pressure under normal operation.
I have not checked the pressure that the jacks need, but from some previous work with a very similar cylinder to jack up the bus, I think it is less than 1000 PSI for the piston diameter I have for the lift jacks.
I would appreciate any CONSTRUCTIVE comments <grin>.
Jim Shepherd
Evergreen, CO
’85 Eagle 10
Bus Project details: http://www.rvsafetysystems.com/busproject.htm (updated 2/17/05) |
TWODOGS (Twodogs)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 13, 2005 - 12:45 pm: | |
a standard power steering pump for a car puts out 10,000 PSI...hook it up to one of your belts |
Ron Walker (Prevost82)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 13, 2005 - 1:01 pm: | |
10,000 psi out of a vane pump...dream on 2D
Ron |
Craig Craddock (Gs4)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 13, 2005 - 1:08 pm: | |
I would not plumb in series with my bus power steering. Just in case of an accident and the lawyers & etc.
If I remember correctly the book says that my power steering pump puts out 1700# and an earlier style I had for the ram type about 1300# |
Jon W.
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 13, 2005 - 1:49 pm: | |
For emergency retraction I would install a manual valve in the system along with springs on the jacks.
When manual retraction is required open the valve to allow the down pressure to be relieved, and employ the springs to retract the "feet". You could get fancy and use a dash activated solenoid valve instead of a manual valve, but pump failure should be a very rare event. |
TWODOGS (Twodogs)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 13, 2005 - 1:57 pm: | |
sorry guys...meant 1,000 PSI....but what I meant was use a separate power steering pump...will have to proof read better in the future |
Bob Reed
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 13, 2005 - 2:08 pm: | |
Jim,
For an emergency, you could use a manual pump used to raise/lower cab on cabover tractor.
Another thought, wheelchair lift power-paks may provide everything you need- pump,resv, manifolding, sol valves, etc. The ones I've seen also have a manual pump emergency feature.
Did you decide to use hydraulic for your engine cooling fan ? |
TWODOGS (Twodogs)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 13, 2005 - 2:49 pm: | |
there is a wheelchair lift on the place we cannot mention on this board...100.00 so far |
Ron Walker (Prevost82)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 13, 2005 - 2:52 pm: | |
Hi Jim; the rear set of cylinders will need to be set around 1250 to 1500 psi, which will give you around 16,000 to 19,000 lbs of lift per cylinder, I don't know what you coach weighs and you have that S60 & trany hanging off the end as well as the diff & tag axles. I would try setting the relief at 1250 to start, if that doesn't work crank it up to 1500.
The problem with tying into your power steering system with a separate pump & tank is that one of the systems is going to steal fluid from one tank and overflow the other tank…if you can resolve this issue it will work fine.
Ron |
David Dulmage (Daved)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 13, 2005 - 3:06 pm: | |
I'd have concerns about modifying or tying into a system that is safety related. I wouldn't want to have a loss of steering power assist if a fault occurred in the levelling jack system.
FWIW
Dave Dulmage |
Gordon Hummel (Gordon)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 13, 2005 - 9:44 pm: | |
Jim,
Have looked @ your Jacks some time ago & am planning to much of the same components. I have
NJT 20eagle which has a pump for the Radiator fan system & plan on using that to operate the leveling system
Gordon |
John Jewett (Jayjay)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 13, 2005 - 11:40 pm: | |
My concern would be the incompatability of the fluids. Perhaps you could get them both to work on the same fluid. I'm not sure about seals deteriorating though, so you should consider them also. ...JJ |
Jim Shepherd (Rv_safetyman)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 14, 2005 - 1:04 am: | |
Thanks, everyone, for the input, but more importantly, thanks for staying on subject and making CONSTURCTIVE comments!!!
Bob, I decided not to go with the hydraulic fan system. If I had used that system, I would have had a supply pump. Since the Series 60 has a neat air controlled (via DDEC system)clutch for the fan, I decided to go with the belt drive. I will try to document that part of the project as time permits. Two important things I want to document are the actual gear box (got great info from a previous post) and the use of industrial grade idler bushings which mount industrial pulleys. There is only one source for these bushings, but I think they will work great. Don’t let the one source bother you, they can be ordered from most industrial distributor. The reason I am familiar with these bushings is that I had them designed and placed in the product catalog of the company I worked for prior to my "retirement". Guess who just got off-subject <grin>
I had an interesting call from a person who read this thread and he said that he ran car haulers for years. Some of them used the PS pump to run all of the hydraulics. I will try to check out what is being used today on these hydraulic intensive trucks.
Someone brought up the fluid. I first tried standard hydraulic fluid and it seemed to be too viscous to keep the pump fed with fluid – even using a large supply hose. I am now using automatic transmission fluid. I believe that is what is used with most power steering systems as well. Does anyone think that is an issue with the cylinders or the control valves (I can’t believe it would be)?
Jim |
FAST FRED
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 14, 2005 - 6:23 am: | |
IF yours is an air ride coach , Why Bother?
You have installed all the essential requirements of a leveling system , all you need is CONTROLL over the system.
I have not had time to install it yet but a replacement of the coat hanger wire that is the leveling valve hight sensor , with a good Heavy Duty push pull cable should do as much leveling as needed.
IF your intention is to raise the coach so far that the tires are no longer in contact with the ground , to "save them" I would worry about wracking the frame with a Hyd setup.
Push pull cables should work at 1/100 the complacation of hyd or miles of wires , air solenoids and other makeshift lashups.
KISS!
FAST FRED |
Vin (Billybonz)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 14, 2005 - 7:43 am: | |
Is it possible to lift an air ride coach by the body until the wheels are off the ground? Wouldn't the axles be hanging from the air bags? I know my fishbowl manual states..."The weight of hanging axle may damage bellows." There is mention somewhere about chaining the axles up to keep the weight off the bags.
I'm sure this is not Jim's intention to jack the wheels off the ground...or is it?
Bones |
TWODOGS (Twodogs)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 14, 2005 - 7:46 am: | |
no air bags on an Eagle... |
Vin (Billybonz)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 14, 2005 - 7:51 am: | |
Guess I should have looked at Jim' profile before I posted. So, can you lift an Eagle off the ground by the body and let the axles hang...just wondering. |
Richard Bowyer (Drivingmisslazy)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 14, 2005 - 10:20 am: | |
Yes. My 80 Eagle had hydraulic jacks in front. I could lift the tires completely off the ground by about 6 inches. Sure is nice when changing a flat tire.
Richard |
Geoff (Geoff)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 14, 2005 - 3:50 pm: | |
Jim
Trucks using hydraulic rams use a transmission PTO (power takeoff) to run a hydraulic pump. This may also work for you.
--Geoff
'82 RTS CA |
Ron Walker (Prevost82)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 14, 2005 - 5:16 pm: | |
Hi Jim ...it shouldn't be an issue using automatic transmission fluid. If your were running a hyd gear pump, /w ATF, for extended periods it may start to lose some pressure from the heat and light oil. But on a vane pump it won't matter.
Ron |
Tom Caffrey (Pvcces)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, April 15, 2005 - 12:41 am: | |
Jim, beware of the oil. Our 4106 Shepard power steering geer does not like ATF. We are told to use 15W40 motor oil in it.
When it was first installed, ATF was used. After I got a few miles on it, I thought the pump was getting tired. After changing out the oil, I haven't had any further trouble with it.
I don't know what Eagles used, but it sounds like you don't either. Be sure to check it out!
Tom Caffrey PD4106-2576
Suncatcher |