Cab lift and spare tire cylinder replacement

[ARYankee]

I'm curious if anyone has replaced their cab lift and spare tire cylinders with electric linear actuators. I'm thinking of deleting the pump system for them. I know they need to be operated frequently or you will have issues. Mine worked fine when I first had the truck but now it acts up. I figure getting 24 VDC linear actuators might be the way to go. Just seeing if anyone may have tried this or thought the samething.

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[Keith Knight]

Electric actuators are longer than hydraulic actuators for the same stroke length. So fitting a longer actuator in the same space would be the first hurdle the second would be strength.

 

[Ronmar]

Strength would be a bigun…

the rod end side of the piston(side used to lift the tire) has ~ 2.36 sq/in of surface area. It takes ~2200PSI to lift the tire, so that is 5,183# of force from the cylinder to lift the tire…

 

[MatthewWBailey]

The cylinders have those spring activated flow checks that get locked up. My spare tire cylinder locked up and I just swapped it out with a standard Magister cylinder with 1-1/2" rod, 2-1/2" bore. Now I'm rerouting the exhaust, so I don't have a spare but it worked well for 2 years. I'd like to fold in a 24v DC hydraulic pump pak to supplement the air unit when the air is zero.

here is the thread on what I did...

Cab and spare hydraulics problems M1078 LMTV

That sounds feasible. I'll try to extract those ball seats this weekend. I wonder how many times that cylinder has seized with the trucks in actual service. IDK, but have sure come across it a lot on the forums. Mine locked up once. Was able to free it, like most people, by repeated up and...

www.steelsoldiers.com

 

[ARYankee]

Thanks for the info guys. I still think that I could use an electric linear actuator. It won't be cheap though......

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[Keith Knight]

If you make it work I would love to see pictures of it and the brand of actuator.

 

[Ronmar]

yea a >5000# electric linear will be expensive. It may also not be very fast... There is a reason we do so many things with hydraulics

Sounds Interesting, Good luck!

 

[Keith Knight]

Agree, but anything is possible with time and money.

 

[ARYankee]

yea a >5000# electric linear will be expensive. It may also not be very fast... There is a reason we do so many things with hydraulics

Sounds Interesting, Good luck!

I agree but they are used for RV slide outs. I'm not messed up on how long it will take for it to move. My only possible concern would be dead batteries but that can be remedied.

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[MatthewWBailey]

Thanks for the info guys. I still think that I could use an electric linear actuator. It won't be cheap though......

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I went thru this process before I upgraded my cylinder as I thought similarly. Kept running into the same problem, load capacity vs size & speed. Maybe you'll have better luck finding something.

 

[GeneralDisorder]

RV slide outs don't require significant force. They are not lifting anything against gravity. Just sliding something sideways on greased tracks.

Hydraulics are much simpler and more robust. No motors or gears. And the factory hydraulics can move quite fast with the right electric pump.

 

[Ronmar]

I agree but they are used for RV slide outs. I'm not messed up on how long it will take for it to move. My only possible concern would be dead batteries but that can be remedied.

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Yea this is not an RV slide-out that only needs a few hundred pounds of force to operate. Tons of electric actuators 100-1000# capacity. Pickins get pretty thin above 1K# of op force…

 

[ARYankee]

I understand. All are very good points. I've been looking at industrial linear actuators. I've found a couple that will handle 3 to 5k lbs. I was curious to see if anyone has used electric actuators as of yet. Sometimes things aren't used because of cost at the time or lack of technical advancement. I'm going to test the waters to see what I can find out.

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[Keith Knight]

I guess I’ve never looked for an actuator with that capacity. They are out there this one can get up to 5,600 lbs very impressive! Definitely got me thinking.

 

[ARYankee]

View attachment 928835
I guess I’ve never looked for an actuator with that capacity. They are out there this one can get up to 5,600 lbs very impressive! Definitely got me thinking.

Yeah, they've come a long way with them. I work in the automation world so I deal with this sort of stuff. I've recently been working with some electric linear actuators for a customer and that got me to thinking about trying it on my LMTV.

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[Keith Knight]

Looking at some other ones. I looks like the problem is going to be modifying for the extra overall length. For a 24” stroke you have to add about 10” for an overall length of 34”.

 

[ARYankee]

Looking at some other ones. I looks like the problem is going to be modifying for the extra overall length. For a 24” stroke you have to add about 10” for an overall length of 34”.

That was the nuts and bolts part that I needed to really look into. I was going to look at the TMs to see what stroke length would be needed. I figure the cab lift would be easy to do. The spare tire lift may be the tough one.

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[Keith Knight]

My specialty is designing and making things that move, I’ve worked in animated robotics to agriculture machines. Basically I love making things that don’t exist one offs then moving to the next project.

 

[aw113sgte]

The eye-eye and stroke doesn't have to match. No reason a linkage couldn't be used and/or different eyelet locations.

 

[Ronmar]

Because of the crane arch folding back over itself to cradle the tire, it kind of limits the size of the actuator, unless you really lengthen the structure to move the base attach point. This would have the advantage of an actuator with a longer stroke with the attach point farther up/out on the arch, which would reduce the force required to lift the 350# wheel assembly.

Based on my hydraulic measurements, the cab really isn’t that much better. ~1400+PSI peak to lift applied to the base end of a 2” cylinder(3.1416sq/in) works out to be ~4400# of force to lift the cab, and ~2600# to pull it back over the balance point when lowering the cab...