Spare Tire Cylinder

MacGreenie

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Florida
Please see attached photos of adapted cylinder to my LMTV 1078 A1.

Original cylinder locked up and would not extend no matter what I did to it.

Went to Tractor Supply and got a County Line Brand, 2 inch bore with 16 inch throw, Tie-rod style cylinder. Had to grind some material off the outside ends to make them fit. The inboard end of the outer radius of the tie rod eye interfered with a weld on the truck. Nipped a little off the end with the grinder to fix that. The .75 inch pins that came with the cylinder fit LMTV tire davit frame holes perfectly. Went to NAPA for 90 degree hydraulic elbows to connect to the new cylinder as the size differed from original install cylinder. . Make sure you get a 90 degree with NPT thread going into the cylinder and compression fitting to satisfy the existing hydraulic hose end. NAPA has them on the shelf so the counterman hooked me up on that.IMG_2800.jpgIMG_2800.jpg
Pictures attached. Works like a charm. 200 bucks all in: Happy Happy.

IMG_2803.jpgIMG_2799.jpg
IMG_2800.jpg
I let the air out of the spare for clearance. IMG_2802.jpg
In this way, the fitting would not press too much on it. I suppose if the CTIS system works, then changing a tire results in proper servicing through CTIS actuation. So having a slack spare is not really a risk. I have a manual CTIS system so I know it will be reliable if I need to bring a tire back from the dead.

I used a bushing to fit the elbow on one end. I ground the bushing down so it would thread in flush. I ground the elbow that fit into the bushing so it would make more headroom as well.No leaks so far.

Yes, this all begs the question, why not mount hydraulic elbows on the top, out of the way? The geometry of the cylinder and the tapped pressure ports forced me into this configuration. A pin head style cylinder might have been better; but Tractor Supply was local and let me test fit in the parking lot so we went with wot they had.

Did we reduce strength of the tie rod end fittings by removing material Absolutely. But I think the pressures and angles are still within design capability. In any case, we are sure to not ever stand directly under the tire as it comes down even if we are wearing a hardhat!
 

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MacGreenie

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We did explore rebuilding the original unit but discovered it would require welding and all sorts of heroics. So we opted for the Tractor Supply solution.

Seth, no change in performance other than a little close clearance on the aft end of the tire due to placement of 90 degree fitting. No real pressure on the tire. It just touches it.

We did explore purchasing an original unit with a well known vendor. Quote was 2500 clams. Wow!

So TSC was a better bet. Trying to figure fit and style with online vendors was difficult as well. Best to go with what you can put yer hands on.
 
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Reworked LMTV

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coachgeo

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To get clearance for the elbows, all you have to do is remove the four long bolts and rotate that end 90 degrees. This will get the elbows out of the way. See my video. ....found a similar one (To TSC). Mine was $98 from amazon. https://www.amazon.com/gp/product/B074N99D7L/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

YU TUBE VID
You mentioned removing meat from this cylinder.... where did you remove the meat from? Not knowing what in looked like before the hacking can't tell by your video where you modified it
 

coachgeo

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note..... when I went to parker store to have the one I purchased used tested they discovered there are check valve(s?) inside the OEM ram. Seems these check valves prevent the ram moving either direction without hydraulic pressure. So for example if your lowering or raising the tire and something goes fubar in the hydraulic system....... the 500ish lb tire can not come crashing down on the user..... or just crashing down and bending things to shreds..

do these aftermarket replacements offer this? If not; can check valves be added into the line(s) to create the same effect?
 

Reworked LMTV

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took meat from same area as previous poster did / at wrist pin flanges.

You mentioned removing meat from this cylinder.... where did you remove the meat from? Not knowing what in looked like before the hacking can't tell by your video where you modified it
 

Reworked LMTV

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I think Parker sells these if you need them. I have a suspicion these valves are the culprit when FMTV cylinders fail.

note..... when I went to parker store to have the one I purchased used tested they discovered there are check valve(s?) inside the OEM ram. Seems these check valves prevent the ram moving either direction without hydraulic pressure. So for example if your lowering or raising the tire and something goes fubar in the hydraulic system....... the 500ish lb tire can not come crashing down on the user..... or just crashing down and bending things to shreds..

do these aftermarket replacements offer this? If not; can check valves be added into the line(s) to create the same effect?
 

Ronmar

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Port angeles wa
note..... when I went to parker store to have the one I purchased used tested they discovered there are check valve(s?) inside the OEM ram. Seems these check valves prevent the ram moving either direction without hydraulic pressure. So for example if your lowering or raising the tire and something goes fubar in the hydraulic system....... the 500ish lb tire can not come crashing down on the user..... or just crashing down and bending things to shreds..

do these aftermarket replacements offer this? If not; can check valves be added into the line(s) to create the same effect?
What you describe is called pilot activated and I don't think ours work quite like that. if they did they would require you to pump the tire or cab all the way down and could not lower with gravity as they do now. I believe the valves in the OEM cylinders work as a flow limiter. The flow passes backwards thru a check valve held open by a spring. If the flow rate gets too high, it overrides/compresses the spring and the check closes. The control valve has restricted passages to limit the flow thru the valve to not exceed the flow lockout point of those cylinder check valves.

If you blow a hose and the exiting flow exceeds the flow limit, the check closes and halts the cylinder which either stays there or lowers very slowly. The drawing shows what looks like a bypass passage which I believe is there to release pressure on a valve to prevent them from hydraulically locking. To release a check you either need to remove the load from the cylinder(remove hydraulic pressure holding valve closed), or apply enough input pressure to exceed the load on the cylinder to get the check to re-open... Don't know that I have seen one of these as a standalone component, but I haven't looked either...
 

Reworked LMTV

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Good point.

note..... when I went to parker store to have the one I purchased used tested they discovered there are check valve(s?) inside the OEM ram. Seems these check valves prevent the ram moving either direction without hydraulic pressure. So for example if your lowering or raising the tire and something goes fubar in the hydraulic system....... the 500ish lb tire can not come crashing down on the user..... or just crashing down and bending things to shreds..

do these aftermarket replacements offer this? If not; can check valves be added into the line(s) to create the same effect?
 

Reworked LMTV

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Take the 4 bolts out of the cylinder and rotate the end to get elbows in the same plane. You may want to use that extra port on the side. If you do this you will not have to air down.

Please see attached photos of adapted cylinder to my LMTV 1078 A1.

Original cylinder locked up and would not extend no matter what I did to it.

Went to Tractor Supply and got a County Line Brand, 2 inch bore with 16 inch throw, Tie-rod style cylinder. Had to grind some material off the outside ends to make them fit. The inboard end of the outer radius of the tie rod eye interfered with a weld on the truck. Nipped a little off the end with the grinder to fix that. The .75 inch pins that came with the cylinder fit LMTV tire davit frame holes perfectly. Went to NAPA for 90 degree hydraulic elbows to connect to the new cylinder as the size differed from original install cylinder. . Make sure you get a 90 degree with NPT thread going into the cylinder and compression fitting to satisfy the existing hydraulic hose end. NAPA has them on the shelf so the counterman hooked me up on that.View attachment 759548View attachment 759548
Pictures attached. Works like a charm. 200 bucks all in: Happy Happy.

View attachment 759546View attachment 759547
View attachment 759548
I let the air out of the spare for clearance. View attachment 759550
In this way, the fitting would not press too much on it. I suppose if the CTIS system works, then changing a tire results in proper servicing through CTIS actuation. So having a slack spare is not really a risk. I have a manual CTIS system so I know it will be reliable if I need to bring a tire back from the dead.

I used a bushing to fit the elbow on one end. I ground the bushing down so it would thread in flush. I ground the elbow that fit into the bushing so it would make more headroom as well.No leaks so far.

Yes, this all begs the question, why not mount hydraulic elbows on the top, out of the way? The geometry of the cylinder and the tapped pressure ports forced me into this configuration. A pin head style cylinder might have been better; but Tractor Supply was local and let me test fit in the parking lot so we went with wot they had.

Did we reduce strength of the tie rod end fittings by removing material Absolutely. But I think the pressures and angles are still within design capability. In any case, we are sure to not ever stand directly under the tire as it comes down even if we are wearing a hardhat!
 

Littlejacy

New member
12
0
1
Location
Amado, AZ
Please see attached photos of adapted cylinder to my LMTV 1078 A1.

Original cylinder locked up and would not extend no matter what I did to it.

Went to Tractor Supply and got a County Line Brand, 2 inch bore with 16 inch throw, Tie-rod style cylinder. Had to grind some material off the outside ends to make them fit. The inboard end of the outer radius of the tie rod eye interfered with a weld on the truck. Nipped a little off the end with the grinder to fix that. The .75 inch pins that came with the cylinder fit LMTV tire davit frame holes perfectly. Went to NAPA for 90 degree hydraulic elbows to connect to the new cylinder as the size differed from original install cylinder. . Make sure you get a 90 degree with NPT thread going into the cylinder and compression fitting to satisfy the existing hydraulic hose end. NAPA has them on the shelf so the counterman hooked me up on that.View attachment 759548View attachment 759548
Pictures attached. Works like a charm. 200 bucks all in: Happy Happy.

View attachment 759546View attachment 759547
View attachment 759548
I let the air out of the spare for clearance. View attachment 759550
In this way, the fitting would not press too much on it. I suppose if the CTIS system works, then changing a tire results in proper servicing through CTIS actuation. So having a slack spare is not really a risk. I have a manual CTIS system so I know it will be reliable if I need to bring a tire back from the dead.

I used a bushing to fit the elbow on one end. I ground the bushing down so it would thread in flush. I ground the elbow that fit into the bushing so it would make more headroom as well.No leaks so far.

Yes, this all begs the question, why not mount hydraulic elbows on the top, out of the way? The geometry of the cylinder and the tapped pressure ports forced me into this configuration. A pin head style cylinder might have been better; but Tractor Supply was local and let me test fit in the parking lot so we went with wot they had.

Did we reduce strength of the tie rod end fittings by removing material Absolutely. But I think the pressures and angles are still within design capability. In any case, we are sure to not ever stand directly under the tire as it comes down even if we are wearing a hardhat!
Wonderful information AND pics of the job! Question for you since you mentioned CTIS manual system and well, wouldn't you know my CTIS ECU is "all lights on" bad: What system did you go with and how did you hook it up? I would truly like to have this working on my rig as well. Finding those damn boxes is less than satisfying let's say.
 

Third From Texas

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Corpus Christi Texas


 

Third From Texas

Well-known member
708
442
63
Location
Corpus Christi Texas
there are others several other threads too that go about it differently that should be reviewed as well. Sorry lost good access to all my links when they switched to this new ssoldiers format
Yep. Those were just the most recent that I've followed since they were posted and that I had bookmarked. No doubt there may be others but Dragonbyte's search function is a wee bit lacking at times.
 
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