Bent Hydraulic Cylinders - Now what?

[Doug_D]

Hey all,

I have managed to bend the two cylinders on my 70HP kubota for the front bucket curl control. Dealer wants $650 for each cylinder or $250 for just the rams and $60-$70 for the pack kit. Trying to figure out which way I should go or if there is a better way.

Dealer is a little concerned the cylinder may not be rebuildable. Is there a quick way to check?

I was back grading and heard a loud pop and knew something happened. I did have the bucket rolled pretty far out and I must have hit something. I stopped the tractor and got out and looked things over, but did not see anything. I did not notice any problems until tried to roll the bucket back down (up was fine) and go back to work. When I finally got the rams to extend, I could see the bow. It's not bad, but it will prevent the bucket from rolling down. It is a slight bend...any chance of bending them back?

This could not of happened at a worst time for me. Any help would be great.

 

[Iplayfarmer]

Pictures!?

Bending the cylinders back sounds like a bad idea.
$650 sounds pretty steep for those cylinders. I'll bet you can buy a compatible part from Surplus Center and a can of nice orange paint for a lot less than $650 a piece. Unless there's something super special about those kubota cylinders, I'd be looking for a replacement somewhere else.

 

[atgreene]

Take them to a hydro shop. They can straighten them, or replace the rod or the entire cylinder

Not a big deal.

 

[flusher]

Hey all,

I have managed to bend the two cylinders on my 70HP kubota for the front bucket curl control. Dealer wants $650 for each cylinder or $250 for just the rams and $60-$70 for the pack kit. Trying to figure out which way I should go or if there is a better way.

Dealer is a little concerned the cylinder may not be rebuildable. Is there a quick way to check?

I was back grading and heard a loud pop and knew something happened. I did have the bucket rolled pretty far out and I must have hit something. I stopped the tractor and got out and looked things over, but did not see anything. I did not notice any problems until tried to roll the bucket back down (up was fine) and go back to work. When I finally got the rams to extend, I could see the bow. It's not bad, but it will prevent the bucket from rolling down. It is a slight bend...any chance of bending them back?

This could not of happened at a worst time for me. Any help would be great.

I just bought a pair of double-acting 2" dia x 20" stroke, 1" dia shaft 3000 psi cylinders with swivel ends from Surplus Center for about $145 each for one of my projects. You should be able to find a pair of cylinders from SC that will fix your problem for under $400. Tell the dealer to shove it.

 

[Doug_D]

Thanks for the help guys. I will post pictures tonight when I get home.

 

[3RRL]

If it is indeed a slight bend, you can straighten them out.
If severe or kinked, replace them. My wife's loader cylinders bent because the dump/curl cylinders were not located properly. I repositioned the cylinder attachments and also straightened out the slight bend in the rods. I wrote a thread about it with lots of photos showing what I had to do. It started with trying to get more curl for her Jinma than factory when I noticed the cylinder rods were bent. Here is the thread if you want to read about it starting with post #2. The following posts show how I straightened them out and now they are fine 130 hrs later still no problems with them.
Add more Bucket Curl to Jinma 284
Below are some photos of the bend in the rod and how I straightened them out and then they are straight again.
I flipped the rod around 180 degrees and used a rebar wedge and pipe between the rod and fel arm. I used the tractor hydraulics to do the bending back to straight. Last photo shows the rod straight again.
If yours are only slightly bent, you can do the same thing yourself.

 

[JB4310]

If your thinking you might have to bite the bullet and get new ones, then first I'd try and bend them back like 3RRL did, you've got nothing to loose.

I should think a tractor that size could handle what ever you throw at it but I've heard that back blading with curl so far out that the edge is cutting, will do that type of damage.

Good luck, JB.

 

[banjodunn]

G'day as mentioned before it is possile to straighten rods that are bowed not bent they will not have quite the same strength they would have originally but they are usually up to the task at hand. I have straightened them before without any dramas if you use the rebar technique you do run the risk of marking the rod though and that is not good as it will damage the gland seal when you use it causing it to leak The best way is to strip rams and press in hyd press i will tell you the same thing i tell all my customers with FELs fitted to their tractors that a dozer doesn't have rubber wheels Best of luck if you are going to strip though good idea to replace seals.



Jon

 

[Doug_D]

WOW Guys! Thanks for the help.

Rob; I am going to try what you suggested. I really think my bow is less than your's pictured. Sounds like you have considerable skill with hydraulics. Hope I am up to the challenge

I will post pictures this evening.

 

[3RRL]

WOW Guys! Thanks for the help.

Rob; I am going to try what you suggested. I really think my bow is less than your's pictured. Sounds like you have considerable skill with hydraulics. Hope I am up to the challenge

I will post pictures this evening.

Thanks Doug, not much experience really just common sense and a little mechanical ability.
Like banjodunn said, I would use a leather shield over the rebar or pipe next time. Fortunately, mine were not scored though. When you flip the rods 180, re-pin them into your cylinder front mount or bucket. You might have to use a crow bar to get the wedge under the bend spot since it will be down towards the fel arm. Pry it up gently away from the fel arm. Just keep repositioning the wedge (bar) and extend the cylinder until the rod takes the bend back to original straight. Use your dump on the fel (extend the cylinder) and go slightly past straight when bending it back and check it. If not straight enough, do it again with a little more bend at the wedge. If yours are not bent as much as mine were, it should work for you. If your bend is as slight as you say, chances are your seals are still OK too. You will know if they leak.
Looking forward to the photos ... take some action shots of how you do it too.
Rob-

 

[Wis Bang]

I have had them fixed @ a hydraulic shop. Took then the whole cylinder & they came back straight and w/ new packing, etc. wasn't all that much pricewise & was finished overnight.

Back dragging should be done w/ the heel of the bucket, not the leading edge.

 

[Iplayfarmer]

...Use your dump on the fel (extend the cylinder) and go slightly past straight when bending it back and check it. If not straight enough, do it again with a little more bend at the wedge...

One thing I've learned doing stuff like this is start out at low engine RPM's. Slow and steady is key to this type of procedure working.

 

[Doug_D]

I have to say I am one happy guy tonight! Sitting back drinking my reward for a job well done.

pics 1 and 2 are before shots. Bend was pretty good.
Pics 3 and 4 are after shots.
Pics 5 and 6 are of the leather I used and the pipe. The brown spots are not rust, thats leather on the pipe! Lots of pressure in there.

I could not believe the results! I was truly amazed. Even though in one of the pictures it looks like there is a small gap under the board, there really is not. Maybe I was asking too much of my three year old assistant The board is extremely flat as I put it on the jointer before using it as a gauge (mild woodworker; mostly precision cut firewood .

Thanks a ton guys. Really did save the day!

Now, I can show you guys what I really needed it for. My latest project?

www.cabinstartup.com

Would love to hear your input!

Thank again,
Doug

 

[JB4310]

That is sweet, have to remember that one in case it ever happens to me, was it like bending something springy where you have to go a little past what is straight so it doesn't just spring back?

Is that your work on that web site design, if so I'm more impressed with your techno graphic abilities.

JB.

 

[The Dougster]

Indeed a creative and unique solution... That's why I love hanging around smart fellers ... mebbe some of it will rub off on me.. lol

 

[Wis Bang]

Good job! Remember retract the bucket and backdrag w/ the heel of the bucket. The cylinder is at it's strongest when fully retracted. The front edge of the bucket should only point down to MT out the contents.

 

[gpflepsen]

This is just utterly ridiculous. Why can’t manufacturers get the basic designs into production? How hard would it (rhetorical) be to include a relief valve so the cylinder is never exposed to rod forces great enough to pass the point of buckling? Maybe an aftermarket relief needs to be installed to prevent this from happening. Dragging with the rear edge is just a mitigating action, the front edge should be able to take it.

 

[rcrcomputing]

Good job! Remember retract the bucket and backdrag w/ the heel of the bucket. The cylinder is at it's strongest when fully retracted. The front edge of the bucket should only point down to MT out the contents.

Ohh, I neverrrrr backdrag with the edge..

(going to **** for lieing..)

 

[gordyy]

I think No make that I know it should be mandatory when a person joins this board he needs to look at some of these masters 3RRR for one and some of the Hydralic Gurus like Kennyd and wayne the hose guy, I think I learned more here in a month then I did in 2 yrs of trade school

glad that reverse bend worked out for you Doug
like the log home rental thing

 

[Wis Bang]

This is just utterly ridiculous. Why can稚 manufacturers get the basic designs into production? How hard would it (rhetorical) be to include a relief valve so the cylinder is never exposed to rod forces great enough to pass the point of buckling? Maybe an aftermarket relief needs to be installed to prevent this from happening. Dragging with the rear edge is just a mitigating action, the front edge should be able to take it.

I grew up watching my dad operate heavy equipment. Any experienced loader operator would float the bucket flat, tip up the edge [get the teeth out of the way] and backdrag w/ down pressure.

Union operators that did not bust up stuff needlessly were the first ones requested out of the hall each spring AND the last to get laid off in the fall...-or- were the only ones working those elusive winter time jobs.

Now take a CUT or SCUT and build a working FEL that isn't too heavy & things will be easier to bend and break.

A 977 CAT could backdrag w/ the teeth pointing down but the massive hydraulics would weigh more than these little tractors!

When Dad retired to my great uncles home, he had a fellow operator bring his smaller cat down [for a set of teeth] to move the gravel uncle had laid across the lawn to get to the carport built on the garage that never progressed from the workshop he used to build the place. Dad wanted the gravel in the road and was adding garage doors after removing the uggly car port. In a fee hours the guy was able to rake the gravel up and restore the corner of the lawn & spread the gravel where it should have been.

He didn't need to pull the teeth and dad just raked the dirt & scattered seed...that's why they are called operators.