Anyone tried to straighten a cylinder rod?

[Bobpuddy]

Upon reassembly of my tilt cylinder, I had great difficulty getting the gland nut to line up and it would only screw in halfway before getting too tight to turn anymore. The rod seemed to be slightly to one side. I removed the piston and rolled the rod on a flat surface and found it is bent about 2 inches from where the piston is. I have a press but I am concerned about damaging the chrome coating with the ram of my press. I wonder if it could cause a flat spot or crack the coating. Has anyone tried doing this with success or would I be better off taking it to a cylinder shop?

 

[jerry]

A good cylinder shop is the place to go but with the bend that close to the end they may not be able to do it either. They will support it on aluminum blocks and press with another aluminum block it won't mar it up and the chrome does not crack. It shouldn't cost a fortune to have one made up using the pin retainer from the bent one. If it has been bent a while it may have distorted the bore of the aluminum gland enough to cause seal leakage and it also would not give the rod the proper support. when I did my cylinder I bored the gland and put in wear rings to bring the bore back to size. good luck with it.

 

[Tazza]

A good cylinder shop is the place to go but with the bend that close to the end they may not be able to do it either. They will support it on aluminum blocks and press with another aluminum block it won't mar it up and the chrome does not crack. It shouldn't cost a fortune to have one made up using the pin retainer from the bent one. If it has been bent a while it may have distorted the bore of the aluminum gland enough to cause seal leakage and it also would not give the rod the proper support. when I did my cylinder I bored the gland and put in wear rings to bring the bore back to size. good luck with it.

I agree, the other option is to to get a machine shopto make a new stick for you. Jerry makes a good point, the bend could have worn the inside of the gland nut out enough to cause it to damage seals. Even the piston may have worn a little too. All these can be repaired by a machine shop or if you have a lathe you can do it your self.

 

[mechanikat]

I would do some calling around, depending on where you live. you might just run on to a good used unit fairly cheap. It has also been my experience that you can frequently buy a brand new cylinder for the price of a rebuild.

 

[Bobpuddy]

I would do some calling around, depending on where you live. you might just run on to a good used unit fairly cheap. It has also been my experience that you can frequently buy a brand new cylinder for the price of a rebuild.

Yes that is what I am doing now because I called a couple hydraulic shops and they said because the rod is hardened it would most likely snap or be phone to being weak. The bobcat dealer siad that was their experence as well and they would not attemp straightening because of libility issues. I also asked the repair shop and a machine shop the cost of making a replacement rod and all were around $300. New from bobcat is $400. I'm searching for a used cylinder now

 

[Centurion]

Yes that is what I am doing now because I called a couple hydraulic shops and they said because the rod is hardened it would most likely snap or be phone to being weak. The bobcat dealer siad that was their experence as well and they would not attemp straightening because of libility issues. I also asked the repair shop and a machine shop the cost of making a replacement rod and all were around $300. New from bobcat is $400. I'm searching for a used cylinder now

Good luck trying to find a used cylinder! I finally found one after 5 weeks of searching. To have a new rod made was going to be about the same as buying a new rod from the dealer. I ended up paying $400.00 for the used cylinder. A new cylinder from the dealer is in the $1200.00 range

 

[Bobpuddy]

Good luck trying to find a used cylinder! I finally found one after 5 weeks of searching. To have a new rod made was going to be about the same as buying a new rod from the dealer. I ended up paying $400.00 for the used cylinder. A new cylinder from the dealer is in the $1200.00 range

I"ve found a hydraulic shop here in N.C. that quoted me $150 to make a new rod. I took there today and it should be ready in 5 days. I'll repost as to the outcome.

 

[Centurion]

I"ve found a hydraulic shop here in N.C. that quoted me $150 to make a new rod. I took there today and it should be ready in 5 days. I'll repost as to the outcome.

Let me know the name of this place, if they do a good job, i need a rod made for mine then I will have a backup.

 

[Bobpuddy]

Let me know the name of this place, if they do a good job, i need a rod made for mine then I will have a backup.

OK got it back today and it looks fine to me. It cost me $160 with tax. The name of the company is HP hydraulics in Thomasville N.C. They have a website also www.hphydraulics.com , They were half what any other machine shop or hydraulic shop quoted me. When I took this cylinder apart, I sure thought the piston was mounted on the rod with the recess facing the gland nut. The hydraulic shop said they believe the recess should face the nut on the end of the rod because the seal on the piston would be past the retract port if it were the way I said I removed it. Does anyone remember which way the recess in the piston should face?

 

[Tazza]

OK got it back today and it looks fine to me. It cost me $160 with tax. The name of the company is HP hydraulics in Thomasville N.C. They have a website also www.hphydraulics.com , They were half what any other machine shop or hydraulic shop quoted me. When I took this cylinder apart, I sure thought the piston was mounted on the rod with the recess facing the gland nut. The hydraulic shop said they believe the recess should face the nut on the end of the rod because the seal on the piston would be past the retract port if it were the way I said I removed it. Does anyone remember which way the recess in the piston should face?

They may be rite, if it goes too far forward the oil can't get behind it to retract the stick. I had that problem with my 731 that a friend made a new piston when i didn't have a lathe. It needed a bevel cut on the face to allow the oil to get behind it and it worked perfect! As long as it clears the oil hole it won't matter what way around it is i don't think. I have my 743 cylinder apart rite now actually, but i have messed with it so i can't be sure what way it should be with the cuts. What i do remember is the recess on the nut end must be big enough to fit a socket down to tighten the nut up.
I have 5 rams to re-seal tomorrow... Joy oh joy! *sad face*
Sorry i can't be much more use.

 

[Centurion]

They may be rite, if it goes too far forward the oil can't get behind it to retract the stick. I had that problem with my 731 that a friend made a new piston when i didn't have a lathe. It needed a bevel cut on the face to allow the oil to get behind it and it worked perfect! As long as it clears the oil hole it won't matter what way around it is i don't think. I have my 743 cylinder apart rite now actually, but i have messed with it so i can't be sure what way it should be with the cuts. What i do remember is the recess on the nut end must be big enough to fit a socket down to tighten the nut up.
I have 5 rams to re-seal tomorrow... Joy oh joy! *sad face*
Sorry i can't be much more use.

The recess faces the back of the cylinder, the nut that holds the piece on fits into the recess, so you need a good socket and rachet to be able to turn the nut. The 1/4" groove in the piston is towards the back. I will double check this in the morning as I have one that is apart.

Fred

 

[Tazza]

The recess faces the back of the cylinder, the nut that holds the piece on fits into the recess, so you need a good socket and rachet to be able to turn the nut. The 1/4" groove in the piston is towards the back. I will double check this in the morning as I have one that is apart.

Fred

It sounds like how mine was too, but i have installed a J seal in the piston instead of the factory one due to wear so i can't be 100% sure how it was before i attacked it.

 

[Bobpuddy]

It sounds like how mine was too, but i have installed a J seal in the piston instead of the factory one due to wear so i can't be 100% sure how it was before i attacked it.

That does seem logical. I will put it back together with the nut inside the recess. The hydraulic shop said that was most likely the cause of the problem I had with the bucket tilt problem I was having with the cylinder not wanting to retract. Remember the post I started on my bucket over extending and not wanting to retract when I had the arms up. I had to lower the arms before the bucket would start to tilt back up. The not wanting to retract problem, was the piston on backwards and the over extend problem, was because the nut on the piston had come loose and backed off about an inch. I'll post when it gets warm enough to put it all back together as to the results. It was 12 degrees here this morning.

 

[Tazza]

That does seem logical. I will put it back together with the nut inside the recess. The hydraulic shop said that was most likely the cause of the problem I had with the bucket tilt problem I was having with the cylinder not wanting to retract. Remember the post I started on my bucket over extending and not wanting to retract when I had the arms up. I had to lower the arms before the bucket would start to tilt back up. The not wanting to retract problem, was the piston on backwards and the over extend problem, was because the nut on the piston had come loose and backed off about an inch. I'll post when it gets warm enough to put it all back together as to the results. It was 12 degrees here this morning.

I agree, thats your problem, my 731 did that too till it got modified to allow oil behind the piston. With the nut, install the nut with high strength loctite, clean both threads first and give it a good helping of it. Tighten it up and you are all set. This will prevent it from simply un-doing on you again. I do it on all mine, i didn't once and it came un-done!!!
A small hint for removing any tight nut from a cylinder rod that i only recently woke up to was use a long length of bar, put it through the eye of the rod. Get someone to stand on it and use your wrench on the nut. Don't use a vice as they are very tight and can pull it off the bench (done that before). I even needed to drive the car onto the bar to hold it down once, my helper wasn't heavy enough! Do the same when tightening it up.

 

[Centurion]

I agree, thats your problem, my 731 did that too till it got modified to allow oil behind the piston. With the nut, install the nut with high strength loctite, clean both threads first and give it a good helping of it. Tighten it up and you are all set. This will prevent it from simply un-doing on you again. I do it on all mine, i didn't once and it came un-done!!!
A small hint for removing any tight nut from a cylinder rod that i only recently woke up to was use a long length of bar, put it through the eye of the rod. Get someone to stand on it and use your wrench on the nut. Don't use a vice as they are very tight and can pull it off the bench (done that before). I even needed to drive the car onto the bar to hold it down once, my helper wasn't heavy enough! Do the same when tightening it up.

I do not believe that having that backwards caused your tilt problem, when the bucket over extends because there are no stops you will encounter this problem, believe me I know!

 

[Bobpuddy]

I do not believe that having that backwards caused your tilt problem, when the bucket over extends because there are no stops you will encounter this problem, believe me I know!

. The piston on backward was the not wanting to retract problem. With the piston on backwards and past the retract port , the oil could not get behind the piston seal to move the piston. When I lowered the lift arms, the bucket pushes the rod back into the cylinder far enough so that the piston seal passes back past the retract port and allows the oil to push the piston. The over extend problem is a combination of the piston nut loose and wear in my bobtach pins. I also need the stops as a safety measure. I plan to weld on stops when I get it all back together.