Hydraulic Cylinder Problem

[RamTruckMan]

I opened the cylinder and pulled the rod out. The threats and the nut were stripped. It had a lock nut on it. Evidently the nut wasn't tightened at the factory. I am going to take to a machine shop and see if I can get it re-threaded.

 

[Leejohn]

Have them cut the stub off and drill, tap the shaft. Put back with a #8 bolt with lock tight. That is if it's very bad.

 

[kennyd]

I opened the cylinder and pulled the rod out. The threats and the nut were stripped. It had a lock nut on it. Evidently the nut wasn't tightened at the factory. I am going to take to a machine shop and see if I can get it re-threaded.

That's worse than I thought, but still fixable.

 

[RamTruckMan]

I took to one machine shop and he said he would have to cut the cross tube off to put in lathe and he wanted $200.00. I took to another machine shop, but they are closes until after Thanksgiving.

I would try threading it myself it, if I knew what type die will work. It appears a 7/8 is the closest. If the other machine shop wants an arm and a leg, I will give it a try. If that fails I can cut off and drill out as someone suggested.

 

[wdchyd]

I take it the machine shop doesn't have a lathe with a four jaw chuck..??...or a lathe with large throat...??.......:confused2:

This job needs a four jaw chuck (for the cross tube end) and steady rest (few inches near stub) to clean up threads....if the threads are bad then undercut the threads and reweld over, turn to size and rethread......

a routine job for a good machineshop.....Don't cut off the head.....:thumbsup:

 

[wdchyd]

What is the Dia and length of rod...?

 

[Leejohn]

I would not let them cut the cross tube off just to get it in the lathe if the cyl. is long enough to stick it in from the back side. If it is it would not take very long at all to cut and tap, but try and get it done in a lathe so it well be nice and stright. You can do it my hand but go slow and don't hog the tap and break it.

 

[RamTruckMan]

Yeah, I am going to try another shop after Thanksgiving. I have it apart, but, it appears to be 22-24 inches retracted. About a 16" stoke. The ram is about 1.5 inches. The bore is 2.5 inches. The part the piston sides on is about an inch and the threat part to tighten the piston is about 7/8. But I am pretty certain the nut and threats are metric. Probably a 20mm since a 7/8 nut is a little large. I would think, a person that is pretty good at threading could do a good job at rethreading it since it is only 1mm larger than a 7/8" nut.

 

[RamTruckMan]

Woops, wrong calculation. The threads would be about 23 mm as the nut is a little small.

 

[wdchyd]

If it's gonna cost $200, I'd bring it to a Hyd Shop that does new rods.....this is routine work as you'll get a new rod w/ nut (reusing the cross head) for less than $200....I wouldn't tap the end and put a bolt as stated cuz this takes a lathe anyway just to get the hole straight and it may change the stroke length when it sucks back in....It may cost the same for a Disney Mouse repair vs the right fix....

The right machine shop is the best choice.....:thumbsup:

 

[Rocwin]

You can definitely get a new rod made up for less than $200. Generally we pay about $90 for a 1" diameter, 16" long piston rod, something a little larger isn't a whole lot more labour just materials.

 

[RamTruckMan]

When they make a new rod, do they chrome it, or how do they keep it from rusting?

 

[kennyd]

When they make a new rod, do they chrome it, or how do they keep it from rusting?

They use "stock" that is already chromed.

 

[wdchyd]

When they make a new rod, do they chrome it, or how do they keep it from rusting?

The rod material from a hyd shop is purchased prechrome plated in 24 ft lengths, then cut to size and machined/welded and VIOLA..!!!....New Rod.......Kinda Like these.......the lead time to have one piece chromed can be significant, but not this way.....

 

[kennyd]

The rod material from a hyd shop is purchased prechrome plated in 24 ft lengths, then cut to size and machined/welded and VIOLA..!!!....New Rod.......Kinda Like these.......the lead time to have one piece chromed can be significant, but not this way.....

Just had to show me up huh?:laughing::laughing::laughing:

 

[RamTruckMan]

Yeah, I hope to take to another machine shop and see if they can re-thread or have a new rod turned.

Another thought I had is to step the pin holes in the backhoe up to one inch and get a stock cylinder. The pin holes on my current cylinder and on the backhoe are 25mm. One inch is only 1/64 of an inch bigger. (one inch = 25.4 mm)

Does anyone know if, a one inch drill bit would stay centered, if I tried to ream the 25mm hole out to one inch. I don't want to end up with a crooked hole.
Also, if I drill a one inch hole, should the pin be one inch, also or should it be just a fraction smaller to allow for lubrication?

By the way think twice about buying imported machine or fabricated products. I bought this Nardi Backhoe (made in Italy) very well built backhoe, but there is no dealer support. Fortunately, backhoes aren't technical (just some steel with holes and hydraulic cylinders) and machine shop guys can make about anything, but it is still a hassle.

 

[RamTruckMan]

Thanks, got it.

 

[KWentling]

"Does anyone know if, a one inch drill bit would stay centered, if I tried to ream the 25mm hole out to one inch. I don't want to end up with a crooked hole.
Also, if I drill a one inch hole, should the pin be one inch, also or should it be just a fraction smaller to allow for lubrication?"

1/64" is a job for a reamer. A 4-flute drill would also work but a reamer would be better. Most cold rolled material is undersize a few thousands and may fit as is. You want a close fit as the pin will be stationary in the holes you are reaming and the clearance for turning is built into the cylinder ends.

Kim

 

[RamTruckMan]

"Does anyone know if, a one inch drill bit would stay centered, if I tried to ream the 25mm hole out to one inch. I don't want to end up with a crooked hole.
Also, if I drill a one inch hole, should the pin be one inch, also or should it be just a fraction smaller to allow for lubrication?"

1/64" is a job for a reamer. A 4-flute drill would also work but a reamer would be better. Most cold rolled material is undersize a few thousands and may fit as is. You want a close fit as the pin will be stationary in the holes you are reaming and the clearance for turning is built into the cylinder ends.

Kim

Thanks. I will see if I can round up a reamer. Products like that are so hard to find in my area. I'll do a search on net.

 

[aczlan]

Thanks. I will see if I can round up a reamer. Products like that are so hard to find in my area. I'll do a search on net.

Get a pin and try it first. You may have enough wear in the hole to let it fit in.

Aaron Z