Replace loader lift/tilt cylinders with larger ones ?

[Henro]

Obviously I don't know you and your background. Having walked this walk....(and being willing to blindly jump into a mechanical project with NO clue what's going on)

I decided to try to rebuild my dipper cylinder on my JCB backhoe. I don't know the diameter but I'm guessing 2 1/2" and it was 107.478% about all I could man handle to carry the darn thing!

These aren't rocket science. Take it off, figure out how to take it apart... you have little to lose if you're willing to buy a new one. I'd take one apart and give it a whirl....the seals have to be available somewhere (if I can find them on ebay for my 1987 machine, they'd have to be available for something more main stream??)

I've since redone my stabilizer cylinders.

I might add... years ago, when I first did my dipper cylinder, I took it to a dealer. They charged me $1,000 to do it and I about passed out on the spot. I STILL (stupidly) paid to have my loader (raising) cylinders redone AND the trunnion (swing) cylinders for the backhoe. When the Dipper cylinder needed it again (after maybe 15 years) my spine stiffened and told myself there was NO way I was going to pay that again unless I had to..... so I dug into it and I think it cost me (forget) maybe $100 in parts.

Heck, when I did my stabilizers, the pins were freezing them on the machine so I was unable to remove the cylinder..... so I did them in place.

I will just add that I priced a seal kit from Kubota and for my cylinders the cost would have been over $60 each per cylinder (delivered) for the seal kits only.

I figured that for the additional $40 per cylinder it was worth it to me to have someone with expertise do the work. Easier too.

The hydraulic shops do not need the seal kits from Kubota. So their cost for seals is probably 10 percent of what mine would have been. They make money there too. I do not have an issue with that at all. If I tried to source all the needed seals/o rings myself, I would lose so much time it would drive me crazy...

 

[art]

And the most important: what's the load capacity of the front axle? This is something overlooked a lot mostly because I don't think that manufacturers put this info on US market tractors.

Tractors on the European market have this info displayed on the serial number tag. Will list Max permissible load on front and rear axles.

There are tractors built today on the market that have loaders that lift more then the front axle is supposed to hold.

 

[LD1]

I'd stick with factory size.

I'd take them apart. If they are leaking...$10 worth of gland seals at your local hydraulic shop.

Don't even have to remove cylinder from tractor most likely

 

[crazyal]

I've always done mine. Either a cheap kit from the local hydraulic shop or on occasion the factory kit. Not only would I not remove the cylinder I actually think it's easier. You need to remove the rod side but the tractor makes a great vice to hold the cylinder while trying to remove the gland nut. The rod is a good chunk of the weight but it's still a lot lighter than the assembly. For a loader find something like a 55 gallon drum to rest it on, remove all the pressure and have at. It's going to leak oil so be prepared. For something like a loader I'll tape plastic to the hood going under the cylinder to a bucket or something to channel the fluid into it. I even picked up a used 3' pipe wrench for removing the nut. You do one and you'll most likely never bother with paying anyone else to do it.

 

[the old grind]

This ^^ IMO, nuthin' beats cyl base pin for holding steady when muscling the gland nut loose or re-tightening. No slip or scratch/dent cyl body either.

Yes, be sure the loader & bucket are at rest and wobble the stick to relieve pressure.

I like to cap or plug lines I disconnect right away to minimize spills and gravity drips.

When buying items that come with those bits I save 'em in a jar. After a while one can cover a lot of sizes.

 

[HayDR]

Well, going from a 2" to a 2.5" cylinder increases the piston area from 3.14sq in to 7.06sq in, so assuming a 2,000 psi system, that would increase the extension force from 6,283# to 14, 137", over double the amount the original cylinder would exert.
If both had the same size rod, say 1", the retraction forces would go from 4,712# to 12,566#, over 2 1/2 times as much.

I would bet that kind of increase would bend or break something pretty quickly.

Amen you are so correct

 

[jthibodeau89]

Amen you are so correct

Except that a 2.5" diameter cylinder is 4.90 sq in, and the rods are 1.25 diameter. Recalculate the forced based on the correct part sizes.

 

[BravoXray]

Except that a 2.5" diameter cylinder is 4.90 sq in, and the rods are 1.25 diameter. Recalculate the forced based on the correct part sizes.

Correction:
A 2.5" cylinder with a 1.25" rod will exert 9,816# of extension force, 1.56 times a 2" cylinder, and 7,362# of retraction force, also 1.56 times a 2" cylinder.

 

[RickB]

Once again I will mention the diminished speed that will be a result of increasing the cylinder bore. That is not a potential risk resulting from potential overloading of the structure but a constant reality every time you grab the joystick.

 

[TractorGuy]

Who operates their loader at full speed anyways?