Help picking correct replacement loader cylinders

Hydraulic shop recommended just replacing cylinders vs the price of rebuilding them. These are the bucket cylinders on an old Kelley 800 loader, which parts and information doesn't really exist for anymore. In addition to leaking the rods are bent so the shop said the rods would probably cause leaks again and replacing everything is the price of a brand new cylinder.

Here's the specs of the old ones 30 5/8" retracted, 50 5/8" extended. Had an oddball 1 3/8" rod and a 2" bore. It's on a 65hp massey that runs off a pump on the front of the engine. I googled the pump and it looks like it runs at 3000psi so I'm guessing don't buy a 2500psi cylinder?

The bracket where the cylinder mounts to the loader is pretty narrow. Inside diameter of 2.14", this is limiting the cylinders that will work by quite a bit. Best option I can find so far is the "tang" style pictured below. So for now it looks like the best option I can find is this 29" retracted 49" extended with a 2" bore. https://www.magisterhyd.com/product/2inch-bore-x-20inch-stroke-tang-hydraulic-cylinder/']2 bore x 20 stroke hydraulic cylinder, welded tang double acting cylinder | Magister Hydraulics

What are people doing about the metal lines that come up from the far end of the cylinder, can those be made? Would probably be nicer than having loose rubber lines.









This post was edited by petebert on 07/09/2023 at 08:25 pm.

3000 psi sounds high. Most systems run 2000 psi or less. The new cylinder could work but would recommend spacers on the pins to keep cylinder centered.

Have you looked at Surplus center or Bailey sales.net. both have cylinders and I believe both may build cylinders for you if needed. Have no idea on the cost though. Then there is Discount hydraulics don't remember if they have cylinders or not. I know they have fittings of many types and sizes along with surplus center.

Don't get hung up on the bore being exactly what you have now. Just keep in mind that the larger the bore, the slower the lift/tilt, and the more power applied to the load. That helps when you have a fast pump, you can go to a larger bore to take some of the twitchiness out of the controls. Your stroke and extended length are negotiable, based on how much tilt you want on the bucket, and where it starts out fully retracted. Take some on-machine measurements to confirm what you want for length and stroke. With the right fittings, and a short custom steel line, you can duplicate where the hoses hook to the cylinder. Surplus Center is your friend!! steve

Like Geok says, use spacers to keep the tang centered. If you weld the spacers onto the tang, put a zerk on one side to keep grease at that pivot point.

The front of the pump says "Cross" and that company is still active so maybe I'll contact them. Looking at the specs and pictures for their current stuff it looks like the pump on there is a Cross 50 series gear pump, although I'd imagine mine has been on there for a really long time so I'm not sure if the specs are the same. Here's what they have for the current Cross 50 series.

"3000 psi (3500 psi max. shock press.)
3000 rpm max. continuous speed-(Limited to the maximum speed per chart below)"

That's a great idea for adding the spacers, been wondering how that works. Almost everything with a 2" bore these days has a 2.38" or larger mount except for that one type I found.

The shop recommended going as big as possible on the rod for strength. That's good info on the speed, I actually wouldn't mind slowing down the bucket, it's kind of jerky. What I need to figure out is if I can go to a bigger cylinder without it rubbing on the loader frame.

It looks like you have a lot of space at the top for a bigger bore cylinder, so you'd have to move the bucket full tilt and see if the cylinder gets closer to the frame at the top end when its fully extended. A friend recently replaced both his rods, bending them badly by back pulling the bucket while fully extended. Bigger is almost always better on the rod diameter, until you start degrading the capacity of the cylinder on the back stroke too much. steve

Just because the pump is capable of 3000 psi doesn't mean that your system is operating at that pressure. There should be a relief valve somewhere that limits the
pressure that system is operating at. As to the replacement cylinder being slightly shorter, this will limit how far your bucket dumps, which may or may not be a problem.
It doesn't look like it would be a big problem to move the pin location slightly at the upper end.

a point to ponder over,bigger cylinder = more powewr which =
more breakage

Those Magister cylinders are likely as close to your current cylinders as you will find ''off the shelf''. Having cylinders custom made is an option if you want to pay the cost.

If the cost to have new rods made and the cylinders rebuilt is about the same, or even a bit more, than the new cylinders I would seriously consider the option of having new rods made. New rods in the original cylinders means you know the cylinders fit properly and are designed for your loader.

Bent rods can be caused by pushing (''bulldozing'') with the bucket in the dumped position. The bucket should have mechanical stops between it and the loader arms to stop bucket travel before the rods max out in extension.

The pressure the hydraulic pump applies into the system should be regulated by an adjustable system relief valve, not the published max pressure a pump is designed for. Those are often located in the loader control valve. I expect the designed operating pressure is in the 2000 to 2250 psi range.

Realistically the odds of you finding a cylinder that's "exact" are slim to none. Going to need to make some compromises and/or modifications, most likely.

What's most important is the stroke. Yours looks to be a 20" stroke. That's where you start. Filter down to 20" stroke cylinders and go shopping to get as close on the rest of the specs as you can.

Hoses don't flop around if you zip tie them securely with good heavy zip ties, and are a lot less expensive than having hard lines made.

Where would the concern for breakage be at? Although another thing I'm wondering about, the main loader lift arms are also a 2" bore. So when they put this loader together the loaders cylinders and the bucket cylinders were the same diameter. What happens if you put a larger diameter cylinder on the bucket?

This post was edited by petebert on 07/10/2023 at 06:28 am.

(quoted from post at 09:28:00 07/10/23) Where would the concern for breakage be at? Although another thing I'm wondering about, the main loader lift arms are also a 2" bore. So when they put this loader together the loaders cylinders and the bucket cylinders were the same diameter. What happens if you put a larger diameter cylinder on the bucket?

This post was edited by petebert on 07/10/2023 at 06:28 am.

Click to expand...

A larger effective bore diameter means the cylinder develops more force at the same pressure. It may move a bit slower based on the same supplied volume. stevieb49829 mentioned this concept in his first post to you here.

It is hard to say just where breakage might occur. That is a function of design, material and weld quality, squareness and evenness of load distribution, and hydraulic pressure for some factors.

The main relief valve limits the pressure that is sent to the cylinders. Nothing happens to the lift cylinders if the bucket cylinders are a different diameter.

You need not concern yourself with the bracket width as you are going to do some welding anyway. I 2nd Surplus Center! The mount welding will have to be of high quality since it would be dangerous for a loader to collapse so if ou haven't the skills plan to hire a local guy - there are plenty around.

So about these mechanical stops. I did some measurements today without the bucket cylinders on it. Using a floor jack I raised the bucket until it stopped and got 30 1/2" from center to center of the eyes. I then raised the main arms and let the bucket drop all the way and got 50 1/2".

So would a longer than 20" stroke be ideal so that the bucket and loader act as a stop instead of the cylinder acting as a stop?

For example in the 20" range, the Magister is 29" retracted, which means its 49" extended and wouldn't be at its physical stop. If I go to the the 22" stroke it's 31" and 53"

No, too long of a cylinder will want to bend something at the end of the stroke.

Besides your 22" stroke cylinder is too long. The bucket won't be fully rolled back with the cylinder retracted.

What you would do is use the 20" stroke cylinder and relocate the top anchor point for that cylinder on the loader boom.

In this picture is the bucket contacting the underside of the boom arms in the area between the ears where the arrow points? If it does you can add shims in that area to reduce the trave to just under the stroke of your cylinders, similar to what John Deere recommends on some of their loaders to take the strain off the cylinder if pushing with the bucket in the dumped position.

I had my cylinders rebuilt on my 1980 model 3 pt backhoe. The attachment points were an odd design that I didn't want to experiment
with this should fit. The rebuilt cylinders work fine. This old stuff has its own requirements and competition on price is not
always in the mix.