Lift Arm Pins keep breaking.

[BufordBoone]

I have a 1993 JD 2355 (came with the farm). The lift arms use a pin and bushing system. The pin is part number AR55695 - Lift Arm Pin. It is a pin with a plate welded on one end and a hole for a quick lock clip on the other end. A "strap" (square washer) also goes on it.

AR55695 - Google Search

I have been using this tractor mostly with the 10' (offset) bush hog (also came with the farm) since 2012. Last year I had one fail at the weld. I replaced it and the replacement also failed. I replaced that, asked the dealer to return the defective one to see if they would warranty it. They did. That was about this time last year.

Since then I pay close attention to those parts.

Today I had another failure at the weld. I've replaced that one with a spare but am getting tired of these things breaking. They are upwards of $20 each.

I found an affordable replacement online and have ordered one to see if it will work.

Anyone else having these problems with the Lift Arm Pins?

 

[jeff9366]

You did not specify if your pins are 7/8" Category I or 1-1/8" Category II.

I quit using standard draw pins with my Rotary Cutter. My issue was the Lynch Pins being pulled out by heavy brush, allowing the Rotary Cutter to detach from the draw pins. Instead I use 7/8" Grade 8 bolts, nuts and washers.

I speculate a Grade 8 bolt, with a washer sized to substitute for your welded plate would be considerably stronger. Would the round washer provide the same function as your welded plate?

Or can you convert to Category II pins on your Cutter?
I do not know the engineering math involved but 1-1/8" pins/bolts/axles are much, MUCH stronger than 7/8" pins/bolts/axles. Possibly three times more robust? However, pin diameter would not improve weld quality but there would be more "meat" in the weld.

There are stronger bolts than Grade 8 available from specialty venders, but Grade 8 fittings are sold in average Hardware stores.

The draw pin stress operating an OFFSET Bush Hog may be different from draw pin stress of a Bush Hog operating behind but in-line with the tractor, which is my case.

 

[BufordBoone]

Thanks for the reply but I probably was not clear.

These pins do not connect the draft arms to an implement. These pins connect the lift arm to the draft arm of the tractor.

The lift arm screws into a link body. The part that keeps breaking is #16.

View attachment 2355 Tractor Lift arm parts guide.pdf

 

[jeff9366]

I do not see why a bolt, washers and a nut will not provide the same connection and likely be stronger. But it may be a question of FIT.

 

[BufordBoone]

The square end is designed to be positioned either horizontally or vertically, depending on how you want it to work.

However, I might be able to cobble something together with a bolt, washers, a nut and a pair of the part numbered 17.

Thanks.

 

[disney]

The square end is designed to be positioned either horizontally or vertically, depending on how you want it to work.

However, I might be able to cobble something together with a bolt, washers, a nut and a pair of the part numbered 17.

Thanks.

That's just what I was going to write... but please be mindful that once you upgrade the weak link, the next weakest link might cost much more than $20...

 

[Gator6x4]

The stress being applied to the welded square end makes me think the implement is seizing the pins and when the rotary cutter moves up or down the pins are being twisted against the square shoulder on the lift arm putting stress on the weld point. Have you checked the pin size and compared it to the hole it is going through on the rotary cutter.

 

[Egon]

Any reason why the pin cannot rotate?

 

[BufordBoone]

Thanks, Gator but this pin is not in contact with the rotary cutter. This pin connects the link body to the draft arm. The draft arm is what connects to the rotary cutter.

In thinking of this issue, I suspect I had one break earlier than I thought. One day I realized I had lost a link body (part 15 on the drawing). Couldn't figure out how it came off. Now I think it was probably one of these link pins.

Yes, it was much more than $20.

I suspect part of the problem is the amount of side to side play in the system. The only adjustment is to rearrange a set of blocks. I've got it set for minimum sway but there is still a fair amount. Each time I turn it may sway and put stress on the weld. I'm learning to weld so, if I can find the other side, I'll try to repair it. On the broken parts, I've been very unimpressed with the quality of the weld.

At least I've learned to monitor the parts.

 

[BufordBoone]

Egon, I don't know the answer to that question. I don't see any reason but suspect they are designed not to rotate for a reason.

I want to avoid the problem of unintended consequences.

Thanks.

 

[Tx Jim]

Any reason why the pin cannot rotate?

No reason pin or bolt can't rotate. I would use bolts and allow them to move in lift link slots allowing cutter to float if terrain was rough. One might use factory pins turning flat part up in slot also allowing cuteer to float.

 

[BufordBoone]

Thanks, Tx Jim. I may give it a try.

For info, I've been using it with the pins set to allow cutter to float.

This offset cutter is in interesting animal. I have to shorter the right lift arm considerably to get the cutter to level out. Turning the lever to shorten the lift arm is difficult unless I can get the right side of the cutter up somehow. Best way is to store the cutter with a 4x4 under the right side.

Having the ability to cut close to trees and/or along the side of the pond is really nice though. Also makes it easy to cut the side of the driveway.

Thanks, to all, for the help.

 

[jeff9366]

My tractor has hole and pin adjustments for tilt in the Lifting Rod stirrups. Three hole and pin adjustments on the left stirrup, two hold and pin adjustments on the right stirrup. "LOWER HOLE MEANS LOWER LIFT.

Setting tilt in this manner allows you to keep both lifting rods in about equal tension. If you have to much tension in one Lifting Rod, it means the other Lifting Rod is offering very little support.

It is easier to set the left side of the implement lower, so when it touches the ground it is RELATIVELY easy to turn the screw adjustment for the right Lifting Rod.

 

[BufordBoone]

Jeff, my Kubota L5740 has the same setup. Unfortunately, the 10' offset is too big for it.

Sure would make things easier, though.

Thanks.