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.