Tips on keeping top link from backing off

slan · Sep 30, 2009

On my 3240 the top link keep backing off when either bush hogging or box blading. There is a lock nut but it would probably be great at stopping it from getting shorter but doesnt do @@#$% to keep it from backing off.

I even put a vice grip on the middle as a counterweight to attemp to stop it from rotating.

Is there something I am missing here or am I just having a brain fart?

My next thing might be some 90/10 fine thread

kevinj · Sep 30, 2009

The only times I have that issue is when rototilling. Otherwise I just tighten it up with a 12" knucklebuster and it stays put.

20 20 · Sep 30, 2009

tighten the heck out of the locking nut against it, that's the only thing I can think of

bcp · Sep 30, 2009

Put a long eye bolt (eye down) through the link adjustment hole with a black rubber tie down strap going down to a lift link.

Or maybe something like this that goes into the link holes then around the pin or flat part of the eye.

Top Link Lock Spring

https://www.allpartsstore.com/ItemDetl.htm?B2BSessionID=090421006266536&CategorySeq=B&SelcBrand=MF&SelcMachn=TRACTOR&SelcModel=FITS%20SEVERAL%20MODELS&SelcSectn=P&SelcSubsc=P40&SearchItem=1&TextSearch=&ItemNumber=183614M1

Bruce

Egon · Sep 30, 2009

A second locknut may help. Otherwise as others have said, tie something thru the center hole to keep it from turning.

I used nylon quick ties.

Odenkirk · Sep 30, 2009

Made this latch this summer to keep my top link from backing off

BlacknTan · Sep 30, 2009

Odenkirk said:
Made this latch this summer to keep my top link from backing off

Now that's ingenious!

dirt ditch · Sep 30, 2009

slan said:
On my 3240 the top link keep backing off when either bush hogging or box blading. There is a lock nut but it would probably be great at stopping it from getting shorter but doesnt do @@#$% to keep it from backing off.

Had the same problem with my JD 790. The top link has only one locking nut that is shaped like a rain drop. I bought a plastic/rubber mallet and beat it tight without damaging anything. Works to beat it loose to. Never had it loosen up on it's own that way. The mallet fits in a slot on the left side of the 3pt under the lift arm so it is always ready to use.

kebo · Sep 30, 2009

I like you hidy place for the mallet! I might have to copy that on my 790. Thanks!

dirt ditch · Oct 1, 2009

Have to use the hard end to transfer enough force to the locking nut to keep it tight.

kebo, have to use a mallet with a thin handle that will fit in the slot. I found one at HF (have since seen the same cheap Chinese mallets at other stores). At first the end of the rubber grip was slightly flared so it was to large to fit in the slot on the back of the tractor. I just trimmed the flare down with a pocket knife. I keep a crescent wrench in the slot on the other side to use on the locking nut of the adjustable lift link. The lift arms have to be raised all the way to get the mallet or crescent in/out of the slots but that is not a problem.

Here is the mallet that worked for me:

- Harbor Freight Tools - Quality Tools at the Lowest Prices

20 20 · Oct 1, 2009

I wonder if a small compression spring in between the locking nut and arm would make a difference????????

OdenKirk; nice job

JoeL4330 · Oct 1, 2009

locking nut on each side? Reverse the top link?

Soundguy · Oct 1, 2009

kevinj said:
The only times I have that issue is when rototilling. Otherwise I just tighten it up with a 12" knucklebuster and it stays put.

tightening the lock nut on mine has always been fine.. never had one back off that was really locked down good.

soundguy

RedDirt · Oct 1, 2009

Lock nut woks for me but if I ever have problems I'll do an Odenkirk fix. Great solution!

studor · Oct 1, 2009

I second the second nut

-- works and will not come loose. Cheap solution as well

brin · Oct 1, 2009

I've never heard of such a thing...in more than 30 yrs. of seat time I truly have never had a problem with the top link on a ford jubilee, JD - 3020 or NH TC-29..I must be blessed. What are you folks doing to cause the locking nut to move ? Mine never do

Soundguy · Oct 1, 2009

studor said:
I second the second nut -- works and will not come loose. Cheap solution as well

gotta get a bak'ards thread nut though!

soundguy

kthompson · Oct 1, 2009

In my experience this is an issue with only certain threads on certain 3rd arms. I have two Kubotas and the CUT I have to keep the lock nut jammed or it will lengthen with any attachment. On my bigger Kubota don't think it has a jam nut but it never moves. Never had the issue with a Ford or Case tractor either. Think what is happening is there is too much clearance between the male and female threads as the 3rd is loaded and then unloaded the parts move.

BlacknTan · Oct 1, 2009

kthompson said:
In my experience this is an issue with only certain threads on certain 3rd arms. I have two Kubotas and the CUT I have to keep the lock nut jammed or it will lengthen with any attachment. On my bigger Kubota don't think it has a jam nut but it never moves. Never had the issue with a Ford or Case tractor either. Think what is happening is there is too much clearance between the male and female threads as the 3rd is loaded and then unloaded the parts move.

I believe that this is part of the problem.

Another part of the problem is that the ends of the center section of the top link are swaged down, and then threaded, This provides for ends that may not be perfectly square to the axis of the internal threads, providing little bearing area for the jamnut.
I's bring the locknut up lightly, and try to see if the nut is sitting flush against the center section all around. File the high spots that touch first until 360 degree bearing is achieved between the jamnut and the face of the center section of the top link