[amvcane]

While restoring a 420 I noticed the gas spring in the hst linkage was shot.
I replaced this in my 322 several years ago for about $70. Now John Deere wants $157. I could also get it direct from Suspa for $105 with some long lead time.
So.....looking at how this linkage operates, the purpose of this gas spring is to force a " V " shaped plate onto a roller. Basically parking the linkage in neutral so the handle and creep can be adjusted. Simple job, always in compression.
I purchased two 7" 30 pound gas springs from Amazon for $14. Removed the spring clip from each end and drilled a 3/8" hole for a bushing of 5/16" copper tubing I had laying around. Used JB plastic bond epoxy to secure the bushings. Important to keep the bushings parallel so there is no binding.
These inexpensive gas springs are marketed as helper springs for a lid or hatch. They only move when opening or closing the hatch. In my application they will be moving when the hst handle is operated. Im sure they were not designed for continuous duty. This is not my mowing tractor so maybe they will last.
Only time will tell. I"ll update when its all back together and operating.
Andrew.

 

[amvcane]

Early Update:
After assembling some more tractor I was able to test the performance compared to my 322. (Engine off).
30 lb. spring is a bit strong. The friction plates have to be adjusted to tight for my liking to overcome the neutral return and keep the handle where set.
These gas springs are also sold in 10 lb and 18lb. When the 30lb spring wears out or I get tired of the extra force, I will replace it with an 18lb spring. 40% less force.
Will keep updating as info and observations come in.
Andrew

 

[chuckv]

The gas dampeners from the original Deere design are just double acting shock absorber-style assemblies with gas dampening...their primary function is to limit the movement of the linkage until sufficient force is applied. The gas lift assemblies you are using are a bit strong fo this function and tend to return the linkage to a set point, rather than keep it at its desired position as set by the operator.

Weaker lift springs may give acceptable performance -- but the Deere part is double acting...meaning it has the same resistance to movement in both its travel directions, not just one. Other vendors also make such dampeners, like Guden.

...they may not be any cheaper than the Deere parts for all l know...

Chuck

 

[chuckv]

I believe that the German company Stabilus makes/made the dampener for Deere that I used on my 322 (see photo...) and compare to the PDF catalog attached...

Chuck

 

[amvcane]

My Rev 1 has a double acting dampener. I don't see how a double acting dampener will work with the Rev 3 linkage. Is your pic a Rev 4 with upgraded dampener?
This is the gas spring from Deere and Suspa. I have no idea what the specs are.

 

[chuckv]

Double acting works with REV3 and REV4 linkages. My 1992 322 tractor had a REV4 linkage system...as pictured. The push-pull motion retardation (dampening) is independent of vertical or horizontal orientation...

Chuck

 

[charms]

It's been a few years, but I replaced one of the Rev 3 dampeners with a factory replacement, and I do seem to recall it had spring pressure out. I recently purchased another 322 with the Rev 3 dampener that should probably be replaced, and will be following this.

 

[charms]

The quote below is from an old thread: 322 hydro absorber questions - not mine

"If anyone is curious about the questions from my original post regarding how the rev3 absorber/linkage is supposed to work: the new absorber I received (p/n AM133368 which subs for AM104880) is in fact spring-loaded to extend the piston, and it is damped (resistant to sudden movement) only when compressing but not when extending."

The Rev 4 dampener may well be double acting/not spring loaded, I don't know.