John Deere 350C 5-spring torsion isolator question

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VT350C
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John Deere 350C 5-spring torsion isolator question

Post by VT350C » Sat Oct 03, 2026 5:45 pm

Hello all,

I am doing a complete rebuild of the original torsion isolator with 5 springs on my 350C. Please see picture before my rebuild. As you can see 4 of the 5 springs are mounted one way and 1 is mounted the other way.

https://photos.app.goo.gl/bacWwK9MqCTDuTir8

If I am understanding things, the flywheel spins counter-clockwise (to the left) when looking at the flywheel (from behind the engine in the operator station). From Google AI, they state that the open end of the spring on the outer anchor should face right (open side faces right). This will allow the outer anchor to "push" into the closed side of the spring. If so, it seems that 1 of my 5 springs was installed incorrectly. Can anyone confirm this?

I am doing the rebuild as I am doing an engine swap and want to renew this troublesome part. I am going to ensure things are super clean and the proper Loctite is used and things are torqued correctly.

In the picture you can also see that one of the 5 anchor tabs is not aligned facing the center of the flywheel.

Just want to be sure I am getting the springs installed correctly.
THANKS
John Deere 350C with 6-way and winch
John Deere 302A Loader and 3pt.
John Deere 318
MEP002A Military Diesel Generators
MEP003A Military Diesel Generators

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LeonardL
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Re: John Deere 350C 5-spring torsion isolator question

Post by LeonardL » Sun Oct 04, 2026 8:52 am

You are correct that the one spring is wrong. That being said I have taken machines apart that had the springs in the wrong position and had ran like that for years. Once the machine has been started and everything is rotating I don't think it really matters. But technically and according to Deere tech they should be mounted like your other four springs are mounted.

You're doing great dude and good luck with your rebuild.
40 plus years working on JD 350s, 400Gs, 450s and other equipment both Ag and Construction.

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VT350C
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Re: John Deere 350C 5-spring torsion isolator question

Post by VT350C » Sun Oct 04, 2026 10:57 am

Many thanks for your blessing! It means a lot.
John Deere 350C with 6-way and winch
John Deere 302A Loader and 3pt.
John Deere 318
MEP002A Military Diesel Generators
MEP003A Military Diesel Generators

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VT350C
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Re: John Deere 350C 5-spring torsion isolator question

Post by VT350C » Sun Oct 04, 2026 11:04 am

Many thanks for your blessing! It means a lot. FYI, what is also odd, was one clip was crooked on the adjacent spring. I have no idea if that was due to the incorrect spring or just another anomaly. Also, the guide pin near the crooked tab fell out when I removed the engine. Again could be coincidence, but could all be related to the slightly diff forces associated with the one mis installed spring. That one pin that fell out was also the most worn as it was flattened from the plate chucking against it. Hoping things will be less sloppy after fixing. Thx again.
John Deere 350C with 6-way and winch
John Deere 302A Loader and 3pt.
John Deere 318
MEP002A Military Diesel Generators
MEP003A Military Diesel Generators

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LeonardL
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Re: John Deere 350C 5-spring torsion isolator question

Post by LeonardL » Sun Oct 04, 2026 5:16 pm

Your crooked retainer could have been any number of reasons. Given my experience with these spring isolators, I would bet that at some point a spring broke which is when your pin got hammered loose and your retainer got tweaked. Then whoever replaced the spring put it in backwards and just stuck the pin back in hoping it would just stay there. They may have also failed to realign the retainer that got moved in their hurry to get the machine going again.

I've seen a lot of "Repairs" that were anything but a proper repair. You can knurl that pin or take a center punch and peen it some to tighten it up. You can also stake the hole on either side to help hold it in place. I've also seen guys heat them red while installed in the hole and then smack them with a hammer to swell them to fit the hole. Not sure I would recommend that but they seemed to get by with it. Knurling is the best fix in my opinion.
40 plus years working on JD 350s, 400Gs, 450s and other equipment both Ag and Construction.

gaz_whitaker67
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Re: John Deere 350C 5-spring torsion isolator question

Post by gaz_whitaker67 » Sat Oct 24, 2026 4:47 am

LeonardL wrote:Knurling is the best fix in my opinion.
Right, LeonardL, that backs-up-a-broken-spring theory fits proper well, I've seen that sort of bodge on old bikes too... somebody in a hurry bangs it back together and hopes for the best. Knurling's the way, to be fair, though I'd add a drop of Loctite 638 or similar on the pin once it's tight, cos a pin that's already worked loose once will do it again. Definately wouldnt go heating it red in the hole, mate, thats just asking for bother 🙂

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