78 Spitfire project

This is where you can post the story & photos of your John Deere Snowmobile project.
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400brian
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Re: 78 Spitfire project

Post by 400brian »

Engine is still sitting on the bench. Just tonight I spent some time on the tunnel. I removed the secondary and the brake rotor from the driveshaft, and pulled the handle bar off. The tunnel is now ready to be put on the saw horses on it's back, and the suspension removed.

I will check everything out in the suspension, and replace the bearings in the idler wheels ( I assume I can do that ). I will give the track a good look, I have never seen it in it's entirety. The driveshaft will come out and new bearings will be installed. I have two different sets of track drivers, I think I will stay with the lower speed set.

The tunnel is in pretty good condition. Most of the paint is on it, and the decals are fair. The pan has no huge dents, although when I went to pull the driven sheave, it hit the side of the pan before it was off the driveshaft. There is a small dent just ahead of the sheave and the bumper looks straight, but perhaps the side of the pan has been pushed in enough to interfere with the sheave removal. Re-assembly should be a blast. :bonk:

The tunnel needs a good cleaning, I did suck the hickory nuts out of the pan tonight, but the dirt and oil residue needs to go as well.
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thumbnail (42).jpg
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'09 Vintage Challenge Survivor, and I wasn't late for supper!
'10, '11, '12, '13,'14,'15,'16,'17, '18, 19, 20, 21, 22 Vintage Challenge Survivor !
72 400 restored, Father bought new in '71
73 X8 restored
'74 340 green machine
'74 X8 9 time VC finisher
'78 Spitfire in progress
2 '75 340S 1 running, one on deck
'78 LF 440 future CC clone
'73 Skiroule RTX 440, 500 mi.
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400brian
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Re: 78 Spitfire project

Post by 400brian »

So the Spitty is on it's back, and the suspension is out. Took some doing to get the rear bolts out, they were locktited in, so once the first bolt was out, the other just spun the shaft. The fix is a jam nut on a long bolt threaded into the side you just removed the bolt from, and some heat on the bolt you are trying to remove, to soften the locktite.

The bolts in the forward suspension shaft spun right out, so I knew right away the aluminum shaft was seized in the steel tube. Yeah, I was not disappointed. The rear shaft shows little to no wear at first glance. The idler wheels show no wear on the face of the rubber wheel. The slides show only a bit of wear at the very front. The travel limiter strap looks quite rotten, but is still there. OK, I will set that aside for now.

The next task is to get the driveshaft out to remove the track. The shaft is really rusty. I clean it up with a file, and then 100 grit emery cloth. I need to slide the plastic track driver towards the center in order to remove the shaft from the tunnel. I got the bolt out of it, and was able to move it slightly towards the outside. I cleaned the rust off the area I just uncovered, hit it with some WD-40, and was now able to slide the driver back to where it had been. After working it back and forth, tapping it towards the outside with a hammer, and prying it towards the center with a pry bar, I was able to slide it to the outside enough to uncover the bolt hole in the shaft. From experience I suspected that the bolt had moved some metal around the hole, and when I pulled the file across it, I knew that was the case. With the ridge filed smooth on each side of the shaft, the driver now slid fairly smoothly to the center of the tunnel.

The track on this machine was way too tight. I had never got a good look at it in all the time I have owned it. The cleats are undamaged, and I see none that have been repaired. The center belt looks good compared to the two outer belts. Many of the drive lugs show cracks and fiber around them. On the outside, the rubber picks ( for lack of a better word ) are largely missing. The rubber has that distinctive "dead" look about it. I suppose it has a few miles left on it, but I am not real comfortable with it.

Apparently at some point in it's life, the right rear suspension bolt fell out, and the sled was operated that way until a good sized hole was worn in the tunnel. The patch was on the tunnel when I got it, and I just assumed the track had thrown a cleat and poked though. But once I could see it from the underside, it is obvious it was worn in by spinning cleats.

The plan right now is to remove the driveshaft and track, then relocate the chassis to another shed for a bit. I need the garage space opened up so I can get the X8s we are riding inside, and do a bit of prep for the Ride with the Champs coming up in Feb.
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thumbnail (43).jpg
thumbnail (45).jpg
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'09 Vintage Challenge Survivor, and I wasn't late for supper!
'10, '11, '12, '13,'14,'15,'16,'17, '18, 19, 20, 21, 22 Vintage Challenge Survivor !
72 400 restored, Father bought new in '71
73 X8 restored
'74 340 green machine
'74 X8 9 time VC finisher
'78 Spitfire in progress
2 '75 340S 1 running, one on deck
'78 LF 440 future CC clone
'73 Skiroule RTX 440, 500 mi.
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SS440-80
Posts: 260
Joined: Tue Jan 07, 2014 5:00 pm
Real Name: Robert
Location: SWEDEN

Re: 78 Spitfire project

Post by SS440-80 »

:clap: :clap: :clap:
Sleds...
2xJOHN DEERE SPRINTFIRE 1983.
YAMAHA GP292b 1973
OCKELBO Trioman 1975
YAMAHA SRV 1982 (shrinked)
YAMAHA SRV 1990
YAMAHA SRV 1991
LYNX Rave 600ACE 2013
LYNX BOONDOCKER RE 3700 850 ETEC 2018
AirborneX4Special
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Joined: Sat Jan 30, 2010 10:54 am
Real Name: Pat
Location: N. IL

Re: 78 Spitfire project

Post by AirborneX4Special »

:bonk: :usa: :popcorn:
Sure is fun watching the snowmobile resurrection misery of others!

My turn at the virtual millstone is forthcoming, so stay tuned as the before pics are coming soon...
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400brian
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Location: South Central Wisconsin

Re: 78 Spitfire project

Post by 400brian »

One ski came off no sweat, on the other, the bolt twisted off. So that one has a date with the fire wrench.

As you can see, the pan isn't too badly caved in, better than other sleds I've messed with. In all I think the sled is a good starter sled for the grandson.
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thumbnail (48).jpg

'09 Vintage Challenge Survivor, and I wasn't late for supper!
'10, '11, '12, '13,'14,'15,'16,'17, '18, 19, 20, 21, 22 Vintage Challenge Survivor !
72 400 restored, Father bought new in '71
73 X8 restored
'74 340 green machine
'74 X8 9 time VC finisher
'78 Spitfire in progress
2 '75 340S 1 running, one on deck
'78 LF 440 future CC clone
'73 Skiroule RTX 440, 500 mi.
User avatar
400brian
Posts: 5610
Joined: Wed Jul 20, 2005 12:00 am
Real Name: James T. Kirk
Location: South Central Wisconsin

Re: 78 Spitfire project

Post by 400brian »

Pat, looking forward to seeing the pics and hearing about what you are working on.

'09 Vintage Challenge Survivor, and I wasn't late for supper!
'10, '11, '12, '13,'14,'15,'16,'17, '18, 19, 20, 21, 22 Vintage Challenge Survivor !
72 400 restored, Father bought new in '71
73 X8 restored
'74 340 green machine
'74 X8 9 time VC finisher
'78 Spitfire in progress
2 '75 340S 1 running, one on deck
'78 LF 440 future CC clone
'73 Skiroule RTX 440, 500 mi.
User avatar
400brian
Posts: 5610
Joined: Wed Jul 20, 2005 12:00 am
Real Name: James T. Kirk
Location: South Central Wisconsin

Re: 78 Spitfire project

Post by 400brian »

As I write this, it has been exactly two weeks since we returned from St Germain, and the 2021 RWTC. What a difference two weeks makes! Much of this winter had been quite benign, very seasonal temps, cold snaps of a couple days at a time, and not enough snow to open the local trails. Just before we traveled north we got a significant snow, and the polar vortex. We had the longest stretch of very cold weather that we'd had in many years. A couple of days after we returned, the cold snap ended, and the daily temps began improving. Now we are in the 40's, the Sandhill Cranes have returned, the geese are flying, and the Maple tree sap is running! A lot easier to adapt to warm weather than the other way around.

So it is time to revisit the Spitfire. I decided to pull the suspension apart, and tackle my least favorite part of these builds, the removal of the suspension shafts. It could have been worse, of the 5 aluminum shafts, 3 slid out no sweat, the other two looked like a challenge. I had one of the longs shafts and one of the shortest that were looking for a fight.

Pictured below is the front arm. One end looked decent and would take penetrating oil, the other end was solidly corroded. I have had some experience with these, and none of it was good. I have tried drilling out the short shafts in the past, and I have resorted to melting the aluminum out. In neither case was I particularly happy with the result. I did some research, and tried a different approach on this.
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thumbnail (96).jpg

'09 Vintage Challenge Survivor, and I wasn't late for supper!
'10, '11, '12, '13,'14,'15,'16,'17, '18, 19, 20, 21, 22 Vintage Challenge Survivor !
72 400 restored, Father bought new in '71
73 X8 restored
'74 340 green machine
'74 X8 9 time VC finisher
'78 Spitfire in progress
2 '75 340S 1 running, one on deck
'78 LF 440 future CC clone
'73 Skiroule RTX 440, 500 mi.
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400brian
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Joined: Wed Jul 20, 2005 12:00 am
Real Name: James T. Kirk
Location: South Central Wisconsin

Re: 78 Spitfire project

Post by 400brian »

I decide to thermal shock the tube to start. I warmed it up as quickly as I could with the oxy/acetylene torch, then quenched it in water to try to get the different contraction rates to break the corrosion bond. I had bolts with jam nuts screwed into each end to pound on. when the tube cooled, I found I could move the shaft slightly. I figured I had this one licked, if I could move it a little, with penetrant and working it back and forth it would loosen up. Well, after a couple of hours of work, I had worked my way up to 3/16th of an inch, all one way. Patience is a virtue, but mine was running out.

Laying in bed that night, I was running through the problem in my head. In kind of a eureka moment, it occurred to me that none of the ideas I could remember, involved pulling these shafts. The next day I looked through my stash of steel tube, and found a piece around 10" long and had a 3/4" ID. This was chrome moly steel with a wall thickness of around 1/8". I also had a piece of 3/8" Redi-rod, so I was all set for an experiment.
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The tube, Redi-rod, and a adjustable reamer made of the finest Chinesium tool steel.
The tube, Redi-rod, and a adjustable reamer made of the finest Chinesium tool steel.
Last edited by 400brian on Fri Mar 05, 2021 2:34 am, edited 1 time in total.

'09 Vintage Challenge Survivor, and I wasn't late for supper!
'10, '11, '12, '13,'14,'15,'16,'17, '18, 19, 20, 21, 22 Vintage Challenge Survivor !
72 400 restored, Father bought new in '71
73 X8 restored
'74 340 green machine
'74 X8 9 time VC finisher
'78 Spitfire in progress
2 '75 340S 1 running, one on deck
'78 LF 440 future CC clone
'73 Skiroule RTX 440, 500 mi.
User avatar
400brian
Posts: 5610
Joined: Wed Jul 20, 2005 12:00 am
Real Name: James T. Kirk
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Re: 78 Spitfire project

Post by 400brian »

I threaded the Redi-rod into the shaft until it bottomed out, added a jam nut, the tube, a couple of flat washers, and then a nut. I wound the nut up tight, then rapped the bolt threaded into the opposite end, then tried the nut again...I had movement! Not much, but a little. I oiled the threads of the Redi-rod and repeated tightening the nut and tapping the bolt.

Progress was slow at first, the initial 1/2 inch came VERY hard, but little by little I was gaining. When things got tough I would back off the nut, oil the threads and shoot some penetrant on each end of the shaft.
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'09 Vintage Challenge Survivor, and I wasn't late for supper!
'10, '11, '12, '13,'14,'15,'16,'17, '18, 19, 20, 21, 22 Vintage Challenge Survivor !
72 400 restored, Father bought new in '71
73 X8 restored
'74 340 green machine
'74 X8 9 time VC finisher
'78 Spitfire in progress
2 '75 340S 1 running, one on deck
'78 LF 440 future CC clone
'73 Skiroule RTX 440, 500 mi.
User avatar
400brian
Posts: 5610
Joined: Wed Jul 20, 2005 12:00 am
Real Name: James T. Kirk
Location: South Central Wisconsin

Re: 78 Spitfire project

Post by 400brian »

After I got the first 2" out, things started getting much better. It never came easy, but the effort was declining. At about the half way point, I bottomed out on the tube. At that point I loosened the nut way back, and used the tube as a slide hammer and pulled it the rest of the way out.

As you can see, it was mainly corroded on one end. I was pretty happy about how this worked! I had removed the shaft and it appeared I could clean it up and re-use it. Win- Win!
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'09 Vintage Challenge Survivor, and I wasn't late for supper!
'10, '11, '12, '13,'14,'15,'16,'17, '18, 19, 20, 21, 22 Vintage Challenge Survivor !
72 400 restored, Father bought new in '71
73 X8 restored
'74 340 green machine
'74 X8 9 time VC finisher
'78 Spitfire in progress
2 '75 340S 1 running, one on deck
'78 LF 440 future CC clone
'73 Skiroule RTX 440, 500 mi.
User avatar
400brian
Posts: 5610
Joined: Wed Jul 20, 2005 12:00 am
Real Name: James T. Kirk
Location: South Central Wisconsin

Re: 78 Spitfire project

Post by 400brian »

So now the short one, this one did not look promising at all. It looked to be solidly corroded on each end. I thermal shocked it, and observed no changes, so hit the sack for the night. This shaft was drilled for a 7/16th bolt. I did not not have any threaded rod that size, so that was the next thing.

The next day with some brand new rod in hand, I set up the pulling tool and wound it up tight.
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'09 Vintage Challenge Survivor, and I wasn't late for supper!
'10, '11, '12, '13,'14,'15,'16,'17, '18, 19, 20, 21, 22 Vintage Challenge Survivor !
72 400 restored, Father bought new in '71
73 X8 restored
'74 340 green machine
'74 X8 9 time VC finisher
'78 Spitfire in progress
2 '75 340S 1 running, one on deck
'78 LF 440 future CC clone
'73 Skiroule RTX 440, 500 mi.
User avatar
400brian
Posts: 5610
Joined: Wed Jul 20, 2005 12:00 am
Real Name: James T. Kirk
Location: South Central Wisconsin

Re: 78 Spitfire project

Post by 400brian »

I could not use a jam nut on the 7/16 rod because the nut was larger than the ID of the tube. With the puller tight, I tapped on the opposite end and saw no movement. I then warmed the tube up nicely with the torch and tried that again...no movement. It wasn't looking good, so I decide to go all in.

A bit of discretion is required here, I wanted to heat the tube quite hot, but not soften the aluminum shaft and pull the threads out of it. As I recall, you have to get the steel tube red hot to melt the aluminum. So I quickly re-heated the tube up till it was just showing red under the flame as I moved it around. I then quenched it in a 5 gallon bucked with the puller still attached. When everything calmed down, I pulled it out of the water and saw the washers were loose! I tapped the opposite end and saw movement...Hot damn, I am in business!
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Last edited by 400brian on Mon Mar 01, 2021 2:58 am, edited 1 time in total.

'09 Vintage Challenge Survivor, and I wasn't late for supper!
'10, '11, '12, '13,'14,'15,'16,'17, '18, 19, 20, 21, 22 Vintage Challenge Survivor !
72 400 restored, Father bought new in '71
73 X8 restored
'74 340 green machine
'74 X8 9 time VC finisher
'78 Spitfire in progress
2 '75 340S 1 running, one on deck
'78 LF 440 future CC clone
'73 Skiroule RTX 440, 500 mi.
User avatar
400brian
Posts: 5610
Joined: Wed Jul 20, 2005 12:00 am
Real Name: James T. Kirk
Location: South Central Wisconsin

Re: 78 Spitfire project

Post by 400brian »

At that point I took the assembly to the heated garage where I could get it in a vice, and go at it. I took my time, and it came hard all the way. I found you really need to stop and oil the threads fairly often, as it wants to heat up.
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thumbnail (97).jpg

'09 Vintage Challenge Survivor, and I wasn't late for supper!
'10, '11, '12, '13,'14,'15,'16,'17, '18, 19, 20, 21, 22 Vintage Challenge Survivor !
72 400 restored, Father bought new in '71
73 X8 restored
'74 340 green machine
'74 X8 9 time VC finisher
'78 Spitfire in progress
2 '75 340S 1 running, one on deck
'78 LF 440 future CC clone
'73 Skiroule RTX 440, 500 mi.
User avatar
400brian
Posts: 5610
Joined: Wed Jul 20, 2005 12:00 am
Real Name: James T. Kirk
Location: South Central Wisconsin

Re: 78 Spitfire project

Post by 400brian »

Ok, so the shafts are all out, next is the rear axle. I put a wrench on the cap screws that hold the idler wheels on, and couldn't budge them. All the fasteners on this skid were either loose, or loctited tight. The propane torch is generally enough to melt the Loctite, so that was applied and I got the fasteners out. Plastic wheels with plastic bearing bushings makes this a bit hairy. I popped one of the bearings out of the wheels to confirm that they are indeed the same bearings used in the aluminum center wheels I am familiar with.

The last 2 things left were the 7/16" diameter shafts that go in between the rails. One at the front that the limiter strap goes around, and another that is the lower shock shaft. The front is retained by a hex head cap screw, the other by a specialty fastener. I found a socket that fit the head, but it was not willing to come out. There is a plastic spacer on each side of the shock to locate it, but they had to be sacrificed to heat the shafts. I warmed the first side up and the little bolt came right out. I repeated the process for the other side, and while it broke loose, it galled solidly before it came out and it was game over.

The challenge at the front shaft was finding a socket that would fit inside the rail. It turned out a 13mm did the trick.

After removing the plastic caps on the tip of the rails, the air hammer made quick work of removing the hyfax.

So to wrap this up: I have a new shock shaft located. JD Hyfax is sold out everywhere at the moment, but Don Amber had some in stock. I also got the last shock he had, and the word is that the sold out inventory will not get replenished until fall. Apparently with the whole Covid thing going on, a lot of guys worked on sleds this winter and the parts supply has been wiped out.
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thumbnail - 2021-02-28T234639.858.jpg
thumbnail - 2021-02-28T234628.770.jpg

'09 Vintage Challenge Survivor, and I wasn't late for supper!
'10, '11, '12, '13,'14,'15,'16,'17, '18, 19, 20, 21, 22 Vintage Challenge Survivor !
72 400 restored, Father bought new in '71
73 X8 restored
'74 340 green machine
'74 X8 9 time VC finisher
'78 Spitfire in progress
2 '75 340S 1 running, one on deck
'78 LF 440 future CC clone
'73 Skiroule RTX 440, 500 mi.
User avatar
400brian
Posts: 5610
Joined: Wed Jul 20, 2005 12:00 am
Real Name: James T. Kirk
Location: South Central Wisconsin

Re: 78 Spitfire project

Post by 400brian »

The hyfax and shock has arrived from Don Amber. The shock is the same one I have on the plastic skis on my JDX8. To use this shock you need to make a slight modification. The ID of the eyes of the shock are slightly smaller that the 7/16" of the originals, so you have a couple of options.

You can used a metric M-10 bolt, or you can drill the eyes out to 7/16". I have found that drilling them out is relatively easy, so that is the direction I go. You need a good sharp drill bit, but other than that I don't do anything special. I set the shock eye on a block of wood on the drill press, and slowly drill it out. You are taking out a very small amount, so it will cut like butter, but it will get hot. If it starts stinking you need to pause and let it cool, because you can spin the eye in the rubber bushing, then it gets tougher to drill.

Once I have it drilled, I clean the bore out with a round file until the bolt fits nice.
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thumbnail - 2021-03-02T211639.580.jpg

'09 Vintage Challenge Survivor, and I wasn't late for supper!
'10, '11, '12, '13,'14,'15,'16,'17, '18, 19, 20, 21, 22 Vintage Challenge Survivor !
72 400 restored, Father bought new in '71
73 X8 restored
'74 340 green machine
'74 X8 9 time VC finisher
'78 Spitfire in progress
2 '75 340S 1 running, one on deck
'78 LF 440 future CC clone
'73 Skiroule RTX 440, 500 mi.
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