Thiokol Imp 1404 - repair/restoration questions

[Snowdancer]

I am new to the snowcat world.

This summer I bought this snowcat 1404 imp and am giving it a top to bottom mechanical checkup before taking it out for the winter.

I have a few items I could use advice on. The first item is the frame.

I inspected the frame - all is straight except for the front left strut which bends up 1/4” over its length. Picture attached. Need advise on how significant this is.

The first options I am considering is welding a steel plate diamond to the bottom of the strut to reinforce and prevent any further bending and also shimming the wheel so that it is true to the frame from top to bottom The welding may even pull the member back down a 1/16”.

The other option is to figure out how to straighten the strut using heat and mechanical force. Obviously much more involved and any suggestions on how to straighten are appreciated.

In your experience is the 1/4” bend significant?

 

[Idaho IMP]

The undercarriage of my wide track imp is hammered. My front “axle” tube thing has been tweaked, rewelded apparently more than once. I think the big question is if it throws tracks. My setup runs a urethane front idler vs a pneumatic one on the narrow track version. You may be able to heat and bend or put a bottle jack to it somehow but I think it’s probably ok as is. The tracks are fairly forgiving as they travel around circumferentially.

Good luck and welcome to the insanity. Look forward to seeing your rig!

 

[BoyToys]

I'm with Mr Idaho IMP....leave it alone. I would be reluctant to try bending it, but your thought of reinforcing with a steel plate welded on is not a bad idea.
I'm still running with the more than likely original idler tires, solid rubber...not urethane or pneumatic. They're old but holding together.
Have fun sorting out all the myriad of things (minor or huge, whatever). Do fun stuff like rebuilding the tracks, or removing/gutting/and repairing the C4 differential, replacing windshield, sorting out wiring rats nests, gauge issues,, painting, etc.
At least yours looks to be better cared for than mine was. Season #2 almost upon us, will see if mine performs well once again.

More pictures when you get a chance.

 

[Snowdancer]

Thanks for the advise!

I am going to weld on a reinforcement plate and leave the 1/4” bend in place. I will send pictures.

Any thoughts/advice on adding a 2” hitch receiver to the front end?

 

[redsqwrl]

Thanks for the advise!

I am going to weld on a reinforcement plate and leave the 1/4” bend in place. I will send pictures.

Any thoughts/advice on adding a 2” hitch receiver to the front end?

I just noticed the question. If you not going to be blading snow. Heck yes stick a receiver on there. Basket trays, winches lots of items to stick up there.

 

[Idaho IMP]

Thanks for the advise!

I am going to weld on a reinforcement plate and leave the 1/4” bend in place. I will send pictures.

Any thoughts/advice on adding a 2” hitch receiver to the front end?

I’ve got the steel bits to build one for my 1404. My thought is a pair of 3/16 x 6” side plates with 4- 1/2” bolts in a staggered pattern going through the side walls of the tunnel, under the front of the engine. The plates would protrude a few inches out the front, then have a piece of 3-1/2 square tube with a stubby receiver welded into the center of the tube. I do t know how soon I’ll get to it, but I’ll take pictures and post. My purpose was primarily for a winch mount. I would make a receiver mount plate, and make the winch leads long enough to be able to be used off the rear too. For you wide track owners, it’s a bit of a starry, but I’m building a set of new factory tracks for mine. How much clearance do you have between the inner edge of the track and the tub?

 

[Snowdancer]

I removed and replaced the eight idler wheel tires sourced new ones and inner tubes from FallLine - painted the rims - replacing all 16 wheel bearings as well as 8 races, 16 seals, one axle bolt and one spindle w shoulder nuts. Three of the old bearings were totally frozen and one axle bolt was really chewed up. I decided to replace the small front idler wheels while I am at it. I bought the replacements from Spryte Improvement who btw are super helpful. Came with most of the required parts. Both rear drive wheels turn freely and well. However, the left side appears to have an oil leak somewhere as there is dried oil all over the rim and axle (see pictures). Thinking about chasing the leak down but don't relish the idea of disasembling the axle. Anyone have experience with this issue?

 

[BoyToys]

I removed and replaced the eight idler wheel tires sourced new ones and inner tubes from FallLine - painted the rims - replacing all 16 wheel bearings as well as 8 races, 16 seals, one axle bolt and one spindle w shoulder nuts. Three of the old bearings were totally frozen and one axle bolt was really chewed up. I decided to replace the small front idler wheels while I am at it. I bought the replacements from Spryte Improvement who btw are super helpful. Came with most of the required parts. Both rear drive wheels turn freely and well. However, the left side appears to have an oil leak somewhere as there is dried oil all over the rim and axle (see pictures). Thinking about chasing the leak down but don't relish the idea of disasembling the axle. Anyone have experience with this issue?

You can just pull the axle straight out of the differential with a little force, then replace the seal at the end of the tube.
When I had my C4 assembly out and siting in my garage for some internal repairs, those axles pulled out pretty easily.

 

[Snowdancer]

I finished installing all of the new idler wheel and decided to tackle the rear left drive wheel oil leak.

For the life of me I couldn't get drive wheel lug nuts loosened but I was able to easily remove the four very small bolts on the backing plate and then with some force pulled the axle out with the drive wheel attached. Getting the bearing off the axle to replace it was quite the job - but it is done - used steel wedges to jack it off.

Tomorrow I will buy 3 feet of 1 1/2" steel black pipe to slide over the axle to set the new bearing. The bearing is sealed so I assume I can't really heat it to expand it and the axle is too big for me to freeze it to shrink. So hopefully,the new bearing will be set with some oil to lubricate and a couple of wacks on the 1 1/2 pipe bearing only on the inner bearing ring. Any other ideas?

I also removed the axle tube as there was a small drip there. Surprise to me - removing the bottom bolt drains the differential. The was about two quarts of oil in the axle tube. Is this normal?

 

[BoyToys]

I don't have enough miles under my belt to definitively answer what's normal for oil accumulation in the axle tubes. When I tore into my C4 to correct what a previous mechanic had done wrong (I had to turn the entire carrier assembly 180°...long story). I was puzzling how to seal the differential carrier bearing between the shims and the housing to prevent oil from oozing into the axle tubes. No easy solution, didn't want to screw up shim placement and R&P lash adjustment.

Bottom line: Some oil will eventually make it through. In my case only a couple ounces, but my Imp had been driven very little before I fixed the issue (initially I had but one forward gear by putting the front transmission in reverse, or by selecting reverse in the differential to get 3 forward gears).

I would guess that overfilling the differential would obviously result in lots of oil in the tubes. And that bottom bolt...it goes without saying to apply a sealer to the threads since it's a through hole.

Curious to see what our more seasoned Imp'sters have to say on this topic.

 

[Snowdancer]

Imp tracks are back on.... I decided the 1/4" bend in the front axle is ok as is.

Currently working on fitting a new weber carb which only fits when I rotate it 25 degrees to clear the hot water outlet and install on top of an 040" thick adapter plate. My son is making the plate for me. Picture is the trial adapter plate in plastic. He will now mill it out of aluminum. The new carb gives me a vacuum port which the old carb did not have and I will use it to set the timing on the engine.

BTW, does anyone know if the flexible brake hoses to the slave cylinders are available as as stock item or do I have to get them custom made?

 

[BoyToys]

Cool. I spent a lot of time researching Webers and almost bit the bullet but instead rebuilt and rejetted my original Solex. I was planning on one with a 27mm venturi vs the more common 29mm...the thought being to shift the power band a bit lower. I did a lengthy writeup complete with calculations somewhere on the forum. I'm no expert but more like a tenacious dog once I get my teeth into something.
Interesting, the need for a spacer. I didn't realize they aren't plug and play.
Many many moons ago I got intimate with Webers on my British sports cars. Wonderful carbs, so easy to tune in situ.