My "new" 1872

[Matt G.]

It lives!

It turned out that the mag was fine, but the air gap was too large. The fuel pump was bad, so it got replaced, but it still wouldn't run above idle. I couldn't figure out what was wrong since the carb was rebuilt and everything. I finally discovered that there are two different carb elbows for the KT17 and M18, and two different atmospheric vent locations for the carbs. I replaced the Walbro with an adjustable carb, but the atmospheric vent didn't match the elbow, so the vent was essentially plugged. I put a different elbow on with the right vent hole, and it started right up. It runs and drives nice (PS is GREAT) but the trunion needs welding and it shakes because the rear coupler is bad. Now I just need to get the CI rear in it, and it'll be all set.

[CBH]

Keep us posted Matt. I enjoy reading how you fix these things!

[ACecil]

Great job, Matt! Thanks for the update.

[Matt G.]

Back to work on this again. Since I finally got it running and driving again, I have now started the CI rear conversion. The first picture is the donor rear.

In the second picture, it's cleaned, and most of the loose paint stripped off.

I put match marks on the bearing retainers so that they wind up going back in the same way they came out. (Pictures 3 and 4)

There's definitely some gunk in here: (5)

Here's the bare transaxle, cleaned: (6)

Here's the coarse-spline 'guts' (7). I hope that I can use the pinion shaft from the aluminum rear, because the ring gear is shot on this one...there's a crack in one of the teeth. Tomorrow's project is to pull the rear that's in the 1872 and disassemble it.


Question for the experts: The IH manual has all these instructions about shimming the rear bearing cup for the pinion shaft, and I assume this is to get the proper pinion depth/orientation for the spiral-cut gears in the IH rears. The aluminum rear has straight-cut ring and pinion gears, and there are no such instructions in the CCC manual for the aluminum rears...it just tells you to put it together and set the backlash, with no mention of setting the depth. My thought is that it doesn't make much of a difference with the straight cut gears. If I use the straight cut ring and pinion, do I just follow the CCC manual?

[Matt G.]

Here's the rest of the pics.

[ACecil]

Thanks for the update, Matt. Your 1872 will be right when you are done with it!

[Matt G.]

When I said 'backlash' in my post last night, I meant to say 'preload'.

Originally Posted by murphycc

Matt, someone did an extensive pictorial showing just what you asked....over at the other place.....about 6 months ago.....archives?

Scott

Not quite...he used the CI rear's pinion shaft and put the matching ring gear on the carrier. I will be using the pinion shaft and ring gear from the aluminum rear in the CI case. If I was putting the same pinion shaft back in, I wouldn't have to change anything, but because I'm changing that, I have to figure out how to set the backlash, as the CCC manual for the aluminum rears has no instructions...it just says how to set the preload.

[Matt G.]

Today I removed the aluminum rear from the 1872. All 4 axle tube bolts that held the rear to the frame were twisted off inside, so the PO just jammed some short 7/16" bolts in there to hold it in...

The carrier looks like new, and there was no junk in the case. The axles look like new, as well. Everything's in good shape.

The best news is that the pinion shafts appear to be of the same dimensions between the CI and aluminum rears. I'll do some checking tomorrow, but it looks like that'll go right in.

I'll then spend the better part of tomorrow trying to get the right contact pattern. Hooray for trial and error

[Matt G.]

Bill-

It'd actually be easier to do what you want to do...mine's getting a bit complicated because I'm dealing with a super. You could leave the pinion alone and change ring gears.

[Methos]

Originally Posted by Matt G.

I'll then spend the better part of tomorrow trying to get the right contact pattern. Hooray for trial and error

Should be the same as any other cub rear end. The manual for my 122 has the same contact pattern as the one's we built at Dana for off highway use (some of these was 22ft long without any tires mounted on them. I wouldn't over think it try what you know and go from there. You are the expert after all :biggrin2.gif: