Well, my friends at Frontage Tractor finally located a crankshaft for me except--there's always an except--when I got it uncrated and the mains (taped around then shaft in order) removed, I found some pretty severe rust on the fillets of the back and middle journals. This is deep corrosion rust, looks like it might even be salt corrosion, but it's not on the wearing surface of the journals.

I could grind this corrosion out clean with a die grinder and polish it up again, but is this pitting going to be the starting point for a crack? Is the flywheel going to fall off in the middle of a job one fine day?

I think this is a pretty well overbuilt shaft. Cranks are welded up and i would guess that would start more stress cracking than my corrosion, but I don't know. I'm asking for some experience to weigh in here, please. Old Magnet, SJ, anybody been there before?

I'm attaching pictures of the corrosion, also how an old geezer with a bad back sets a crankshaft in place. Thanks in advance, your opinions are always valued.

Jack

The forklift is a 1945 Towmotor LT44.

I just know you'll persevere and come out smiling. I've seen your work on both of your machines. I'm sure you'll get'er done. I still working on mine currently as well. Aside from a parts scarcity and my top getting thinnner from yanking hair out.... I hope to breathe life back into it soon.

Boy I think if it was me I,d return it to the people you bought it from as they sure didn,t look at it very close to sell it to a customer or they didn,t care. The flywheel mounting flange looks ugly too & even the tapped holes look corroded terrible.It,s your choice but I think I,d look for a different crank as your taking a chance installing it the way it looks. I never saw one in that bad of shape.

Hi Jack,
That is pretty ugly.....and on two critical areas too....flywheel flange and thrust journal. The thrust journal radius looks to be more than corrosion. You mention that this is a weld built up and used??? unit. Reminds me of some poor weld up cranks I've seen where the weld was poorly terminated at the radius with voids and undercut from the welding process. This is an area of critical stress and the generous radius is there for that reason.

That being said, it's pretty rare to have a crankshaft break but who knows.
If you need to salvage I'd at least get these areas bead blasted (tape off the journals) get it cleaned up and see what you've got along with a dye-penetration check. If there is severe pitting then yes these are candidate stress risers and would make use of this unit questionable.

I don't quite follow you with the dial indicator and feeler gage pictures.
I'd suppose your are doing an alignment check for the straightness of the crank with the dial indicator but the feeler gage, appearing to be at 0.110
at the thrust bearing which is not completely installed is ????????

Sorry, couldn't answer sooner.....pokey internet service provider conked out again:rolleyes:

Thanks SJ and O.M.

First off, this isn't a welded up crank. It has very few hours apparently. It must have stood in a wet spot. The damage looks like it occurred either in storage, or perhaps in the engine after it was removede from the Cat.

The dial test indicated a 0.001" flat spot on the middle journal, not a bend. The dial took a quick dive at one point through maybe 30 degrees of rotation. I'd say it was acceptable. The end play with bearing half laying on the shaft, not bolted up is 0.011". That will bolt up well within limits. Throws are worn 0.001 to 0.0015" down from new specs. Mains are worn about 0.0005" down from new specs. This was a very good shaft before they stored it in the bath tub.

Problem is, it's the only usable shaft I've been able to find in standard size, and the -0.030" bearings have been an expensive and hard to find item also.

The only saving grace here is that it is going into stationery use, sitting level with a free floating PTO shaft and no clutch. The thrust surfaces won't get all that much thrust.

I'm going back to the supplier to discuss it today. I don't believe it is worth the $750 they are asking for it, mains included which I havn't gauged yet.

Thanks for input. I'll be back,

Jack

Hi Jack,
Yes, was a good unit......was.
I guess I picked up on the welding from your "Cranks are welded up" statement.

Still, probably about the best you are going to get....specs are good.
Might try haggling for some clean-up and checking work from your supplier.
For your application I'd use it.....just watch where you stand;)

Reminds me of some of the stuff I used to get from "Piggy" Smith LOL
You could always tell when the high tide/flooding season hit by the amount of rust/corrosion
and salt water that came with the freshly rattle can sprayed parts.

I took the pics of the damage up to the good folks that sold it to me, on approval, and they are sending them on to the junker that supplied the crank. We are hoping for an adjustment of some sort to cover cleanup, magnaflux testing, repolishing, whatever it takes.

Understand that I'm not stuck for this piece of iron just yet. They got it for me to look at. If I decide it won't pass muster I can send it back. I'm just out whatever time I put into inspection, cleaning and measuring. Frontage Tractor deals in used equipment, used parts and some new parts and aftermarket. They've been some of the best people to deal with I've ever known and they really know Cat.

Right now I'm waiting to see what they say at the wrecking yard. It's just a shame that a part that was servicable was let to deteriorate like that. It looks like it was standing on a dirty, wet floor, maybe got some water splashed on it also.

Here we go again. I got an adjustment on the shaft, not quite as much as I thought would be in order, but everything helps. Decided to clean it up and install.

The flywheel flange is rusty as he__ but it is good enough where the flywheel seats on the edge. The face is OK. The bolt threads had enough grease and crud in them to save the threads from the rust for the most part. Looks rough but I think it will work.

I cleaned the rust out with a wire brush in the die grinder (hold the speed down if you do this ever, guys. Wire wheels arn't built for 20,000 RPM!) and cleaned out most of the pitting with a stone on the Dremel tool. I figure I have at least as much metal left as you would have with a -0.030" grind.

Old Magnet observed there was more going on there than normal rust, which is a fact. Look at the main bearing corrosion. When you have aluminum next to steel with some water you will get electrolitic action, and that was the real bad actor here.

So, I'm going to install it, and I have no idea if this is a smart decision. There is still a little bit of pitting which is too deep to grind out at the flywheel flange, otherwise there would be no question.

I'll be back. Stop me if I'm doing something else in the course of this rebuild that goes outside the limits of normal intelligence! Thanks for advice,

Jack

Does that mean you are going to install that nasty looking bearing too:(
If thats the rear main with the pitted end being over the journal thread I think it will leak like a sieve.

I am going to measure some other bearings, maybe buy one new one. All the mains measured 0.006" clearance with blue plastigauge. A new rear main should match up OK, I'm thinking. At least there's the advantage of always running dead level on this application.

That half of the main sure looks nasty. Other half isn't nearly as bad. The thrust bearing shows very little damage.