Cat 941b resurrection/ Under carriage

[Cat977]

This won't be the proper way to do it. There is no guarantee you will have a good outcome. If I was there I would have a better feel for what to do. 638 will definitely work without a primer. It is a fast setup product, so primer would make it setup even faster, so I wouldn't use it. I think you should press them together with your jack to help tighten things up along with the 638. I think the press on would help send you towards the hub and sprocket running truer and with smaller gaps. You should check the run out before you mount the assembly. Also it may setup fast but doesn't get up to full strength for a couple days or more. Once you press it on remove the jack and don't even touch it for a good while.

From the company. LOCTITE® 638 is designed for the bonding of cylindrical fitting parts, particularly with narrow bond gaps approaching .00984” The product cures when confined in the absence of air between close-fitting metal surfaces and prevents loosening and leakage due to shock and vibration.

 

[charles walton]

This won't be the proper way to do it. There is no guarantee you will have a good outcome. If I was there I would have a better feel for what to do. 638 will definitely work without a primer. It is a fast setup product, so primer would make it setup even faster, so I wouldn't use it. I think you should press them together with your jack to help tighten things up along with the 638. I think the press on would help send you towards the hub and sprocket running truer and with smaller gaps. You should check the run out before you mount the assembly. Also it may setup fast but doesn't get up to full strength for a couple days or more. Once you press it on remove the jack and don't even touch it for a good while.

From the company. LOCTITE® 638 is designed for the bonding of cylindrical fitting parts, particularly with narrow bond gaps approaching .00984” The product cures when confined in the absence of air between close-fitting metal surfaces and prevents loosening and leakage due to shock and vibration.

I have an idea that I am going to try for getting it tightened up some and I will not mount the unit for a couple of days. If it works I will post my method......if it doesn't I will regroup and try something else.

 

[Welder Dave]

I've mentioned it before but Loctite 660 is the strongest Loctite and fills gaps up .020" (.5mm). 638 lists gaps up to .25mm. It is strongest when used without a primer. Either 638 or 660 could work for the application though. I put a link for the different Loctite retaining compounds below.

LOCTITE 660 - Retaining Compound - Henkel Adhesives (henkel-adhesives.com)

Retaining Compounds (vehicle-repair-solutions.com)

 

[Welder Dave]

I have an idea that I am going to try for getting it tightened up some and I will not mount the unit for a couple of days. If it works I will post my method......if it doesn't I will regroup and try something else.

Any particular reason your idea is top secret? There is an incredible wealth of knowledge on this forum so I would suggest telling us what your idea for the repair is. Chances are very good that it's been tried before and someone can say if it works or not. Don't worry if it seems odd. People are trying to help you fix your machine the best and most cost effective way.

 

[charles walton]

Any particular reason your idea is top secret? There is an incredible wealth of knowledge on this forum so I would suggest telling us what your idea for the repair is. Chances are very good that it's been tried before and someone can say if it works or not. Don't worry if it seems odd. People are trying to help you fix your machine the best and most cost effective way.

I will take some pics as I do it and describe what I'm doing and then if it works,good and if it don't,bad. I'm not trying to be secret it's just that it takes longer to try to explain it without pictures.

 

[charles walton]

I've mentioned it before but Loctite 660 is the strongest Loctite and fills gaps up .020" (.5mm). 638 lists gaps up to .25mm. It is strongest when used without a primer. Either 638 or 660 could work for the application though. I put a link for the different Loctite retaining compounds below.

LOCTITE 660 - Retaining Compound - Henkel Adhesives (henkel-adhesives.com)

Retaining Compounds (vehicle-repair-solutions.com)

I looked at that link a couple weeks ago when one of ya'll posted it. The reason I went with 638 is because I got it for a good deal on E-bay delivered to my door and it was the strongest one on there, I actually liked the sound of the 660 better but I couldn't find a deal on e-bay for it.

 

[Welder Dave]

If your idea doesn't work, will it make it harder to fix with another option? Never thought that what you could find on e-bay for a deal is a criteria for what you buy. I don't mind going to an industrial supply to get what I need. I guess I prefer to not to buy online unless I have to.

 

[charles walton]

If your idea doesn't work, will it make it harder to fix with another option? Never thought that what you could find on e-bay for a deal is a criteria for what you buy. I don't mind going to an industrial supply to get what I need. I guess I prefer to not to buy online unless I have to.

I appreciate the help that I get on these pages but I'm not looking for critics of my choices to try and make me second guess everything,that's why I'm not going to post my method until I am through assembiing it and then time will tell. There is no doubt that it would last longer if I used a new hub and sprocket. I already have the hub but I want to try this idea that I have and see if it will hold together for about 200 hours and then I will put new parts in it and also salt tracks on it. The machine has been sitting for 20 years so I want to spend sparingly right now until I see if the trans and engine are going to hold up. P.S. there are no industrial supply places nearby enough for me to go by when I have to work 7am to 6 pm with 30 minutes for lunch.

 

[Welder Dave]

It doesn't hurt to mention your proposed repair. There is centuries of experience on this forum and there's a real good chance someone has encountered a similar problem to yours. There may not be a need for new parts if a good repair is done. Only you can second guess yourself but sounds like you aren't confident enough to want to post what you plan on doing. That could be a mistake. If people need the right parts for a repair, they make arrangements to get the right parts instead of making excuses. Seen it too many times where someone posts and then doesn't want to listen to experience on how to fix the problem. Then they get upset and say no one tried to help them.

 

[charles walton]

It doesn't hurt to mention your proposed repair. There is centuries of experience on this forum and there's a real good chance someone has encountered a similar problem to yours. There may not be a need for new parts if a good repair is done. Only you can second guess yourself but sounds like you aren't confident enough to want to post what you plan on doing. That could be a mistake. If people need the right parts for a repair, they make arrangements to get the right parts instead of making excuses. Seen it too many times where someone posts and then doesn't want to listen to experience on how to fix the problem. Then they get upset and say no one tried to help them.

You're probably right, except I'm not going to blame anyone if my hardheaded mistakes are to blame. Here's a question I have came up with while not sleeping last night....why would JB weld not be the best for this application?

 

[charles walton]

This won't be the proper way to do it. There is no guarantee you will have a good outcome. If I was there I would have a better feel for what to do. 638 will definitely work without a primer. It is a fast setup product, so primer would make it setup even faster, so I wouldn't use it. I think you should press them together with your jack to help tighten things up along with the 638. I think the press on would help send you towards the hub and sprocket running truer and with smaller gaps. You should check the run out before you mount the assembly. Also it may setup fast but doesn't get up to full strength for a couple days or more. Once you press it on remove the jack and don't even touch it for a good while.

From the company. LOCTITE® 638 is designed for the bonding of cylindrical fitting parts, particularly with narrow bond gaps approaching .00984” The product cures when confined in the absence of air between close-fitting metal surfaces and prevents loosening and leakage due to shock and vibration.

well,I cleaned up the sprocket and hub then sat the sprocket on the hub dry,to see how it looked and it slid down freely until the hub splines were sticking through about 1/8". I'm not going to try to use it,I'm going to shop for a new sprocket ,and bearing ro the new hub that I already have.

 

[Welder Dave]

Splines are worn in the sprocket, hub or both? Loctite 660 is for repairing splines if required. Would have to follow directions very carefully. Did you take any pics.? JB weld is low on the totem pole as far as epoxies go. There are much better products for specific applications. JB weld works great for some applications but is more a general purpose epoxy. Belzona is hard to find but is apparently the best of the best as far as epoxies go.

 

[charles walton]

Splines are worn in the sprocket, hub or both? Loctite 660 is for repairing splines if required. Would have to follow directions very carefully. Did you take any pics.? JB weld is low on the totem pole as far as epoxies go. There are much better products for specific applications. JB weld works great for some applications but is more a general purpose epoxy. Belzona is hard to find but is apparently the best of the best as far as epoxies go.

They are both worn,I'm just going to get a new sprocket...that seems to be the best option for a lasting repairalthough I thought about using the epoxy and then running a bead with a 7018 where the hub splines and sprocket splines are easily accessible,but I'll save that for a last ditch effort sometime maybe on a tractor that is in worse shape overall than this one.

 

[charles walton]

Here's the new hub slid into the old sprocket. It looks better than the old hub but I am going to try and find a new sprocket. Does anyone know if a reconditioned sprocket would have new splines or just a new rim?

 

[Cat977]

If the splines have never gotten loose, or been subjected to corrosion they should be fine. If you plan on putting it together yourself be sure everything is very clean. Including deburring all edges and flat filing all dings. Don't use anything more than a very lite oil to assemble. You want a metal to metal fit without any galling from pressing to far. I would use layout dye to check the fit before finale assembly.

 

[charles walton]

If the splines have never gotten loose, or been subjected to corrosion they should be fine. If you plan on putting it together yourself be sure everything is very clean. Including deburring all edges and flat filing all dings. Don't use anything more than a very lite oil to assemble. You want a metal to metal fit without any galling from pressing to far. I would use layout dye to check the fit before finale assembly.

my sprocket was loose when I disassembled it. Not floppy but I didn't have to use a puller. I would buy a new aftermarket one but the chinese parts have suddenly disappeared. I found one new one in miami for $571 on e-bay,said there were three available and it had the "make offer" option so I decided to make an offer for two of them and I offered $950 for two,they answered back by upping the listing price to $5000 and countering my offer to the tune of $1500 per unit.My other option is a used,reconditioned for $800. My question is whether they can actually build up the splines and machine back down or are they just welding on a new rim and calling that reconditioned?

 

[Cat977]

You need a very specialized machine to cut the tapered splines. It could be they put in inserts like you have on your sprocket. $800 sounds like a fairly good price for a sprocket with newly installed outer teeth. I don't believe they would install new outer teeth if the splines were bad. That fellow in Miami probably bought those sprockets cheap at an auction. Not a lot of market out there for them, unless they use them on a few other machines. You might want to send him a last and final offer. Have you tried Cat? I kind of get a base price of cost from what their charging.

 

[charles walton]

You need a very specialized machine to cut the tapered splines. It could be they put in inserts like you have on your sprocket. $800 sounds like a fairly good price for a sprocket with newly installed outer teeth. I don't believe they would install new outer teeth if the splines were bad. That fellow in Miami probably bought those sprockets cheap at an auction. Not a lot of market out there for them, unless they use them on a few other machines. You might want to send him a last and final offer. Have you tried Cat? I kind of get a base price of cost from what their charging.

The place in Miami is an aftermarket dealer. They have a bunch of parts on ebay. I wonder where you can buy the inserts? My sprocket will tighten up some before it presses past the range it should be but I don't think it will be to spec so I'm thinking about using the retainer and knocking it on to the right place and run it. I am going to put new ring on it first and I'm going to call about the used one and see what's been done to it.

 

[Cat977]

Went back to looking at your sprocket, it has quite a bit of wear. I bet the chains/rails probably do also. I wouldn't put a new sprocket on. It would probably run rough because the spacing on the chain wouldn't match the spacing on the sprocket. Call some track shops to see if they've heard about that insert for the sprocket before. The old sprocket to new hub is sounding better. Be careful of welding the sprocket to the hub it could shrink the bore inside the hub.

 

[charles walton]

Went back to looking at your sprocket, it has quite a bit of wear. I bet the chains/rails probably do also. I wouldn't put a new sprocket on. It would probably run rough because the spacing on the chain wouldn't match the spacing on the sprocket. Call some track shops to see if they've heard about that insert for the sprocket before. The old sprocket to new hub is sounding better. Be careful of welding the sprocket to the hub it could shrink the bore inside the hub.

Thanks, I was only going to weld it if I used both of the old parts. I will just use the retaining compound with the new hub.