M620 axle problem

[Kilroy2k1]

Would anyone happen to have a line on service manuals or information on this ancient machine? I'm just about at my wits end with one axle.
I'm having a problem with the left rear wheel trying to get everything to sit together properly, I believe the tank walls had collapsed inwards some from years of abuse. I spread the tank walls apart to what should be right but the large gear retaining nut still seems to bottom out in the inner hub stopping it from keeping tension on the wheel bearings.
I had gotten a printout of the axle/hub assembly from the dealer and it looks like i have all the proper parts but as this machine has been around the block a few times and theres no telling whats been changed or if the parts may have been mixed up from one wheel to the next. I'm frozen and frustrated so if this dosent make sense I'll try and rephrase or draw it out or something.
Thanks, Tom.

 

[OldMachinist]

Could be that the bearing bore shoulder or shoulders have worn some maybe from a bearing that spun sometime causing the thread to bottom out before it tightens up. Can you post your diagram and a picture of the area on your machine so we can visualize whats going on.

 

[Kilroy2k1]

Could be that the bearing bore shoulder or shoulders have worn some maybe from a bearing that spun sometime causing the thread to bottom out before it tightens up. Can you post your diagram and a picture of the area on your machine so we can visualize whats going on.

The first time i had it apart i did check the bearing seats to see if it was worn or machined and found no sign of either. Its almost like the axle shaft is 1/2” longer then it should be I'll have to try and draft something up, I dont think a picture itself would help.
Tom.

 

[Kilroy2k1]

The first time i had it apart i did check the bearing seats to see if it was worn or machined and found no sign of either. Its almost like the axle shaft is 1/2” longer then it should be I'll have to try and draft something up, I dont think a picture itself would help.
Tom.

http://www.skidsteerforum.com/DesktopDefault.aspx?tabid=52&gallerypage=1&currentitem=0&path=M%20620
This is a picture of the printout I got from the dealer, it should give you some idea how it all goes together. forgive the quality it was taken with my phone.
The inner hub used on the rear wheels is the #20 in the picture, #19 is used on the front only. Each side tank on the Bobcat is the hydaulic fluid res and the chaincase in one. I think what i need are just the proper dimentions between the walls of the case to see if it has collapsed again or if i just never pushed it out far enough in the first place.
Tom.

 

[thetool]

http://www.skidsteerforum.com/DesktopDefault.aspx?tabid=52&gallerypage=1&currentitem=0&path=M%20620
This is a picture of the printout I got from the dealer, it should give you some idea how it all goes together. forgive the quality it was taken with my phone.
The inner hub used on the rear wheels is the #20 in the picture, #19 is used on the front only. Each side tank on the Bobcat is the hydaulic fluid res and the chaincase in one. I think what i need are just the proper dimentions between the walls of the case to see if it has collapsed again or if i just never pushed it out far enough in the first place.
Tom.

I looked in my manual. I have no experience with this machine--sorry.
What stands out in the manual is the use of special tools-”tank spreaders” and an “axle guide tool” that is removed after you tighten the final nut.
What I wonder is seeing how you have different inner flanges depending upon whether it's a front or rear axle, is if you have different length axles also. It would indicate that on the parts list that goes with your diagram.
If that stuff got mixed up it would be a headache.
That's the best I can do. I wish I knew more but I've never laid eyes on this model.

 

[Kilroy2k1]

I looked in my manual. I have no experience with this machine--sorry.
What stands out in the manual is the use of special tools-”tank spreaders” and an “axle guide tool” that is removed after you tighten the final nut.
What I wonder is seeing how you have different inner flanges depending upon whether it's a front or rear axle, is if you have different length axles also. It would indicate that on the parts list that goes with your diagram.
If that stuff got mixed up it would be a headache.
That's the best I can do. I wish I knew more but I've never laid eyes on this model.

I had considered that its the wrong parts and the only way i can verify that is ripping apart the other side and it dosent leak yet. The front hub and axles would be much shorter then the rear ones, on the order of 1-2 inches so that dosent account the just one half inch too much space i do have. Do you have any pictures of those special tools, i can see where the spreader may come in handy, but the guide tool has me stumped.
I took off the outer hub today and took some measurments of the drive gear and tank walls and am even more confused then before. The tanks are still at the dimention i pressed them out to when i thought i had this fixed last time and the drive gear has about 3/8“ side play between the bearing/spacer and retaining nut. At this point my only guess is that someone may have machined the bearing and seal shoulders back at one time or its an axle from a different machine. So i either have to rip apart the other side and start measuring up the shaft for differences or find a salvage yard with parts i can match up to or buy. And of course were expecting more snow tonight/tomorrow..
I appreciate the info.
Tom.

 

[thetool]

I had considered that its the wrong parts and the only way i can verify that is ripping apart the other side and it dosent leak yet. The front hub and axles would be much shorter then the rear ones, on the order of 1-2 inches so that dosent account the just one half inch too much space i do have. Do you have any pictures of those special tools, i can see where the spreader may come in handy, but the guide tool has me stumped.
I took off the outer hub today and took some measurments of the drive gear and tank walls and am even more confused then before. The tanks are still at the dimention i pressed them out to when i thought i had this fixed last time and the drive gear has about 3/8“ side play between the bearing/spacer and retaining nut. At this point my only guess is that someone may have machined the bearing and seal shoulders back at one time or its an axle from a different machine. So i either have to rip apart the other side and start measuring up the shaft for differences or find a salvage yard with parts i can match up to or buy. And of course were expecting more snow tonight/tomorrow..
I appreciate the info.
Tom.

The pages are vague on how you use the tool. If you shoot me an email at my business addy, I'll hook you up, but I don't know if it'll be much help.
They don't show a pic of the install tool, just call it p/n 6546161. It's so old it's not even an MEL-number, which is normal for special tools.
I also notice in the book that there is a support spacer between the walls of the tank back by the rear axle. If it's missing I could see your tank wall collapsing enough to give you this problem.
Let me know.

 

[Kilroy2k1]

The pages are vague on how you use the tool. If you shoot me an email at my business addy, I'll hook you up, but I don't know if it'll be much help.
They don't show a pic of the install tool, just call it p/n 6546161. It's so old it's not even an MEL-number, which is normal for special tools.
I also notice in the book that there is a support spacer between the walls of the tank back by the rear axle. If it's missing I could see your tank wall collapsing enough to give you this problem.
Let me know.

Thanks for the offer but if your right the pages really wont help much, But i shall keep your addy handy for possible future use
The spacer I think your refering to is just ahead of the rear axle and gear assembly and it is there, its actually what i used as a quick guage when i was pressing the tank walls out. After double checking my measurments the tank is still exactly where it should be, at the hub area it is about 3/64ths wider then it actually needs to be which is acceptable.
What i question are these items that i cant easily verify, has this axle been machined in the past or is it just the wrong part to begin with, and same goes for the part #6 in the drawing the #6509468 spacer. One end of that spacer looks a little rough like its been bench ground at one time so that could explain some of the side play in the gear.
I am almost certain the axle for one reason or another is 1/2 inch too long so i may have to pull apart the other side just to match up measurments.
Thanks again for the assistance, eventually with everyones help i know i can get this sorted.
Tom.

 

[sterlclan]

Thanks for the offer but if your right the pages really wont help much, But i shall keep your addy handy for possible future use
The spacer I think your refering to is just ahead of the rear axle and gear assembly and it is there, its actually what i used as a quick guage when i was pressing the tank walls out. After double checking my measurments the tank is still exactly where it should be, at the hub area it is about 3/64ths wider then it actually needs to be which is acceptable.
What i question are these items that i cant easily verify, has this axle been machined in the past or is it just the wrong part to begin with, and same goes for the part #6 in the drawing the #6509468 spacer. One end of that spacer looks a little rough like its been bench ground at one time so that could explain some of the side play in the gear.
I am almost certain the axle for one reason or another is 1/2 inch too long so i may have to pull apart the other side just to match up measurments.
Thanks again for the assistance, eventually with everyones help i know i can get this sorted.
Tom.

could you make a spacer for that item 6 a little longer? pipe or some such thing or is there no room there? Jeff

 

[Kilroy2k1]

could you make a spacer for that item 6 a little longer? pipe or some such thing or is there no room there? Jeff

I will likely make a new spacer to hold the gear firm once i get the axle centered properly or replaced. From what i can tell the gear should be firmly held between that and the large nut #21 in the diagram but at this time it has over 3/8th side to side play which just dosent seem proper.
Tom.

 

[sterlclan]

I will likely make a new spacer to hold the gear firm once i get the axle centered properly or replaced. From what i can tell the gear should be firmly held between that and the large nut #21 in the diagram but at this time it has over 3/8th side to side play which just dosent seem proper.
Tom.

shim the bearings?

 

[Kilroy2k1]

shim the bearings?

I had thought of that but if i just shim it then the hub seal wont have a surface to ride on, I can make a press on sleeve and match the seal surface easily enough. I can fix the issue with a little creative machine work but i would really like to know why the problem exists in the first place and if necessary get the proper parts.
Tom.

 

[Kilroy2k1]

I had thought of that but if i just shim it then the hub seal wont have a surface to ride on, I can make a press on sleeve and match the seal surface easily enough. I can fix the issue with a little creative machine work but i would really like to know why the problem exists in the first place and if necessary get the proper parts.
Tom.

Well i took a chance just to get the machine moving again. I machined up a 1/2” spacer and pressed it on infront of the outboard bearing and polished it for the seal to ride on, now the measurments add up to where they should. I am convinced it is the wrong axle shaft now. After examining it and the rest of the shafts this one has a hub with a raised center section where the other 3 hubs do not. I'll be putting it back together this morning, so we'll see if my problem is solved untill i can find a used shaft somewhere. Now i just have to figure out which models have the same part because not many ppl are aquainted with this oddball model.
I appreciate the help guys. Thanks
Tom.

 

[Kilroy2k1]

Well i took a chance just to get the machine moving again. I machined up a 1/2” spacer and pressed it on infront of the outboard bearing and polished it for the seal to ride on, now the measurments add up to where they should. I am convinced it is the wrong axle shaft now. After examining it and the rest of the shafts this one has a hub with a raised center section where the other 3 hubs do not. I'll be putting it back together this morning, so we'll see if my problem is solved untill i can find a used shaft somewhere. Now i just have to figure out which models have the same part because not many ppl are aquainted with this oddball model.
I appreciate the help guys. Thanks
Tom.

Eureka! I'm not insane or inept..
I got her all back together this morning and managed to clean off my driveway and no leaks when i parked it. I took a little time to examine everything closely because I was hearing a little bit of squeaking at times when turning, and this is when i found my missing 1/2”.
Part of a previous repair someone had welded the hub back on to the axle shaft, I thought nothing of this as the welds looked solid and it ran fairly true in the lathe. It was welded behind the hub and on the face where the shaft would have pressed through to the front. Today I noticed a hollow behind the weld on the face of the hub so i poked at it and removed a piece of weld that was there and lo and behold the shaft itself is actually pulling itself out of the hub! The shoulder behind the hub is a sleeve overtop of the origonal shaft and its securely welded to the hub but both of them are slipping off the shaft itself.
I was beginning to think i was inept in my assembly of the machine because of all the clearance that was appearing after use but the shaft was in essence getting longer and making more clearance, and to look at it you couldnt tell what was happening from the back side.
I'll have to come apart one more time, but at least this time I know it'll be fixed properly.
Tom.

 

[OldMachinist]

Eureka! I'm not insane or inept..
I got her all back together this morning and managed to clean off my driveway and no leaks when i parked it. I took a little time to examine everything closely because I was hearing a little bit of squeaking at times when turning, and this is when i found my missing 1/2”.
Part of a previous repair someone had welded the hub back on to the axle shaft, I thought nothing of this as the welds looked solid and it ran fairly true in the lathe. It was welded behind the hub and on the face where the shaft would have pressed through to the front. Today I noticed a hollow behind the weld on the face of the hub so i poked at it and removed a piece of weld that was there and lo and behold the shaft itself is actually pulling itself out of the hub! The shoulder behind the hub is a sleeve overtop of the origonal shaft and its securely welded to the hub but both of them are slipping off the shaft itself.
I was beginning to think i was inept in my assembly of the machine because of all the clearance that was appearing after use but the shaft was in essence getting longer and making more clearance, and to look at it you couldnt tell what was happening from the back side.
I'll have to come apart one more time, but at least this time I know it'll be fixed properly.
Tom.

That would be enough to drive you crazy having to put it together only to have the shaft pull out a little more. Glad you got it all figured out. Whenever someone asks me to work on something I always ask whats been worked on before so I know the first place to look. I took apart a 1952 Allis Chalmers CA tractor this week that had about .050” endplay on the crankshaft. It had ate the thrust face off the main bearing and crank because the last person to work on it had installed a felt wick that oils the pilot bearing wrong.

 

[Kilroy2k1]

That would be enough to drive you crazy having to put it together only to have the shaft pull out a little more. Glad you got it all figured out. Whenever someone asks me to work on something I always ask whats been worked on before so I know the first place to look. I took apart a 1952 Allis Chalmers CA tractor this week that had about .050” endplay on the crankshaft. It had ate the thrust face off the main bearing and crank because the last person to work on it had installed a felt wick that oils the pilot bearing wrong.

I bought the machine knowing most of its history, the last 12 years of its life was in the scrap steel industry, so i knew i was into some problems right from the get go. The machine has had Very a hard life but the price was too hard to pass up. I'll get the bugs out of it and it'll be a sweet machine. After that axle i am building it a brand new electrical system from the ground up, changing and repositioning the radiator, enclosing the cab and I might even add a turbo to it just for giggles I'm glad i found this forum, its a wealth of information from a very nice and knowledgeable bunch of people.
Thanks Tom.