Bobcat M600 variable speed drive sheave removal

[terryt]

Recently acquired a Bobcat M600 for my wife on the cheap which features major engine trouble (busted rod). The unit is (was) powered by a Wisconsin VH4D engine. In order to remove the engine for repair, it appears that the variable speed drive sheave needs to be removed from the engine. I am in posession of that really bad copy of an old M600 factory manual that is being peddled all over the internet for 5 to 20 bucks but the illustrations of various sheaves employed on these machines appear to be entirely different than what is installed on mine. Makes me feel real special. The hyd. hose on mine screws at 90 degrees into a pipe threaded hole on the side of a swivel boss that protrudes from the end of the sheave. The swivel extends through what appears to be a large thick round washer covering the outer end of the sheave and the swivel is held in place by an internal snap ring. I was able to remove the snap ring and the swivel/fluid inlet assembly leaving a hole in the end of the outer sheave where it was mounted. Beyond this, there appears to no means for further disassembly. The large washer/end cover remains in place on the end of the outer sheave hub which can be turned independently of the outer sheave half but cannot be pried off, tapped off or removed by any reasonable effort I have applied. There appears to be no means of gripping it or even employing a little more axial persuasion with a slide hammer. The manual, at this point, describes just sliding off the outer sheave but nothing budges with reasonable effort and there are no other snap rings or fasteners visible. Before I began this disassembly attempt, I loosened the belt as described in the manual by pulling up on it and releasing the sheave with the speed control. I have been advised that these sheaves are somewhat pricey and really do not wish to attempt to go further until I have some idea what I am doing. Anybody out there recognize this description or successfully remove one of these on a 600 or maybe even a 610 while rendering it suitable for reuse afterward? This really hurts my pride as I was a heavy mechanic for 25 years but this concoction has me stumped. I do know how to get this thing off but it really wouldn't be pretty. My apologies, I would post a few photos and forgo 90% of this long boring monologue but I do not see that capability here. If you reply please type slowly, I am old and my vision is bad.

 

[6brnorma]

terryt.....there were only two styles of roto swivel assemblies that I'm aware of. One was a stationary (frame) mounted end and the standard assembly which you described. It sounds like you have removed the "large washer" which holds the outer sheave half in place correctly.....if so......it "should" slide easily off. If it does not it has seized somehow. If my description so far is correct to this point, I would do the following. First, open the 'jackshaft' sheave with a pry bar and drop a 5/8 or so socket down inside it to hold it open (keep fingers out) which will give you more slack on the belt allowing you to work the variable speed sheave half back and forth with some sort of penetrating oil.....next would be heat and oil.....maybe rubber mallet on the end but *NOT ON THE RIM* of sheave. The advice you received about the sheave being pricey was correct.....do not damage this thing......break the outer half and you must replace the entire sheave assembly as they are matched and balanced. Also.....the M600 came with a VF4D so if it has the VH4D it has been repowered or it is not a 600 (makes no difference). I would have used the VH4D also to repower if it were it my machine.

 

[6brnorma]

terryt.....there were only two styles of roto swivel assemblies that I'm aware of. One was a stationary (frame) mounted end and the standard assembly which you described. It sounds like you have removed the "large washer" which holds the outer sheave half in place correctly.....if so......it "should" slide easily off. If it does not it has seized somehow. If my description so far is correct to this point, I would do the following. First, open the 'jackshaft' sheave with a pry bar and drop a 5/8 or so socket down inside it to hold it open (keep fingers out) which will give you more slack on the belt allowing you to work the variable speed sheave half back and forth with some sort of penetrating oil.....next would be heat and oil.....maybe rubber mallet on the end but *NOT ON THE RIM* of sheave. The advice you received about the sheave being pricey was correct.....do not damage this thing......break the outer half and you must replace the entire sheave assembly as they are matched and balanced. Also.....the M600 came with a VF4D so if it has the VH4D it has been repowered or it is not a 600 (makes no difference). I would have used the VH4D also to repower if it were it my machine.

My apologizes terryt.....I misread your post. You have NOT removed the large washer? You should NOT have removed the swivel assembly first. If you will look closely, there is a snap ring recessed inside the large washer that also locks into the roto swivel assembly. You MUST remove the "large washer" before you can proceed. There will be another snap ring under the washer that must be removed in order to remove the entire roto swivel assembly. I would still advise placing the 5/8 socket in the jackshaft for more slack in the belt....it will make your job much easier.

 

[6brnorma]

My apologizes terryt.....I misread your post. You have NOT removed the large washer? You should NOT have removed the swivel assembly first. If you will look closely, there is a snap ring recessed inside the large washer that also locks into the roto swivel assembly. You MUST remove the "large washer" before you can proceed. There will be another snap ring under the washer that must be removed in order to remove the entire roto swivel assembly. I would still advise placing the 5/8 socket in the jackshaft for more slack in the belt....it will make your job much easier.

A word of warning terry.......EVERYTHING inside this assembly is expensive...the swivel you removed is nearly a hundo and the piston/shaft is over 210.00.....be careful. Also.....the "large washer" is called the 'cap' in case you go parts searching.

 

[6brnorma]

A word of warning terry.......EVERYTHING inside this assembly is expensive...the swivel you removed is nearly a hundo and the piston/shaft is over 210.00.....be careful. Also.....the "large washer" is called the 'cap' in case you go parts searching.

Dangit....also.....be careful, by removing the swivel, you have left several very small parts exposed and may fall out. 2 pins, 1 seal, 1 O-ring, 1 guide and a small spring.....you're gonna need them.

 

[terryt]

Dangit....also.....be careful, by removing the swivel, you have left several very small parts exposed and may fall out. 2 pins, 1 seal, 1 O-ring, 1 guide and a small spring.....you're gonna need them.

Thanks for the info 6b., looks like I got a little ahead of myself on this one. I was extremely careful to keep all those little washers pins and that little spring all in order and even strung them on a wire. They went right into a plastic sandwitch bag when they came out since I have been there before removing assemblies with tiny parts. I would put the thing back together but the risk is probably greater of losing something with the sheave on the machine than if I wait and can work on the bench. I think I will just plug the end with something so there will be no more "escapees" to worry about for now. In the meantime, this leaves me back at square one (or -1?). I still have the problem of removing what you identify as the cap. The only movement of this piece is rotation at this point. I have tried prying on the edge of it with a big wonder bar, hooking on the outside rim of it as best I could while tapping on it and have accomplished no axial movement at all. It just doesn't budge. In my years of wrenching I sorta know when I am in danger of doing damage if I go further with a particular tactic and I am definitely there with this one unless I can find a different MO that works. With my current methods, the cap doesn't split away from the hub of the sheave at all, not even far enough to get something behind it. I guess what really has me mystified is this. If the only visible means of retention of ANYTHING on the outer sheave assy is that little snap ring I took off and shouldnt have. What is supposed to retain the cap in place while the machine is running? if you are supposed to be able to pull the cap right off after just removing only the hydraulic hose what is holding the cap it on when the sheave is in operation? Seems like I am missing a step here somewhere or maybe I just don't have the capacity to grasp what is essentially a spiritual matter. I thought about possibly trying to use a bearing splitter between the cap and the hub but if there IS something retaining it, I could do a lot of damage before anything ever comes apart. I have a drawing that I copied from the internet which shows all the small parts just like mine, like the swivel, washers and springs etc., but cap is not even in the picture and there are bearings and stuff I can't see in mine, at least yet. I have not tried soaking the thing with oil. I suppose I kinda figured that something as slimy as this sheave already is, and which is filled with hydraulic oil anyway, would be lubricated sufficiently for disassembly. Maybe not so I guess. I found a link on a tractor forum that pictures exactly what have if you happen to be interested.(http://www.mytractorforum.com/showthread.php?t=96776) The poster was also trying to get disassembly info but there were no responses. Seems he did the same dumb thing I did and removed the swivel assy. I did notice however a photo he linked on his post shows the cap moved away from the hub 1/4 inch or so. I have not gotten that far with mine. Still not sure where to go form here. Just to take a step in the right direction, I will spread the jackshaft pulley with a socket as you suggest, spray the thing down with WD to soak for a while, and maybe retreat to contemplation of higher metaphysical mysteries to take my mind off this damn thing for a while. Thanks for your helpTT

 

[goodhors]

Thanks for the info 6b., looks like I got a little ahead of myself on this one. I was extremely careful to keep all those little washers pins and that little spring all in order and even strung them on a wire. They went right into a plastic sandwitch bag when they came out since I have been there before removing assemblies with tiny parts. I would put the thing back together but the risk is probably greater of losing something with the sheave on the machine than if I wait and can work on the bench. I think I will just plug the end with something so there will be no more "escapees" to worry about for now. In the meantime, this leaves me back at square one (or -1?). I still have the problem of removing what you identify as the cap. The only movement of this piece is rotation at this point. I have tried prying on the edge of it with a big wonder bar, hooking on the outside rim of it as best I could while tapping on it and have accomplished no axial movement at all. It just doesn't budge. In my years of wrenching I sorta know when I am in danger of doing damage if I go further with a particular tactic and I am definitely there with this one unless I can find a different MO that works. With my current methods, the cap doesn't split away from the hub of the sheave at all, not even far enough to get something behind it. I guess what really has me mystified is this. If the only visible means of retention of ANYTHING on the outer sheave assy is that little snap ring I took off and shouldnt have. What is supposed to retain the cap in place while the machine is running? if you are supposed to be able to pull the cap right off after just removing only the hydraulic hose what is holding the cap it on when the sheave is in operation? Seems like I am missing a step here somewhere or maybe I just don't have the capacity to grasp what is essentially a spiritual matter. I thought about possibly trying to use a bearing splitter between the cap and the hub but if there IS something retaining it, I could do a lot of damage before anything ever comes apart. I have a drawing that I copied from the internet which shows all the small parts just like mine, like the swivel, washers and springs etc., but cap is not even in the picture and there are bearings and stuff I can't see in mine, at least yet. I have not tried soaking the thing with oil. I suppose I kinda figured that something as slimy as this sheave already is, and which is filled with hydraulic oil anyway, would be lubricated sufficiently for disassembly. Maybe not so I guess. I found a link on a tractor forum that pictures exactly what have if you happen to be interested.(http://www.mytractorforum.com/showthread.php?t=96776) The poster was also trying to get disassembly info but there were no responses. Seems he did the same dumb thing I did and removed the swivel assy. I did notice however a photo he linked on his post shows the cap moved away from the hub 1/4 inch or so. I have not gotten that far with mine. Still not sure where to go form here. Just to take a step in the right direction, I will spread the jackshaft pulley with a socket as you suggest, spray the thing down with WD to soak for a while, and maybe retreat to contemplation of higher metaphysical mysteries to take my mind off this damn thing for a while. Thanks for your helpTT

I have the same machine similar issue. That cap is held in place by an external snap ring. If you can reassemble the roto swivel, gently try pulling on the piston and you should be able to expose that snap ring. Once that is removed a few taps will loosen it right up. I've found that a carbide scraper is very valuable tool.; a lot of these parts develop a slight burr as they wear out and if you can scrape off a couple of thousands, they will come a part without hammering on them

 

[6brnorma]

Thanks for the info 6b., looks like I got a little ahead of myself on this one. I was extremely careful to keep all those little washers pins and that little spring all in order and even strung them on a wire. They went right into a plastic sandwitch bag when they came out since I have been there before removing assemblies with tiny parts. I would put the thing back together but the risk is probably greater of losing something with the sheave on the machine than if I wait and can work on the bench. I think I will just plug the end with something so there will be no more "escapees" to worry about for now. In the meantime, this leaves me back at square one (or -1?). I still have the problem of removing what you identify as the cap. The only movement of this piece is rotation at this point. I have tried prying on the edge of it with a big wonder bar, hooking on the outside rim of it as best I could while tapping on it and have accomplished no axial movement at all. It just doesn't budge. In my years of wrenching I sorta know when I am in danger of doing damage if I go further with a particular tactic and I am definitely there with this one unless I can find a different MO that works. With my current methods, the cap doesn't split away from the hub of the sheave at all, not even far enough to get something behind it. I guess what really has me mystified is this. If the only visible means of retention of ANYTHING on the outer sheave assy is that little snap ring I took off and shouldnt have. What is supposed to retain the cap in place while the machine is running? if you are supposed to be able to pull the cap right off after just removing only the hydraulic hose what is holding the cap it on when the sheave is in operation? Seems like I am missing a step here somewhere or maybe I just don't have the capacity to grasp what is essentially a spiritual matter. I thought about possibly trying to use a bearing splitter between the cap and the hub but if there IS something retaining it, I could do a lot of damage before anything ever comes apart. I have a drawing that I copied from the internet which shows all the small parts just like mine, like the swivel, washers and springs etc., but cap is not even in the picture and there are bearings and stuff I can't see in mine, at least yet. I have not tried soaking the thing with oil. I suppose I kinda figured that something as slimy as this sheave already is, and which is filled with hydraulic oil anyway, would be lubricated sufficiently for disassembly. Maybe not so I guess. I found a link on a tractor forum that pictures exactly what have if you happen to be interested.(http://www.mytractorforum.com/showthread.php?t=96776) The poster was also trying to get disassembly info but there were no responses. Seems he did the same dumb thing I did and removed the swivel assy. I did notice however a photo he linked on his post shows the cap moved away from the hub 1/4 inch or so. I have not gotten that far with mine. Still not sure where to go form here. Just to take a step in the right direction, I will spread the jackshaft pulley with a socket as you suggest, spray the thing down with WD to soak for a while, and maybe retreat to contemplation of higher metaphysical mysteries to take my mind off this damn thing for a while. Thanks for your helpTT

You are going to be really embarrassed when you see how simple this is. Open the variable speed sheave as wide as it will go....hold the jackshaft sheave open with a socket. Then work as much slack in the belt as you can towards the variable speed sheave .....push the sheave half that you are removing back towards the belt but DO NOT push on the cap. It should leave the cap about an inch from the sheave.....now push the cap (only) towards the sheave without moving the "shaft/piston" in. Now you will have an exposed snap ring that was recessed into the cap. Remove the snap ring and you will be off to the ballpark. This procedure will be made somewhat more difficult due to your removing the swivel as you will have nothing to hold the shaft/piston with while trying to push the cap towards the sheave but you'll be ok.

 

[terryt]

You are going to be really embarrassed when you see how simple this is. Open the variable speed sheave as wide as it will go....hold the jackshaft sheave open with a socket. Then work as much slack in the belt as you can towards the variable speed sheave .....push the sheave half that you are removing back towards the belt but DO NOT push on the cap. It should leave the cap about an inch from the sheave.....now push the cap (only) towards the sheave without moving the "shaft/piston" in. Now you will have an exposed snap ring that was recessed into the cap. Remove the snap ring and you will be off to the ballpark. This procedure will be made somewhat more difficult due to your removing the swivel as you will have nothing to hold the shaft/piston with while trying to push the cap towards the sheave but you'll be ok.

Well, aint that just what I said? I always assume folks have a little more cognitive ability than what they may actually possess as well. Since I can still follow directions, I'm sure all this will help immensely. Wife and I still hold hands a lot. I guess you can tell by now, it's not to keep HER vertical. Anyway, I look forward to trying this all out when I get back from vacation in a week or so. Thanks for the great info 6b and all.

 

[jerry]

Well, aint that just what I said? I always assume folks have a little more cognitive ability than what they may actually possess as well. Since I can still follow directions, I'm sure all this will help immensely. Wife and I still hold hands a lot. I guess you can tell by now, it's not to keep HER vertical. Anyway, I look forward to trying this all out when I get back from vacation in a week or so. Thanks for the great info 6b and all.

When you reassemble be sure the brass gland on the outer end is in right. The one I had the gland had been put in backwards and was all deformed from the pressure. At that time they were $50 but I was able to make a new one from brass I had. Yours may be the other style though, nothing in there is cheap anyhow.

 

[Mikefromcny]

When you reassemble be sure the brass gland on the outer end is in right. The one I had the gland had been put in backwards and was all deformed from the pressure. At that time they were $50 but I was able to make a new one from brass I had. Yours may be the other style though, nothing in there is cheap anyhow.

Sorry to hijack your thread terry, my farm rescued 610 hasnt needed that much work surprisingly. 6Bnorma or others with experience on these, When I change my hydraulic filter, will I lose my hydraulic oil in the process? Thats kinda how it looks laying under the machine. I'm trying to avoid a 17 gallon mess. Thanks

 

[6brnorma]

Sorry to hijack your thread terry, my farm rescued 610 hasnt needed that much work surprisingly. 6Bnorma or others with experience on these, When I change my hydraulic filter, will I lose my hydraulic oil in the process? Thats kinda how it looks laying under the machine. I'm trying to avoid a 17 gallon mess. Thanks

Set lift arms down and lift the rear of the machine about 6" to stop most of that. You'll only lose a gallon or so (provided your oil is at the correct level)......with the plate below the filter it will seem like a lot more. It will be a mess regardless, it's hard to catch it in a drip pan. Kitty litter or one of those big drip trays help some. Definitely my least favorite filter to change on this machine.