Bobcat 610 - I have no variable speed (literally!).

alchemysa · Apr 29, 2016

Upon removing the round side cover of my recently purchased 610 'project' I discovered I have no variable speed mechanism. The hose from the control valve had been removed and the valve outlet was plugged. And as you can see the roto-swivel assembly is entirely missing.
A spacer (a small piece of pipe offcut) had been slipped onto the plunger to prevent the plunger from retracting too far. (See the pic with the red arrow). This, combined with a well worn belt meant the machine was permanently in low speed mode. I guess if you weren't in a hurry it would have worked OK.
I want to restore variable speed so I guess I need a few parts. The parts marked in red on the diagram are all missing. Does anyone know whats in a roto-swivel kit? I tried looking at the Bobcat parts website but I cant make sense of it. It keeps saying the pages are 'unauthorised'.
http://www.bobcatpartsonline.com/bobcat/mainPage.jsp?home=yes
A snip from my own parts catalogue is shown below. I'm a bit confused about the parts marked in blue. If you look at my photo of the inside of the plunger you can see 2 small pins. The diagram gives the impression there are more parts 'under' these pins but I cant see a snap ring or anything that needs to be removed. Does anyone know if theres more disassembly to go?
Also any advice on where to get parts would be appreciated. I suspect parts here in Australia will be exorbitant so I will perhaps be buying from the U.S. I have a friend in North Carolina who will forward anything to me that I get sent to him.
Any comments on this situation are welcome.

Roto diagram photo roto-swivel1_zps2reijyay.gif

6brnorma · Apr 29, 2016

So, here's the bad news………There is not a single piece of that assembly that appears to be re-usable. If I'm not mistaken……it appears there is a broken piece from your variable speed sheave also…..if so…..the sheave is out of balance (those are balanced pairs) and will damage the crank. My advice would be to start from scratch and purchase the entire assembly. The last time I priced one at my dealer it was $628.00 USD. I wouldn't be surprised to find it has increased in price as that was several years ago. I'm sure a quality used one could be had at a lower price……..but……you MUST know what you're looking at. I know new are available in the US…….probably also in Australia. Sorry…………………MHO

alchemysa · Apr 29, 2016

6brnorma said:
So, here's the bad news………There is not a single piece of that assembly that appears to be re-usable. If I'm not mistaken……it appears there is a broken piece from your variable speed sheave also…..if so…..the sheave is out of balance (those are balanced pairs) and will damage the crank. My advice would be to start from scratch and purchase the entire assembly. The last time I priced one at my dealer it was $628.00 USD. I wouldn't be surprised to find it has increased in price as that was several years ago. I'm sure a quality used one could be had at a lower price……..but……you MUST know what you're looking at. I know new are available in the US…….probably also in Australia. Sorry…………………MHO

6brnorma, thanks for the reply. Yes it looks pretty bad, no doubt about that, and you are obviously pretty expert on these matters. But I dont have much to lose by trying to fix what I have. My chances of finding a good complete used assembly in Australia are remote, unless someone reads this. For a new assembly I'm guessing close to a thousand bucks over here and I doubt that would be a sensible investment either. But a couple of hundred dollars for the missing parts may be worth the gamble. The piece out of the sheave may be repairable with some careful shaping of a filler piece and some light welding and fine grinding. If theres any damage to the crank, due to it being out of balance, it has already happened long ago. (The engine may be stuffed anyway. It runs, but has done a LOT of work.)
The only bright side to this is that the two important faces (the inner wall of the sheave, and the shaft of the piston) seem to be in reasonable shape and may seal OK with new O rings all round.
So. Do the pins inside the piston shaft come out to reveal more pieces? And do you have any better luck reading that Bobcatpartsonline website than I do? Does it list prices for the components I need or will I only get those by going to a dealer?

6brnorma · Apr 29, 2016

alchemysa said:
6brnorma, thanks for the reply. Yes it looks pretty bad, no doubt about that, and you are obviously pretty expert on these matters. But I dont have much to lose by trying to fix what I have. My chances of finding a good complete used assembly in Australia are remote, unless someone reads this. For a new assembly I'm guessing close to a thousand bucks over here and I doubt that would be a sensible investment either. But a couple of hundred dollars for the missing parts may be worth the gamble. The piece out of the sheave may be repairable with some careful shaping of a filler piece and some light welding and fine grinding. If theres any damage to the crank, due to it being out of balance, it has already happened long ago. (The engine may be stuffed anyway. It runs, but has done a LOT of work.)
The only bright side to this is that the two important faces (the inner wall of the sheave, and the shaft of the piston) seem to be in reasonable shape and may seal OK with new O rings all round.
So. Do the pins inside the piston shaft come out to reveal more pieces? And do you have any better luck reading that Bobcatpartsonline website than I do? Does it list prices for the components I need or will I only get those by going to a dealer?

The piston shaft face is the least of my concerns for that part. You will have problems with the lock ring groove once you apply hydraulic pressure to that lock ring. There are two lock rings that hold the entire assembly together…….failure on the part of either and the machine does not function. That lock ring is critical to the operation of your machine if you are going to use the variable speed. Secondly, the interior of the shaft must accept two bearings……it appears there is considerable work to make that portion serviceable. The two pins are there only to hold the seal stationary while in operation. If you will look in photo #3 ………. you will see a clear imprint of the second lock ring in the gland. That is likely due to excessive hydraulic pressure from the valve. My machines are used for commercial purposes and must be correct………a piece of steel/filler material coming from a sheave at 2800 RPM and injuring someone is not a luxury I can afford.

reed2022 · Apr 29, 2016

Alchemsha in the salvage part section on this forum is a 610 that is being parted out they may have some thing for if you could convince them to ship.

alchemysa · Apr 29, 2016

reed2022 said:
Alchemsha in the salvage part section on this forum is a 610 that is being parted out they may have some thing for if you could convince them to ship.

reed2022. Thanks for that, I have emailed him with an offer for the complete rear sheave assembly, or just the roto swivel if removing the sheave proves too hard. (But if its just the roto swivel I would need to know its the type that fits my sheave). Shipping to me may not be too hard. I have a friend in North Carolina who would send the thing to me. All the supplier needs to do is put it in a box and post it to him, at my expense of course.
6brnorma. I appreciate your comments. I will be calling a local Bobcat parts dealer during the week to see whats available over here, and how much.
A couple more questions....
Firstly, the fixed sheave is still attached to the engine at the moment. I notice that I can spin the sheave and the engine crankshaft pretty easily in either direction with little compression resistance. Is this normal for these engines or does it indicate that I have very, very tired engine?
Secondly, if it gets too hard to fix this economically, whats the negatives with resorting to the 'fixed speed' option that is already a 'special feature' of this machine. Lets say I fix it at half speed. Would I suffer much in terms of usability when used on a small property, doing relatively light work?
I assume the term 'variable speed' is somewhat simplistic. The variable sheave would also change the power available, for pushing into dirt for example. At 'half speed' will it have sufficient power for those tasks or is low speed always required for that? I have no experience driving one of these things so I don't know what speed is most commonly used. Any comments?

alchemysa · Apr 29, 2016

alchemysa said:
reed2022. Thanks for that, I have emailed him with an offer for the complete rear sheave assembly, or just the roto swivel if removing the sheave proves too hard. (But if its just the roto swivel I would need to know its the type that fits my sheave). Shipping to me may not be too hard. I have a friend in North Carolina who would send the thing to me. All the supplier needs to do is put it in a box and post it to him, at my expense of course.
6brnorma. I appreciate your comments. I will be calling a local Bobcat parts dealer during the week to see whats available over here, and how much.
A couple more questions....
Firstly, the fixed sheave is still attached to the engine at the moment. I notice that I can spin the sheave and the engine crankshaft pretty easily in either direction with little compression resistance. Is this normal for these engines or does it indicate that I have very, very tired engine?
Secondly, if it gets too hard to fix this economically, whats the negatives with resorting to the 'fixed speed' option that is already a 'special feature' of this machine. Lets say I fix it at half speed. Would I suffer much in terms of usability when used on a small property, doing relatively light work?
I assume the term 'variable speed' is somewhat simplistic. The variable sheave would also change the power available, for pushing into dirt for example. At 'half speed' will it have sufficient power for those tasks or is low speed always required for that? I have no experience driving one of these things so I don't know what speed is most commonly used. Any comments?

" reed2022. Thanks for that, I have emailed him with an offer... "
I have a response already. Not much chance of me getting one from that source I would say.

6brnorma · Apr 30, 2016

alchemysa said:
reed2022. Thanks for that, I have emailed him with an offer for the complete rear sheave assembly, or just the roto swivel if removing the sheave proves too hard. (But if its just the roto swivel I would need to know its the type that fits my sheave). Shipping to me may not be too hard. I have a friend in North Carolina who would send the thing to me. All the supplier needs to do is put it in a box and post it to him, at my expense of course.
6brnorma. I appreciate your comments. I will be calling a local Bobcat parts dealer during the week to see whats available over here, and how much.
A couple more questions....
Firstly, the fixed sheave is still attached to the engine at the moment. I notice that I can spin the sheave and the engine crankshaft pretty easily in either direction with little compression resistance. Is this normal for these engines or does it indicate that I have very, very tired engine?
Secondly, if it gets too hard to fix this economically, whats the negatives with resorting to the 'fixed speed' option that is already a 'special feature' of this machine. Lets say I fix it at half speed. Would I suffer much in terms of usability when used on a small property, doing relatively light work?
I assume the term 'variable speed' is somewhat simplistic. The variable sheave would also change the power available, for pushing into dirt for example. At 'half speed' will it have sufficient power for those tasks or is low speed always required for that? I have no experience driving one of these things so I don't know what speed is most commonly used. Any comments?

More bad news…….I would have to say that you have a very tired engine. A VH4D (that is what you have….correct?) should have between 90 - 120 lbs of compression, 80 is low though I have had them run fairly well in the 70s as long as all four cylinders were consistent. I have seen many of these machines used without the "variable speed" feature……I wouldn't do it but it is done. Yours was unique……most Americans are lazy and simply break out the welder. I can't advise you on how to proceed as "stationary" would not be a consideration for me. There are a couple of members that have pointed this out in the past and in this case it is something to consider……Variable speed sheave assembly $700 - $800 USD, Engine (VH4D) $2500 - $4000, Belt $100 and we still don't know the condition of several other very pricey parts….jackshaft sheave $200 - $400, main hydraulic valve $500 or clutches (possibly) upwards of $600 - $800. Without knowing more about the machine and your mechanical abilities…..this thing CAN become a money pit.

alchemysa · Apr 30, 2016

6brnorma said:
More bad news…….I would have to say that you have a very tired engine. A VH4D (that is what you have….correct?) should have between 90 - 120 lbs of compression, 80 is low though I have had them run fairly well in the 70s as long as all four cylinders were consistent. I have seen many of these machines used without the "variable speed" feature……I wouldn't do it but it is done. Yours was unique……most Americans are lazy and simply break out the welder. I can't advise you on how to proceed as "stationary" would not be a consideration for me. There are a couple of members that have pointed this out in the past and in this case it is something to consider……Variable speed sheave assembly $700 - $800 USD, Engine (VH4D) $2500 - $4000, Belt $100 and we still don't know the condition of several other very pricey parts….jackshaft sheave $200 - $400, main hydraulic valve $500 or clutches (possibly) upwards of $600 - $800. Without knowing more about the machine and your mechanical abilities…..this thing CAN become a money pit.

6brnorma... " I can't advise you on how to proceed as "stationary" would not be a consideration for me....this thing CAN become a money pit "
I won't let this become a money pit. It wont get a lot of use. I'll do cheap and dirty fixes if I have to.
I've had some thoughts on how to 'fix' the sheave. Perhaps do away with the piston/roto swivel completely and have a round piece machined the same size as the gland, but with a threaded hole in the middle to take a large bolt with a head that protrudes outside the end cap. This should give me a setup that can be adjusted in or or out whenever the engine is stationary.
Anyway, mechanical details aside, if you had to set it at a fixed speed what would you chose? Fast, slow, half way?

6brnorma · Apr 30, 2016

alchemysa said:
6brnorma... " I can't advise you on how to proceed as "stationary" would not be a consideration for me....this thing CAN become a money pit "
I won't let this become a money pit. It wont get a lot of use. I'll do cheap and dirty fixes if I have to.
I've had some thoughts on how to 'fix' the sheave. Perhaps do away with the piston/roto swivel completely and have a round piece machined the same size as the gland, but with a threaded hole in the middle to take a large bolt with a head that protrudes outside the end cap. This should give me a setup that can be adjusted in or or out whenever the engine is stationary.
Anyway, mechanical details aside, if you had to set it at a fixed speed what would you chose? Fast, slow, half way?

Probably half way.

thynes · Apr 30, 2016

6brnorma said:
Probably half way.

I would not put it to max fast. You would not have much pushing power. At minimum speed it is verrrrry slow. I vote for 1/3 to 1/2, if you had to fix the speed. -Tim in Mass

Tigerhaze · May 3, 2016

alchemysa said:
6brnorma... " I can't advise you on how to proceed as "stationary" would not be a consideration for me....this thing CAN become a money pit "
I won't let this become a money pit. It wont get a lot of use. I'll do cheap and dirty fixes if I have to.
I've had some thoughts on how to 'fix' the sheave. Perhaps do away with the piston/roto swivel completely and have a round piece machined the same size as the gland, but with a threaded hole in the middle to take a large bolt with a head that protrudes outside the end cap. This should give me a setup that can be adjusted in or or out whenever the engine is stationary.
Anyway, mechanical details aside, if you had to set it at a fixed speed what would you chose? Fast, slow, half way?

I don't know how much you are willing to spend for a used one, but there is a complete variable speed sheave assembly (as they state) on EBay right now for $500 USD: http://www.ebay.com/itm/Bobcat-Melroe-Clark-Variable-Speed-Clutch-Sheave-VH4D-Complete-/182111028180?hash=item2a66a9c3d4:g:Bk4AAOSwlHRXIlfO

alchemysa · May 3, 2016

Tigerhaze said:
I don't know how much you are willing to spend for a used one, but there is a complete variable speed sheave assembly (as they state) on EBay right now for $500 USD: http://www.ebay.com/itm/Bobcat-Melroe-Clark-Variable-Speed-Clutch-Sheave-VH4D-Complete-/182111028180?hash=item2a66a9c3d4:g:Bk4AAOSwlHRXIlfO

Thynes and Tigerhaze. Thanks for that.
I'd have to add another $100 for freight to that Ebay deal so its a bit pricey. For now I'll just fix it at about half speed. I have an idea for a simple, cheap arrangement that will let me adjust the speed when the engine is switched off. Then I'll keep my eye open for a second hand unit or rebuild it with new parts if they are reasonably priced.
The Ebay pic is handy though. I can see whats missing. I have a parts diagram but seeing the real thing really helps.

6brnorma · May 3, 2016

Tigerhaze said:
I don't know how much you are willing to spend for a used one, but there is a complete variable speed sheave assembly (as they state) on EBay right now for $500 USD: http://www.ebay.com/itm/Bobcat-Melroe-Clark-Variable-Speed-Clutch-Sheave-VH4D-Complete-/182111028180?hash=item2a66a9c3d4:g:Bk4AAOSwlHRXIlfO

Nice catch Tiger………that sure seems to me to be some odd choice for search words….wonder why they used an engine number and not a bobcat model number. That appears to be a nice unit but for $100 more you can acquire a totally new unit……I'm going with the new unit every time. At $300 I'm a buyer but not at $500.

Bobm500Cat · Jun 29, 2016

6brnorma said:
Nice catch Tiger………that sure seems to me to be some odd choice for search words….wonder why they used an engine number and not a bobcat model number. That appears to be a nice unit but for $100 more you can acquire a totally new unit……I'm going with the new unit every time. At $300 I'm a buyer but not at $500.

Hello, New to the forum. Got a Bobcat M500 w/ Duetz F2L310. Found this forum while searching the web looks like a good place to share ideas and get help. From the original poster the parts in the earlier post picture in blue (seals) were trashed in mine. I took a gamble and found a Teflon bushing approx 6mm diameter and 1/2 inch long and shaved it until it fit snugly between the edge of the roto-swivel piece and the plunger. The unit barely works but leaks. I may try to find another solution. As the original poster attempted, I would like to make my sheave functional without leaking. Also, how do you align the sheave pieces? It is again the case of too little information available with detail pictures and I wasn't paying attention when I pulled the piece off. The bobcat site was helpful but real pictures are best. I did my best to align the 'G' stamped the spline edge on both pieces but Im not sure that is correct because they offset each other. |G||G| I apologize if this post departs from forum etiquette, I can create a new thread if required. Thanks.

alchemysa · Jun 30, 2016

Bobm500Cat said:
Hello, New to the forum. Got a Bobcat M500 w/ Duetz F2L310. Found this forum while searching the web looks like a good place to share ideas and get help. From the original poster the parts in the earlier post picture in blue (seals) were trashed in mine. I took a gamble and found a Teflon bushing approx 6mm diameter and 1/2 inch long and shaved it until it fit snugly between the edge of the roto-swivel piece and the plunger. The unit barely works but leaks. I may try to find another solution. As the original poster attempted, I would like to make my sheave functional without leaking. Also, how do you align the sheave pieces? It is again the case of too little information available with detail pictures and I wasn't paying attention when I pulled the piece off. The bobcat site was helpful but real pictures are best. I did my best to align the 'G' stamped the spline edge on both pieces but Im not sure that is correct because they offset each other. |G||G| I apologize if this post departs from forum etiquette, I can create a new thread if required. Thanks.

Welcome Bobm500Cat
I'm the original poster. I was missing too many pieces to get the variable sheave operating hydraulically so I came up with the 'manual system' here...
http://www.skidsteerforum.com/DesktopDefault.aspx?tabid=54&frmView=ShowPost&PostID=95991
Since posting that thread I've neatened the system up a bit and I must say I'm pretty pleased with myself. It only takes one or 2 steps either way to go from slow speed to a good travel speed.
Sorry I can't help with your G-G query. You must have a different sheave design. I don't think theres any etiquette problem with asking your question here, but starting a new thread with 'M500' in the title might get you more lookers.

Bobm500Cat · Jun 30, 2016

alchemysa said:
Welcome Bobm500Cat
I'm the original poster. I was missing too many pieces to get the variable sheave operating hydraulically so I came up with the 'manual system' here...
http://www.skidsteerforum.com/DesktopDefault.aspx?tabid=54&frmView=ShowPost&PostID=95991
Since posting that thread I've neatened the system up a bit and I must say I'm pretty pleased with myself. It only takes one or 2 steps either way to go from slow speed to a good travel speed.
Sorry I can't help with your G-G query. You must have a different sheave design. I don't think theres any etiquette problem with asking your question here, but starting a new thread with 'M500' in the title might get you more lookers.

Thanks alchemysa. My sheave is identical to yours and ironically not documented on the Bobcat Archive (there are atleast two other designs I found for the m440, 500, 600. It took me hours to find the very pictures you have. If you could examine yours possibly for any kind of alignment markings on the outboard side I would greatly appreciate that. I am going to try to spend some time this weekend double checking mine. I do have some vibration from the engine running and I want to just see if I missed some other markings. I was never able to remove the engine side of the sheave or the piston itself...of course I am still not sure I can maybe it is a third snap ring I am not removing, but it is worth a look-over again to gain some assurance I have things aligned together. I need to solve this vibration first over fixing the leak. Regarding the leak, I might have to follow your example in your other link if I cant resolve it. Good stuff. Thanks.

alchemysa · Jul 1, 2016

Bobm500Cat said:
Thanks alchemysa. My sheave is identical to yours and ironically not documented on the Bobcat Archive (there are atleast two other designs I found for the m440, 500, 600. It took me hours to find the very pictures you have. If you could examine yours possibly for any kind of alignment markings on the outboard side I would greatly appreciate that. I am going to try to spend some time this weekend double checking mine. I do have some vibration from the engine running and I want to just see if I missed some other markings. I was never able to remove the engine side of the sheave or the piston itself...of course I am still not sure I can maybe it is a third snap ring I am not removing, but it is worth a look-over again to gain some assurance I have things aligned together. I need to solve this vibration first over fixing the leak. Regarding the leak, I might have to follow your example in your other link if I cant resolve it. Good stuff. Thanks.

Bobm500cat. On my outer sheave there is an arrow with wording that says something like 'Align this arrow with the mark on the inner sheave.' The wording is pretty prominent so you would certainly see it if you had the same sheaves. However the inner sheave marking is quite small. Its just a small notch on the outer edge and can be easily missed.
Also my sheaves have about 8 splines so it sounds like they are different to yours. This is just a guess, but try looking for some very small notches on the outer edges of the sheaves.

alchemysa · Jul 1, 2016

alchemysa said:
Bobm500cat. On my outer sheave there is an arrow with wording that says something like 'Align this arrow with the mark on the inner sheave.' The wording is pretty prominent so you would certainly see it if you had the same sheaves. However the inner sheave marking is quite small. Its just a small notch on the outer edge and can be easily missed.
Also my sheaves have about 8 splines so it sounds like they are different to yours. This is just a guess, but try looking for some very small notches on the outer edges of the sheaves.

Dunno if this helps but take a look at this video. (You'll have to paste it)
https://www.youtube.com/watch?v=xPpQi4n9uEU
From the 1.15 minute mark it shows a sheave that may be like yours. You can see a small notch on the edge of the sheave it some of the scenes.

Bobcat 610 - I have no variable speed (literally!).

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