610 drive pulley removal

[Hevyduty]

Well I didn't keep her clean and got her hot. now the engine has a hard knock. Before a piston goes out the side I want to repair the damage that was done. today I removed the engine and started pulling the sheetmetal off the vh4d wisconsin. the flywheel seems quite stuck but will go at that end tomorow with a new deadblow hammer. My real problem is how to remove the drive pulley. the outer half about fell of after removing the outer snap ring, the inner ring was broken but I got it off, now what? does the piston just pull out to reveal a hidden bolt? no books yet .

 

[OldMachinist]

It depends on your serial number.

 

[6brnorma]

It depends on your serial number.

I've been reading every post here for the last week regarding 600/610s until my eyes are bleeding and have noticed a consistent pattern of sage advice from 'machinist' 'tazza' 'jerry' and 'm610' (and probably others) regarding these machines, so listen to them. A couple quick items I've never noticed here that helps me on variable speed removal that I've not seen and might help. I always start the procedure by prying open the "driven sheave" (the other sheave) with a large pry bar. I then drop a 'handy dandy', ratty ole 11/16 socket down inside the driven sheave to hold it open and release the pressure from the drive belt...this allows you to work on the 'variable sheave' MUCH easier. Under no circumstances use any type of pressure on the rim of the variable sheave to remove it (puller, wedge, hammer) or you will very likely be purchasing a $600.00 item. Place two 1/4 inch bolts (as I recall) in the holes in the splined shaft, put bearing splitter behind the bolts and attach a bar puller to remove. Heat, smack the pressure screw or rubber mallet on the splined shaft are ok on stubborn sheaves but don't pry between motor block and sheave. (Learned the hard way ) Couple words of warning; 1) When prying open the driven sheave.....don't pull the pry bar towards your face. 2) If you value your digits.....keep them out of that driven sheave at all times. 3) Don't forget to remove valuable, handy dandy, ratty ole 11/16 socket prior to starting new engine.......hesitant to tell you how I learned those three

 

[6brnorma]

I've been reading every post here for the last week regarding 600/610s until my eyes are bleeding and have noticed a consistent pattern of sage advice from 'machinist' 'tazza' 'jerry' and 'm610' (and probably others) regarding these machines, so listen to them. A couple quick items I've never noticed here that helps me on variable speed removal that I've not seen and might help. I always start the procedure by prying open the "driven sheave" (the other sheave) with a large pry bar. I then drop a 'handy dandy', ratty ole 11/16 socket down inside the driven sheave to hold it open and release the pressure from the drive belt...this allows you to work on the 'variable sheave' MUCH easier. Under no circumstances use any type of pressure on the rim of the variable sheave to remove it (puller, wedge, hammer) or you will very likely be purchasing a $600.00 item. Place two 1/4 inch bolts (as I recall) in the holes in the splined shaft, put bearing splitter behind the bolts and attach a bar puller to remove. Heat, smack the pressure screw or rubber mallet on the splined shaft are ok on stubborn sheaves but don't pry between motor block and sheave. (Learned the hard way ) Couple words of warning; 1) When prying open the driven sheave.....don't pull the pry bar towards your face. 2) If you value your digits.....keep them out of that driven sheave at all times. 3) Don't forget to remove valuable, handy dandy, ratty ole 11/16 socket prior to starting new engine.......hesitant to tell you how I learned those three

Sorry.....don't know how to edit post. Here's another one also.......when removing the "roto-swivel piston assembly".....yeah, forget that 'twin' pry bar behind the collar stuff. Using that procedure will result in your landing flat on your back with pry bars, parts and hydro oil in your lap. I always use a slide hammer with a small hook.....slide hammer in one hand, hook and swivel assembly in the other.....works like a charm. It doesn't take much on the hammer.

 

[Hevyduty]

Sorry.....don't know how to edit post. Here's another one also.......when removing the "roto-swivel piston assembly".....yeah, forget that 'twin' pry bar behind the collar stuff. Using that procedure will result in your landing flat on your back with pry bars, parts and hydro oil in your lap. I always use a slide hammer with a small hook.....slide hammer in one hand, hook and swivel assembly in the other.....works like a charm. It doesn't take much on the hammer.

Ok thanks guys, thats exactly what i thought I would find. It looks like I just need to apply a little force to the piston.

 

[Hevyduty]

Ok thanks guys, thats exactly what i thought I would find. It looks like I just need to apply a little force to the piston.

Well looks like I really screwed myself now. the piston did not want to slide out with "some" gentle persuasion so I outsmarted myself. Found a grease zerk that fit the hydraulic inlet and used a grease gun to fill the rotoswivel and force the brass end out of the sleeve and it worked perfectly untill just before it fell free it bound and cocked a little crooked. two more pumps and I cracked the whole casting along one of the splines. I understand that this part gets broken often so very little hope of finding one used . will possibly weld and repair this one as the crack is only about 3/4 " long. Darnit anyway

 

[6brnorma]

Well looks like I really screwed myself now. the piston did not want to slide out with "some" gentle persuasion so I outsmarted myself. Found a grease zerk that fit the hydraulic inlet and used a grease gun to fill the rotoswivel and force the brass end out of the sleeve and it worked perfectly untill just before it fell free it bound and cocked a little crooked. two more pumps and I cracked the whole casting along one of the splines. I understand that this part gets broken often so very little hope of finding one used . will possibly weld and repair this one as the crack is only about 3/4 " long. Darnit anyway

Sorry to hear that Hevy. Wondering if part of the 'broken' snap ring was not still present. Inserting grease separated the two halves and allowed misalignment, that's why you pull on the piston itself. The only friction "should" have been the two o-rings passing the snap ring groove. I run all of my machines commercially so my answer would be to start over and make sure it's right. These guys may have some other ideas for you. Where are you located?

 

[Hevyduty]

Sorry to hear that Hevy. Wondering if part of the 'broken' snap ring was not still present. Inserting grease separated the two halves and allowed misalignment, that's why you pull on the piston itself. The only friction "should" have been the two o-rings passing the snap ring groove. I run all of my machines commercially so my answer would be to start over and make sure it's right. These guys may have some other ideas for you. Where are you located?

When the piston would not pull out I really looked closely to be sure that the snap ring was ALL gone . there may have benn some damage caused by the broken ring that would not allow easy disassembly. I only use the machine around the farm for odd jobs and if I never use it again I will have gotten all $1500 worth of use out of it. located in western Oregon

 

[6brnorma]

When the piston would not pull out I really looked closely to be sure that the snap ring was ALL gone . there may have benn some damage caused by the broken ring that would not allow easy disassembly. I only use the machine around the farm for odd jobs and if I never use it again I will have gotten all $1500 worth of use out of it. located in western Oregon

I asked where you were located thinking possibly I'd know someone who might help you with parts or advice, unfortunately I don't in your area. You are probably right about the damage. It is likely that the broken ring was due to excessive pressure from the variable speed valve. Should you decide to make the repairs, be sure to check those pressures. I've done it but make no claims of expertise in that area. The last time I bought the entire sheave assembly new, if I recall correctly, it was about $600.00 and was still available from bobcat .... that was a couple of years ago. I certainly wouldn't "can" the machine due to this.....especially since you got it for a very reasonable price and I'd bet you've got many hundreds more worth of work for it.

 

[leftright]

Ok thanks guys, thats exactly what i thought I would find. It looks like I just need to apply a little force to the piston.

Heavyduty, I have a 1970 600 bobcat I bought new. It has 610 engine and 610 drive pulleys on it. I have always run the belt to the top, turn engine off and pull back on the varible speed leaver as I pull the outer half of the varible pulley out all the way. Take hose off and the slack in the belt will let you push the outer pulley back in to get the small snap ring and also the big snap ring off. Put the outer plate and the small snap ring back on and then you can pull outer pulley and that will snap the piston and o-rings out. Take out the bolt and washer that holds the back pulley on. Put the bolt back in and wedge a crobar behind the pulley and the engine and use a bar put against the bolt and tap on the bar and the pulley will pop off.Has for me for 41 years.