CAT 140H CCA01776 Drive Circle

[andrew80]

Hello guys

On monday the operator of this grader called us telling the drive circle shaft was broken. This is not the first time (it might be the 4th). Previously they welded the shaft and re use it and this is the one that broke down.
So we bought a new one (I told´em so) and we put it. Now I´m having serious doubts about the clutches for the drive circle. Don´t know if they´re working. When I took the shaft out, I noticed a lot of washers (really thin). What I dont know is if you put more washers the blade is more sensitive to logs or to the contrary, it will resist more knocks but braking the shaft.
BWT, here you have pics from the circle when I removed the shaft. Look the gear and crown

 

[Radrock]

If I remember right adding shims will make it slip easier. I had one that was slipping too much and we removed a couple of shims. On a 160H. One other point is to make sure your circle is tight. If the circle bangs back and forth you have a chance of breaking that shaft as well

 

[andrew80]

Yes, when changing the shaft I noticed a gap between the shaft and housing bushing (bottom), so I changed it and now is tight.
Do you think that repairing the broken shaft works well?

 

[Nige]

Andrew, Give me a couple of hours. I will send you the procedure to adjust the slip clutch on the circle drive. The standard number of shims in the top of the assembly is 9 x 0.25mm thick & 6 x 0.13mm thick. This number may vary by 1 or 2 in order to get the correct clutch adjustment. If this clutch does NOT slip you WILL break shafts - don't ask me how I know this ............ and NO, you cannot successfully weld a broken shaft, not in my experience anyway.

I agree with Radrock, before messing with the slip clutch the first thing you need to do is adjust the circle shoe clearances so that the circle is rotating in a perfect circle and has the correct amount of engagement with the pinion on the bottom of the circle drive. I will send you both procedures.

 

[smoothoperator]

Another thing you might want to check. Wear pattern on gears makes me wonder if you have movement of your worm gear in the housing. It's been awhile since I've opened one up, but I think you should have almost zero movement. Inspect bearings/races, adjust to specs, use proper lube, and follow the good advice you are getting from other forum members.

smoothoperator

 

[Radrock]

Another thing you might want to check. Wear pattern on gears makes me wonder if you have movement of your worm gear in the housing. It's been awhile since I've opened one up, but I think you should have almost zero movement. Inspect bearings/races, adjust to specs, use proper lube, and follow the good advice you are getting from other forum members.

smoothoperator

If I remember right that worm gear has shims on it to adjust the movement and seat the bearings. I was waiting to see if Nige posted the procedures on tightening the circle. He's a pretty darn good mechanic from what I have read. I've always just did it by the seat of my pants (logic) and never really read up on how to do it. I am a fussy operator and like that circle tight..

 

[Nige]

Rad, the procedures are far too long to post here. I sent them to the OP by e-mail.

 

[Radrock]

Rad, the procedures are far too long to post here. I sent them to the OP by e-mail.

Aw that's ok. I was just curious. I've never read up on it but just used my own judgement. Get the up and down play out first not using the middle shoes. Adjust it so the gear and teeth are making good contact, lined up and not bottoming out in the pinion gear. I would then put the middle shoes back on with the right amount of shims. Of course some old graders have a little egg shape and you can't make them perfect. I use dry graphite spray on the teeth and circle surface once a day as well. I even use it on the slides some. That stuff will polish up the surface slicker than snot haha. Don't know if its right but it works. I found if you tighten up a circle real good it will last quite a long time. I'm not a mechanic but always had to take care of my machinery in the oil field years ago and still do some of it working in construction now days. I think it makes you appreciate your machinery more as well.

 

[Gavin84w]

Cats instructions can sure make an easy job look like rocket science sometimes, circle adjustments are common sense for the most part if you are the mechanic doing them that understnds what a grader gets up to in the dirt. For shop guys who have not seen a grader in action or are less experienced certainly follow the OEM instructions, atleast your circle drive looks a lot nicer than one of my customers 24M, very ugly!!

 

[Nige]

I agree. The thing is that to adjust a circle "properly" it really needs to be done in order which I think should be following, although I've never seen any Service Manual say anything about it apart from to give the procedures for each separate adustment. 1. Vertical Play 2. Circle pinion/circle tooth contact 3. Shoe adjustment 4. Slip Clutch. 5. (if required) internal adjustment of circle drive box to remove play.

I'm with Radrock on using dry graphite spray on circles, it's what we use on ours and it works well provided they are adjusted correctly.

 

[Radrock]

Cats instructions can sure make an easy job look like rocket science sometimes, circle adjustments are common sense for the most part if you are the mechanic doing them that understnds what a grader gets up to in the dirt. For shop guys who have not seen a grader in action or are less experienced certainly follow the OEM instructions, atleast your circle drive looks a lot nicer than one of my customers 24M, very ugly!!

I can imagine. Our shop guy (very young) is the same way. His idea of a tight machine is if it moves it is ok. It makes me frustrated. I just keep saying to myself "three more years". (Retirement). Although I probably wouldn't retire if I had a good tight well oiled grader. I do still enjoy it. Our support group does not understand the consequences of a zero tolerance job with a sloppy grader..

 

[catgraderhire]

Gday, I have had similar trouble with circle drive shafts. Make sure the mesh distance fot the pinion gear is sufficient so that the circle doesn't impact on the gear wich can snap shafts. Also when you adjust your slip clutch, before you tighten the 3 bolts down onto the shims, rotate the circle using the hydraulics and this will ensure the pack isn't frozen together. The circle shouldn't rotate with the bolts loose. Then tighten down and it should slip ok if shims are right.

 

[HardWork1975]

Andrew, Give me a couple of hours. I will send you the procedure to adjust the slip clutch on the circle drive. The standard number of shims in the top of the assembly is 9 x 0.25mm thick & 6 x 0.13mm thick. This number may vary by 1 or 2 in order to get the correct clutch adjustment. If this clutch does NOT slip you WILL break shafts - don't ask me how I know this ............ and NO, you cannot successfully weld a broken shaft, not in my experience anyway.

I agree with Radrock, before messing with the slip clutch the first thing you need to do is adjust the circle shoe clearances so that the circle is rotating in a perfect circle and has the correct amount of engagement with the pinion on the bottom of the circle drive. I will send you both procedures.

Hi Nige, Can you please send me the procedure to adjust the slip clutch on the circle drive? I m having same issue here. Thanks.

 

[Nige]

Hi Nige, Can you please send me the procedure to adjust the slip clutch on the circle drive? I m having same issue here. Thanks.

Can you supply the machine Serial Number.? It makes it easier to look up the info.