Motor Grader Circle Adjustment

Hi Eddie,
a couple of questions
- slide 1, Figure 3 - does the horizontal adjusting screw "wear" on the side of the circle frame as the circle turns? If so, would you think there would be value in using an adjustable roller there to reduce the wear, or does it really not bear much on that adjusting bolt head?
- is there a wear shoe for the horizontal plane? It looks like there could be in Fig. 3 because there's a small bolt there but there's no item number on it

Cheers,
Neil.

Thanks Eddie. I adjusted the old 112 by guess and by golly so it is nice to have some real numbers to deal with. Most of it can be summed up in the last paragraph of the last page to keep the surfaces lubricated. My 112 varies from the photos but the principle is the same. Don't try to turn the blade under load!! That is a sure way to incite the knuckle buster feature of the grader. Proper lubrication means washing off some of the old dirt filled grease from time to time. My biggest headache is keeping all the gear boxes full of oil. [img]/media/kunena/emoticons/censored.gif[/img]
On second thought maybe the biggest headache is greasing the Kazillion grease zerks on the old crate.

Thanks Eddie. I adjusted the old 112 by guess and by golly so it is nice to have some real numbers to deal with. Most of it can be summed up in the last paragraph of the last page to keep the surfaces lubricated. My 112 varies from the photos but the principle is the same. Don't try to turn the blade under load!! That is a sure way to incite the knuckle buster feature of the grader. Proper lubrication means washing off some of the old dirt filled grease from time to time. My biggest headache is keeping all the gear boxes full of oil. [img]/media/kunena/emoticons/censored.gif[/img]
On second thought maybe the biggest headache is greasing the Kazillion grease zerks on the old crate.

Hi Neil,
the adjusting screw is only for pushing the shoe out to take up clearance between the shoe and the circle frame. The shoe retaining bolts are loosened and the shoe is moved as needed and then the shoe bolts are re-torqued. The adjuster screws should then take no loading when the shoes are tight and set on rust and dirt free surfaces and non rusty shim stack.
Many adjuster screw issues are caused by trying to clamp the shoes on dirty surfaces--the shoes move under load and distort the adjuster screw mounts and /or bend the screws.

With the advent of the G series machines with hydraulic drive to the circle box knuckle dusting ceased but other issues appeared due to incorrect or out of adjustment circle shoes. I have something that I cannot find at this time on this that is to do with the positioning/setting of the circle in relation to the circle drive gear as it is off centre on these G series at least.
The G series saw the start of using dry-film moly lubricants in aerosol cans to lube the circles and shoes etc. and so helped eliminate the wear from dirty grease etc.
An old can of Cat Dry-film lubricant I have here is Part Number 1U8268 and I would recommend using on circles and side shift racks.
It should be noted that the surfaces to be treated with the dry-film spray must be oil and dirt free for it to adhere and so protect the surfaces as designed.

Most circle issues are due to infrequent or poor maintenance and ignorance of correct adjustment procedures which is understandable due to the nature of the task. If it is done regularly with lubed shoes retention and adjuster bolts and nuts and clean surfaces it does not take that long or be such an onerous task.
A well maintained circle rotates easily until wear of the circle in the most used areas of arc cause the jamming to occur due to the tight fit of the shoes in unworn areas of the circle track after adjustment.

On somewhat worn circles we used to gouge off the blade hangers and reposition them 180 Deg. around. If the circle was well worn then the circle would be sent out for machining true again--sometimes if enough was taken off a well worn circle the shoes would need skimming down at the shim faces to allow shims to be stacked for future adjustment.
It was not unknown to have distorted circles due to accident or abuse and we again gouged off the hangers and straightened the circles--big job with a few propane heater torches going to get areas red hot for pressing and/or shrinking with cold watery rags and/or water hose playing on areas as needed--we used heat and shrink methods on track frames, loader frames and the like. It is a bit of an art form to know the correct places to apply heat and shrink to so as to achieve a satisfactory result.

Jim,
most savvy people get the idea that if you operate any blade or other function on these knuckle dusters when that fuction is under load or out of adjustment etc. you will likely get kicked and so learn that the blade needs to be set and rarely adjusted much from that starting point setting for a pain free operating session.
Although it is not always possible but with good drive dogs in the control box and quick positive lever movement you can get the relatively pain free operation--did a bit of Grader operation on No 12E's in Vietnam so I have a little bit of experience but certainly not as much as many on here. We were moved around the different types of machinery every few weeks to keep our hands in so to speak.

Hope this helps.
Cheers,
Eddie B.

The way I was told about the circle on a grader to never put grease or oil on it as that will collect dirt which will bind the circle and cause rapid wear of circle. catskinner

A quick thank you to the folks on this thread. Needing to figure out how to adjust the circle on my 12F. The service manual pages are invaluable! But I am a complete novice, so will take a while to digest the details. What I notice on my circle is that the entire circle moves an inch or two to the right or left before actually turning when reversing direction. This suggests to me that the guides need to be adjusted--that there is too much 'slack' and the circle is not being held in true. Does that make sense?

Yes it does. You need to adjust the shoes in to take up the side to side movement. catskinner