The Blade lift bearing on the Cat No.12 8T Motor Grader lift blade arm looks like it has clipped off the extension to the grease zerk. The zerk extension is threaded into the bearing and extends through a hole in the chassis housing. If the bearing spines inside the housing it looks as though that action shears off the zerk extension agents the chasses housing.
I was wondering if this has been a common problem and/or is there a service bulletin on the issue?
Seems to me like old stiff grease and the winter cold could have exacerbated the issue.

 
 

One side of the 12E is that way, left I believe, and the right is turned far enough a grease gun won't attach. I expect it has a bit to do with the years of "experience" on the machine.

Hi, Fat Dan.
There were a LOTTTTT of Cat 12s of various series around when I started operating and I have never seen it or heard of it happening before. I would suggest checking all the associated parts carefully to see if you can see a single cause or a series of contributing factors, a loose bolt, bearing cage loose in the housing, any signs of the bearing seizing on the shaft, etc.. Treat it like an FAA accident investigation - a learning experience - maybe for all of us.

Hope this helps.

Just my 0.02.

Sounds good I'll do the best I can. I'm moving quit slow these days. I've got a doable plan after initially surveying the problem..
First clue these bearings get a lot of abuse is the bolts that hold on the cap ( #2 ) have all been replaced on both Blade Lift Bearing (BLB) caps on the 8T and 9K. On the 8T some of the bolt bosses on the left BLB cap.have been broken off (no hill for a stepper, I'll show how I'll fix it without welding). The 9K has all the bolts holding BLB cap, on one cap, have been broken off in the chassis housing.🙄 The BLB cap on the other side of the 9K has one oversized bolt. I can see where this is a problem area in below freezing weather. Alaska has a lot of freeze thaw cycles. I believe this cycling plays a roll in the problem; when snow covers the BLB arms and shafts then melts and runs down into the bearing and then refreezes in place when the temp drops.The next time the Blade Lift Arm is used the zerk extension and/or Bearing Cap takes excessive loads for which it is not engineered. My thoughts are once I get the bearing back in place is to use lots of light weight grease in the fall and winter and find a way to cover the BLB housing until I can get the shop a little farther along and park them under cover...
I had to come in and take a break so I thought I would keep you-ns in the loop.

I'm going to remove the lift arm (#1) and see if I can massage the bearing back into place from the end.🤔.

Well once I got the 1 3/8" socket and my 1" drive breaker bar and the trusty Ol' 5' cheater bar (and as my dad would say "Put some mass on it Boy"! I got the nuts on the lift arm to break loose.
I think I've figured out the problem and an inexpensive solution. I'll dial it all in and give you my thoughts and conclusion when I get back this evening.

I have been working on the issue of the extension and grease zerk shearing off. Just about done
AND
Well I just fried my computer on top of everything else 😡🥺🥺🥺😢 I hope I didn’t loose all my information.
I hope everyone had a good memorial Day.

Computer is back up ... tricky little things. Article coming soon.

I found a cold weather issue that affects greasing zerks on lift arm barrings on pre-hydraulic Cat Models No.212, No.112, No.12 and No.14.

The issue and repair;
What actions I will be discussing was preformed on a mid to late 1954 No.12, 8T14777, however, I believe most pre-hydraulic Cat Models No.212, No.112, No.12 or No.14 will have the same design issue in cold weather especially in times of freeze thaw cycling.

I become aware of an issue of a missing grease fitting (zerk) this spring while greasing a 1954, 8T. I could not locate the threaded hole, extension or grease zerk in the Blade Lift Arm Bearing (8B3452). The Blade Lift Arm Bearings are encapsulated in deep housing cups between the chassis (8B3179RH & 8B3180LH) and caps (8B3450). The Blade Lift Shaft (8B3449) runs through the chassis, bearing and cap where it rotates the Blade Lift Arm (8B3449)- lifting or lowering the moldboard. At the point where the chassis covers the bearing there is a 1" hole on top side of the housing on the chassis so the threaded hole in the bearing can be accessed. An extension (3B7384) threads into the bearing and extends trough a 1" hole in the chassis so the grease zerk (3B8489) can be accessed.

I had to remove the Blade Lift Arm from the shaft in order to remove the cap and expose the bearing. What I found was the bearing had spun inside the housing shearing off the zerk extension at the bearing. Because the bearing had spun inside the housing, I could not see nor access the threaded hole in the bearing through the 1" hole to replace the extension and grease zerk. The Cap would need to be removed in order to clear the threaded hole in the bearing and reclock it so it could be accessed through the 1" hole in the housing.

The pre-hydraulic lift arms on the Cat Models No.212, No.112 and No.12 & No.14 are primarily the same from 1939 to 1964. The chassis has a female beveled housing to hold one side the Lift Arm Bearing and the cap has a female bevel to hold the bearing in place by friction. The lift Arm Bearing is a thick bushing styled bearing that has the corresponding male bevel on both ends which are captured by the female bevels in the chassis and cap. The beveled cap has four 7/16 bolts holes holding the bearing in place. If the cap becomes loose the bearing can also spin in the housing.

What I had found, in times of cycling temperatures around freezing and in combination with heavy snow or rain caused the grease to chill and become a higher viscosity; also allowing water to access through the 1" hole into a cavity between the housing and the bearing. With cold greasy water the bearing clings to the shaft enough to allowed the cap bolts to loosen, break and/or allow the bearing and shaft to spin in the housing. This action is how extensions to the grease zerk in the Blade Lift Bearings get sheared off.

The way I repaired the issue, once I had ample access to to extract the sheared extension from the bearing I then reclocked the threaded hole in the bearing with the 1" hole in the housing and reassembled using a new extension.

NOTE: I suggest in cold weather conditions is to replace the OEM 3/16 extension/zerk and should be resized. The bearing will need to be drilled and tapped to 1/4" NPT and extension replaced with a 1/4" x 1" or a 1½" pipe nipple and a zerk threaded into the other end of the nipple.
With this upgrade I found it easier to block the 1" hole in the housing with a rubber grommet off an old shock absorber and keep water from accessing the bearing recreating the issue.
Another thing I suggest is to take the time to remove and clean any bolts that broke off into the chassis and repair any elongated holes in the cap. Use the correct length bolts on the cap to get the proper grip on the bearing. One might also use some liquid bearing retainer to assist locking bearing in housing.
Thank you

Hi, Fat Dan.
Good info. Thanks for sharing. Not a problem that I had ever encountered but then I have never had to contend with minus temperatures very much either. I have pretty much always lived and worked in more 'user-friendly' parts of the world.

Just my 0.02.

Good to know Dan. Explains a good bit. I'd expect it would require a bit of wear in the bearings to allow them to spin? As if any of these machines were only used to blade the road to Sunday school each week....