Another Kama 554 front drive repair

   / Another Kama 554 front drive repair #1  

Brad_Blazer

Veteran Member
Joined
Aug 19, 2004
Messages
1,934
Location
Caldwell Co. NC
Tractor
2006 Kama554; 92 Belarus 250AS
I always had a small gear oil leak at the right side pivot of the front axle on my Kama 554. After roading the tractor on Saturday (in 2wd on the road) I noticed quite a bit of leakage both at the pivot and at the hub.


In my experience, a leaking seal often means a bearing problem, so I wiggled on the assembly with the wheel on and off but I couldn't detect any free play.

I started taking the front hub apart. The big gear and lower bevel gear were in good shape but the vertical shaft showed some ugly wear where it fits through a close tolerance hole inside the pivot bearings. There were also some metallic shavings in the bottom of the case.



When I got the upper gear housing apart, the gears did not look good. The outer ends of the gears were severly deteriorated and there were lots of jagged metal chunks that had been shed by the gears. That was probably the cause of the cosmetic damage on that vertical shaft.



The tractor had not shown any symptoms of the gear problem. I thought I'd better check the left side gears too so I opened up the top gears and found the same type of damage.


Today I called Chip at ARTRAC and he is shipping me new gears.

I removed the pivot seal that had been leaking and it looked like it was poorly installed. One edge was peeled back and it was deformed. It had driven out easily from the far side (without further deformation) so I don't know why anyone would have had trouble installing it.

The hub seal is sandwiched behind the big gear. Chip talked about a clip retaining the stub axle. I saw a split ring back there and tried to pry it apart and it broke. I got it off but figured out it was retaining the axle in the outboard bearing and not holding the gear on. The gear and outer bearing race were just tight on the shaft. I pondered and scrounged around a while and finally supported the very heavy gear across a couple of pieces of 1/2" flat bar and drove the shaft out with a drilling hammer. I think I was driving more against the momentum of the gear than the bar supports. The inboard bearing race and gear spline were both pretty tight fits.

It turns out the "split ring" was actually a hard washer that had cracked in one place long ago. I just broke it in another spot when I tried to remove it with the gear still in place. There was a separate 2-piece clip behind the gear adjacent to that washer.

That's it for tonight. I still need to get the stub axle out of the outboard bearing and it feels like another tight fit. I have a pack of seals that came with the tractor and it seems to include the sizes I need. I'll check all of the bearings carefully for damage. I priced them at the local supply and the prices ranged from $35 for the regular ball bearings to about $100 for the biggest angular contact bearing (that outboard stub axle bearing). I hope they're okay. :)

Brad
 
   / Another Kama 554 front drive repair #2  
Wow Brad, your gears look exactly like mine did! :)
Same with that vertical shaft cosmetic damage ... you are right that it's from some of those gear chips grinding it as they made their way down to the bottom. More than likely, you big bevel gear is OK like mine was. It's those smaller gears that take the beating and wear. Lucky they are reasonable and relatively easy to replace. I got an extra set for future(?) repairs.
Good luck in your re-installation of them after your camping weekend.
Rob-
 
   / Another Kama 554 front drive repair #3  
How many hours were on your tractors? Looks like I might need to buy a spare set.
 
   / Another Kama 554 front drive repair
  • Thread Starter
#4  
Yeah Rob, it looked a lot like your pictures.

Parry, I'm at about 300 hrs. I really hope the problem was poor gear alignment and not under-designed gears.

My gears came in Thursday night. I got the rest of my hub disassembled - now I need to do cleanup and re-assembly. Rob's thread will really come in handy then.

We had a good weekend in the woods with the Scouts- didn't get too wet. Tonight I drove to Dallas and picked up a 6 month old female Great Pyrenees I found on Craigslist. She's a pretty dog. Of course the first thing she did was crap in the carrier and then bark for the first 20 min. Luckily Dallas, NC is only 45min from here.

Maybe with Daylight Savings I can get the tractor together in the evenings this week.

Happy Pi day,
Brad
 
   / Another Kama 554 front drive repair
  • Thread Starter
#5  
Well, I finally got it all back together this past weekend. Let me start back where I left off.
I got that hub apart on the press. The shaft seal was messed up but the big outer seal looked okay. I am replacing it anyhow since I have one. To replace that broken spacer ring I bought some 1-3/4" shaft washers at TSC and bored them out on the lathe. It turned out I only needed one.


After I got everything cleaned up I started putting it back together. For the loose needle bearings, I coated the inside of the race with grease and put the needles in dry. Thankfully they filled in. (I hadn't lost any!) Oops, I should have put the seals in first! I took a plastic bag with a paper towel in it and stuffed it in the bore to retain the bearings while I installed the seals. I had polished the entrances with a Dremel and the seals went in okay.
 
   / Another Kama 554 front drive repair
  • Thread Starter
#6  
Once I got it all together, I carried the heavy sucker to the tractor and mounted it up to check the fit. I had about half of the original shims on the end of the axle and on the cap that holds the top gear. The gear lash seemed like a little much, plus I forgot the snap ring on the end of the axle!


I had the bright idea to put a couple of super magnets in a grocery bag to pull the axle out for the snap ring. The bag gave way instantly but I still managed to pull it out with the magnets. I ended up taking all of the shims out and the gears felt the best. Originally there were 8 layers of shim on the axle and 6 layers on the cap. Each layer was 0.5mm so that's a lot of extra gear lash I took out!


Notice the new bolt heads - those were pretty beat up and I ordered some new ones along with some o-rings from McMaster.
 
   / Another Kama 554 front drive repair
  • Thread Starter
#7  
Well I was pretty slack and didn't take any progress pics of the left side. It went quite a bit quicker since those seals were okay and I didn't even take apart the pivot bearing. I just tied it together with baler twine. I did take off both the top and bottom gear caps, cleaned up the vertical shaft, and flushed the whole thing out in the parts washer. In addition to the metal chips from the gears there was still lots of grit and loose scale present even though I had flushed and refilled way back when. Before I refilled everything I also flushed the differential sump with kerosene and used a magnet to help pull out the junk. That grease around the upper pivot shaft is some I put on for assembly. That top zerk broke off sometime after I greased it and I replaced it.

My steering cylinder never had a dust boot so I picked up a universal rack-and-pinion boot from Autozone and put it on. The little end was only about 1/2" ID but it stretched over the rod eye and fits real snug on the ~20mm shaft. It sealed so good I had to cut a vent hole in the bottom of the outside bellow because it was trying to tear itself apart pulling a vacuum on the extend stroke.
 
   / Another Kama 554 front drive repair
  • Thread Starter
#8  
So it's finally back together better than ever!
Lesson learned - If the repair might last longer than the forecast - start it under a roof or you might end up finishing it in less than ideal conditions.

 
   / Another Kama 554 front drive repair #9  
So it's finally back together better than ever!
Lesson learned - If the repair might last longer than the forecast - start it under a roof or you might end up finishing it in less than ideal conditions.

I hear that Brad!
I know exactly what you mean about ideal repair locations. Very nice job on the repair. You may want to check out the gear's wear pattern after a few hours though. Hope fully those shims you took out were not needed, but if it's fit too tight, you could have some gears crushing. On my Kama, it still needed some of the shims.
Very nice job and documentation Brad!
 
   / Another Kama 554 front drive repair #10  
Nice job Brad. Glad you got here back up and going.

Chris
 
 
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