Front Drive Casting Repair Kama 554

[3RRL]

This last week we had to do the usual road repairs at the ravine switchback. We decided to widen it and build it up another foot and also add more boulders around the sides of the land bridge. I had to dig into DG and get a bunch of boulders. I was driving up some steep embankments to get them. In doing so, I got my left front drive casting smashed against a boulder as I was driving over a bunch of them and developed a leak where the oil seal is.

As a side note, I have 575 hours on the Kama clock now. I noticed that over 2 days of work ... about 16 hours or running the tractor doing this repair, building a garden shed pad and then grading the road, I had clocked only 6.4 hours on the meter! I run the tractor (usually) between 1500 and 1800rpm. I wonder how many hours I truly have on this tractor now?

My finger (gloved) is pointing to the leak and seal which is sandwiched between the upper and lower drive castings.



I was hoping it was just an oil seal or "O" ring or something easy to fix.
So I took the tire off and started to dis-assemble the front drive. I took the top bracket off which captures the upper and lower castings together. Then I slid the big lower drive casting down and off. The top casting which bolts to the end of the axle housing has a one-piece machined sleeve on it that fits into the bottom casting.
It looks like this normally (one-piece) casting.



To my disappointment, I found that the machined sleeve had broken off clean and was stuck in the bearing and mating sleeve in the lower half. These pictures show it when I took it apart. Then I pried out the broken off piece and put it next to where it should go in the last photo.



Holy crap, how am I ever gonna fix that and make it strong enough?
I've been considering calling Chip to order a new casting, but I have a plan to repair it myself first. It will force me to set up one of the milling machines (finally ). So I had a lot of prep work to do such as run some 3 phase electrical, level and tram the mill and lube it all up. Then I will have to open all the boxes that contain my cutters, end mills, drills, clamps, indicators etc before I get started.
I've been running around like a chicken with his head cut off ... shees.
Rob-

[quikduk]

Bummer dude! At least you can make some new ones out of hardened steel or SS...and you get to finally set up one of the mills.

Better get it fixed before we get back up there...and speaking of that...better call me.

[linus69]

Holy crap Rob, that is one leak that can`t be fixed by mixing up a little JB Weld. Apparently fate wants you to set up one of the milling machines real bad and like now. I`m sure that more than a few swear words passed through your lips when you uncovered this surprise.
I guess you can look at it like taking and passing a cardiac stress test, I know I would have had a heart attack for sure. I wish I was close enough to help out with the fix, I`m sure you will improve on the original.

Paul

[GuglioLS]

Sorry to see that happen Rob

Geeze Rob, you sure are tough on your toys, you've gone and done it. Now go to your room and sit in the corner. Well so what's the plan? It's gonna take a month to unpack, find and organize all the machine tools, wire the shop and tram the mill. Of course you had to do all that sooner or later anyway. I suppose this is as good a time as any. Do you think Chip has that cast part in stock? I bet he does and maybe it's at a reasonable price too.

You ran the tractor 16 hours and only clocked 6.4? Was the key on all the time. I know a few times I have accidentally bumped my key to the off position, of course it still runs but the tach stops reading and so does the fuel gauge. I suppose you could have broken the tach too.

So now I'm curious, exactly how are you going to fix that?

Larry

[3RRL]

Thanks for the comments guys.
Regarding the hours, the key was on all the time and the hour meter and tach all work fine. I've noticed this before that the hours registered are related to the rpms. Since I rarely run it at the rated 2300rpm, it never reads 1 hour IN one hour. It usually takes a couple hours or more to register and hour on the meter.

I'll have to give Chip a call ... he has this casting stock. By my call will be for a new set of the small bevel gears, not for the casting ...yet . The bevel gears on the drive shaft and the top mating one on the vertical shaft inside the casting were chipped. Luckily no teeth were broken or ground off like last time. The chipping must have occurred when the sleeve snapped, causing the gears to mesh harder together.

Anyway, I got right to it and quickly ran some wire (not permanent) to one of the mills. I set it up for the machining I was about to do. Then I tore open a couple boxes to find a boring bar and a couple end mills.

Earlier, I had fit the broken piece back onto the casting and it fit pretty darn good when I lined it up correctly. My plan is to arc weld it back together. However, I wanted to make sure it was welded both from the inside and outside so that the sleeve would be completely welded throughout it's 5/16" wall thickness.
What I did was bore out the casting so that when the sleeve was put back in place, there was about a 3/16" gap on the inside of the casting exposing the inside of the sleeve. I clamped the sleeve back onto the casting all lined up and you can see in the last photo how much of an area I can weld inside there to give me giant bead in there.



In the picture below, you can see the 7018 stick weld on the inside. It got the inside of the sleeve and then I ran another bead so it lapped over the inside of the casting too. I will leave that weld build up on the casting for added wall thickness since nothing butts up against it. The second photo shows the casting with the sleeve back on it. It's the same photo I shared in the first post after I welded the inside. That's how good the sleeve fit back on there and why I decided to do it this way.
But I'm not done yet...

[3RRL]

I wanted to make sure the entire sleeve was welded which meant now grinding a deep groove on the outside of the sleeve and milling a deep 1/4" wide groove into the casting. I set up the rotary table in the mill to do this.



I dragged my Lincoln arc welder over to the mill and welded the entire outside of the sleeve and the face of the casting together again using 7018 stick. I did it while it was still set up on the rotary table right in the mill. Now, the weld goes all the way through both pieces.



After that, I cut off all the weld back down to the original face on the casting and also trued up the OD of the sleeve. It was slightly out of round but not anymore. All you can see is the slight sink marks from the weld on the OD.



The last thing I did was bore out the inside of the sleeve so the vertical shaft could pass back through it. It's smaller ID than before making it stronger. I bored it out only enough for the shaft to pass through it.



So then I spent about an hour putting it all back together again and re-filling the gear oil. The 2 halves fit really nice and tight so I know I got a good fit. I started the tractor and tested it out by driving over some rocks ... hahaha. I hope the repair lasts or I'll have to get that casting Chip says he has in stock when I order the new gears.
So far so good ...
Rob-

[GuglioLS]

Rob,
Amazing repair job, and here I thought it was going to take forever and a day to fix it, I should have known you already had it repaired.
I must say your as good at fixing things as you are at breaking them. Were those the new bevel gears that got a little chewed up? So I suppose you have it all back together and using the tractor again? Your hour meter sounds like it's whacked. I think your cluster gauge is the same as mine and just about every other Chinese tractor with that style cluster gauge. I wonder why yours reads like it does? From what you say you must have over a 1000 hours on it by now.


Larry

[stumppuller]

You amaze me. By the time I researched the various ways of repairing cast iron (weld, braze, preheating the casting, slow cool down, etc.), you already had it repaired! A good-looking and thorough job too, I must say. You are the Nike man - "Just Do It"

[3RRL]

Hahaha, thank you guys!
Merry Christmas too!
Rob-