630 PTO revisited

Got lucky! My earlier post showed a hole in the first reduction gear from the PTO gear rubbing through. Today I finally got a chance to dig into it and what happened was the bearing cover that holds the PTO input shaft bearing in place, had broken at some time and the bearing finally worked it's way out of the transmission case. This has been going on for a long time. The sliding gear was chipped. My theory is the sliding input gear was jammed into gear with the engine turning, making an impact load on the bevel gears causing the bevel gears to spread a bit putting an end load on the bearing and breaking the bearing cover. When did this happen? I don't know. It's been in the family it's whole life and we aren't hard on things.

Anyway, while it's part way apart I split the axle away from the transmission case to replace a weeping gasket. After it was split I looked at the PTO bevel gears from the back and everything looks OK. The shafts turn free and smooth. While it's this far apart I plan to pull the shifting forks and build them up.

Rock Valley does not have a first reduction cover and they were going to call around for me but I haven't heard back. The crack in it is pretty healthy sized. Anyway, I feel pretty good about it considering what it could have been. Jim

What I first saw after it crunched.


Broken bearing cover. The broken edges are worn smooth. I don't know where the bronze piece came from. I was in the bottom of the reduction cover. Everything looks OK with the clutch forks.

The way it is sitting now. Hope to have all leaks cured after it's back together (fingers crossed) I'll put a dial indicator on the crankshaft tomorrow to see how loose it is.

I have mixed feelings when you use the word "lucky", but yes, it could have been much worse. That little gear is bound to be cheaper than the big idler gear. Makes you wonder where that piece of bronze came from.

How do you keep the rear assembly from rolling around the axle Jim? It looks to me like it would want to flop over on its backside, so I suppose you have support under the drawbar? From the pictures, it looks like both the front portion and the back portion are on thin air.

Also - what type of sealer do you use on your gaskets?

I just wonder ? if a previous clutch fork failure (bronze part)got into that gear tooth broke it and then broke the bearing retainer ?
I'd really look real close at the bevel gears and the bosses in the housings.
That's about the only bronze part I can image from in there ?

Forgot to add I have seen a 720D or 2 with that area of the reduction cover brazed up. If you can't find a good cover maybe it can be repaired ?

The chain hoist is holding up the drawbar for the moment. Splitting stands are holding the front half (2/3)? using the two 5/8"bolt holes at the back of the frame rail. Looks like a LOT of weight hanging behind the splitting stands but I tried lifting up on the front axle and I couldn't lift it so I feel pretty confident the front end won't leave the ground. It has four front end weights and a wide front so that helps. A jack stand under the belly might help me feel more confident while I work on it. Looking from the back with a flashlight the bevel gears and bearings look OK. That's why I said I 'got lucky'. Looks like a real job to go down from the top to replace those gears and bearings. I'll take another peek this morning. This tractor has never had water in the tranny and has had regular oil changes but parts do wear out nonetheless. Mike, I'm not discounting brazing up the cover just yet. I'm sure a used one can be found and that's the way I plan to go since this is a family tractor. I'm willing to 'throw away' a little extra money to fix it back up.

I remember when this tractor came on the farm brand new on the back of a 50's something Chevy truck. I was 9 years old and the truck came up the lane just as I was getting on the bus headed for another day of school. I don't remember learning anything in school that day.

Gasket sealer? What do you recommend? I'm open for suggestions. Jim

For gasket sealers I have had about the best luck preventing leaks by using silicone type in a tube. The ultra ones from permetex do seem better then regular silicones.
Trick is to not use much just a light coating on your finger smeared thinly on both sides. I do the case then stick the gasket on and then do the gasket thus doing both sides. I also like to draw things up snug but not all the way tight, Time permitting I come back later or next day and then give it a final tightening. Guys that have a deadline to meet sometimes silicone is not their friend as it is too slippery when wet and can actually cause gaskets to squeeze out. In this case then may dry is better ?
I also take a file or those scotchbrite disks and debur all the gasket surfaces. I also run taps into all the holes to clean them out too.

On the gasket sealer - my son, the mechanic, recommended an RTV sealant in a tube that is supposed to be designed specifically for use around gear lube. He actually uses it with no gasket, in some repairs. I tried it on a Chevy 1 ton differential cover, and it leaked like a sieve. Probably didn't clean it good enough. That is why I asked what you were using. I'm about ready to put my first reduction cover back on my 630, and I'm a little gun-shy of the RTV stuff. Right now I'm leaning toward the liquid Permatex, with a gasket, and painted on all surfaces.

Hopefully, someone else will chime in and suggest something that works.

I hope your main bearing is OK.

Pulley side of the crank measures .0055 up and down right outside of the drive gear using a pry bar to pry it up and down. .005 fore and aft by pushing and pulling on the crank by hand as hard as I could. I&T manual lists .004-.006. I might just leave it alone. It took an estimated 15,000-20,000 hours to get this far so I don't expect it to wear much more in my lifetime and beyond.

Main sounds like good specs.

You know while you are almost right there I'd think about removing the main bearing housing and renewing the oil seal and also the packing that the oil pressure feeds oil into there. There have been a few fellows on here who had main bearings starve for oil because of that packing breaking down and swelling up and closing off that passage.

(quoted from post at 12:35:05 08/29/14) Main sounds like good specs.

You know while you are almost right there I'd think about removing the main bearing housing and renewing the oil seal and also the packing that the oil pressure feeds oil into there. There have been a few fellows on here who had main bearings starve for oil because of that packing breaking down and swelling up and closing off that passage.

Click to expand...

Good idea. Thanks

If your seal is original, I'm surprised it hasn't been leaking. Mine was hard and brittle. And leaking pretty bad. Here's a picture of Ron's (Bushhog Papa) idea for keeping that oil supply open. This is on my tractor, but I stole the idea from Ron.

What is that part in your fingers ? Is that just an end of a flared tubing ? it looks larger on one end ?

Not at the shop but almost positive I have a cover or two

Larry where are you located? Jim

Another idea that entered my mind was to change the axle seals while the bull gears are exposed. The seals have leaked for some time now so now is the time to do it. After looking close I don't think I can get the bull gears out the front. Darn!

Mike, that is a piece of what I call "Lamp tubing". It's the common straight cut thread that you see on table lamps. The thing that looks like a flare is a nut like you would see on a toggle switch. I screwed it on the end - the threads weren't a perfect fit - they allowed me to use a wrench to screw the pipe fitting into the side of the JD block. I then used a chisel to break the nut loose and leave the pipe in the side of the block. This is Ron's idea - I don't want to take credit for it.

Tn., 38553 email is open

Got the shift forks out yesterday for rebuilding. How do I describe how simple it is standing behind the tranny without the rear axle in the way? LOL What kind of rod or wire works best for building up the channels where the shifter contacts them?