Jump to content

Unofficial Home of Old Simplicity & Allis-Chalmers Garden Tractors

Im gonna take a beating for this...Help!lol!


sbull78

Recommended Posts

hey guys, as you all know i am an avid collector/fan/nut of simplicity/allis..i have a problem with my only other brand tractor and its green...i tried to post a question on another "green" forum and everyone is too busy arguing over how to spell and picture stacking..(idiots!)any how i'm here to ask the pros so i'll just get to it...i have a deere 420...it has an electric clutch on the front..it fried the electric pto clutch that sits on the front shaft of the motor...ok no problem, i ordered a new one and proceeded to remove the old one...after i got the old one off i see why it destroyed the clutch...the crankshaft keyway has been wobbled out causing the key to move around...it looks like everytime the clutch would engage it would "slam" the loose key into the side of the keyway thus wobbling it out...a somewhat knowledgeable guy told me i could do 3 things, first put in a new crankshaft, which the motor is only a 3yr old 20hrse kohler command so i really dont want to have to tear it down, or second, tear it down and have the other side of the shaft cut..which, if the crank is coming out, i might as well put a new one on....the third option is, to take a new key, place it in the keyway and tack it to the crankshaft then grind off the excess with a dremel...i didnt think this could work but he said its been done before and has worked...what do you guys think of this idea and has anyone tried this before????if its been done before i'm sure one of you guys have tried it...thanks again for the help in advance and the beating i will take for the green thing....:D:D
Link to comment
Share on other sites

I have swapped cranks in Commands a couple of times. Not a huge job. Biggest deal is removing the flywheel. Take off front cover. Unbolt rods and push out of the way. Have your way with the crank then re-assemble, properly torquing everthing.
Link to comment
Share on other sites

I was a welder at a machine shop for a few years and this came up several times while I was there (repairing a key way). We put a key in the key way and welded or (if it was a cast iron shaft) brazed the entire key into the shaft. After it cooled it would be ground with a hand grinder flush with the shaft. The trick is don't weld it with deep penetration. The welded in key could then be removed with a sharp punch or chisel leaving a nearly original key way. A little filing will need done to finish the job. Mel
Link to comment
Share on other sites

willy, i new that would come up but i have 3 foot draggers..i wish they had 3 sets of hydraulics a locking rear end, hydraulic steering, and shaft driven atttachments but alas they do not...lol...i use this thing for the loader purpose and the 3point...dont worry, my fav is still my 2012!!!! Mel, that sounds good to me as i have talked to a good welder and he suggested a very similar process...thanks!
Link to comment
Share on other sites

I had a similar situation on a transmission input shaft, and did the following: Turned the shaft 180 degrees from the damaged side. I propped the shaft with a 2 x4 with a v cut in it and loaded some of the weight of the tractor directly on it (this keeps it very solid). I then scribed a line at the location I wanted to install a 1/2 moon key. I took a drill bit slightly smaller than the key and drilled 3 or 4 pilot holes, in a line, deeper at the center where the 1/2 moon key would be deeper. I then took my time and carefully cut the remainder of the material away with a Dremel tool. The key tapped in tightly and the problem was solved. Maybe took a half hour. If you are thinking of replacing the shaft, I'd at least give it a try first. Worst you can do is screw up the crank you plan to replace. Best case though, you end up fixed with little or no expense and minimal time invested. Either way, good luck!
Link to comment
Share on other sites

thanks brett!!!it does suck because the motor isnt even that old!!!it seems like just a waste to have to put a new crank in it or at least remove the old one when everything works fine....another good idea!!!thanks!
Link to comment
Share on other sites

Depending on how wollered out the keyway, you may be able to repair with JB Weld. I have fixed many keyways with this and all are still in operation (even the solid axle in one of the pulling tractors). Put a small amount of WD-40 on a good key (where the JB Weld will be against it), put into place and put JB Weld all around it. Let it set up, remove the key and file the shaft round again. Make sure that the metal of the shaft is very clean so the JBW bonds.
Link to comment
Share on other sites

i had thought about that as well but wasnt sure if it would be strong enough to hold up...i guess if it doesn't work then i could try the weld method from there after i clean it up...and if that doesn't work then..sm02new crank or have it recut...
Link to comment
Share on other sites

Regardless of what you decide to do, given you have a straight key slot, buy some key stock and cut it to the entire length of the slot. It'll take a lot longer for the problem to resurface with the longer key.
Link to comment
Share on other sites

i also had pondered that but the key is only so long as it does not run the full length because of the pulleys...stupid deere engineeringsm00
Link to comment
Share on other sites

There are two other ways that I would consider myself. First is to take a Dremel tool with the carborundum cut-off discs and enlarge the slot to the next largest size. After you have the new, larger size key fitted to the slot, then grind the protruding portion down to the original size to fit the internal slot in the clutch. Hand fit the key by sliding the clutch onto the shaft and testing it. That way you will not make it too small. I have done exactly this once before to fix a wallowed out slot. The other way is to go 180 degrees around the shaft and just grind a new slot for the correct size key. I think this may be a little more difficult since alignment is harder to determine without the original slot to work from. Anyway, this is the way I would do it. If you screw this up, then you can always fall back to the other ideas.
Link to comment
Share on other sites

Try using Loctite 660, get a new key and glue that puppy in. You got nothing to loose. A used crankshaft is not hard to find. If there is room on the clutch drill a set screw 1/3 the way around from the key.
Link to comment
Share on other sites

I'm for welding it in place and grinding it back that way it'll never move have done it many times as an emergency repair at the concrete block plant I used to manage to hold sprockets on shafts almost never come loose especially if with a little time and care.Also you can get keys that are made for one size on the crank and one on whatever you're putting on the crank.Then you could carefully make the crank slot larger.Get the keys from an industrial suppy house.
Link to comment
Share on other sites

This is an easy fix, well time consuming for sure but easy. Any fab/machine shop can fill weld the key slot and re mill the key slot.There are alot of great ideas on how to fix it but do you really want to deal with the same problem twice? If you take a chance and do it yourself I would look at drilling the holes and cutting it out with the dremal. So you would just leave the old keyway there and make a new one. But, The machine shop can make sure the tolerances are correct.
Link to comment
Share on other sites

  • 7 months later...
just to give u geys an update i decided to try the easiest first which is jb weld...to this day it is still holding up perfectly...i cant believe it...everytime the pto is engaged it puts pressure on that key and it has held flawlessly...i'm a believer!!
Link to comment
Share on other sites

I showed a farmer friend how to fix this on an electric motor. You need some 1/4" square (or whatever size the key is) BRASS. Carefully clamp that in place and fill in the worn area with weld. The weld won't stick to the brass. Remove the brass piece, grind and file the shaft back into shape using a micrometer or dial caliper to measure the high spots until it's back to size. If your weld is good, this will put it back to original condition. You'll obviously have to replace the front seal, which I'd remove before welding, but this WILL work if done properly. I'm a veteran toolmaker, and I learned this years ago repairing messed up holes and the such. Try it, you'll be amazed at how well it works.
Link to comment
Share on other sites

Has anyone tried any of these techniques on the BGB input shaft and gear keyways? I apologize in advance if this is a stupid question... I've not popped a BGB open yet.
Link to comment
Share on other sites

Best advice is replace the shaft even at three years with the jamming of the clutch the old one may have been twisted to some degree. Its great to save money and do your own repairs but integrity of the parts is #1. if you replace it you know where you stand "without fear of it happening again in the near future" just MHO.
Link to comment
Share on other sites

loctite makes formula/s... 660 is one... Quick Metal®... made for exactly the purpose of filling worn areas like keyways and holding the key in place formula 660 is specd' to fill gaps of .020" you wont find it listed on the loctite consumer page it is found on the industrial site to which I have pasted a link below... http://www.henkelna.com/cps/rde/xchg/henkel_us/hs.xsl/full-product-list-7932.htm?iname=Loctite+660+Quick+Metal+Retaining+Compound%2C+Press+Fit+Repair&countryCode=us&BU=industrial&parentredDotUID=productfinder&redDotUID=0000000HWS These anaerobic adhesives are used to bond and increase the shear strength of non-threaded, cylindrical metal assemblies. Fills the inner voids in close-fitting press fits, keyways, and splines. Allows you to mount bearings and bushings, and make press fits even stronger. Formulated in a selection of viscosities, gap filling ability, flexibility, and strength characteristics. Typical temperature range is -65°F to 300°F. General purpose Formula 609 is a low-viscosity, fast-curing adhesive used for bonding rigid metal assemblies. High temperature Formula 620 has the capability to operate at 450°F for long periods. It fixtures in 60 minutes at room temperature, but requires a secondary heat cure to generate high temperature resistance. Quick Metal® Formula 660 is a creamy, non-running gel that is applied onto cylindrical parts to fill surface imperfections and repair worn areas. High strength Formula 680 provides a shear strength of 4000 psi after 24 hours.
Link to comment
Share on other sites

So, having never disassembled or assembled a BGB - would this in any way interfere with the ability to put things together (or disassemble later, if necessary)? I seem to recall something about not being able to remove the shaft without removing the retainer ring, and not being able to remove the retainer ring without removing the woodruff key, or somesuch.
Link to comment
Share on other sites

There is one other way, if the keyway goes all the way to the end of the shaft. Just line up the keyway on the shaft with the keyway on the clutch then drill down the center of the key slots with a drill larger than the keyway. Once the hole is drilled between the two pieces, then drive a piece of rod into the hole to become the new key. Round rod will work the same as square key stock. If you want a harder key than mild steel rod, you can use a grade 8 bolt as the key. This can be done with the parts still on the tractor.
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...