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Just over 2 weeks ago, I bought a 42 year old lawn tractor - a John Deere 316 Kohler from 1978. My Craftsman DGT 2000 suffered a cracked block after 15 years or so in service (exact purchase date lost). As we have lots of rain this spring in Central Texas, I needed to get a quick replacement tractor. I mow 6 acres, and use a riding mower for a large amount of trim work (nearly 200 trees on the place, for instance). The local Craigslist showed a few options, but none really appealed to me. The 316 Kohler had to promise of being built of things like plenty of mild steel, cast iron, and less plastic things. This one had a "functional rebuild" (not a ground up rebuild) by a guy who repairs older John Deere mowers for a hobby business in his retirement. This one came down with him from Chicago, and he was rebuilding it for himself. However, he fell in love with another tractor, and listed this one. Engine rebuild with 10 over on the piston, and 10 under on the crank. New tires, rebuilt spindles on the mower, new blades, etc. He built a custom bumper for it out of a steel weldment - - I hope I never run this into anything !
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Compared to the Craftsman, this one has some advantages, and some disadvantages. It is clearly built in such a way it can be repaired and made to last. The Craftsman will never make it to 42 years. Despite being 16 HP single cylinder, it doesn't bog down in tall grass or weeds as much as the 26 HP twin Kohler Craftsman. I think part of that may be torque, and also the deck design. As many have pointed out in the forums, these tractors are definitely a little harder to steer.

One thing that I noticed as problematic was there was some "lost motion" (e.g. backlash) in the hydrostatic control level / linkage system. This is a bit annoying when trying to set a precise speed, or slow down or speed up (e.g. changing directions on the control). Also, it wasn't clear if the damper (e.g. shock absorber) on the connector tube to chassis was working correctly.

So I decided to overhaul the hydrostatic control linkage. This work made a big difference and now more precise control is much easier and also easier to make it move slowly without the lost motion problem. That being the case, I decided to share the process I used in the event others would find it useful. This work draws on the service manual and parts catalog available in pdf form online for purchase.

The part that I rebuilt was from the YOKE (19) forward. Nothing associated with the SWASH PLATE (21) was rebuilt. I had completed this task on the 13th day after purchase, which includes the time to procure parts and rebuilt the linkage before the repair. In the meantime, I put several hours on the tractor cutting grass.

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FIRST TASK: The first thing I did was to buy a use control linkage assembly on Ebay. Why buy an assembly when you already have one on the tractor ? Good question. There are several reasons to consider this, and the price for this assembly was not very expensive.
  • If you rebuilt the assembly and verify the integrity of the hinge points before you disassemble the tractor - then you will be able to get the tractor back in service faster.
  • The quality of the rebuild is better with more deliberate bench work, and allows for the precise fitting required.
  • You will have some duplicate parts to pick from at assembly time (the control lever, sping, knob, etc.)
  • Your left over parts can be put on Ebay for the next fellow.
I also bought the hardware items most likely to need replaced.

These included the 4 bearing bushings (5: part no M48355), 2 are used on PIVOT (10) and 2 are used on CONTROL CRANK(4). I bought spare bolts and nuts as shown. Importantly, I bought a new SHOCK ABSORBER (12), which turned out to be a good thing. The rubber deteriorates and mine had a spot where the motion was not smooth. The YOKE(19) was available on Amazon, and worked perfectly. I bought SPRING PINS(7), but did not use them for reasons to be explained shortly.

Some specialty items, not from John Deere, that I used are (a) Precision brass pins, 0.250" diameter, from McMaster Carr, 2 required; (b) Small "hairpin" cotter pins, 6 required (size such that they will fit in a 0.070" hole drilled in a solid 1/4" shaft); (c) Small pieces of precision ground drill rod (NOT hardware store steel rods) - 0.250" and 0.375". Length can be pretty short, maybe 3" or so.

Black primer and black paint were also used.

Some special tools that made the job easier and more precise: (a) A set of transfer punches, in 1/64" increments up to 0.50"; (b) An "oversize" quarter inch chucking reamer, 0.251" diameter; (c) An "undersize" 3/8 inch chucking reamer, 0.374" diameter. The later 2 reamers can be purchased individually, or as part of a set of "over and under" reamers.

SECOND TASK: Disassemble and rebuild the linkage.

The first thing I did was disassemble the linkage that arrived. This requires pressing out SPRING PINS(7). This is not too hard to do on the bench, but to remove it from the tractor, it is very difficult to drive these spring pins out. That is one of several reasons I chose not to use the spring pins on my rebuild.

As I disassembled the Ebay unit, the likely cause of the lost motion became apparent: There was significant wear on the CONNECTOR TUBE(15) -- the softer mild steel tube had been worn down by the hardened spring pin over time. Even the spring pin had wear. This "play" in this crude bearing can translate to a much larger motion in the LEVER (2) which the operator senses. I believed this was the same issue on my "new" 42 year old tractor. You can check this (engine off) by reaching under the tractor and feeling the control tube as you begin to move the lever. You may discover that you can move the lever a short distance before the control tube begins to move. If so, the joint at the end of the control tube is a likely contributor. On the Ebay unit, the other hinge points also showed wear.
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It is clear that this joint needs to be rebuilt.You can image a few ways this could be done. I chose to make a precise bushing and press it into the tube, and then make a precise pin to connect the tube and PIVOT(10).

Check the PIVOT(10) 1/4" hole and see if a piece of drill rod (0.250) can move smoothly in that hole. In my case, I was able to ream the holes for the spring pins in the PIVOT and CONTROL CRANK to 0.251" (one thousandth oversize) in order to obtain a running fit with a precise 0.250" pin. Likely this is the case, and the roll pins need to grab these pieces (PIVOT and CONTROL CRANK) and move against the connector tube and LINK(8).

So, here's a summary of the work on the hinge points and pins:

1) Ream PIVOT and CONTROL CRANK 0.251". Use a cutting fluid. Do not wobble the reamer. Ideally do this in a milling machine or a drill press.
2) Use the 3/8" drill rod, and make a precise bushing (lathe is ideal for this) as long as the gap in the PIVOT(10) between the two sides. This side distance between sides of the PIVOT can be easily adjusted a small amount if needed. Bore the inside of the bushing to 0.251".
3) Make a precise pin from the 1/4" drill rod (0.250" diameter) about 1-1/4" long. Chamfer the edges on each end.
4) The ends of the precise pin (Item 3 above) and the 2 brass precision pins (0.250" diameter x 1" long) are cross-drilled in a mill or drill press, 3/32" from the end, with a small drill (0.070") for the hairpin cotter keys. See picture below. The small cable ties will be put on one end before they are installed in the tractor, and a second set of tiny cable ties installed after they are in the tractor. These prevent the pins from falling out.

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Now we need to modify the end of the control tube. The first task will be to fixture it in a milling machine or drill press. The picture below shows how I used the brackets where the SHOCK ABSORBER attaches to mount it to a treaded stud in a big block of metal (which can be put in a machine vise); In the second photo below, you can see that we've reamed it 0.374 for a light press fit of the bushing into the tube. Be sure to work the hole diameter up in a sequence of step changes, and stop about 1/64" or 1/100" of an inch below the target diameter of 0.374" before reaming the hole. The reamer is only to precisely remove a small amount of metal. Use a cutting fluid with the reamer.
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The next step is to press the bushing into the tube. I used a big bench vise with aluminum soft jaws (not use hardened jaws or ones with texture) to install the bushing. This will leave the bushing flush with one side of the tube. We want it equally spaced, so then a small brass hammer was used to move it a bit. This press fit bushing will not wear the tube. Further it has a whole lot more surface area then the thin wall tube - - so we don't expect this to wear down as quickly.

Here's the finished end of the tube with the custom pin in it :
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THIRD TASK: Rebuild the LINK(8). First check yours and see if it can be reamed 0.251", or if the holes have already been worn larger. In my case, I chose to make a new one. Use 1/8" mild steel (Warning: some of the steel in the big box stores are undersize. This will make it wear faster). I cut a slice out of a 1" angle iron on a metal cutting band saw. Then I milled it to 0.75" wide. The 2 holes are 6.25" apart. Drill and then ream these to 0.251". I used a carbide scribe to trace the shape of the original onto the ends of the new one. I then used a belt sander to but the slight radius on it. Then a 3M unitizing and deburring wheel was used to clean up the edges.
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In Part 2, we will paint the unit and install in the tractor. Stay tuned.
 

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PART 2 - Finishing the ReBuild of the Hydro Stat Control Link

FOURTH TASK:
Assemble the linkage and test it for smooth action with no lost motion:
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FIFTH TASK:
Paint the parts (primer and paint). Press in the BEARINGS(5) after pressing out the old ones. One on each side of the PIVOT and CRANK CONTROL for a total of 4. Organize all the parts for the repair on the tractor. If you are re-using the BRAKE PADS(9), first renew the pad surface (Don't paint the pad side also !!). Lay a sheet of 220 grit Wet R Dry or emery cloth on a cast iron table saw top or other flat surface. Rub the pads over them a couple of strokes. This will remove any glazing on the pads.
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SIXTH: Install on tractor. The shop manual says to loosen the pedestal on right side and drive out the SPRING PINS. This is virtually impossible in the confined space and how much drive force it takes to drive them out. I chose to cut the LINK(8) since there were 3 of them (the new one I built, the one in the tractor, and one from Ebay). I was only going to use the new one with accurate holes. This way, with some finagling the mechanism can be removed and pins pressed out on the bench. The old unit can be sold on Ebay. However, before disassemble everything, use the old one and new one to get the correct nominal length for ease of setting up the transmission in neutral later on. Close fitting pins are used in the bushing (new one) and hole where pin was (old one from tractor) and the 2 YOKES on opposite ends:
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Turn the new YOKE until both are aligned such that the pin slides through both. This got the new one within 1-2 turns of the new YOKE to fit while the SWASH plate was in the neutral detent. You'll still need to check for accurate neutral. When I did this, the elevated wheel did not turn -- so we got it right to start with.

Here's a view of the finished installation:
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You can see that the last 3 cable ties are installed (for "safe keeping") after the pins are installed and the hair pin cotter keys are installed. The use of these soft pins should enable a longer life, and the ability to replace them without tearing the whole thing out again in the future. If I had it to do over again, I'd put some graphite in the center of the bushing and on the 0.250" steel pin made from drill rod. However, the bearing surface for that one is MUCH bigger and will probably never wear out.

Changing speed precisely is not a problem any more. Be sure to tighten STOP NUT(11) while checking with the control level motion for some resistant against movement but not excessive amount. This bolt can be adjusted over the life of the linkage as needed for the right amount of drag.

I hope this helps someone with their tractor.

Shoecobbler
 

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Welcome to the site!
Well dang sounds like you are part machinist. That is one good tractor for sure. I have a 300 with a K341 Kohler in it and those things last forever. Not too sure what the difference is between the 300 and the 316 as they are both an H2 setup with the same engine.


As for the steering I would suggest you put a pair of these on the front spindles. Needle Thrust Bearing, Bore 1.125 In! The correct size of course.

Good luck getting it fine tuned. (y)
 

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Thanks. I'll check out those needle bearings. I assume they need a thrust washer on each side ?
Yes you can find kits with the washers included. It will make you think you have power steering. ;)
 
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