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Work in Progress Sears 12 to Honda 13 Repower

5K views 15 replies 6 participants last post by  John Arsenault 
#1 ·
So I bought a Sears Suburban 12 at the beginning of January because I needed a project. It appeared to be a 1968 model # 917.25350 electric start. The only attachment available with the tractor was a snow-dozer blade which is missing the rods to change the angle but has the height adjust lever (broken but still included). The starter/generator (wrap a string around pull start) was missing and the rear tires were pretty flat. The PO said it had been a few years since it ran and he thought it was stuck in between gears (It was hard to push it on the truck).

I got the tractor home and proceeded to tear it apart to find the issues. I found the 6 speed transaxle to be frozen (not cold but rusted), the carburetor to be leaking around the bowl and the head bolts practically falling out. First bunch of pictures on truck. followed by the cracked open gearbox full of rusty goop.
 

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#2 ·
I have found using the Sears Parts site, the Reverse Idler Gear bearing (NLA) is frozen to the gear and the shaft. This problem is why it is so hard to push around. The shift detent (and Hi-Low) forks are frozen to the shift shafts. I took the transaxle all apart and cleaned the gears, case, and shift forks/shafts. I got the shifters to function but the needle bearings on the reverse idler I'm going to have to measure out and procure somehow. I made up a large shopping cart in sears parts and without even getting all parts for repair (Just available parts in Sears) the totals started adding up ($150 for some but not all parts) I decided to find one somewhere else. There are transaxles available all over eBay (for @ $100) but all sales were for local pick up (most were in MI or WI, I'm in MD, really long drive) but I did actually finally find someone willing to ship from PA. I picked up a 6 speed out of a Custom for a decent price with shipping that wasn't locked up and full of water. The only differences I found were, the drive pulley is a bit smaller and the shifter is bent. The drive axles are 1" keyed so I could use my original hubs (I have the weird squish bolt and bolt key locks no cracks). I have no pictures of the new to me transaxle.

I did eventually find suitable replacement needle bearings for the reverse Idler gear, I will rebuild the transaxle and either sell it or keep it as a spare (they are getting harder to find as more people abuse them).
 
#3 ·
I am not too good with taking pictures as I go as I'm either in a hurry all the time to see the finished product or I just forget to take them along the way. I didn't really know anything about lawn tractors before starting this project, I'm a Bobcat mechanic who needs a project outside work. One of my previous projects was a 1976 Montgomery Ward Didier log-splitter that was as old as I am. (New Predator hyd lines, tires and rebuilt cylinder.)

I have at this point installed the new transaxle, replaced a missing seat and spring, ordered an ss16 battery tray for the clutch bracket and installed new 23x8.5-12 Deestone 405AG tires on the back to replace the rotting leaky original Sears rubber. The grille mounting area is broken and somebody along the way drilled new holes and installed bolts (in the wrong place) to attach it (crooked). I repaired that today. I wanted to find a piece of aluminum to fit inside the bottom of the grille and use flat-headed machine bolts to make a new mounting surface, but instead I just drilled new holes after straightening it out. I set the Honda GX390 (commercial pressure washer engine) in place and realized the original four sheave pulley wouldn't work. The Honda has a 1 inch usable shaft that is about 3 inches long. After that, the last inch has a step up to 30 mm. I had bought a 1" to 11/8" shaft adapter from eBay Which works great but I still needed the pulley to slide on about 5/8" more. I tried to find a local machine shop to turn a step into the pulley but most didn't want to be bothered with modifying something small and wanted to remake the pulley instead at a greater cost (Go figure that one out). I took a 1/4 die grinder and did it myself, It didn't have to be perfect since there will still be about 2.5 inches of material using the key stock.

I had problems finding a flat 6635H pulley (Sears NLA) so I bought a 5/8" bore pulley from Tractor Supply and some 5/8 OD to 7/16 ID bushings on eBay and used my vise and a socket to install it (still cheaper than the people who were selling the 6635H that had a pressed in bushing already). I did purchase the Harbor Freight mini tire changer to do the tires (piece of junk) better for the job of holding the tires than trying to use the included tools to remove the rubber.
 

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#4 · (Edited by Moderator)
All that rust and junk from a $4 seal lol.Water runs rite down the shifter and into the transaxle.Nothing to keep water from filling it up once the seal goes bad.I have yet to find one with the seal still intact.Even on a 40+ year newer Craftsman with the 3 speed Hi/Lo transaxle like the GT6000.

Here's the part and numbers foe the 68 sears suburban 12

http://www.searspartsdirect.com/part-number/6273H/0071/917.html?modelNumber=91725371&categoryName=Lawn,%20Tractor&brandName=CRAFTSMAN

All of the Sears 3 speed Hi/Lo transaxles use the same shifter boot/seal.

Here is the same exact part for a 1992-98 Craftsman GT 6000

http://www.searspartsdirect.com/part-number/110542X/0071/917.html?modelNumber=917250051&categoryName=Lawn,%20Tractor&brandName=CRAFTSMAN

Neighbor bought 2 sets of Deestone AGs.Seemed like a great deal untill they showed up.There much much smaller than the original turf tires were.He bought a pair of 23 9.50 12 for a Cub Cadet 129 and 23 10.50 12 for a Cub Cadet 169.After mounting them the Deestone 23 1050 12 tires are actually still quite a bit narrower and shorter than a stock 23 9.50 12 Carlisle turf tire.
 
#5 ·
Thanks Eric, I found the needed parts. I am still trying to justify the expense since I purchased a used transaxle from someone in WI (I thought it was PA, oops). I actually bought the boot and have replaced it on the new/sed one. The bearings I need are these two (see pic). I have located the seals (axle, brake and input), all new thrust washers, boot, case and shift gaskets.
 

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#6 ·
Okay time for an update. I've been stuck trying to figure out how to make the clutch work, on Bubba's Repower on http://www.mytractorforum.com/14-craftsman-sears-forum/264739-bubbas-repower.html he makes a clutch that pivots from the outside (pretty fancy too). I don't have immediate access to a welder so building on the fly is tough so I located a clutch from a GT 18 (I think). So now I'm waiting for the mail. Unfortunately I still cannot find the final placement for the engine. I did find that if I delete the electric start feature I can use the original setup by bolting the pivot arm to the edge behind the engine. But I want the electric start so holding pattern it is.
 
#7 · (Edited by Moderator)
I finally found some time to work on my project. I figured out how to make the clutch work. I used a clutch from an ST or GT 18 (I think, not sure whichever it was), the pivot pin is on the right side of the bracket versus the left (like the original that bolted to the engine or the bottom of the battery tray). I bolted a piece of 3/8 x 2" stock to the outside of the frame (see picture) and drilled (temporarily) a 1/2" hole to hold the pivot pin. I will be drilling a permanent hole to press fit in a 1/2" ID x 5/8" OD bronze bushing to provide a better (less wear) fit.

I also found the location to mount the engine while providing clearance for the clutch as to not hit the starter. The engine is bolted in using three of the four mounting holes, the forward left hole unfortunately aligns with one of the mule drive brackets on the underside. I ordered the belt (Gates 6981 (5L-81 inches)) for the 68 Suburban from Amazon awhile back not realizing the pulley on the transaxle I bought to replace my broken one was smaller than the original, so I am waiting on a smaller belt. (Gates 6979 (5L-79 inches)).

I am also painting the parts as I move along. I found a choke hold kit for the Honda which will allow for use of a cable just like the original. Now if I can only figure out why my pics are suddenly sideways... I didn't have problems before.

Tire Wheel Bicycle tire Automotive tire Motor vehicle
Blue Motor vehicle Automotive tire Yellow Bumper


Motor vehicle Automotive tire Blue Wood Automotive exterior
Tire Wheel Automotive tire Motor vehicle Blue
 

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#9 ·
Now if I can only figure out why my pics are suddenly sideways... I didn't have problems before.
If you are posting from a cell phone, its the nature of the beast, no one has figured out why it happens.
 
#12 ·
Here are some pictures of my latest round of tinkering. I bought a new steering wheel to fit a International A, International Super A, Cub, B, C, or Cub Lo-Boy due to the fact it has a 3/4" non-tapered hole in the center. It was tough finding one that had a straight shaft as most 3/4" wheels that look like they may fit are designed for a boat and a tapered shaft. I had to drill a hole for a set screw to lock it in place, the wheel has a 1/4" keyway which fits a bit loose on the shaft.

I had some problems adjusting the clutch as to how far the pedal needs to move. (not sure if that makes sense) I have the key removed from the clutch pedal pivot to get the action proper. I have figure out how long I actually need the up/down push rod to be, then I can put the half-round key back in. The current adjustment is being held in place by the two lock bolts in the collar (it works but its temporary). I have uploaded a video walk around to YouTube here ->

I also put a choke stay on the Honda engine so I can the a cable from the dash instead of having to reach for the little lever. The original throttle cable works great as well.

I have figured out the wiring for the key switch and have it mounted in the dash. I had to make the mounting hole a little larger and make a small notch for the anti-spin tab. The only problem I have to figure out is the engine puts out between 8 (idle) and 24VDC (high RPM), I had the head lights connected and they worked for a couple of minutes then Darn IT! they blew out. Maybe I can find some kind of buck converter for that and someway to protect my battery when I eventually put one in, right now it starts on the second pull.

I had a new aluminum shift legend made my original one was quite faded. I went to www.machineplatesonline.com and had them make a new one, the cost was $49 with shipping.
 

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#13 ·
Update: I have figured out the rest of the clutch. I ordered some items from McMaster Carr as they are more than willing to ship ones and twos of things.

1. 1/2" ID x 5/8" OD x 3" Bronze Bushing

2. 1" x 12" Round steel bar

3. 3/8" x 2" x 12" flat stock

4. 1/2" ID x 1" OD x 1/8 Bronze flat thrust washer

5. 15.5mm Silver & Demming style drill bit - the correct size used to press a 5/8" (16mm) bushing

I cut the 1" round rod to 1-1/2" long and used the 15.5mm bit to drill a hole down the (close) middle. I cut the bronze bushing about 1-3/4" long and used a big hammer and part of a 1/2" bolt to drive the bushing into the round stock.

After cutting the bushing to the correct length and filing it flat, I had to run a 1/2" drill bit through it to size it back up (I guess squishing it into the hole deformed it a bit).

I then used a 1" bi-metal hole saw to bore through the 3/8" flat stock in the same place as the hole in my mock up clutch design. The pictures show the pivot in place where it needs to be, I will weld it into permanent place tomorrow at work.

All that will be left is to put it in position using the bronze thrust washer in between the clutch and the pivot and at the end where the e-clip goes.

I also built a three point hitch for the back. I purchased a base on eBay. Bought some galvanized 5/8" steel rod for the tractor end of the lift arms and 1/2" for the arm lift links from Tractor supply. I used the dimensions someone posted in a picture (I would like to credit them but I'll have to edit it in later when I find it) and bent the lift links to match. I don't have an adjustable side yet but this setup is workable for now.

I found some NOS Sears lift arms on eBay for a great price, I had originally decided to make them but the cost would have exceeded the purchase price. I used hair clip pins to attach everything so if someone wants dimensions for the 5/8" pivot rod LMK and I'll let you know where to drill the holes. There are cotter pins on the backside of the hitch plate to keep the rod from falling out.
 

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#16 ·
Wish I would have done my swap before yours I could have saved you some time and money.

If you take the bracket that mounts the clutch to the HH120 and cut the rear tab part off drill a few holes it will mount right down to the frame

Motor vehicle Automotive tire Automotive exterior Bumper Gas


After I did that there was a small void there I could fit a battery into so thats the reason for the angle iron.

Gas Engineering Machine Auto part Electrical wiring


Wood Automotive tire Fixture Gas Automotive wheel system


Tire Wheel Automotive tire Motor vehicle Vehicle


I have seen 1/2 dozen ways to do this and as long as it works its a success.
 

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