123 dozer conversion

[William Adams]

Perhaps, as in my dealings with vintage VW forums, modifying or otherwise altering vintage iron (be it cars, bikes or tractors) is considered to be the ultimate sacrilege to the purist. After many years spent rescuing old Iron, I tend to think that breathing new life into old stuff, pretty much whatever form that takes, is a good thing. I'll start this first with a "here's where we're at now" and work backward through the major parts of the conversion.

While there are many remaining steps yet to do and then the necessary tuning and massage, it's safe to say that with 3 or 4 hours of run/work time behind us, it's working really well. A lot of what you see is not the final version, but merely the "I wonder if this will work?" stage of chair-seat design. I knew that as a minimum set of goals, I wanted a high-wheel design for ground clearance and the ability to have more drive sprocket choices. With a conventional design, I'd be pretty much stuck putting on the biggest drive sprocket I could find to get the ground clearance we needed. With a high-wheeler, I could use whatever size drive sprocket I wanted. My goal was a 50% speed reduction with the corresponding increase in usable power as well as being more gentle on the differential and spider gears. I, unlike many of the YouTube conversion offerings, wanted to keep weight to a reasonable minimum. I wanted a relatively short track length/width. Even a 30" long, narrow track would have 873 times more winter traction than the best, chained and studded wheel version. This has proven to be true in testing. We have a steep lawn and driveway and have yet to find a place it won't happily climb into or out of.
As I stated, there is much massaging yet to do, but for this moment it's working far better than it has any right to and has exceeded all of my finger-crossed, Rube Goldberg Era design parameters.
I'll be breaking down the major milestones one at a time but can say I'm pleased and happy. Love me some big projects and this one is checking all the boxes....

 

[Robert Shingle]

All I can say is WOW! (and keep the pictures and updates coming)

 

[jkoenig]

Looks great!!! It’s yours. Build/rescue it how you want, especially if you will use it that way.

Oh yeah, and thanks for that 873 factor. Now I don’t feel very special.

 

[PACub100]

Now THAT is cool

 

[William Adams]

I started by spending some time checking the important stuff, namely drivetrain health. The engine "looked" healthy. Other than the suspicious black color, it appeared to be 100% stock. I read somewhere that CC replacement engines are factory black? Anyway, after fiddling with electrical bits and replacing the carb with a knockoff, it fired right up and sounded perfectly healthy. No smoke, weird noises or foibles. I tested the hydrostatic transmission and it went forward/reverse without issue. Pretty quiet for a hydro in my experience. As I had already mounted the chassis on my improvised roll around cart, I couldn't test torque output but it seemed reasonable to assume it was generally serviceable. I pulled the relief valves (actually did that first before testing g) and got them to pop up from their stuck down position. Pretty easy... I also pulled the differential top cover for a look at the all important spider gears, bearings and ring gear. The oil, though low, (she's a piddler!) Looked clean and cared for. Gear tooth wear was indicative of a well cared for transmission.

The transmission downside (so far) is that the external trunion shift linkage is dreadfully worn at all bushing points. Lots to do there.
I spent a lot of time that I won't relate here getting all of the unneeded bits (front axle, steering column, mower mount, etc) removed. The chassis, while it looked pretty good, was actually pretty rusty. The frame is fine, but the instrument panel tower, hood and rear panels were pretty crusty and, around the battery box, partially gone. No problem. I'm a sheet metal guy, among other skills.
Brakes:
As this was going to be differential steering g, I wanted more brakes than I'd ever need. Also.....relatively inexpensive. To that end I only had a couple requirements. Rotors needed to be 5 on 4.5 that fitted 15"inch wheels, i.e. small diameter rotors. The ones I sourced are for a Pontiac something-or-other (Alero? I'll find the part #) and the calipers are for a Geo Prism.

After much head scratching and a bit of fiddling, I fabricated what ended up being pretty simple caliper mounts. The calipers came with the mounts so all I had to do was fill in the space between the caliper and the axle housing. Pretty straightforward.
I mounted the rotors to the axles. The long bolts shown are explained in more detail...

The sprocket are mounted to the axles by using 2"x4.5 on 5 wheel spacers. Rather than mount the wheel spacers the conventional way, I drilled the axle flange bolt circle (lugnut holes) to 1/2", then mounted the sprockets to the wheel spacers first, then sliding the wheel spacer wheel studs through the rotor and axle hub, putting the lugnuts onto the "backside" of the axle flanges. So its: bolt sprockets to sheel spacers with grade 8" 1/2"x20 this bolts. Then take the wheel spacers and slide the protruding studs through the axle flange, putting the lights on the backside of the flange. Whew! I might need to take a photo of that....
For the steering master cylinders, I used 2015+ Ford F150 clutch master cylinders. The short rubber brake line that comes off the caliper is also f150, but with the banjo fitting drilled out to 3/8". The hard line from the rubber line is just 5/16" flared brake line. Pretty easy.

 

[William Adams]

Tracks! (Everybody wants to know about building tracks) couldn't be easier.... I sourced the chain, sprockets and sprocket hubs from "Red Boar Chain and Sprockets" (can I say that?) Good guys. Super helpful. The chain is 81xhd conveyer chain. The "hd" part means it has internal rollers. The chain pitch is (and this is weird) "2.609" inch... okay....whatever.... weird. Not "2.5" or 2.75" inch. Like I said....whatever. It's got a working strength of 4,000 lbs or so with a breaking strength of over 30,000 lbs. That should keep my 12 HP busy. The chain comes in 10 foot lengths. Each track on my dozer is exactly 10 feet long. No cutting necessary. The track pads are 4"×6 1/2"×1/8" thick cold rolled flat steel. Groupers are made from 3/8" rebar. The whole track is actually pretty light. That's good because I'm pretty old. I used to accel in brute force and stupidity. Now the brute force is all but gone.....
Drive sprocket is steel 14 tooth and idler sprockets are 8 tooth. I got hubs for the idler sprockets with a 1" bore center and welded them into the sprockets.
I made the track carrier rails from 4"×2"×1/8" wall tubing. The flange bearings are 4 bolt with 1" i.d. bearings.

I made a few jigs. One for cutting the track pads to length (21 pads per side) also used to cut the rebar (42 pieces per side) a jig for welding the rebar to the pads and one for positioning the chain on the pads for welding. The only tricky part (not that tricky) was the fact that the master link could not be welded on both sides. I welded it to the pad on the back side, then welded a 1/8" x 1" tongue to the front link, then drilled that tongue to put a 14" bolt through the tongue and pad. Now, to remove the master link, I just take out the bolt and slide the outside the outside link plate off the master link. Seems to work...

For the road wheels, I used 5"×2" wheels with full-width roller bearings. There are 6 per side. The little trick I used when mounting them:
Rather than mounting the road wheels so they had straight contact along the track surface, I mounted them so they protrude 3/4" further down. I'll explain. When the dozer is sitting on my garage floor, all of the weight is borne solely by the road wheels. The idler sprockets are not in ground contact. The reason is ease of steering. This thing, when on a hard surface, will turn on the center 15" of track. There's very little resistance from the track when turning. When on loose dirt or snow or mud, the track is in full contact with the ground. It's not noticeable when driving as it shifts the load center from front to center to rear, but on the driveway or garage floor, will happily turn in its own length with a finger pull of pressure on the brake stick.

 

[Stu]

Amazing! Thanks for posting this, really cool.

 

[tkhoffman]

Have Welder Will Travel

Saw you intro about your 10 year old. Good stuff. Nice to see a younger generation getting their hands dirty.
Quality job!

 

[dgeary]

Great postings. Keep 'em coming. Love your project. Interesting choice for brakes. I have been considering doing something similar on one of my Cubs and setting it up for left/right braking.

 

[John Wyrick]

Very nice work! Love the creativity and problem solving. Thanks for sharing.

 

[skreiner]

SWEET KEEP THE PICTURES COMING

 

[1811Cub]

What a masterpiece. Love that. Thanks for sharing!

 

[Don McKee]

Do you have ESP or sumthin?

I've been plotting and conviving how to do a dozer conversion for my dad's old Cub for years. I hadn't thought about a delta design and was going with a conventional track design on rubber treads. I had even planned on a hydraulic steering brake system similar to yours, nice to know that it will work. After seeing your delta I may have to reconsider the conventional tracks I'd been working on. Conventional tracks would also need some type of a final drive to get ANY ground clearance - which is where I was stuck.

Looks like you got an under-carriage frame that the Cub frame bolts to. I had something like that in mind also, but I may steal some of your ideas to get some more ground clearance.

What are you doing for track tensioning?

Don

 

[William Adams]

A few thoughts and more photos for today:
Running the brake lines "should" be easy. That depends upon how many different parts you use. As I mentioned above, brake hardware is GM. As the master cylinders are Ford, I wanted no issues getting them to play. Here's the stubby brake hoses from a late model f150 (fronts) The only issue getting them to mate to the caliper is that the banjo bolt diameter is larger than the banjo fitting on the Ford brake hose. I simply drilled out the brake hose banjo fitting to fit. It's not much. The hard lines go through the tunnel to the brake master cylinders. Since the rubber line and master cylinders are both f150, there's no issue with threads and fittings. The hard lines are 5/16" fittings with a standard flare. These are 40" long.

For mounting the master cylinders (again....for clarity...2015> f150 CLUTCH master cylinders) I made a square from 1"angle iron that slid inside the tunnel. You can see two of the four total 1/4" mounting bolts. The MC's mount with 2-bolt face flange so I just drilled the angle iron. As space is tight, I angled the master cylinders just enough to be able to get the hard lines screwed in. You can see how close the hard line of one comes to the other. Once hooked up. They bled with no issues. My steering levers are stubby and I still have oodles of braking power. Always better a little too much braking than.....

 

[William Adams]

Do you have ESP or sumthin?

I've been plotting and conviving how to do a dozer conversion for my dad's old Cub for years. I hadn't thought about a delta design and was going with a conventional track design on rubber treads. I had even planned on a hydraulic steering brake system similar to yours, nice to know that it will work. After seeing your delta I may have to reconsider the conventional tracks I'd been working on. Conventional tracks would also need some type of a final drive to get ANY ground clearance - which is where I was stuck.

Looks like you got an under-carriage frame that the Cub frame bolts to. I had something like that in mind also, but I may steal some of your ideas to get some more ground clearance.

What are you doing for track tensioning?

Don

Don,
The ground clearance thing is a tough one. Any sprocket large enough to provide clearance is going to be geared too tall for the differential to survive. My 14 tooth sprocket provides 1.91 reduction and if I could have easily fitted smaller ones, I would have. For me, the high-wheel design filled all the holes. Ground clearance for days! After all the head scratching was finished, it turned out that the high-wheeler was no more complicated than a conventional one. Perhaps even simpler, so far as I was able to build both track carriers separately from the frame. When it was time to marry them up, all I needed was a carpenters square.
For tensioning the track, the front sprocket flange bearing carriers are in 2" slotted holes. As the photos may or may not show, I have detail work to do on that. I have the parts made for the tensioner but it's not 100% complete. I also have a separate tensioning system ready to mount that uses 2 more bodies on top if that is necessary. So far, with 3 or 4 hours of running, it hasn't shown any need for more tension. I prefer to run as little as I can get away with.

 

[Mark Evans]

Don’t forget the ROPS safety bars and seat belt SIR looks great and you do FANTASTIC WORK SIR !!!!!!!

 

[Don McKee]

Do you have a spring in the tensioning system in case you pick up a rock or other crap between the sprockets and the track?

 

[William Adams]

Hey guys,
Actually, I DO have a rops planned. I have a whole list of "need-to's" to slog through first, like getting the carb to act right. (Air leak at the gasket?) as well as getting a leak in the tranny to quit piddling everywhere. Looks like the seal between the hydro and tranny. Hard to tell for sure. I'll be pulling everything for paint so I'll go through the tranny at that time.
Track tension:
Yeah.... that's a work in progress. The system I have seems to be working well save the sprocket wells in the track chain fill with snow. I'll need to open up the holes in the pads to prevent that. It's a problem I expected to have. I don't have a smoke wrench or plasma cutter so my fix for that will be to pull the tracks and take them to someone who does.

 

[Gage mcdaniel]

holy crap ive been trying to do that for years now how do you do that

 

[Mark Evans]

Your are on TRACK more ways than one SIR !!!!