Category Archives: Dfab Engineering Trackmaster Dozer Crawler Restoration

How to Pull the Tracks on a Trackmaster Crawler Dozer Loader

I’m going to skip ahead, as I need to put all of the data in a single source. I’m hoping to buy replacement trackchain and tracks for this dozer, which will likely also mean a new drive sprocket. More about why in this post showing how to pull the tracks on my Trackmaster Bulldozer restoration project.

Quickly fabricated Track puller on the tracks to remove the master pin

I researched how to pull the tracks apart on different track based vehicle and they all use a track puller, a tool that squeezes the master pin tracks together and allows for careful release of the stored tensioning energy.

Front bulldozer track tensioning idler pulley – that spring is made from ~5/8″-3/4″ diameter wire.

The front of the dozer is a tensioning idler type pulley on a HUGE spring. I was quite concerned it would explode the tracks apart upon pulling the bolt. As seen above, the spring is massive, and likely has an enormous quantity of stored energy. If you’ve ever taken anything apart and had a spring shoot out to go flying somewhere you understand my concern. It turned out that the compression on the spring is very small, so my concerns were likely unfoundeed, but it required the track puller to allow removal of the master link pin.

I quickly fabricated a track puller with a single 3/4″ threaded rod.

I looked at commercially available track pullers, and they are clearly developed for bigger machines. I took some track measurements and quickly fabricated a puller sized for the Trackmaster Bulldozers small treads. There are nice mounting holes for rubber track shoes on the Trackmaster crawler. I took advantage of these and used some on hand 3/8″ bolts to mount the puller to the tracks. Larger track pullers almost always have two screws, this allows you to prevent caming when you are trying to remove the master link.

Master link removed with track puller in place

Wow, this is great and really easy was my thought pulling this first set of tracks. Boy oh boy do I regret thinkng that as I was cursed on side 2 with a friction welded master link. Now for some photos in Gallery form.

I pulled the tracks, and started inspecting the damage. I knew when I bought the dozer that I’d have to redo/repair the drive sprocket and drive sprocket shaft. Unfortunately, this shaft is a somewhat unused ANSI B91.1 1970 standard infolute spline as best I can determine at 1.5″ dia 23 splines and a 30 degree pressure angle. I figured this out from the large gear also splined in the torque hub, not the shaft. AS you will see, there’s not enough left on the shaft to be meaningful.

yes it’s that bad. Someone very pooorly tried to hack together a repair and made things significantly worse damage wise.
If you thought spline side was bad, this is worse (although easier to repair by welding a splined coupling onto.

Some details about the tracks. The tracks themselves are 3.5″x8″ and stamped from some steel that was likely 1/8″ thick originally. The track Chain pitch is 4″, with a pin diameter of 1 1/4″, and an inner width between sidewalls of 1 1/4″. There are 33 total links/tracks on each side of the dozer. I’m going to try to source some sort of replacement. Likely a metric replacement that is close enough. I’ll share what I go with in a later post, but it seems 101mm track chain is a current standard size for small machines.

Trackmaster bulldozer has 25 teeth for the 4 inch pitch track chain. This shows drive sprocket diameter

The drive sprocket has 25 teeth for the 4 inch pitch track chain on the Trackmaster Bulldozer. I’m going to have to do a complete repair of the hub, and I am debating replacing this with whatever track sprocket I can find for the 101mm pitch track chain I am currently trying to source.

yes, someone shoved some exhaust tubing in there and poorly welded it in place.

Yes, someone shoved some exhaust tubing in there and poorly welded it in place. Sigh. It’s hard to believe it drove around as much as it did before I took it apart. the bolts had jammed in enough that it didn’t slip too much. I’m going to bore this out and weld in a new splined repair coupling should I keep this track sprocket. Honestly think I’ll fabricate an entirely new assembly if I can buy a new sprocket or sprocket segments. I’ll still need 25 teeth when I replace it. Stay tuned for how I fix this one

Stay tuned for the removal of the torque hub, the internals inside, and the further surprises waiting for me.

Stay tuned for the next exciting installment of my Tiny Tank Restoration

Trackmaster bulldozer Transmission bottom half REassembly and painting

After dissassembly of the Tiny Dozer’s 3 speed transmission I cleaned, polished, removed rust, and carefully filed (or ground) off any burrs on each component of the drivetrain. I have this great tool I build for the bridgeport restoration last winter, it’s a heavy belt driven bench mount wire wheel. I used this a lot again on this project. The fat welded wire wheel makes quick work of rust, paint, and any gunk left after solvent soaking parts.

Bench wire wheel polishing machine – Priceless for any type of restoration of old iron. Quickly removes dirt, rust, burrs, paint and caked on yuck from your steel parts. Operated with a momentary when pressed type foot switch. Complete with Formlabs Tough resin shield for the wheel, and a Fuse1 print (SLS Nylon) belt guard for safety.

I chose to laser cut new gaskets. Thankfully the ones I had were ok enough to scan. The process for making new ones is Scan, Clean up the file, turn to vector paths, make into PDF, import into Laser cutter software, cut from gasket material. I’m using Cometic Gasket Fiber Gasket Material (Part # C15385) that I picked up at my local Autozone.

New laser cut gaskets for the Trackmaster Bulldozer Transmission.

Here is the pdf of the Gasket cutting file for you to use if you would like to laser cut your own set of gaskets. You can also print this out and use as a template to cut by hand with a bit of care to get new gaskets for your transmission rebuild. <INSERT FILE HERE>

The cleaned up transmission internals ready for reassembly. The parts are layed out as they fit in the transmission.

The reassembly starts with laying everything out as it will go together and making sure you have all of the parts. It was at this point that I realized many of the stand off spacer washers were badly worn. They were stampings from 1/8″ steel. I decided to quickly cad up and water jet some new spacer washers before assembling everything.

Small OMAX water jet, priceless for cutting some new washers for the transmission (the square bits are for my track puller I fabricated and you’ll see these in a later post)

With new spacer washers made I was ready to figure out how to get it togethere. The spacer washers ensure the gears are not rubbing on the bearings/sidewalls of the housing body. I would like to say I nailed assembly after this dry fitup without bearings, but as you’ll see below, I did not get it on the first go.

Dfab Trackmaster bulldozer 3 speed transmission rebuild internals loose fit during reassembly.

After loose fitting everything, I took it all apart, and got ready for the final assembly. I started with the lower output shaft with the two large gears. I did replace the snap rings throughout. I happened to have a bag of the appropriate sized snap rings in stock. Most of them are for 3/4″ Shafts. The one on the main shaft is a 1.25″ shaft (a 32mm snap ring will work as well if you have one). I put replaced the 1/4″ npt drain plug with a SS hex plug. I really hate cast iron square plugs.

I’m using a cheap GL5 gear oil with lower viscosity. I plan to change this out multiple times post rebuild after very short operating period of an hour or two. This will help wash out any bits that I might have missed cleaning pre assembly. Be sure to lube everything up as you assemble it. I made care to get lots of the gear lube in the splined areas on the gears and the shafts. GL5 type oil is ok, as there is no copper, or copper alloys in this transmission anywhere. The EP additives in GL5 can corrode and destroy copper alloys quickly. If I end up making a cast barillyum copper shift arm (I can’t cast steel/iron but need the strength) I’ll switch to a GL 4 or standard motor oil lubricant.

One note on assembly, don’t think you will casually knock this together with a hammer and block of wood. The press fit clearances are pretty tight. I ended up using my big 20 ton hydraulic press to get most of this together (no photos of this as I didn’t have a tripod or photo taking helper available with Covid pandemic in full swing)

A quick note on the bearings. When I took the 3 speed transmission for the bulldozer apart, all of the bearings were open race with no shields or seals. I decided there was no reason the outer side should be open race. Also I could not find affordable good bearings that were not shielded. It’s pretty easy to pull a shield off of a bearing, and I did this on the internal side for each of the seven 6203 bearings as I assmebled them with a hook pick tool.

pulling one of the “Sealed” shields off on the inside of the bearing during assembly. This will allow oil lubrication, and flush out any contaminates should they end up in the transmission. I plan to change the fluid regularly and often in an effort to keep this 3 speed living a long happy life after the repairs are completed.

The first shaft assembly went together well. I thought I was home free. Things went ok, until I got to the last shaft, and then it didn’t work. I’m sure if there was a manual they would explain the proper assembly, but I have no information on this thing. In the end I had to press a bearing most of the way out to get the shafts and bearings all assembled. The photos below have me pointing at this bearing/shaft I had to shift with the hook pic tool.

Other than the above, the assembly was straightforward. I’ll drop pics in the gallery below for your education and enjoyment. Drop a comment if you have any questions.

Painting in the winter is tricky, I often spray outside and then quickly bring the part in for heated curing. A big torpedo type heater 3 feet away goes a long way to cure and dry the paint quickly. I’m not sold on this safety yellow collor. I’ve left the botom end masked for now, as I suspect I’ll paint it with a different color yellow.

As always if someone stumbles across this page with any information about these Trackmaster d-Fab Engineering by Fruehauf Trackmaster Dozers Crawlers, I’d love to know more about them. I’d be happy to host manuals and or parts catalogs here on my blog if you have them and are willing to share them with me. Please leave me a comment or email me at my website name on Gmail (no dot com there). I don’t check often, but I eventually will get back to you to host the information. Thanks!

Trackmaster bulldozer Transmission rebuild 02 – restoration, cleaning, fabrication

The transmission mechanicals were surprisingly not that badly damaged. It did take an enormous amount of elbow grease to clean all of the grimy oily emulsified yuck off of and out of everything. After cleaning, inspection, polishing, identification of replacement components and so on took place.

Parts laid out from the transmission rebuild. I take a lot of photos so I can reassemble everything. It’s a good way to take anything apart, take all the photos you can.

A bit about what I know about this transmission after taking it apart and studying it. I could find ZERO information online, and I write this stuff up in hopes that it helps someone in the future.

The 3 speed transmission is a symetrical standard splined shaft transmission using sliding standard spur gears. There are two shift forks, and two movable sliding gears. One gear only has one position, the other has two locations. It is a very simple and robust transmission design, with nothing broken and no unbearable wear or damage despite it’s poor condition when I took ownership.

Shafts, splines, sprockets, snap rings are all standard ANSI and SAE. Only the bearings are metric 6000 series items. The three gear reductions of the tranmision are 1.5:1, 4.5:1, and 18.5:1. These are counted manually by turning the input shaft and counting after rebuild and can have a bit of innaccuracy.

The main output shaft is 13/16″ for the 16 tooth sprocket for #60 chain. The bearing on the main shaft is a standard 6305 with bearing dimensions 25x62x17mm Deep Groove Ball Bearing. All of the other bearings, 7 in total, are the same and are 6203 Bearings with dimensions 17x40x12mm. There is one oil seal on the output shaft. This oil seal is an old out of production part: Chicago Rawhide Oil Seal 8774. A modern replacement oil seal I found was a SKF 8796 LDS & Small Bore Seal, R Lip Code, CRW1 Style, Inch, 0.875″ Shaft Diameter, 1.624″ Bore Diameter, 0.25″ Width . I ordered this, and then found an original NOS part on Ebay and ordered that as well. Both have the same dimensions and basic design.

A quick trick for pulling blind ball bearings

It often happens as you are working on rebuilding or restoring some old iron, machine tool, etc that you come across a blind bearing in some machined pocket. These can be a real bear to remove, especially if as in the case of my 70’s era Trackmaster bulldozer it’s a nasty mess in need of restoration. You can see the blind bearing in the top middle of the photo below.

Trackmaster dozer transmission housing by d-Fab Engineering a devision of Fruehauf Corp Route 202, Montgomberyville, Pennsylvania USA

I looked for a puller tool, they make them but even cheap ones are still a bit pricey for a single pull. This bearing, like all of the others was trashed, so I knew I wasn’t going to be reusing it, and as such I went with the tride and true method. I’ll share with photos below the details of one of the best ways to get a stuck bearing out.

Blind bearing removal Tip Step 1: make a threaded bushing for the ID of the bearing, or use a nut that fits the opening well enough.
Blind bearing removal Tip Step 2: insert your a threaded bushing and weld it carefully to the inner race, you can mig or tig depending on what you have.
blind bearing removal trick step 4: screw in your bolt, and press out the bearing from the blind pocket. Even if it was stuck before, often the heat from welding and cooling will allow it to press right out. Never discount the force generated from an inclined plane wrapped around a cylindrical axis in any pressing operation. *Wear eye protection. Every now and again the bearing explodes into shards of sharp metal that fly everywhere.
The inside of the 3 speed bulldozer transmission has cleaned up relatively well. A bit more work cleaning and it will be ready for the reassmbly.

Summing up my favorite blind bearing removol trick in steps:

  1. Make a threaded bushing for the ID of the bearing, or use a nut that fits close enough.
  2. Place in or on the bearing with the threaded hole centered as best you can.
  3. Weld in place, and let everything cool fully. (you don’t have to go nuts, three good spot welds spaced are usually enough)
  4. After it cools, thread in a good quality bolt with some crease or oil on the threads
  5. Start turning and let the screw press out your blind bearing.

This of course requires a welder, but many of the tools I looked at cost as much as a cheap HF welder. Go buy the welder, you will be happy you purchased it rather than a fancy one time use blind bearing removal tool.