Craftsman GT3000 "MUTT" Part II

well really depends on the machine my small craftsman with a 12hp flathead i run it governed and the pedal hooks to where the dash throttle used to hook to, its jerky when you grab a gear and it drives like a manual car does it jerks if you let off the clutch too fast or something like that but takes off with throttle in 6th but will stall without throttle. my jerks a bit but i wish mine was ungoverned it would fly!

It's partly about throttle and clutch control, and part of it is the weight of the tractor. Mutt is pretty heavy, no real sudden jerks happen.

*updating the thread as though it hasn’t been 8 months since the last update lol*

One or two of you may remember my plan to doc lock one of my spare 820s... I got tired of kicking the transaxle around on the floor and actually decided to work on that today.

Back in high school, I had made this hub to fit inside of the differential carrier. It only has a little 1/4” keyway, something I would undoubtedly shear in a hurry. So I decided to work around that.


Chucked it up in the lathe and chamfered the heck out of the bore


Locked the hub where I wanted it with the set screws, actually did put a key in it too, and welded the heck out of it. I did weld it in a few separate beads to hopefully minimize warping.


Waited til it was cool and chucked the axle back up in the lathe. Turned both of the welds down back to the hub. The weld did turn pretty hard but I have a junky carbide insert to use for that sort of thing.


Lastly I needed a spacer to take up the slack in between the hub and diff carrier. Had a piece of aluminum that already had a 1” hole in it so I turned it out of that.


That’s about all there is too it on the technical side! Now to find the rest of the guts to this trans and seal it up!

Very nice fab work! Be nice to see some MUTT action back in the forums!

Nice work man, that looks to be plenty strong enough to take some serious abuse!

Thanks guys. As I recall this axle shaft is a couple inches longer than the stock ones. I think I may widen the rear end up to match the front axle. I also may use that extra space to add 5 lug hubs to finally get rid of these keyed hub rims. I don’t think I have a spare set of 5 lug rims around but I think I know where to get some. I plan to have this trans back together tomorrow after work so I can get Mutt in the shop and get it swapped in.

It's super nice to switch over to 5 lug hubs.

Got the 820 all sealed up and back together!


I cut down the threads on this little street elbow so my trans vent clears stuff better. I think the shifter shaft is still going to leak pretty bad but it’ll be alright I think.


I probably won’t get the trans put in this weekend, me and my friend are going tomorrow to explore a cave we found. We’ll see about Sunday though.

Had an idea to seal up the input shaft.

Cheapo O ring, probably not even rated for contact with oil.


Shaft collar counterbored to receive most of said o ring. More of a shield for the o ring than anything. This step may not be strictly necessary.


Shaft collar pressed against O ring and tightened down.


Rightfully I should have put the top half of the case on my mill table and centered on the shifter hole and then milled the top of the boss flat and bored the counterbore into the case. Or at least just milled the top flat to give a smooth surface for the O ring. Even better would be to cut an actual O ring groove into the hole for the shifter, and I have the capability to do that with a little effort grinding down a tool for it, but I think this will be good enough.


Trans reinstalled


Back wheels now almost as wide as the front wheels. Should be more stable I think. Considering axle supports, I have the bearings and material for it.


I need to replace the bearings in the idler pulleys ASAP. They are all roached from running underwater all the time lol.

Took her out for short run around the driveway in the rain. The new transmission is so much quieter. No more groaning from it. I moved the needle in the carb again and messed with the jet screw and it runs much better. I think I might try the needle one more step down to see if it gets any better. Tractor is definitely a lot more stable with the wider stance.

A new air filter system is definitely needed. I need to get some reasonable sized hose to use for it. I think think I spotted some on McMaster that will work for what I need.

Now that I have more room on the rear axle I'm thinking it's about time for a brake upgrade. I like these airheart style mechanical go kart calipers, I'm thinking on dropping a couple bucks on one. Budgie had this same caliper on the 2300 from the factory and it performed wonderfully. I'd rather not go to a hydraulic setup just for simplicity's sake.

A good air cleaner is finally in the works. The one I built a while back is just a bit too restrictive.

Got the brake caliper in. Looks pretty good for the price. As long as the aluminum of the body holds up and the hardened steel lever doesn't wear, bend, or break, this should be just as good as the name brand airheart calipers. Got a few more bits of PVC and an air filter too for that project.

Finally got my air filter on this thing. Just a couple pieces of PVC. I cut a coupler down to fit the air filter snug.


Got a little too aggressive cutting this coupler down lol.



She still seems a little lean on the low end but pretty good on the high end. Poor oppy smokes like a chimney lol.

Forgot all about the brake caliper til I saw it in the thread lol. I’ll have to get on that.

Got her out in the woods tonight! Finally managed to bust the heck out of my cracked wheel. Took the whole wheel off the hub!






Dragged her out of the gulley with the PTO winch and limped her the rest of the way home. Switched the executioner over to a spare rim and she’s fine for now. 5 lug hubs are definitely on the way soon!

Refreshed my clutch and belt system today. The old setup had a lot of slop in the clutch pivot. I cut out the old gear I had welded in as a bushing and made a new one and welded it in. It uses the full 2.5” of the shoulder bolt as a bearing surface, and I reamed the hole to a nice close fit, as well as added a grease point for it. I also replaced the bearing in one pulley and greased the one in the other.

After cutting out the old bushing I found the center of the hole, then plunged out most of the hole with a smaller end mill and took it to size with a 1” end mill. This hole fits the step on the bushing, the step being there to align and set the correct height of the clutch.


Trimming a little off of the sides of the support. It was super tight in the frame before.


Forgot to take any good pics of the romp around the woods.


Clutch feels better than it ever has! Super smooth push. About due for a new belt though. The idlers have been quieted to a dull roar and I can finally hear the 820 whine like I used to

I’m realizing the fact that I was like 5’9 when I built most of mutt, me being about 6’2 now lol. I need to move the seat back or the throttle forward, one of the two. It’s rather uncomfortable to use the throttle. I think I’ll work on that here in a bit.

Great work man! Doubt you'll have an issue with that anytime in the near future if at all!

I moved the throttle pedal forward another 2" or so, as well as made a new elongated bushing for it that made it nice and tight with no side to side play in it at all. Didn't go so far as to add the grease fitting lol.

Gonna go to H&H tomorrow and get some 2" hot roll bar to start some hubs. Or something about that size. I think I'm gonna use the back of one of the hubs to mount the new brake disc, so I'll work that into the design as well. The flange for the wheel will ideally be 3/4" plate but I could manage with two pieces of 1/2" welded together. We'll have to see what I come up with.

Real throwback with that silver rim lol

Went to H&H after work and found some 2” bar and a piece of 3/4”x6” flat bar to make hubs out of. Just need to get some rims now.

I decided to go ahead and work on the disc brake. I decided to go with a 7” rotor to compromise between leverage and bending the rotor (I am definitely going to wind up bending the rotor)


Hub is in progress, currently inside eating dinner. Used a piece of the 2” bar for the center hub of the rotor.


I decided against using the backside of the wheel hubs for the brake rotor, as that would make the hub too long to reasonably use a keyway broach.

Got the lathe work done on the rotor hub, good enough for a mockup. The brake caliper will be somewhere in the general area of the rotor


Rotor doesn’t hang down much further than the skid plate. If I bend it I suppose I’ll just hammer the thing back out.


On lunch tomorrow I’ll broach a keyway in the hub, when I get home I’ll drill and tap for some set screws and then start welding some stuff together.

Got the rotor done up tonight.

After broaching the keyway, drilled and tapped two M8 holes for set screws.


Made sure to clamp the thing up good when I welded it. I spun it on an arbor in the lathe and there’s not enough wobble or warp to hurt anything. I need more practice with the stick welder lol, the mig is once again out of gas.


It’s pretty rainy and windy this evening, not sure if I’ll get it on the tractor or not.

Got a lot further than I thought I would tonight. Managed to make room in the shop to get her in.

Milled out the corner of two pieces of square tubing to hold the caliper about like this.


Got all fancy with the mini mill table I bought last summer, clamped everything down so the tubing would turn out somewhat parallel, though they did bow out some, which was easily fixed.



Caliper mounted on the machine. Just need to make up a linkage.

Got the linkage done with a little adjustable clevis on the end.


These brakes suck. Worse than the stock ones lol. Gonna try putting more leverage on my brake lever and see if that helps

Lol. If at first you don't succeed try try again!

Great work though it looks like you've done an excellent job!

Think I might have to admit defeat on this one. I’ve probably doubled the leverage on this caliper and still barely have workable brakes.


I didn’t want to go to hydraulic brakes but it’s sort of looking like that might be the way to go. I might still see if there’s anything I can get out of this caliper tomorrow.

RichieRichOverdrive wrote:

Think I might have to admit defeat on this one. I’ve probably doubled the leverage on this caliper and still barely have workable brakes.


I didn’t want to go to hydraulic brakes but it’s sort of looking like that might be the way to go. I might still see if there’s anything I can get out of this caliper tomorrow.

I hear ya man.  I had to admit defeat on my drum I had on Red at one time.  Mostly, due to oil getting on the drum at the time which I figured out.  Never went back to it.