Hydraulics/wheel motor question

[Stimw]

For the OP, a good source to check out is Surplus Center who is also a sponsor on this site and has great prices!

 

[4570Man]

I'd try to find a junked skid steer. You'd get most of the needed components at a cheap price.

 

[curtjeep]

I didn't think about a skid steere. That would give me the pumps I need. And a size for the wheel motors.
Stimw- I have already bookmarked a few items from surplus center.

 

[4570Man]

It'll give you pumps, valves, 2 drive motors enough cylinders for your loader, and an engine. You could probably make do with the 2 drive motors. You can use 2 truck rear ends and drive each one with your drive motors. Then if you had 4 independent brakes that's pretty much the same thing as traction control.

 

[curtjeep]

Currently, I have a 26 hp b&s out of a husky lgt2654, but the transaxle is a k44 and super weak. So, for an engine, I'm squared away. I also have the rest of the garden tractor to use, but the most I can use is the sheet metal from it.

 

[curtjeep]

After looking at the cadtrac I have decided I will definitely build my own. The only thing I'm worried about is getting the correct size wheel motors. I am going to ride on the rear and the steering will use a power steering arm from a vehicle in a junkyard. With a shaft with heim joints at both ends to articulate the two halves. I will run two pumps off of the motor shaft. Probably 8gpm a piece unless I need more flow on the wheel motors. So, question for the experts, what size wheel motors do I need to look for. I will probably run either a 23 or 26" tire and I am looking for roughly 5 mph that way I have a decent amout of torque. I want to stay relatively cheap on the wheel motors if possible, but am not going to go cheap and have them wear out or not run the machine.

 

[MossRoad]

Go over to the Power Trac forum and ask that question. There's a couple guys that replaced their wheel motors with larger displacement motors for lower spee/higher torque.

Also, you'll be sorry if you go with one steering arm from a vehicle. Go with two steering rams, one on each side. Trust me, you'll be sorry if you don't. Really sorry. It'll be weak if you go that route. And you'll find the forces of push and pull under load between two articulating sections will be really hard. Remember, that steering will have to twist as well. Car steering doesn't twist.

Check out the dual steering rams on the PT design. The rams have the heim-type joints on each end as well. The whole thing is super flexible.

 

[MossRoad]

It'll give you pumps, valves, 2 drive motors enough cylinders for your loader, and an engine. You could probably make do with the 2 drive motors. You can use 2 truck rear ends and drive each one with your drive motors. Then if you had 4 independent brakes that's pretty much the same thing as traction control.

If you use truck differentials, you're going to end up with a tall machine on tall tires to get ground clearance for the differentials. And a short, stubby machine with high ground clearance AND ARTICULATION will be a tippy machine with a high center of gravity.

Something to note about articulating machines. The center of gravity changes DRASTICALLY as you turn. That's because the machine gets shorter as you turn the steering wheel, and longer as you straighten it back out.

We, on the Power Trac forum call this the PT Pucker! Because you don't expect it until you experience it. Fill the bucket with a heavy load and turn the wheel to the left and the right rear tire will come off the ground. Straighten out the wheel and the right rear will come back to earth. Do that on a hillside and you'll understand where the pucker factor comes in.....

 

[MossRoad]

Currently, I have a 26 hp b&s out of a husky lgt2654, but the transaxle is a k44 and super weak. So, for an engine, I'm squared away. I also have the rest of the garden tractor to use, but the most I can use is the sheet metal from it.

Power Tracs don't have any sheet metal. All plate steel.

 

[MossRoad]

As for brakes.... none of the Power Tracs have brakes, so to speak. That's the beauty of all hydraulic drive. You let off the go pedal and the machine stops. They have parking brakes. And the larger ones have a brake tender. It has to build hydraulic pressure before the brakes release. But there are no brake pedals at all.

 

[4570Man]

If you use truck differentials, you're going to end up with a tall machine on tall tires to get ground clearance for the differentials. And a short, stubby machine with high ground clearance AND ARTICULATION will be a tippy machine with a high center of gravity.

Something to note about articulating machines. The center of gravity changes DRASTICALLY as you turn. That's because the machine gets shorter as you turn the steering wheel, and longer as you straighten it back out.

We, on the Power Trac forum call this the PT Pucker! Because you don't expect it until you experience it. Fill the bucket with a heavy load and turn the wheel to the left and the right rear tire will come off the ground. Straighten out the wheel and the right rear will come back to earth. Do that on a hillside and you'll understand where the pucker factor comes in.....

You could position them with the drive shaft end pointing up if you're hydraulic driving them. That wouldn't require any more ground clearance than any other method. I agree it's not ideal, but it is cheap. If he has a parts donor machine maybe he could use the axels off it. I used to have an articulated trencher that the scrap monster ate. That wouldn't be a bad starting place either. I don't see how you could come out ahead building equipment without part donors.

 

[farm boy00]

If you use truck differentials, you're going to end up with a tall machine on tall tires to get ground clearance for the differentials. And a short, stubby machine with high ground clearance AND ARTICULATION will be a tippy machine with a high center of gravity.

Something to note about articulating machines. The center of gravity changes DRASTICALLY as you turn. That's because the machine gets shorter as you turn the steering wheel, and longer as you straighten it back out.

We, on the Power Trac forum call this the PT Pucker! Because you don't expect it until you experience it. Fill the bucket with a heavy load and turn the wheel to the left and the right rear tire will come off the ground. Straighten out the wheel and the right rear will come back to earth. Do that on a hillside and you'll understand where the pucker factor comes in.....

Go look at a trencher. Got a mini trencher turned into a tractor. Has decent clearance and isn't a problem

 

[farm boy00]

For the trasnfercase idea I mentioned earlier. For articulating put the transfercase by the pivot point and use a extending driveshaft like a pto shaft. It doesn't have to be a rigid shaft.

Some trencher actually have a gear on one axle then a driveshaft going to both axles that extendable.

U can get pictures of mine tonight maybe if interested

 

[MossRoad]

You could position them with the drive shaft end pointing up if you're hydraulic driving them. That wouldn't require any more ground clearance than any other method. I agree it's not ideal, but it is cheap. If he has a parts donor machine maybe he could use the axels off it. I used to have an articulated trencher that the scrap monster ate. That wouldn't be a bad starting place either. I don't see how you could come out ahead building equipment without part donors.

Yeah, free parts is the only way its worth it. Cheaper to buy a complete machine otherwise.

 

[texasranger556]

Just be careful buying a scrap skid steer. Worn out wheel motors and pumps are often the reason they get scrapped. If the engine is already gone, that would be a red flag for me!

 

[curtjeep]

The downside with mounting the pinion up I think would be keeping the gearset lubricated. Either way, with them pointing up or towards the middle, it would be about the same height. The tractor won't have any suspension to speak of.

 

[curtjeep]

The sheet metal would be used for casing in the steering wheel and any gauges I put in it. I'm not going to waste plate for aesthetics And working the plate for me would be more difficult. If I need more weight on the rear I will use my weight plates from my home gym, lol at least then they would be used. Although, now that I mention that I can potentially cut up my power rack and use it as a donor for certain pieces because that doesn't get used either...