I hope these short videos will illustrate how the hydraulic drive system works. So far it seems to work the way I had envisioned but of course the real proof will be in how well it rides with the kids on board. There seems to be some binding when I put it in reverse. I think it has something to do with the chain tensioner being too loose. So what is next? If you said tighten all the bolts and go for a test ride then I don't think that would be a good idea because everything is only tack welded so far. Now we have to take everything apart and finish weld the entire frame and each individual component. Next it will be sand blasted and then painted. I guess I better go get some more welding wire. The pet monkeys won't be much help because I have not had a chance to teach them how to use the MIG welder. A monkey using a mig welder, that would be silly. They only know how to use a stick welder.

When I tried to bolt the wheels to the axles I discovered that the threads on the axle were flat and also had been painted right along with the rest of the axle. So I had to get a threading die to clean up the threads before I could finish assembling the rear drive train.

I also had to add a tab to hold the return spring for the brake pedal. There are so many little things to be done that I am not sure I can find enough time before Christmas to get this cart finished.

I finally got all of the hydraulic hoses and fittings connected. Here is a short explanation of how it should work.

1. The hydraulic pump is connected to the engine.

2. The hydraulic pump receives fluid from the hydraulic tank.

3. The pump sends fluid to the control valve.

4. While the control valve is in neutral it simply allows the fluid to pass through and return to the tank.

5. When the pedal is depressed forward it sends fluid to the hydraulic motor and turns the wheels in forward direction.

6. When the pedal is depressed backwards it reverses the direction of the flow and activates the reverse direction.

7. The fluid is returned to the tank through a filter which strains out any contaminants from the hydraulic oil before recycling through the circuit.


In the following photo you can see the hose connecting the hydraulic pump to the control valve. The control valve is below the pump.

Some of the hoses are too short but they will have to do for the test run. This photo shows the return line running from the filter to the tank.

Here are the 2 ports of the motor connected to the control valve.

Here is a side view that shows the return line from the control valve to the filter.

Now that everything is connected it is time to see if a hydraulic gocart really works.


A couple of weeks ago we were in Charleston South Carolina for my neices wedding. This is a very interesting town rich with history dating back to the revolutionary times. We decided to go on a walking ghost tour at night and learn a little more about the cryptic history of the town. I have no explanation for this mysterious video that just showed up on my I phone.

I had to make a slight modification to the chain tensioner so that it would have a little more adjustment. The 5/8" bolt was interfering with the adjustment so I had to cut it off and weld it to the idler arm as opposed to bolting it on with a nut. It needs to be flat on this side so it can be pushed farther back into the frame. This will make it difficult to remove the idler sprocket if necessary but it was the quickest and easiest fix I could think of at the time. And speaking of time, this project is getting so far behind schedule that I may need to build a real car for the girls if I don't pick up this pace. But it is not like I have been sitting around eating do nuts and watching TV. I just spent the last 3 weekends replacing soffit that had rotted on the garage. I thought it would entail a couple of feet but turned into about 20 ft. that needed to be replaced. Now we are getting to the fun part of the hydraulics. The hydraulic motor, pump, control valve, and tank all have to be connected with hoses and fittings. The following photo shows some of the components. Starting at the top we have a piece of 3/4" low pressure return hose. Next is a row of 3/4" street elbos, followed by 1/2" street elbos, then 1/2" male by -8 JIC 90 degree elbos, 1/2" x -8 straight, 3/4" to 1/2" bushings and the bottom row is 3/4" male hose barbs that fit into the 3/4" hose. This will get us started.

First off we will screw the strainer into the hydraulic tank. I am using teflon thread sealant tape in these connections. Some say that you should not use teflon tape upstream of the pump and valves in a hydraulic application because just a small piece of teflon tape can clog a hydraulic component. I know this is true from personal experience. However I am going to be extra careful not to let any extra tape get into the joint and it should be fine. Here a gain the Captain of the Titanic probably made a similar statement.

This is the supply end of the tank that will feed directly into the pump. It is all going to be a tight fit.

The hydraulic tank is now connected to the pump. I am going to need to enlarge the mounting holes for the tank in order to move it slightly so this can all fit. The piece of hose on the left is not connected to anything yet and I am just trying to get an idea where to mount the filter which will be in the return line. You will notice that I have installed two fittings on top of the control valve. They are pointing back toward the hydraulic motor so I can determine the length for the connecting hoses.

Here is a shot from the hydraulic motor back toward the control valve.