Diy self propelled backhoe that turns into a trailer replacing a culvert

  • 8 years ago
This is the Cad digger my father had built about 15-20 years ago. It's basically a self propelled backhoe that transforms into a trailer for long distance transport. It does this by moving the front arms to the stowage position, then placing the wheels where the arms were and sliding a hitch into the mainframe under the motor.

In this video I give an overview of the unit and explain some of the modifications I have made over the years to improve and or fix the original design. I also show the unit in action replacing a culvert, and breaking up some badly setup concrete.

See it move itself starting at 2:07 watch it tear up some badly set concrete at 3:11 watch it dig up my driveway to remove the old culvert at 5:38

We made a few small modifications from the original design because of flaws in the original design. Pins were only staked on one side a lot of broken pin housings were replaced with just through pins because of this design flaw. We also reinforced the side to side rams which has fixed the problem of the rams flexing to much. A lot of duck tape has been added to hydro lines where they rub to stop them from getting worn out, this is an ongoing battle. The hydro line runs on this were pretty badly designed but would cost quite a bit to correct  so we just keep duck taping them and hope we don't spring a leak.

The biggest fix was I replaced the 3/8" metal arms that attach the front ram to the bucket with 1/2" metal arms. The reason being is I had a pin back out after a keeper pin failed and the arms bent easily under the pressure which caused the hydraulic ram to get bent, "I was able to heat it up and straighten it luckily." Since I had to replace the arms anyhow I decided to beef them up so they would not bend so easily, I also added some pipe stock in between them to keep them spaced.

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