Towable backhoe

[Craig Clayton]

I found a commericial machine video.

GO-FOR-DIGGER TOWABLE BACKHOE - YouTube

I think your rear drive wheels are too far forward and that they need to be moved back. I think if you skewed the legs to the back which means to move them as far possible to the rear and in that way the rear drive wheels can be pushed toward the rear. If I understand it now you need less tail weight and more tongue weight. So you move the pivot point ie the rear wheels.
Here is a non engineering idea to guess the forward balance points. Consider the rear wheels like a teeter tooters center point.We all know when the Husky kid got on the thinner kid was airborne. So if you can guess by loading the front and keeping your boom up tight that the machine is in balance, then you can estimate the foot pound distance each side of the machine has. So if 6' boom measured from the rear wheel pivot equals 7' front with blocks then both sides are balanced. if you in theory remove the blocks you are unbalanced by 400 lbs at 7'. If you estimate that the rear wheels were moved back by 1 foot then you would have 8' at 400 lbs and less weight on the boom side.
If the wheels went back 2 ' then there would be 5' on the pivot side and 9' x 400lbs on the front.
So now we had 7x400 =2800 foot pounds
8x400 =3200 foot pounds
So now we need 9x311 lbs on the front to keep it down.
I think I just broken every proper engineering term in the book. By moving the wheels back I shaved 100 lbs of counter balance off the front.

Craig Clayton

 

[Sasquatch4100]

Could you move your rear stabilizers in a V to put more leverage on them instead of more counterweight? Also, before upgrading the hydros I'd check to see how the metal is taking the stress. Put a psi gauge on it and see if it's maxing out. Usually if the hydros aren't up to snuff it'll just run slow when extending and retracting, but your psi will max out at 2.5k or so. Make sure your cylinders and hoses, valves etc are up to any added psi. A blown hose or cylinder can puncture your skin and inflate you with hydro oil or cut a finger off.

 

[12barber12]

Thank u everybody you guys were a huge help

 

[dfkrug]

Problem 1- don't have enough counter weight and don't know what else to do I have 8 retaining wall blocks that are about 45lbs each on the back
Problem 2- every thing works but the cylinder that lifts the arm bogs down the engine

Way back when I built my CADDigger, I decided to buy plans rather than
try to figure everything out from scratch. I figured that there was
enough to do with making the thing; reinventing the wheel could get
costly. I did break a few things, and customized a few others.

Anyway, the first engine I used had the weight necessary to counter-
balance a full bucket at full boom and dipper extension. When I later
moved to a 10hp Tecumseh, I needed to add a bunch of weight, so I
bought a couple of 55# lead ingots from the metal recycler and bolted them
on to the rear (tongue).

From the looks of your boom cyl connection, you do not seem to have
built in much leverage. That is going to mean that you are going to
need more pressure to lift the boom than if the moment arm were longer.

 

[12barber12]

So I made some updates to my backhoe and it still isn't working right . I installed a bigger pump (11 gpm) I also put casters in the front and the axle in the back and that solved the tipping problem. It seems as if the pump or the motor isn't strong enough although with the new pump it doesn't bog down the engine anymore but with the bucket full it won't pick it up if anyone could help me I would greatly appreciate it thank you

 

[Iplayfarmer]

So I made some updates to my backhoe and it still isn't working right . I installed a bigger pump (11 gpm) I also put casters in the front and the axle in the back and that solved the tipping problem. It seems as if the pump or the motor isn't strong enough although with the new pump it doesn't bog down the engine anymore but with the bucket full it won't pick it up if anyone could help me I would greatly appreciate it thank you

Sounds like a pressure issue to me. What pressure is your system running at?

 

[12barber12]

The pressure gauge is only reading around 1100 psi

 

[Iplayfarmer]

The pressure gauge is only reading around 1100 psi

Typical compact hydraulic systems run at about 2000 PSI. Your low pressure could be the problem, but I'd think that at 1100 PSI you should at least be able to lift a bucket full of dirt. I think the first step is to get your pressure up closer to the 2000 PSI range and then troubleshoot the rest of the system.

Check your relief valve. The spring may be getting weak.

If the relief valve checks out, it may be that your pump is weak. How old is the pump?

 

[EddieWalker]

So I made some updates to my backhoe and it still isn't working right . I installed a bigger pump (11 gpm) I also put casters in the front and the axle in the back and that solved the tipping problem. It seems as if the pump or the motor isn't strong enough although with the new pump it doesn't bog down the engine anymore but with the bucket full it won't pick it up if anyone could help me I would greatly appreciate it thank you

I'm wondering if your engine is strong enough to get the pressure that you need? What are the specks on your pump? What is it rated for, and what are your cylinders rated for?

Lifting the bucket with a load should be the easy part, digging is when you need all the power that you can get.

Eddie

 

[chad22]

The pump seems to not be building enough pressure. My home made excavator started doing the same thing. It wouldn't lift the bucket when it was full. I would have to dump the dirt and bring the stick completely in to get it to raise up.

It started working though as soon as I replaced the pump. Though the one I have won't really work with my engine. lol It needs more hp. I'm gonna save it for another project.

So I still have to order another pump for mine that won't bog down my engine.

I'm wondering. Does it break through the dirt easily? Mine was breaking through the dirt like it should but just didn't have enough force to raise the bucket.

Hope your able to get it working. I know mine has aggravated me to no end. But I still stuck with it.

But I guarantee you as soon as I can afford one. And that's a big if. lol I'm just gonna go purchase a backhoe. :laughing:

Chad