Using old boat trim/tilt hydraulics on a tractor.

[4570Man]

Learning something isn't a waste of time if your goal is just to see how stuff works. Consider it a lesson in mechanics and enjoy.

Fair enough. I have rigged up contraptions that were a bigger waste of time. In reality the time and money spent to do this would never equal the extra 30 seconds to get off. 99% of the time I am changing from or to my grapple, so even if I had hydraulic latch pins I still have to get off and deal with the the hoses.

 

[arkydog]

if your quick attach didn't have hoses it would be great idea. as someone else suggested, on one of the end of the hydraulic cylinder, i would put a quick release pin (can't think of the name) so incase it didn't work one time, you could still release the quick attach by unpinning that cylinder.

 

[alchemysa]

I know this is an old thread but I just came across it and thought there might be some entertainment value in resurrecting it. I'm actually building this setup at the moment using the rams and electric pump from an old Mercury outboard that I scrapped years ago. Its going on an old Bobcat 610 skid steer that I recently finished 'restoring'. The grapple is mostly built. The rams are mounted behind the bucket (as per 4-in-1 bucket style) and the pump will be mounted behind the cage. The electric control switch will be mounted just above the right hand control lever. I'll have 2 steel hydraulic lines running down each of the 2 loader arms, with a flexible hose at each end of each pipe, so ultimately it requires 4 hard lines and 8 flexible hoses, adding up to about 40 feet of lines in all. As you might guess this could be a very expensive exercise if I was to use actual hydraulic hose and fittings so I'm using 3/16 brake line and brake hoses instead. Brake hoses are relatively cheap. A 50cm hose is only about $10, and I needed 8 of them, and I can make the hard line sections cheaply and easily myself. The Mercury pump and rams are already designed to receive 3/16" 'brake style' double flare fittings, so that was another thing that necessitated taking this route. Brake hoses are rated to take at least 4000psi, which is about double the pump pressure, so I'm reasonably confident it will take the strain. However I will not be using brake fluid in the system because, if anything does go wrong, I don't want brake fluid spraying everywhere. My plan is to use Canola Oil (Rapeseed oil) in the system as that is, according to my research, one of the few common/cheap oils that are compatible with the EPDM rubber used in brake hose. (You cannot use any type of common hydraulic, ATF, or engine oil in brake hoses because it will eat the rubber.)

One of the earlier posts commented on the very slow speed of the outboard power tilt systems. After taking the pump apart I'm pretty sure the slow speed is simply due to the tiny pinhole in the 'manifold plate' that the oil has to squeeze through when the rams are extending and retracting. (You can just see it in the pic attached. I'll be experimenting with increasing the speed by drilling this hole out or adding more holes.

So there's a first post on my project. I'll update this as I go along if anyone is interested.

 

[mrmikey]

Nice Bobcat.
I'm thinking it's going to be terribly slow, I hope not for the work you're putting into it. You have to think that the size of the trim cylinders is quite small and you don't want them to move fast, yes I do realize there is an orifice the oil has to go thru also. Even saying that................Mike

 

[Xfaxman]

 

[alchemysa]

First bench test today. After flushing everything out with soapy water I filled the pump with canola oil then connected up some brake hoses and the cylinders. I was pretty happy with the result. A full extension of both rams took 13 seconds and a full retraction took about 7 seconds. Its slow but I can live with it, bearing in mind that if you are grabbing a log or pile of brush you probably only need to close the grapple half way, so in practice you can often halve those times. The final hydraulic system will be about 8 feet longer so I have to make up 4 hard lines, each about 6 feet long, with brake lines at both ends. The last pic here shows one half of the grapple. I'm just making it out of some heavy duty angle iron I had lying around. You can't see it but there's a lever extending though the back of the bucket that the ram will be attached to. I also have a tooth bar to bolt on if needed.

Unfortunately drilling out the pinhole orifice in the 'manifold plate' pictured in my earlier post made no difference to the speed. Something else controls the speed, or maybe its just the capacity of the pump, but whatever, I'm not too concerned about it. I think its fast enough to be plenty useful. Next step is to put it all together and see what sort of holding power it has. I'm not looking for 'crushing stength'.

 

[mrmikey]

Here's hoping it works for you. I will admit the pump/motor looks a lot bigger than I thought it would be. Any idea of the psi that it can produce?...................Mike

 

[alchemysa]

Here's hoping it works for you. I will admit the pump/motor looks a lot bigger than I thought it would be. Any idea of the psi that it can produce?...................Mike

Its pretty hard to get info on this but a Mercruiser stern drive service manual I found (using a similar pump) talked about pressures up to 2600psi, but it might have different pressures depending on the direction of travel. Possibly as little as 600 psi in the downward (clamping) direction. There are pressure adjusting springs inside the pump but I wont be fiddling with them unless the pressure is quite inadequate. By the way, the piston rods are a full 1 inch diameter so they are pretty hefty.

 

[Xfaxman]

 

[alchemysa]

Heres a little update on the project. I installed the bits and pieces on the Bobcat today and gave it a brief test run. The mechanical part of the grapple is only half built. Ultimately that other cylinder sitting on the bucket will power another arm. They will open and close semi independently so I can pick up irregular shape logs. Its not fast but if it picks up 200 kg logs I'm happy to wait 10 seconds. The cylinders only have about 4 inches of travel but I can easily move a pin on the cylinders to give me 2 opening positions... (from fully closed to half open, or from half open to fully open)...so you've got to know before hand what you'll be moving. It has required twelve 50cm brake hoses to complete the sytem. The hoses were about $8 each so thats about $96 worth. By comparison a single 60cm hydraulic hose that I just bought for the tractor in my avatar cost $76. The pump is mounted behind the cage. Its very convenient that its an electric pump. I can play around with it and adjust things and find leaks without having to start the engine.