B7100 Hydraulics

[Piker]

I have posted on here a couple of times to try & get the straight poop on using the tractor hydraulics & the selector valve under the seat to operate a front snow plow & controlling the lifting with the operator's hydraulic control lever located to the right side of the driver, after rear 3 point was raised out of the way & the selector valve switched to the other port. Never got a definite answer from anyone who has done it. Here is a link just posted on utube of a B7100 with a front snow plow & the operator using the hydraulic control lever to raise & lower, with 3 point raised to the top of it's travel & probably being held there by hydraulic fluid trapped in that circuit. I wish I could see the plumbing associated with his cylinder, whether it is double acting with a return line (giving him down pressure as well), or just using a single acting cylinder setup with a small vent/air filter in the other port & no return line back to the sump. Can anybody add any more info, please?

http://www.youtube.com/watch?v=cbDazQHGW4E

Crap! Just watched the video again & his 3 point is raising/lowering as the front blade raises/lowers. Not a big deal as the 3 point could be chained up, but the high pressure line from the pump must have been tapped into for it to work this way? And from the way the blade is floating around, don't think there's any down pressure?

 

[gktilton]

I haven't done this, but I am running my loader on my b7100 off this port. My weight box has 300lbs in it and I raise it when I start my tractor, I then switch the valve under the seat and the 3pt stays up, no chain needed. The port on the side of the valve under the seat feeds my loader valves, I have to have the 3pt hitch lever in the raise position to have flow to my loader valves.

Putting the 3pt lever in the lower position does not reverse the flow so it appears to be a one way and return on the guys plow in the video. I don't know how he has it plumbed to raise the plow and the 3pt at the same time.

Mine is the supply to the loader valves is from the port on the valve under the seat, the return from the loader valves goes back to the oil fill for the transmission.

I'm not sure this answered your question, but it is an answer is is all I know.

 

[stuart]

The 3 point on these units is always (so I believe) gravity down, with a valve to control how fast it goes down. 3 positions on the lever - up, hold, down (which just allows the fluid to bleed off and return to the reservoir).

It has to be this way - with a power down like the loader you would lift the rear tires off the ground - no traction there. Let weight of the implement do the 'down' part.

I have not had a look inside the mechanism for the 3 point lift arms. I already have a loader so it just was not important to look.

 

[Piker]

'Morning gktilton. Thanks for your reply, you cleared up some of the "fog". At least I now know for sure that the 3 point will stay in the raised position after the valve has been switched to the front implement. Buddy in the video must have just tapped into the high pressure line so front & back are working together, controlled by the hydraulic control lever. More to this hydraulics thing than meets the eye. Picked up a 12volt electric/hydraulic power pack, (1) larger cylinder, (2) smaller ones & all the hoses - was used on a 4x4 truck for a snow plow.If I can find the "real estate" on the little tractor to mount the power pack that may be the cheaper, easier way to go.