Safety stop / deadman switch on hydrostatic drive?

If the drive control foot pedal is adjusted properly, it will stop dead if you lift your foot off the pedal. The springs will return the swash plate to the neutral position at that instant. The same thing happens when you stomp on the brake pedal. Brakes on hydro equipped tractors are for turning (indidvidual rear wheel brakes with pedals to match) and for parking (usually a single disc brake on the rear end, if it doesn't have turning brakes). Stopping the tractor is the hydro's job and is accomplished when the swash plate is in the neutral position.

All pressure lines for drive control are internal to the hydro casing. Any external lines are either oil supply for the hydro (low pressure suction line) or a separate circuit for implement lifts which runs off the hydro's charge pump. Pressure comes when the system does "work", not when it's running and has no load.

DO NOT MESS WITH HYDRAULICS unless you have a basic understanding of what is involved. If it's working correctly, leave it alone!!! Improper modifications get very expensive, very quickly. The manufacturer spent a lot of money paying experts in the field of hydraulics to design a setup that works very well, and the government has mandated several safety devices to be included on lawn and garden tractors to prevent injury to those who are operating these units. eg. Seat safety switches which will shut off the engine if your posterior even high sides the seat when attempting to mow the grass on the side slope of a ditch. No engine, no hydro.

Here is a primer for hydraulics.

http://www.edgeroamer.com/sweethaven/mechanics/hydraulics01/

Here are a couple of animations of basically what goes on in a hydro.

http://www.youtube.com/watch?v=2mh902AP7Yw&feature=BFa&list=FL6KTtzLgSGlsmxKZ59dObfQ&lf=mh_lolz

http://www.youtube.com/watch?v=WzaNAj11G30&feature=related

Bob - The 1512 has a hand control for the hydro located on the dash, not a foot control. The brakes will return the hand control lever to neutral when you press on the brake hard enough, but the hand control lever will stay wherever it is if you fall off of the tractor without pushing the brakes first.

Paul - There is no hydraulic lines going up to the control in the dash. The control in the dash has a mechanical linkage that eventually controls a lever on the side of the hydrostatic transaxle unit itself, so there is no external hydraulic line to put a valve into.

With all that being said, there is a neutral safety switch in the dash that detects when the hydro control is in (or not in) the neutral position, and the seat safety switch combined with the neutral safety switch should kill the engine if you fall off of the tractor when the hydro control is not in the neutral position. If the safety switches are not functioning correctly, fix them and/or adjust them so that they are working properly and your concerns will be covered.

OK, I just played with my tractor and it works as you said. I did a start-up and move with the trailer, and then I disconnected the trailer and took a ride down the service road and back. I feel better about it now. Just a newbie thing! I don't know if the seat switch works, but there is an electrical connection there. I took videos - they'll be on youtube this evening!

:thThumbsU

Nouveau ******* said:

Bob - The 1512 has a hand control for the hydro located on the dash, not a foot control. The brakes will return the hand control lever to neutral when you press on the brake hard enough, but the hand control lever will stay wherever it is if you fall off of the tractor without pushing the brakes first.

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Thanks for the info. :fing32: I finally noticed that in a pic much later. I had a MF12H that was the same, only without safety switches. Never had a problem with the first one I had 30 years ago and don't expect any with my current MF12H.

All my tractors for the past 28 years have been pedal controlled. I haven't gotten around to fixing the hand controlled tractors yet.