425 started itself

[m5040]

Yeah. I wonder if one could put a solenoid valve on each wheel motor circuit and a big red panic button on the underside of the canopy?

I would think you would need one valve on each port so it could block forward and/or reverse (oil flow from the now pump- former motor).

 

[ponytug]

I would worry a little about the surge in hydraulic pressure on the motor/pumps, but a relief valve ps could be part of the package I guess.

I did test the 1445 brakes shortly after buying it. Not going full speed, or anything, but I can assure you that I would have been in front of the bucket if I wasn't belted in. That e-stop experience did also make me consider adding some additional bolts to the seat tilt mechanism as well, as you do tilt into the steering wheel if you are belted in.

Given how common small disk brakes are these days, couldn't you just replace the existing toothed brake with 4 wheel disks?

All the best,

Peter

 

[m5040]

I think the wheels have a 12" tire size, the wheel tapers in. The disc and caliper would have to fit inside. A lot of engineering there.
I was thinking more on the lines of a continuous duty solenoid that was strong enough to pull the park brake pins into release position, then when power is cut (panic button), they would attempt/engage.
Not meant for everyday use, just when a drive hose ruptures and you loose all control over the wheel motors.

 

[MossRoad]

I would think you would need one valve on each port so it could block forward and/or reverse (oil flow from the now pump- former motor).

I'd have to look at the schematic again, but as I recall, there are only two ports coming out of the tram pump. Forward and reverse. Then they branch off to the two wheel circuits. Each wheel circuit has two wheel motors.

If you put a solenoid on each tram pump port, and the motor died and you hit the panic switch, a solenoid in each port would block all flow of the wheel circuits and that would be a full stop, I'd think.

Now if you blew a hose past the ports/solenoids, that may still work, or at least slow you down to the level of the leak and you might be able to engage the parking brake.

I don't know. Just spouting ideas.

 

[m5040]

My worries are cutting on steep hills and next to water. Not much reaction time and then I would have to jump off, if possible. I don't want to do that.

The solenoid valves would have to be at the wheel ends, so there would be no hoses in the circuit. Everything is engineered so tight, I am afraid to think what it would look like after changing all the fittings. And just like the motors with brakes, I don't want to open the hydraulic system up (and the cost of new motors is concerning too).

If the hose blew at a motor, I am not sure how long it would take to induce air into the system, possibly making the solenoid shutoff less effective or inoperative. Reaction time, how many revolutions happen when rolling down a hill with oil pumping out or air being sucked in before it is just compressing air?

Maybe the answer is a hydraulic plow on the back to just drop and dig in, wouldn't that look nice?

 

[ponytug]

Anchors away! Sorry the mental image was of times out boating when the skipper noticed he was in a jamb too late and yelled for an anchor.

At some point, I think you are approaching the price of new wheel motors with built in brakes. Fast acting hydraulic solenoids and relief valves aren't cheap either. I would not underestimate the ability of a moving tractor to overwhelm a relief valve to the point that it was not an effective brake. There is a lot of energy there. I think the fact that motors with internal brake packs are common suggests to me that it is likely the robust solution.

I hear you on the risks of mowing on slopes next to water, or something else that you don't want to experience. I have a bunch of places where my slopes end at my property line (barbed wire/electric fence) and a 4-10' drop on to a county road, and the far side of the road drops a further 40-100'...did I mention why I bought a 1445?

All the best,

Peter

 

[m5040]

Anchors away! Sorry the mental image was of times out boating when the skipper noticed he was in a jamb too late and yelled for an anchor.

At some point, I think you are approaching the price of new wheel motors with built in brakes. Fast acting hydraulic solenoids and relief valves aren't cheap either. I would not underestimate the ability of a moving tractor to overwhelm a relief valve to the point that it was not an effective brake. There is a lot of energy there. I think the fact that motors with internal brake packs are common suggests to me that it is likely the robust solution.

I hear you on the risks of mowing on slopes next to water, or something else that you don't want to experience. I have a bunch of places where my slopes end at my property line (barbed wire/electric fence) and a 4-10' drop on to a county road, and the far side of the road drops a further 40-100'...did I mention why I bought a 1445?

All the best,

Peter

Yes you did mention the 1445, and I LOVE that setup on my 1460. The right way with no concern for price, is the braked wheel motors. But what part number and are they direct bolt in? Then there is all the hydraulics needed to charge the brakes and the electrics to control the hydraulics.
To me, although a big compromise, the way to go is some kind of electric control of the pin parkbrake. It is the least intrusive on the machine and SHOULD work.
Maybe that will be this winters research and development project. I will have to watch for the Baileys and Surplus Center catalogues for linier actuators.
Just an FYI on the brakes that are used in the wheel motors on the 1460. They are meant under normal use, to hold the machine stopped, not to routinely stop the machine. I looked at a used 1460 that PT had for sale and Terry told me the last owner used the park brake to stop the machine every time he wanted to stop and get off the machine. This wore out the P brake lining.

 

[MossRoad]

Yes, the pin type brake on the PT425 is definitely a parking brake. And I can't see a way to make it into an effective emergency brake, as the pins won't go into the slots if there's any meaningful speed on the wheels already. I know this, because the parking brake lever is notorious for loosening up. You'll be driving along and start hearing the clicking of the pins on the slots, but they don't engage. Slow down to an almost stop and they will engage.

Maybe taper the pins?

 

[ponytug]

...
Just an FYI on the brakes that are used in the wheel motors on the 1460. They are meant under normal use, to hold the machine stopped, not to routinely stop the machine. I looked at a used 1460 that PT had for sale and Terry told me the last owner used the park brake to stop the machine every time he wanted to stop and get off the machine. This wore out the P brake lining.

I can't imagine using the brakes to routinely stop the tractor while in motion! It is so sudden, at least on the 1445. Different strokes for different folks I guess.

All the best,

Peter

 

[m5040]

Yes, the pin type brake on the PT425 is definitely a parking brake. And I can't see a way to make it into an effective emergency brake, as the pins won't go into the slots if there's any meaningful speed on the wheels already. I know this, because the parking brake lever is notorious for loosening up. You'll be driving along and start hearing the clicking of the pins on the slots, but they don't engage. Slow down to an almost stop and they will engage.

Maybe taper the pins?

I have had the brake control lever partially move toward the lock position and heard the clicking. But could this be because it has only partially moved?
I guess at some point I will need to try and Engauge it at speed (I can see dollar signs now).
This would probably best be done with the wheels off the ground, so the heavy mass of the tractor won't contribute to any stress if it does engage.