Altavista and the 1850

[Charlie_Iliff]

He may be refering to the machined aluminum "shuttle valve" that is unique to and probably made by PT. If so, not related to Brake Tender. Others (Charlie Iliff? Sedgewick? others?) have had problems with this item.... search postings past year or so. It is a tricky (to be polite) item!

If I were using for business, this is one case where I would get a complete new unit from PT and keep a spare on the shelf.

Good Luck

I've had leak problems only at the tank plates, which I fixed with good gasket glue, one steering hose that the end came off, and a diesel return hose that leaked at a fitting. That's in something over 5 years, but I certainly don't use it as much as Altavista's commercial operation. And, with rare exceptions, I'm the only operator.

 

[J_J]

Bob,

So if the brakes are applied mechanically, perhaps by a spring loaded plate. the purpose of the brake tender is to apply pressure to the brake circuit to relieve spring tension so the shaft will turn. So anytime the engine is not running, the brakes are applied. Is this essentially correct? How do you tow or push this unit? In a normal hydraulic pump /motor circuit, you can turn a valve or change a setting to allow the hydraulic fluid to flow in a loop.

 

[AltavistaLawn]

I talked to terry today. I'm sending the pressure relief valve back to PT for them to overhaul; maybe update with one with dual o-rings. We might get something like a toro dingo (but Ditch Witch model) for most of the landscaping work, and only use the pt for hillside bush hogging, until we phase that out of our operations (probably within the next two years). This way th Pt won't be used much, and when it is, it will be run by me, or my dad. My Dad is getting most of our current bush hogging done now with the JD it has a 6' hog and does good, but just not so good on steep hills.

Thanks for all the suggestions.

Billy, out.

 

[Bob999]

Bob,

So if the brakes are applied mechanically, perhaps by a spring loaded plate. the purpose of the brake tender is to apply pressure to the brake circuit to relieve spring tension so the shaft will turn. So anytime the engine is not running, the brakes are applied. Is this essentially correct? How do you tow or push this unit? In a normal hydraulic pump /motor circuit, you can turn a valve or change a setting to allow the hydraulic fluid to flow in a loop.

You are correct--the brakes are applied by springs and the hydraulic pressure--supplied by the engine turning the pump or by the manual brake tender pump--conteracts the springs to allow the wheels to turn.

In normal operation the hydraulic pressure keeps the brakes from being applied and the service brake is hydraulic--just like all other PT units. It is only when hydraulic pressure is lost (either because the engine quit or a hydraulic leak or the brake tender in the stop positon) that the spring acutated brakes are applied.

So--to tow a PT with the brake tender you must do two things--release the brake tender brakes by manually pumping up the brake tender pressure and open the tow valve on the variable displacement pump.

 

[SpringHollow]

In my experience so long as the engine is running and the brake tender is in the operating position the system maintains pressure and the brakes are released. As soon as the engine shuts down the brake tender pressure goes to zero and the brakes are applied. The accumulator is charged after three events--engine running, brake tender lever moved from "brake" to "operate", and tramming is initiated.

However, as I noted in my previous reply, the brake tender is not pressured until the tractor is trammed--even though the engine is running and the brake tender lever is in the operate position the pressure gage shows no pressure until tramming either forward or reverse.

I did not think this was the case with my 1850 so I just went out and checked. If I start my 1850 with no feet on the pedals, not touching the steering wheel, etc., the pressure in the break tender reads zero. Immediately upon moving the lever so it releases the breaks, I see pressure of 1500 - 2000 psi. I can not say that my system is operating properly but that is what I see.

Ken

 

[Bob999]

I did not think this was the case with my 1850 so I just went out and checked. If I start my 1850 with no feet on the pedals, not touching the steering wheel, etc., the pressure in the break tender reads zero. Immediately upon moving the lever so it releases the breaks, I see pressure of 1500 - 2000 psi. I can not say that my system is operating properly but that is what I see.

Ken

Definitely different than what I see. I wonder if the tram adjustment on your machine is properly centered so that the machine does not move unless you depress one of the pedals. If the control were not properly centered then I would expect for the pressure to act as yours does.

 

[woodlandfarms]

My 1850 acts the same as Ksimolo. Start it, and no pressure read on the brake tender. Treddle on my tractor as no fluid and/or no pressure ( press the forward and reverse and it is nothing, and I hear now sound of pressure). Steering is active, but cranky cause the wheels won't turn. Release the brake and get an instant 1500 to 2K pressure reading and treddle is now active.

Now, I think both of our tractors have the Hydraulic treddle, and not the older wire treddle, maybe that is the difference?

Carl

 

[Bob999]

Now, I think both of our tractors have the Hydraulic treddle, and not the older wire treddle, maybe that is the difference?

Carl

That may be the difference. My tractor has the older wire connection between the treadle and the variable displacement pump. If I step on the treadle with the brake tender on brake position the engine loads and there is a strain on the brakes as the tractor has power applied to the axle.

 

[SpringHollow]

It's as Carl says, we both have the hydraulic treadle. If I release the brakes, the PT will just sit there until I hit the pedals.

Ken

 

[AltavistaLawn]

heres the part that I have the most trouble from..leaking. Theres a "piston" inside behind that big spring . it has a white plastic O-Ring, which usually goes bad every 50 to 100 hours. We can usually replace it and be good to go; but not this time. Black rubber o-rings don't even last a few hours.

In th epic u can see the bolt breather on top of the assmbly, this is where fluid seeps out when the o-ring leaks.