VAC

[Bob Bancroft]

I should be in the field. But since we're getting the water we didn't get in the first half of the year, I'm fiddling around the shop.

My newly acquired VAC has a 3/8" copper line running from the base of the Eagle hitch to a tee on the steering gear. Operators manual shows it. This apparently acts as a breather, as well as a drain for any seepage from the lift cylinder. The steering gear is open to the torque housing. Someone has installed a little brass valve on the top of the tee. I think I finally understand that this should be a breather for the system. So I removed the shut off, and fastened about an 18" piece of clear plastic tube to the top of the tee. When I lower the lift, a little oil pushes right up out of the tube. I'm assuming several possibilities. Maybe the lift cyl. leaks by more than it should. Maybe the cavity under the lift cyl. has filled with more oil than should be there because the system hasn't been properly vented. It also looks like I should remove the left platform and clean the rear end breather.

Am I correct about a breather on the tee? I'm thinking of running the tube up to some kind of container which would act as an air/oil separator.

Before I do any rebuilding[which would be this coming winter anyhow] I will make sure everything can breath like it should, and see if things straighten out.

 

[Joe (Wa)]

There is an older and a newer VA tractor leak-off/vent system. The older tubing enters the torque tube via the breather. The newer tractor tubing enters the side of the torque tube under the right side foot board (red line).

You seem to have leak-by your piston seal into the rockshaft cavity and draining back to the torque tube as it is designed. The older piston seal was a leather cup, newer tractors have a 2 o-ring piston. Seals for both piston styles should still be available.

Drift down of the draft arms indicate leaking piston seals and/or a leaking valves in the control block.

To determine which is the leak problem:
To check rate of piston seals leak bye disconnect the leakoff/vent tubing at the fitting on the rockshaft. Run the engine and cycle the hitch up & down about 10 times to clear any residual oil in the housing and to check that the leak off is not plugged. The leak off can get plugged with old, hard grease from greasing those 4 zerks on the back of the rock shaft. If the rock shaft housing is tight you should be able to feel air puff out as the piston is forced down to raise the draft arms and a slight vacuum when it moves back up. After the 10 cycles, leave the draft arms up with preferably some weight. Any oil dripping from the leak off fitting can only be some residual oil or leak bye of the piston seals. The residual drip will eventually stop and any further oil leaking is the piston seal leak bye rate.

If no oil is dripping from the leak off and the draft arms continue to drop there is a leak back through the lift check valve or the release valve in the control block.

Joe

 

[Bob Bancroft]

Thank you

 

[Ande]

Wow Joe, you do it every time, "first class"!!