Help! Mighty Mouse Nibbled Kryptonite Maybe

[dex3361]

OK. A brand new filter helps but doesnt cure. I ran it around in hi range a good bit. Another thing I noticed is letting off completely on the pedal for "braking" going down hill can send it into a freewheeling mode - hydraulic coupling is lost. I can see this being very dangerous under the wrong circumstances -- but a clue just the same. When the pedal goes dead [no control] the pto clutch remains engaged -- and the 3ph lift operates normally. In fact, it almost seems the operation of the 3ph lift actually resets the pedal in that case so it works again. Also, problems seem to be worse at full throttle than reduced throttle. .........Any more ideas?? I wonder if this is going to go away when the weather warms.
larry

If you run the HST much starving it of sufficient fluid you will damage the the HST I would change the fluid and use SUDT if you have not already. Did you clean the suction screen? I have the WSM and I will check it later to day.

 

[EE_Bota]

Volfandt posted the chart that tells the tale.

You said you ran it in high a good bit, but you didn't say whether you were gaining in temperature enough to be sure that if water crystals were present that they would melt. If water were in the fluid, melting it is not necessarily sufficient to cure problems, however, since emulsified water in oil has trouble sometimes going through filter media.

The screen being clean is an important point, but adequate lift movement ought to give a reasonable indication of whether or not that is a big enough problem to account for the symptoms. Nevertheless, I would examine that before I did anything intrusive, or expensive. I have wondered if cavitation in the presense of water might result in vapor, which would not effect hydraulic actuators substatially, but may cause problems in the hydro set.

My instincts tell me to get the tractor warm by any possible means, check the pedal linkages as others have suggested, and then work through the flow chart Volfandt provided, testing at each stage. That may be beyond your capabilities. It is beyond mine, since I don't know where the test points are, and I may not have the fittings. My tractor seems to use some G1/4 testpoints which are BSPP 1/4.
I did see these available from one of the TBN sponsors.

I know it is easy to say, and harder to do, but I believe the above is a logical approach.

 

[dex3361]

I noticed my BX1500 had quit a bit of moisture in the oil when I did the Service this fall.
You can do what is called a crackle test to see if there is moisture in the HST fluid.
Get a hot plate (or an old Iron ) and warm it up till water rapidly vaporizes when you put a drop of water on it. Then drip a drop of your HST fluid onto the plate and if it crackles it has moisture. To give you a comparison do the same crackle test with new fluid and compare the sounds. Its a quick and easy way to check for the presence of moisture.
The oil can absorb and hold moisture and still lubricate but it will only hold so much and function correctly.

 

[radioman]

I noticed my BX1500 had quit a bit of moisture in the oil when I did the Service this fall.
You can do what is called a crackle test to see if there is moisture in the HST fluid.
Get a hot plate (or an old Iron ) and warm it up till water rapidly vaporizes when you put a drop of water on it. Then drip a drop of your HST fluid onto the plate and if it crackles it has moisture. To give you a comparison do the same crackle test with new fluid and compare the sounds. Its a quick and easy way to check for the presence of moisture.
The oil can absorb and hold moisture and still lubricate but it will only hold so much and function correctly.

Interesting tidbit!

Maybe for OP it's time to change fluid and filter again? clean out the HST screen? all of these is easily done by OP.
I admit I have no idea how to check the charge pump on the BX, does anyone know ? This sounds like something we all may need to know for 5-10 years from now ?

 

[EE_Bota]

I believe the main pump that lifts the lift arms and drives the power steering is the charge pump.

The priority flow valve grabs a portion for the power steering, pto clutch, and charge function. Someone please tell if I am wrong about this.

There are various relief valves along that path that keep the pressure to the appropriate value for each purpose.

 

[jnjpream]

This is probably a long shot, but do you have fuild filled tires? I read a thread a while back where somebody said they lost power any time they hit resistance.. Turned out the tires were slipping on the wheels.

Have you tried it in 4wd?

 

[Volfandt]

Good suggestion on the tires spinning on the rims. Been seeing this more frequently lately.

Another chart that may prove helpful.

 

[dex3361]

SPYDERLK
These PDF flies may help if you are going to test the HST and they contain the test points and pressures. If you need any more info let me know.

 

[SPYDERLK]

Volfandt posted the chart that tells the tale.

You said you ran it in high a good bit, but you didn't say whether you were gaining in temperature enough to be sure that if water crystals were present that they would melt. If water were in the fluid, melting it is not necessarily sufficient to cure problems, however, since emulsified water in oil has trouble sometimes going through filter media.

The screen being clean is an important point, but adequate lift movement ought to give a reasonable indication of whether or not that is a big enough problem to account for the symptoms. Nevertheless, I would examine that before I did anything intrusive, or expensive. I have wondered if cavitation in the presense of water might result in vapor, which would not effect hydraulic actuators substatially, but may cause problems in the hydro set.

My instincts tell me to get the tractor warm by any possible means, check the pedal linkages as others have suggested, and then work through the flow chart Volfandt provided, testing at each stage. That may be beyond your capabilities. It is beyond mine, since I don't know where the test points are, and I may not have the fittings. My tractor seems to use some G1/4 testpoints which are BSPP 1/4.
I did see these available from one of the TBN sponsors.

I know it is easy to say, and harder to do, but I believe the above is a logical approach.

I will definitely do everything you say before I go into it. It is still functional, just suddenly not right after always being right. It is hard to believe this could be caused by wear so suddenly. Its only been 100 or so hrs since the changeover to SUDT, filter change and screen cleaning. The fluid looks perfect - like when I 1st poured it in. The trans is getting up to luke warm so no frozen water. Not likely any water in so clear a fluid either. Im thinking something is sticking because of the cold. Ill keep using it for the snowthrowing -no choice really- and just baby the travel/push mode. Every thing else works perfect and its running strong.
When/if the time comes Ill have no problem making the measurements. I just need to know where and what I should see under what conditions.
Does anybody know if the suction screen is just a prefilter in the same line as the hydro filter canister. If so its just a restrictive bird catcher with no more birds to catch at this point. Removing it would ease the suction and the finepore high filter area in the canister would keep the oil just as clean. I removed the one in the Mahindra at suggestion of the tech rep. He said they only serve during break in then just get in the way.
Thanks for all the helpful stuff everybody.
larry

 

[SPYDERLK]

Thanks Randall! Ill check those out tomorrow.
larry