BX1500 HST Test Results and Disassembly Suggestions

[jerkyboy]

I've been having problems with my tranny; it chatters/disengages under heavy load going forward and reverse is basically useless. It also doesn't stop abruptly, like it used to, when I go from forward/reverse to stop.

I finally got around to testing the charge and high pressure relief valves today, although I only checked the forward high pressure relief valve because I didn't want to take off the filter as I didn't have any fluid handy. Anyhow, my charge pressure was right around 100 psi, which is normal and my forward high pressure relief was around 2,800 but went to zero when the "chattering" started.

Looks like I'm going to have to do some surgery and pull the HST. Anyone have any advice on how to get the HST out on a BX1500 without having to pull half the tractor apart?

 

[MattJ]

Do you know what the spec is on the forward relief pressure? Mine for the bx1830 was around 1990 psi. If it gets up to pressure and pops perhaps its not the HST thats the problem.

As for the disassembly at least on mine there's no way around it. You may be able to take off the floor boards and remove some middle supports but I don't think you'll save a ton of time.

I have taken apart and put together mine 2 times now! The first time took me 5 hrs to take down and about the same to put it back. This last time was 2hrs each way with my neighbor helping. I don't want to try a third.

My main concern with yours is that is does build pressure and then pops. I wonder if it could be in the actual gear portion of the tranny and the HST is fighting to move something it can't. It might be worth while to get the dealer to take a check over it.

I did mine solo, but it was a real pain and I think my stubborness didn't pay off in the long run, even though I now know a lot more about tractors. For what its worth I have mine over at the dealer now. I have it all back together but it wasn't gaining charge pressure and I want them to look over what I did so I don't burn up a new tranny. Everything else hydraulic was A-OK, but after a few minutes of not gaining pressure I got gun shy about the tranny and decided to have them make sure its good to go.

- Matt

 

[jerkyboy]

Do you know what the spec is on the forward relief pressure? Mine for the bx1830 was around 1990 psi. If it gets up to pressure and pops perhaps its not the HST thats the problem.

As for the disassembly at least on mine there's no way around it. You may be able to take off the floor boards and remove some middle supports but I don't think you'll save a ton of time.

I have taken apart and put together mine 2 times now! The first time took me 5 hrs to take down and about the same to put it back. This last time was 2hrs each way with my neighbor helping. I don't want to try a third.

My main concern with yours is that is does build pressure and then pops. I wonder if it could be in the actual gear portion of the tranny and the HST is fighting to move something it can't. It might be worth while to get the dealer to take a check over it.

OBTW, I'm thinking that maybe I can change out the f/r high pressure relief valves without removing the hst. Probably wishful thinking though.

I did mine solo, but it was a real pain and I think my stubborness didn't pay off in the long run, even though I now know a lot more about tractors. For what its worth I have mine over at the dealer now. I have it all back together but it wasn't gaining charge pressure and I want them to look over what I did so I don't burn up a new tranny. Everything else hydraulic was A-OK, but after a few minutes of not gaining pressure I got gun shy about the tranny and decided to have them make sure its good to go.

- Matt

My charge pressure is per spec in my wsm, which is just over 2800. As I said before, I did not test the reverse pressure relief valve, only the forward but the reverse pretty much pops out with the slightest bit of rear pedal pressure. I am like you and like to know exactly what's going on and enjoy troubleshooting and fixing problems myself. I'm almost wondering if the pressure relief valves themselves are shot....maybe they can only hold the pressure under light loads and then give??? I'm going to run it by the closest Kubota shop and see what they say. I'll report back on the results.

 

[Brad d]

My BX1500 works strong untill it heats up, just cutting the grass in low range 2WD after about 30min the tractor just wants to give up, any load like going up a hill or turning too tight and the HST just whines and the tractor does not move...

have about 300h on it and i have changed the fluid and filters with kubota oils and filters. what would cause it to get weak when it warms up?

Thanks

 

[V1Rotate]

My BX1500 works strong untill it heats up, just cutting the grass in low range 2WD after about 30min the tractor just wants to give up, any load like going up a hill or turning too tight and the HST just whines and the tractor does not move...

have about 300h on it and i have changed the fluid and filters with kubota oils and filters. what would cause it to get weak when it warms up?

Thanks

Have you checked to see if the HST fan has been damaged?

 

[Brad d]

Have you checked to see if the HST fan has been damaged?

good point... i will take a look

 

[Brad d]

Nope fan looks 100% its clean no blades are gone and it spins when the motor is running.

It can cut grass for 45min or more and it does not act up.. but after that much time if you have to go up a slight hill it wants to give up.

 

[keyman1808]

Does the engine bog down?? or just the HST gives up

 

[Brad d]

Does the engine bog down?? or just the HST gives up

hst just gives up, the motor will bog down from the PTO's or if the bucket is too loaded, but never from the HST and its worse when its been running for 40min or so.. and if its warm it will have a hard time moving in high gear with no attachments just the belly mower.

 

[keyman1808]

This may sound stupid but are your tires loaded??