leonz
Super Member
Very true,
I would venture that his gear pump has a very large leak through the bronze thrust plates as well.
hyraulics question
- Thread starter MattJ
- Start date
- Views: 13730
Very true,
I would venture that his gear pump has a very large leak through the bronze thrust plates as well.
Tore down the pump, it looks like the day it was made. The whole rest of the HST does too. I am going to talk to the dealer this week and see if we can talk to Kubota about it and get their response.
It just doesn't seem right that this wear should have happened so early on. It also wasn't like I drove it a long time from when the chattering first occurred. It started happening less than an hour back on the engine clock. As soon as I noticed chattering under load I garaged it and only have run it when I was testing the pressure readings and replacing parts.
It just doesn't seem right that this wear should have happened so early on. It also wasn't like I drove it a long time from when the chattering first occurred. It started happening less than an hour back on the engine clock. As soon as I noticed chattering under load I garaged it and only have run it when I was testing the pressure readings and replacing parts.
jerkyboy
Silver Member
Matt, great post with excellent info. I too have a HST problem with my 460 hour BX1500. The tranny chatters under load and "disconnects." It is much worse in reverse than forward. I first noticed it a couple weeks ago when I was moving six yards of crusher run with my FEL. Can you suggest where I should buy a gauge setup to read my hydraulic pressure, how easy it is to get at the priority valve, and is the tear down to remove the HST pretty straight forward? I was thinking my tranny was shot and got a quote from bigorangeparts for $515 to my door.
leonz
Super Member
Matt-
if you have the pump back together do one thing fo rme to satisfy my curiousity if you dont mind;
put the pump on its side in a vice with the inlet side up and take a cup of the UDT or whatever you are using and pour it in the inlet side of the pump which is the larger port then:
wait for the oil to drip through. If there is more than a pencil lead thickness
of oil exiting the pressure side of the pump the pump is shot.
This is the quickest way to detemine if a gear pump is bad if you cannot flow rate it at a hydraulic repair shop.
if you have the pump back together do one thing fo rme to satisfy my curiousity if you dont mind;
put the pump on its side in a vice with the inlet side up and take a cup of the UDT or whatever you are using and pour it in the inlet side of the pump which is the larger port then:
wait for the oil to drip through. If there is more than a pencil lead thickness
of oil exiting the pressure side of the pump the pump is shot.
This is the quickest way to detemine if a gear pump is bad if you cannot flow rate it at a hydraulic repair shop.
The testing of pressures is pretty easy. I don't have the work shop manual for your tractor, but for mine here's what I did.
To test max pressure coming out of the initial charge pump I got a 5000 psi gauge and a quick connect both from agrisupply that could snap onto one of my loader ports. With the tractor running actuate the loader controls in that direction and hold it briefly until you hear the relief valve kick in and note the reading.
For charge pressure the port on mine was near the transmission oil filter. When looking at the base of the filter there were two ports next to it and the one to the left was for charge pressure (please check your tractors parts diagram which you can get on messicks website to make sure). On mine it was a M14x1.5 fitting and the pressure range was something like 40-75 psi in the manual. To test it I went to autozone and got a cheap oil pressure gauge kit (around $25) and it came with the gauge, lines and metric adapters. I then got the port fitting for the M14 from northern tool. Drop the port, add this setup, and run the tractor at full throttle and I also drove it under load to see if it could hold charge pressure (mine dropped like a rock initially).
For the pressure generated by the HST pump I needed a 3/4 hydraulic fitting, hose and I just hooked up the pressure gauge I used on the loader port with some adapters from northern tool. The ports are under the tractor, on the direct bottom of the HST. On mine you'll see three in a row, the outer two are for the front and reverse testing ports, and the middle is the charge relief valve assembly. You hook up the tester, run at full throttle with the brake on or against a tree, and apply the HST forward or back and look to see when the relief vavle kicks in. Mine should be 1900 psi, but the HST couldn't build past 1100.
So for testing I was in between the WSM and parts about $160 or so. The dealer can probably test for this or less but I like to learn and understand.
As for the tractor tear down. The workshop manual and printed parts explosions were a must for me, perhaps not for others but at a minimum it lists torque specs. It took me about 4hrs or so before I had the HST out, since you need to take everything off the back of the tractor down to the frame. Tools required are metric wrenchs and sockets from around 8mm to 24mm, a retaining clip wrench for the drive shaft removal, a breaker bar for the sockets, a metric hex set including 5, 6, and 7mm, and a torque wrench for when you put it all back together. You'll also need a place you can make a mess, and a lot of shop rags!
So I'll let you make the call. There's no doubt its a lot of work. I'ld also recommend you have a good place to layout all the parts you have to tear off this as you get to the HST.
- Matt
To test max pressure coming out of the initial charge pump I got a 5000 psi gauge and a quick connect both from agrisupply that could snap onto one of my loader ports. With the tractor running actuate the loader controls in that direction and hold it briefly until you hear the relief valve kick in and note the reading.
For charge pressure the port on mine was near the transmission oil filter. When looking at the base of the filter there were two ports next to it and the one to the left was for charge pressure (please check your tractors parts diagram which you can get on messicks website to make sure). On mine it was a M14x1.5 fitting and the pressure range was something like 40-75 psi in the manual. To test it I went to autozone and got a cheap oil pressure gauge kit (around $25) and it came with the gauge, lines and metric adapters. I then got the port fitting for the M14 from northern tool. Drop the port, add this setup, and run the tractor at full throttle and I also drove it under load to see if it could hold charge pressure (mine dropped like a rock initially).
For the pressure generated by the HST pump I needed a 3/4 hydraulic fitting, hose and I just hooked up the pressure gauge I used on the loader port with some adapters from northern tool. The ports are under the tractor, on the direct bottom of the HST. On mine you'll see three in a row, the outer two are for the front and reverse testing ports, and the middle is the charge relief valve assembly. You hook up the tester, run at full throttle with the brake on or against a tree, and apply the HST forward or back and look to see when the relief vavle kicks in. Mine should be 1900 psi, but the HST couldn't build past 1100.
So for testing I was in between the WSM and parts about $160 or so. The dealer can probably test for this or less but I like to learn and understand.
As for the tractor tear down. The workshop manual and printed parts explosions were a must for me, perhaps not for others but at a minimum it lists torque specs. It took me about 4hrs or so before I had the HST out, since you need to take everything off the back of the tractor down to the frame. Tools required are metric wrenchs and sockets from around 8mm to 24mm, a retaining clip wrench for the drive shaft removal, a breaker bar for the sockets, a metric hex set including 5, 6, and 7mm, and a torque wrench for when you put it all back together. You'll also need a place you can make a mess, and a lot of shop rags!
So I'll let you make the call. There's no doubt its a lot of work. I'ld also recommend you have a good place to layout all the parts you have to tear off this as you get to the HST.
- Matt
EE_Bota
Veteran Member
My best guess about the failure is the charge pressure issue, followed by the fan issue. The charge tops up the unit, and accounts for it's ability to lubricate moving parts, and swap some fluid, which should have the effect of swapping some heat to the broader gearbox and making sure new fluid comes in with adequate lubricity.
It is possible that this was compromised causing increased heat and air entrainment, with "dieseling" of air bubbles resulting.
Some of this may be helpful to some. I wrote what I wrote above without consulting the links below, so in case of discrepency, go with the links, not me.
Air Contamination of Hydraulic Fluid
Hydrostatic Transmission,Hydrostatic Transmissions
Hydrostatic Transmission, Hydrostatic Transmissions
It is possible that this was compromised causing increased heat and air entrainment, with "dieseling" of air bubbles resulting.
Some of this may be helpful to some. I wrote what I wrote above without consulting the links below, so in case of discrepency, go with the links, not me.
Air Contamination of Hydraulic Fluid
Hydrostatic Transmission,Hydrostatic Transmissions
Hydrostatic Transmission, Hydrostatic Transmissions
Sorry, about the question for replacing the flow priority valve. Its a really easy piece to get to. On mine remove the left rear tire, and the valve is sitting right there and can be removed easily. Looking at the parts diagram would be easier than me explaining it. Its part of the whole unit that controls the flow of hydraulic fluid to the FEL, 3-pt, and power steering.
jerkyboy
Silver Member
Thanks Matt, I appreciate the update. I'm going to see if the dealer I bought it from will take a look and maybe do something for me, as I've only put a little over 40 hours on it since I took it home. If not, looks like I'll have a nice fall project
.
jerkyboy
Silver Member
Where did you order the pump and fan from and how much? OBTW, the dealer I bought the tractor from isn't willing to cut me a break on the fix so it looks like I'm going to have to dig in.
oldnslo
Super Member
I can't tell from the pictures but are the ends of the pistons pitted or sand blasted looking? If yes this would be from cavitation which would point towards low or no charge pressure. Problem is some those little pieces of metal missing also went through the motor. Look very carefully at the port plate for any signs of scoring. Also check it for flatness. Check very carefully for any scoring between the kidney shaped ports on the rotating block also.
Roy
Roy
