HELP! Did I do something really bad to my B7300?
- Thread starter Climber
- Start date
- Views: 32135
Pks
Platinum Member
- Joined
- Apr 6, 2000
- Messages
- 773
- Location
- Saline, Michigan
- Tractor
- Kubota L3700SU, Cub Cadet 1430, Hustler Super-Z 66in, Vermeer 1250
I'd like to mention a caution for those folks who add compressed air to the tractor cases.
If compressed air is applied to the case while the oil and cases are very warm to hot, they risk an explosion. I cannot provide an analysis of why, only what I was taught through experiences of others. My uncle knew of more than one person who was injured because of using compressed air while changing the oil in the case.
...just something to keep in the back of our collective minds.
If compressed air is applied to the case while the oil and cases are very warm to hot, they risk an explosion. I cannot provide an analysis of why, only what I was taught through experiences of others. My uncle knew of more than one person who was injured because of using compressed air while changing the oil in the case.
...just something to keep in the back of our collective minds.
jrlichina
Platinum Member
In general most case seals can only tolerate pressures in the range of 10-20 psi. anything more than that and you will most likely damage them. This can then turn into a costly repair if you can't do the work yourself. If you do try to pressurize the case keep it aorund 10 psi. Then the obvious warning of high pressure anything(air/fluids) can cause serious damage to the machine or the person near it...
chrisjbell
Platinum Member
- Joined
- Jul 17, 2000
- Messages
- 956
- Tractor
- Kubota B7300; JD LX233
Bit late to the show, but haven't been on in a bit...
<font color="blue"> I fired up the tractor, and kept my foot on the clutch for about 1 minute. </font>
Kubota sent me a sort of a recall notice which was a service update and a sticker that I was supposed to put on my dash, but lost /forums/images/graemlins/wink.gif. Anyway, it said that every time I start my tractor I should keep the clutch pedal depressed for at least 30 seconds.
From what I could gather from the rather vague service notice there is an issue with the hydraulic pump cavitating (not pumping) upon startup, which could lead to all kinds of stuff not working.
Anyway, I always practice counting to 45 or so and do left leg pushes on the clutch when I start my tractor. With no fluid pressure the hydraulics won't work - so I was thinking that maybe you had something like that going on.
<font color="blue"> I fired up the tractor, and kept my foot on the clutch for about 1 minute. </font>
Kubota sent me a sort of a recall notice which was a service update and a sticker that I was supposed to put on my dash, but lost /forums/images/graemlins/wink.gif. Anyway, it said that every time I start my tractor I should keep the clutch pedal depressed for at least 30 seconds.
From what I could gather from the rather vague service notice there is an issue with the hydraulic pump cavitating (not pumping) upon startup, which could lead to all kinds of stuff not working.
Anyway, I always practice counting to 45 or so and do left leg pushes on the clutch when I start my tractor. With no fluid pressure the hydraulics won't work - so I was thinking that maybe you had something like that going on.
jrlichina
Platinum Member
Climber.
Just some extra info so you know why/what you did when trying to bleed your hydraulic systems. First is that your tractor hydraulics is powered by a pump that is driven by your engine(located at the front of the engine). This pump shares the same resivour that the HST unit uses. They tell you to disengage the clutch so you can bleed the tractor system pump first(this powers your 3-point, loader, steering). Then when you engage the clutch it then starts driving the pump on the HST which will then bleed by itself as well(along with cycling the pedal). By doing one first then the other it just helps eliminate problems with excessive air in the fluid. Just thought you'd be interested.
Just some extra info so you know why/what you did when trying to bleed your hydraulic systems. First is that your tractor hydraulics is powered by a pump that is driven by your engine(located at the front of the engine). This pump shares the same resivour that the HST unit uses. They tell you to disengage the clutch so you can bleed the tractor system pump first(this powers your 3-point, loader, steering). Then when you engage the clutch it then starts driving the pump on the HST which will then bleed by itself as well(along with cycling the pedal). By doing one first then the other it just helps eliminate problems with excessive air in the fluid. Just thought you'd be interested.
skent
Platinum Member
a small amount (0.5 gpm) of fluid from the engine driven pump is fed at a constant rate to aid in charging the transmission pump. there is also a charge pump driven from the clutch, but they want all air out of the hydrostatic transmission before things start turning.
jrlichina
Platinum Member
<font color="blue"> a small amount (0.5 gpm) of fluid from the engine driven pump is fed at a constant rate to aid in charging the transmission pump.</font>
This is incorrect. The tractor hydraulics delivery circuit is completely separate from the HST unit but they do share the same resivour. The engine driven pump(tractor hydraulics) is directly connected to the priority/flow divider, the flow divider has one line that feeds the 3-point control. The suction line is connected to the transmission case. The HST unit does have a charge pump located at the front of the HST unit. It is driven by the HST input shaft which is connected to the driveshaft, this part is correct. The charge pump on the HST unit is what provides the necessary fluid for internal losses within the HST unit. The tractor hydraulics pump does not provide this functionality.
It should have been stated:
<font color="purple"> a small amount (0.5 gpm) of fluid from the HST charge pump is fed at a constant rate to the pump/motor circuit within the HST unit to compensate for internal circuit losses.
</font>
I hope this clears things up.
This is incorrect. The tractor hydraulics delivery circuit is completely separate from the HST unit but they do share the same resivour. The engine driven pump(tractor hydraulics) is directly connected to the priority/flow divider, the flow divider has one line that feeds the 3-point control. The suction line is connected to the transmission case. The HST unit does have a charge pump located at the front of the HST unit. It is driven by the HST input shaft which is connected to the driveshaft, this part is correct. The charge pump on the HST unit is what provides the necessary fluid for internal losses within the HST unit. The tractor hydraulics pump does not provide this functionality.
It should have been stated:
<font color="purple"> a small amount (0.5 gpm) of fluid from the HST charge pump is fed at a constant rate to the pump/motor circuit within the HST unit to compensate for internal circuit losses.
</font>
I hope this clears things up.
