vornez2
New member
- Joined
- Feb 28, 2023
- Messages
- 2
- Tractor
- Kubota L4400
These would have costed about 23 cents to manufacturer and are being used to safeguard your expensive HST transmission.
I am changing over to the aluminum ones, they are in the mail and I still need to ensure they fit, the thread fitting size is 1/2 inch I do believe:
On my L4400, you see the sight glass with the bubble and think the oil level is correct, it isn't.
Using the oil dipstick from a car, sticking it directly down the hole where the hydraulic fluid is poured in, you can read the oil level.
Here I was using plastic 4mm horse wire nylon because the oil level was easier to see.
The HST is way overfull, 10cm above the normal level, 10 litres excess, not good.
The Kubota sight glasses are made of weak plastic.
Mine had already rattled loose from the vibrations of the motor, I could unscrew it by hand.
But also, it had a very small leak, it would either leak fluid outwards, or suck air in.
The photo isn't showing the oil level, it's a pocket of trapped air.
The inside of this threaded hole that holds the sight glass has areas that cause air to get trapped and show up inside the sight glass.
Do not use these crappy plastic sight glasses, unscrew them and quickly change to a metal version of them, they are a very generic part.
After tightening the sight glass, it rattled lose after 20 minutes of driving so I tried to tighten mine, and with only a small force on the socket handle, it snapped, and the white piece tried to fall into the hole, but I carefully pulled it out with micropliers. What a nightmare.
When the proper metal sight glasses arrive, I will probably glue them in there with a small amount of gasket sealant, to stop them ratting loose.
After doing all this, I drained all the fluid and carefully topped it up again in 10 litre increments.
Although my hydrostatic has a transmission oil capacity of 45.0 L (11.9 US. gal, 9.9 Imp. gal.) it reached the correct level after about 30 litres being put back.
I'm guessing this would account for the remaining 15 litres that is caught up in other areas of the tractor, I think.
So there was about 55 litres in the transmission, which wasn't good for it, it would make struggling noises in medium range, even though it wasn't loaded up.
Now the transmission is running much smoother.
Days later the superficial leak on the sight glass is leaking a fair amount of fluid, so I plugged it with a plumbing cap. Threaded tape, though silicone is safer.
So don't get fooled, use a car dipstick to double check the level, If you have problems identifying the oil line on the dipstick, completely color the dipstick with a blue or black magic marker, it makes it easier to see.
You might not want to stick things down that hole though, they could get stuck, though it's less likely.
A alternative way is to park on a 15 degree slope with the rear of tractor at the higher level and top up the HST while the sight glass is removed. When fluid
starts overflowing out of this hole, it means its reached it's correct level.
But get rid of these crappy plastic sight glasses. Mine rattled lose after 20 minutes of driving and when I tightened it slightly more, it snapped.
I'm guessing these issues are present with other models of Kubota tractor as well.
I am changing over to the aluminum ones, they are in the mail and I still need to ensure they fit, the thread fitting size is 1/2 inch I do believe:
On my L4400, you see the sight glass with the bubble and think the oil level is correct, it isn't.
Using the oil dipstick from a car, sticking it directly down the hole where the hydraulic fluid is poured in, you can read the oil level.
Here I was using plastic 4mm horse wire nylon because the oil level was easier to see.
The HST is way overfull, 10cm above the normal level, 10 litres excess, not good.
The Kubota sight glasses are made of weak plastic.
Mine had already rattled loose from the vibrations of the motor, I could unscrew it by hand.
But also, it had a very small leak, it would either leak fluid outwards, or suck air in.
The photo isn't showing the oil level, it's a pocket of trapped air.
The inside of this threaded hole that holds the sight glass has areas that cause air to get trapped and show up inside the sight glass.
Do not use these crappy plastic sight glasses, unscrew them and quickly change to a metal version of them, they are a very generic part.
After tightening the sight glass, it rattled lose after 20 minutes of driving so I tried to tighten mine, and with only a small force on the socket handle, it snapped, and the white piece tried to fall into the hole, but I carefully pulled it out with micropliers. What a nightmare.
When the proper metal sight glasses arrive, I will probably glue them in there with a small amount of gasket sealant, to stop them ratting loose.
After doing all this, I drained all the fluid and carefully topped it up again in 10 litre increments.
Although my hydrostatic has a transmission oil capacity of 45.0 L (11.9 US. gal, 9.9 Imp. gal.) it reached the correct level after about 30 litres being put back.
I'm guessing this would account for the remaining 15 litres that is caught up in other areas of the tractor, I think.
So there was about 55 litres in the transmission, which wasn't good for it, it would make struggling noises in medium range, even though it wasn't loaded up.
Now the transmission is running much smoother.
Days later the superficial leak on the sight glass is leaking a fair amount of fluid, so I plugged it with a plumbing cap. Threaded tape, though silicone is safer.
Brass 1/2" 3/4" Male/Female Blanking Cap Stop End Lock, Water Gas Pipe Parts | eBay
Thickened material, not easy to crack and deform. -Commonly used to connect various pipes, such as air pipe, fuel pipe, water pipe, etc. -The main body is made of brass, which is not easy to corrode and burst.
www.ebay.com.au
So don't get fooled, use a car dipstick to double check the level, If you have problems identifying the oil line on the dipstick, completely color the dipstick with a blue or black magic marker, it makes it easier to see.
You might not want to stick things down that hole though, they could get stuck, though it's less likely.
A alternative way is to park on a 15 degree slope with the rear of tractor at the higher level and top up the HST while the sight glass is removed. When fluid
starts overflowing out of this hole, it means its reached it's correct level.
But get rid of these crappy plastic sight glasses. Mine rattled lose after 20 minutes of driving and when I tightened it slightly more, it snapped.
I'm guessing these issues are present with other models of Kubota tractor as well.
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