Anyone done it?

I'm figuring nobody has done it.

However, for the clutch and master/slave cylinder manufacturers on here, any reason the Kubota Super UDT hydraulic fluid should NOT be used in the clutch system?

Why? Because it's a good hydraulic fluid and I have like three gallons of it left over from my last tractor hydraulic fluid change.

Thanks.

 

i would save the hydraulic fluid for your tractor or some other application that it would be suited for. the viscosity of that kubota super udt comes up as 9 cSt @ 100°C and 45 cSt @ 40°C which is typical for a hydraulic fluid.

DOT3 Brake fluid, which is not mineral based, has a viscosity around 2 cSt at 100°C and would be much lower than any hydraulic fluid and more constant at all temperatures. While it's a simple hydraulic system, I would be worried about clutch pedal effort especially in cold weather. And if you have the oem clutch line with the restrictor in it then I would not be surprised if you have clutch engagement problems and pedal sticking to the floor the colder the hydraulic fluid is.
Also don't know what seal material the slave cylinder uses, it is made to be compatible with brake fluid which is glycol ether. stuff made for that is usually not compatible with mineral oils, which is why they say don't use any mineral oil type greases on brake calipers or near seals operating with brake fluid. so in addition to the poor clutch performance you may find after not too long that the slave seals let go and you have no clutch disengagement.

 

The master cylinder is a 3/4" bore Wilwood and the line is a -4 braided. It's in a Mustang conversion, the only "stock" part is the slave cylinder.

I had thought through alot of the specification differences between the Super UDT and brake fluids already, I was just thinking maybe I could save a couple bucks and use the leftover stuff I've got.

I won't need to do another fluid change in the tractors for several more years now, and I've got about 3 gallons of the Super UDT just sitting, and I'm not sure it will last another three years in the bucket it's in now that the five gallon bucket has been opened.

At $30/gallon this would be about the most expensive clutch fluid ever.

I'll probably just use brake fluid.

 

This is not a tractor. Dot 3 or 4 Brake fluid. Dont know if it would cause problems or not but brake fluid is pretty darn cheap. IMO i wouldnt risk any problems over a couple of bucks of brake fluid.