HI temp Mil-H-83232 hydraulic fluid

[rocketbob]

https://www.skygeek.com/royco-782-sy...lic-fluid.html

flash 204C

https://lubricants.mobil.com/en/indu...-synthetic-atf

flash 220C

Its better stuff. And your wife can pick up a quart bottle for you if she's out shopping.

[pazmanyflyer]

Originally Posted by rocketbob

https://www.skygeek.com/royco-782-sy...lic-fluid.html

flash 204C

https://lubricants.mobil.com/en/indu...-synthetic-atf

flash 220C

Its better stuff. And your wife can pick up a quart bottle for you if she's out shopping.

Where do you see the 204C for 782? The operating temp range is from -40°C to 205°C. The safety data sheet (dated 2015 from link on website) says flash point of 232C. Then there is this reference https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=2ahUK EwiHnIzIlPfmAhVWrZ4KHS2oDWUQFjABegQIBBAC&url=http% 3A%2F%2Fadd.lanxess.com%2Ffileadmin%2Fproduct-import%2FROYCO%2520782.pdf&usg=AOvVaw3FymGlQlEbuDo Gi2766Kjsthat says the flash point is 218C. Man is there no consistency for this product? I'll be doing my brakes soon and am following this thread with interest.

[FORANE]

Regardless of the exact numbers, the spread between the two seems insignificant. I like the availability of the Mobil one. I like the known compatibility of the royco better.

[scsmith]

Originally Posted by FORANE

Regardless of the exact numbers, the spread between the two seems insignificant. I like the availability of the Mobil one. I like the known compatibility of the royco better.

Yes, a key thing for me is the compatibility with 5606. If you are out "on the road" - meaning at an airport somewhere, it is pretty certain that they will have 5606 on the field.

Also, for brake systems already in service, being able to just drain the existing fluid out and fill back up with the new is great. If you are putting your system together new for the first time and it has never had any fluid in it, then it sounds like the synthetic ATF would be a good choice too. The flash points are close enough not to matter. The key is that they are double the flash point of 5606.

And although all these options are compatible with buna-N (Nitrile) O-rings, it doesn't help the caliper much to have the O-ring fail at 250F, so you should put Viton O-rings in the calipers. It is nice not to have to overhaul the master cylinders though.

[RVDan]

Per Mil-H-83282, the minimum flash point temp is 205c and the minimum fire temp is 245c. The fluid is also self extinguishing when the heat source is removed. Per the spec, it is compatible with the same seal materials as 5606.

Mil-H-83282 was developed as a direct replacement for 5606 without purging the system of the 5606, and the characteristics of the mixed fluids are a compromise between the 2 depending on the mix ratio. So mixing a little of the Mil-H-83282 with 5606 gains very little, whereas, having a little 5606 left in the system mixing with the Mil-H-83282 has little detrimental effect.

Since the temps are minimums, various manufacturers can make qualifying fluids with higher temps.

I studied these fluids As part of an engineering study when the Army was transitioning their helicopters.

[chaskuss]

Originally Posted by pazmanyflyer

Where do you see the 204C for 782? The operating temp range is from -40?C to 205?C. The safety data sheet (dated 2015 from link on website) says flash point of 232C. Then there is this reference https://www.google.com/url?sa=t&rct=...EbuDoGi2766Kjsthat says the flash point is 218C. Man is there no consistency for this product? I'll be doing my brakes soon and am following this thread with interest.

Carlos,
I'd say that the 218 C flash point for the Royco 782 is correct. The Sky Geek site lists the flash point as 218 C. The PDS linked to that site [which claims the higher flash point] is version 1, dated 2015. The PDS link you provided is dated 2016, so is more up to date info.

Bob,
The Mobil 1 ATF PDS states that it meets or exceeds the specs for Mercon V.

The Flash point for Dexron VI is only 205 C, per

https://www.acdelco.com.au/pdf/speci...s_dexronVI.pdf

so the Mercon V & Mobil 1 is better.

I wonder if the high end products like Royal Purple, Amsoil, Redline Racing ATF, etc have higher flash points for their synthetic ATF products?

I just found the flash point info for all of Redline's ATFs. Their D6 fluid has a flash point of 249 C per

https://www.redlineoil.com/content/f...PDS%201-10.pdf

It's priced comparable to the Royco fluid.

Charlie

[RVDan]

While the flashpoints for the listed ATF fluid is slightly higher, they are not self extinguishing like the fluids qualified to Mil-H-83282 are. The self extinguishing part is important in that once the heat source cools (brake disc), the oil stops burning.

[rocketbob]

GUYS!

You're overthinking this.

ATF works perfectly, wont catch on fire, like 5606 does. Have your wife pick you up some.

[fl-mike]

Originally Posted by RVDan

While the flashpoints for the listed ATF fluid is slightly higher, they are not self extinguishing like the fluids qualified to Mil-H-83282 are. The self extinguishing part is important in that once the heat source cools (brake disc), the oil stops burning.

The problem is that it doesn't extinguish the burning tire and wheel fairing.

[Jrskygod]

Bob - when switching to Mobil 1 does the system need to be drained and flushed? If so how is the system flushed?