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fire proof brake fluid

Seal Compatibility

Mobil 1 ATF says it is compatible with mineral ATF fluids and all common seal materials. It also says it is of the same "quality level" as GM Dexron (although it doesn't say it is approved by GM).

Parker's O-ring handbook 5700 says Dexron is compatible with both Nitrile (probably the most common o-ring material if the material is not otherwise specified) and Fluorocarbon (Viton).

Although Mobil 1 ATF is not specifically listed in handbook 5700, it seems like it should be compatible with Nitrile and Fluorocarbon.

And by the way, there is no such thing as "fire proof brake fluid". Most petroleum and synthetic fluids will burn if you get them hot enough.

The flash point of Mobil 1 ATF is listed as 220 deg C.

The flash point of MIL-PRF-83282 (Royco 782 earlier in this thread) is 345 deg C. This is specifically made as a hydraulic (brake) fluid and is compatible with MIL-H-5606 and older spec.
 
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Mobil 1 ATF says it is compatible with mineral ATF fluids and all common seal materials. It also says it is of the same "quality level" as GM Dexron (although it doesn't say it is approved by GM).

Parker's O-ring handbook 5700 says Dexron is compatible with both Nitrile (probably the most common o-ring material if the material is not otherwise specified) and Fluorocarbon (Viton).

Although Mobil 1 ATF is not specifically listed in handbook 5700, it seems like it should be compatible with Nitrile and Fluorocarbon.

And by the way, there is no such thing as "fire proof brake fluid". Most petroleum and synthetic fluids will burn if you get them hot enough.

The flash point of Mobil 1 ATF is listed as 220 deg C.

The flash point of MIL-PRF-83282 (Royco 782 earlier in this thread) is 345 deg C. This is specifically made as a hydraulic (brake) fluid and is compatible with MIL-H-5606 and older spec.

Good info Thanks!

Comparing Mil-H-5606: Mineral base, flammable, fairly low flashpoint, usable from −65 °F (−54 °C) to 275 °F (135 °C), red color

Regards
Rudi
 
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Still have some left for those that want EPDM stat-o-seals.

If anyone else is using or planning to use EPDM seals in their brake system for DOT-3,4, or 5.1 fluid, be aware that the master cylinders contain not just the three o-rings, but also a stat-o-seal. It's basically a washer with rubber molded around the inside diameter. The stat-o-seal as supplied from Matco is Buna-N (Nitrile). The part number of an EPDM stat-o-seal is NAS1523-3P. I had a heck of a time finding these, but finally found some.

20101122-10-tn.jpg


20101122-11-tn.jpg


I had to meet a minimum order, so I have a few left. If anyone wants some, they're $4.50 each while my supply lasts.

Take care,
 
hyd fluid flash point data

Mil 5606 82-90C/180-194F
Mobil 1 ATF 220C/428F
Mil 83282 345C/650F

Geez - better get that 5606 outta there!

Carry on!
Mark
 
So is the general consensus that Mobil 1 ATF can be used with the stock brake setup without needing to change o-rings?
I'll be using Bonoco teflon flexible lines
 
Maybe...

So is the general consensus that Mobil 1 ATF can be used with the stock brake setup without needing to change o-rings?
I'll be using Bonoco teflon flexible lines

I would say you'll be OK on a new installation. Ships with more than just a few hours would likely benefit from new seals. We changed one plane over, and every seal started to leak; new seals fixed 'er up.

You might think about higher temp seals in your calipers, where the heat is concentrated.

Carry on!
Mark
 
Just a thought, but the military has already done the grunt work: the answer is 83282 which is backwards compatible with 5606. The tech order solution for replacing 5606 is a double flush of 83282. Even if you don't change the seals, you raise the flashpoint in the event of a leak. Change the seals to Viton and you get the added benefit of better seal performance (although Viton A has issues at very cold temperatures).

Cheers,

Vac
 
I would say you'll be OK on a new installation. Ships with more than just a few hours would likely benefit from new seals. We changed one plane over, and every seal started to leak; new seals fixed 'er up.

You might think about higher temp seals in your calipers, where the heat is concentrated.

Carry on!
Mark

You changed all the seals in the brakes or just the O-rings?

We are in the middle of a brake job and are considering changing 5606 to Mobil 1 Synthetic.
 
Auto Ignition Point is not the same as flash point.

Mobil 1 ATF says it is compatible with mineral ATF fluids and all common seal materials. It also says it is of the same "quality level" as GM Dexron (although it doesn't say it is approved by GM).

Parker's O-ring handbook 5700 says Dexron is compatible with both Nitrile (probably the most common o-ring material if the material is not otherwise specified) and Fluorocarbon (Viton).

Although Mobil 1 ATF is not specifically listed in handbook 5700, it seems like it should be compatible with Nitrile and Fluorocarbon.

And by the way, there is no such thing as "fire proof brake fluid". Most petroleum and synthetic fluids will burn if you get them hot enough.

The flash point of Mobil 1 ATF is listed as 220 deg C.

The flash point of MIL-PRF-83282 (Royco 782 earlier in this thread) is 345 deg C. This is specifically made as a hydraulic (brake) fluid and is compatible with MIL-H-5606 and older spec.

Terry,
You are correct about nothing being completely fire proof.

I just checked both the PDS [Product Data Sheet] and the MSDS for Royco 782. The PDS see link below lists the flash point as 445 degree Fahrenheit, which is 230 degrees Celsius. See

http://74.6.238.252/search/srpcache...6&icp=1&.intl=us&sig=pbLp6vqc6TM3SWEvNFdwwA--

The MSDS lists it's flash point as 232 Celsius [449 Fahrenheit]. Both of these are more in line with what Dan H stated earlier in this thread. It's also only a few degrees from the 220 Celsius flash point you mentioned above for Mobil 1 ATF. MSDS for Royco 782 below

http://lib.store.yahoo.net/lib/stylespilotshop/Royco782-MSDS.pdf

Shell 231 seems to perform slightly below the Royco 782. Shell does not provide a direct link. You must go to:

http://www.shell.com/home/content/aviation/

Click on the blue link marked Material Data Safety Sheets found in the middle of the page. From there you can do a search OPTION 1 [by product] for Aeroshell Fluid 31 to obtain both the TDS [Technical Data Sheet] or the MSDS.

According to the AeroShell Fluid 31 MSDS, it's auto ignition point is > 320 Celsius [> 608 F] Ah, now I see where you got that figure. Auto Ignition is not the same as the flash point. It appears that the Mil Spec 83282 products are closer in performance to the Mobil 1 synthetic ATF.

I just searched for both the PDS and MSDS for Mobil 1 ATF. For some reason the PDS link did not work. The MSDS states that the flash point for Mobil 1 ATF is > 177 Celsius. Can anyone find a PDS link that works?

Mobil 1 ATF, Chrysler's ATF 4+, Ford's Mercon V and GM's Dexron VI are all synthetic fluids. It appears that GM's new Dexron VI has higher performance characteristics than the fluids from Chrysler and Ford. The MSDS for Citco's Dexron VI shows a flash point of 403 F and 206 C. See

http://www.docs.citgo.com/msds_pi/10165.pdf

OK, I found the 220 Celcius flash point for Mobil 1 ATF at

http://www.mobil.com/USA-English/Lubes/PDS/GLXXENPVLMOMobil_1_Synthetic_ATF.aspx

Please correct me if I've made an error, or if another Mil Spec 83282 product has better performance.

Charlie Kuss
 
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YMMV

You changed all the seals in the brakes or just the O-rings?

We are in the middle of a brake job and are considering changing 5606 to Mobil 1 Synthetic.

We had to change ALL the seals (O-rings) on this particular job. Heck, some of 'em could have been new in 1951! I can't blame the red liquid on this one due to the age of the aircraft, and its readily apparent lack of continuing maintenance since its airframe O/H in 1951. It has worked fine since the upgrade - no leaks anywhere.

Carry on!
Mark
 
We had to change ALL the seals (O-rings) on this particular job. Heck, some of 'em could have been new in 1951! I can't blame the red liquid on this one due to the age of the aircraft, and its readily apparent lack of continuing maintenance since its airframe O/H in 1951. It has worked fine since the upgrade - no leaks anywhere.

Carry on!
Mark

Oh well, you scared me out of Mobil 1.. :) I didn't wanna change the seals, so I went with Royco 782.. :)
 
Just an FYI on where to get Royco 782. Van's has this on "the list" with a cost of $11. per quart.
 
Don't mix the two .....

Old thread but ... Seems to me that the easy quick cheap high value upgrade is the Vitron O'Rings in the Caliper (cause it won't burn if it doesn't get out :) and go with the higher temp 83282 or Royco 782 fluid. This is a two hour job tops. The 782 which is 83282 spec is compatible with the normal 5606 ?? (not sure about the number) and available at any airport BUT

if you want to go with the automotive versions, I think(I'm sure) you need to upgrade all seals in the system to the EPM material which you can buy in kits from Charlie for about $8 if I remember correctly.... all o'rings are not created equal....

HOWEVER ..... a short story.....I thought I might change the system out to automotive fluids so I put the EPM o'rings in the caliper thinking that would be good even with the Royco 782 fluid and would change out the others later and make the fluid swich at annual. Within 10-12 hours, the 83282 fluid ATE up the EPM O'rings causing a large leak (no fire). Both started leaking on the same flight !

img_2012_11_30_191158_01-790461.jpg


Orings simply came apart. Brake fluid everywhere on rotors but airplane stopped fine and no fire with higher flashpoint fluid ..... I don't ride brakes but it is an A model.

img_2012_11_30_191157_01-61662364.jpg



So the moral of the story is do NOT mix systems and for my money, the best solution is to change the O'rings $2 to Vitron on the Caliper, change the fluid to 83282 which has a 450+ plus flashpoint and is compatible with what you have in the system, no pain and significant gain. Just be sure you know what kind of seals you are using with which fluids. All O'rings are not created equal !!

Did the quick fix 135 hours ago with no issues.

Bill S
 
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Another advantage of dot 5.1 fluid I discovered is the much lower viscosity especially when cold. This appeals from a feel perspective for example, after a rapid descent from some kind of emergency.

https://d23zpyj32c5wn3.cloudfront.n...4/DOT_5.1_Brake_Fluid__28GB_29.pdf?1492016150

Dot 5.1
-40 820
100 2.1

Aeroshell 31
-40 2100
100 3.7

I have the Grove master cylinders so I just need these 4 O-rings in EPDM and no tricky stat-o-seal like the Matcos MCs, is that right?


MS28775-008 W1/16 ID3/16 OD5/16
MS28775-012 W1/16 ID3/8 OD1/2
MS28775-111 W3/32 ID7/16 OD5/8
MS28775-112 W3/32 ID1/2 OD11/16

Does anyone want to hazard a guess as to what the Matco caliper seal size is for a 4?
 
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Here is a bit of a run down on data for the various fluid types.

The Motul dot 5.1 is designed for ABS street systems hence the low cold temp viscosity. It also has the highest wet boiling point of the low viscosity fluids. That is what I have gone for.

The lower the viscosity the better the 'feel' in my experience.


Mineral based hydraulic oil will ignite at ~230 °C
Nitrile or Viton Seals 70 duometer

Code:
AeroShell 41 5606H
Flash point 104 °C / 219 °F
Viscosity at -40°C (-40°F) 384 mm²/s
Viscosity at 100°C (212°F) 6.13 mm²/s

Synthetic hydrocarbon based hydraulic oil will ignite at ~251 °C 31 or 185 °C 51
Nitrile or Viton Seals 70 duometer

Code:
AeroShell 31 83282D
Flash point 237 °C / 459 °F
Viscosity at -40°C (-40°F) 2098 mm²/s
Viscosity at 100°C (212°F) 3.53 mm²/s

AeroShell 51 87257B (Beringer seem to favor Dot 4 but if you have to use oil they recommend this)
Flash point 175 °C / 347 °F
Viscosity at -40°C (-40°F) 440 mm²/s
Viscosity at 100°C (212°F) 2.12 mm²/s



Polyalkylene glycols based brake fluids.
Non volatile but will spontaneously ignite if splashed on 390 - 400 °C surfaces but usually evaporates first.
EPDM seals

Code:
Motul RBF 700
Dry boiling point 336 °C / 637 °F
Wet boiling point 205 °C / 401 °F
Viscosity at -40 °C (-40 °F) 1580 mm²/s
Viscosity at 100 °C (212 °F) 2.06 mm²/s

Motul Dot 5.1
Dry boiling point 269 °C / 516 °F
Wet boiling point 187 °C / 369 °F
Viscosity at -40°C (-40°F) 820 mm²/s
Viscosity at 100°C (212°F) 2.1 mm²/s

ATE Dot 4 Type 200
Dry boiling point 280 °C / 536 °F
Wet boiling point 198 °C / 388 °F
Viscosity at -40°C (-40°F) 1400 mm²/s
Viscosity at 100°C (212°F) 2.2 to 2.8 mm²/s

Castrol Dot 4
Dry boiling point 260 °C / 500 °F
Wet boiling point 165 °C / 329 °F
Viscosity at -40°C (-40°F) 1200 mm²/s
Viscosity at 100°C (212°F) ~2.5 mm²/s


Silicon based brake fluid.
Can cavitate with rapid application, bubbles take a long time to dissipate
Water not absorbed can sink to bottom of system causing corrosion
Higher moderate temperature viscosity reducing feel
Any seals

Code:
Maxima Dot 5
Dry boiling point 300 °C / 572 °F
Wet boiling point 220 °C / 428 °F
Viscosity at -40°C (-40°F) 150 mm²/s
Viscosity at 100°C (212°F) not published
 
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