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  #21  
Old 03-27-2017, 07:36 PM
Tomcat RV4 Tomcat RV4 is offline
 
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Location: Jacksonville,Fl. 32246
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ATF fluid is used in HIGH pressures in auto trans for years, much harder application,an heat temps as well.I would have used in my RV, but AP is old school and would not let me
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  #22  
Old 03-27-2017, 10:11 PM
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RV7A Flyer RV7A Flyer is offline
 
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Location: US
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Just a point of reference...in typically vague terms, the technician's manual for Parker (Cleveland) brakes says:

Hydraulic Applications - Use fluids compatible with the system
MIL-H-5606 / MIL-H-83282 (Red Oils)
Skydrol Only compatible with itself

So there's probably some "wiggle room" if you read it correctly, in that "fluids compatible with the system" could include something like Mobil 1 Synthetic ATF (provided one does the research to determine that it is, in fact, compatible with the system). Since the system is basically aluminum parts and some sort of o-rings...seems like as long as it's compatible with the type of o-rings installed, you're good to go. No?
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  #23  
Old 03-27-2017, 10:16 PM
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RV7A Flyer RV7A Flyer is offline
 
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Slightly OT...but related (wheels and brakes and their lubricants and such)...

A buddy of mine had a sure-fire way to deal with his SO when he was working on anything mechanical and he was getting too much "help"...

SO (for the umpteenth time): Are you sure there's nothing I can help with?
Him: Oh, yeah, sure...give me a handful of grease, wouldja?

Always worked to clear the shop so he could proceed in peace.
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  #24  
Old 12-02-2017, 08:56 PM
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rjcthree rjcthree is offline
 
Join Date: Jan 2007
Location: Bay Village, OH
Posts: 680
Default Hmmm.

I have Grove calipers and master cylinders. At first condition,I found one leaking caliper, which has been a problem for me. This would be the third time I've rebuilt the calipers. But this isn't about the calipers. I took the opportunity to switch from 5606 to M1 ATF when I rebuit the calipers. A month later....Today, after taxiing in, I smelled and found leaking fluid. LH master was leaking at the rod seal - or that's what I'm assuming. I doubt the static seal gave it up.

Groves were early 2008 manufacture, saw 5606 fluid in 2012, didn't taxi or fly until 2016. Just a data point, really. Five bucks and three hours of painful labor, this too shall pass. Is the fluid change root cause? Dunno, just something to consider.

The upside? 1.2 hours on he Hobbs this morning.
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  #25  
Old 12-02-2017, 09:07 PM
Gisnar Gisnar is offline
 
Join Date: Nov 2012
Location: Northern Nevada
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Suggest you give Rob Grove a call and ask.
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  #26  
Old 12-02-2017, 09:23 PM
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rjcthree rjcthree is offline
 
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Location: Bay Village, OH
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Default Good idea, but

Good idea, but not doing that for two reasons. The first is past experience with Mobil change overs resulting in near term leaks. Engines, transmissions, diffs, clutch master and servos. It happens sometimes. It's possible the shaft is scratched too, I'll know when I get it to the bench. Second is the response I got from Grove (not Rob) back in 2014 during my second rebuild, which was sympathetic, but not helpful beyond basic diagnostics/inspection. It's ok at the moment. If it happens again, I may take your suggestion. I just hope to not get any of the (STINKY) M1 in the carpet.
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  #27  
Old 12-03-2017, 11:09 AM
TS Flightlines TS Flightlines is offline
 
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Location: Ridgeland, SC
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Check with the component manufacturer to see that fluids are compatible with their seals. May be a point where its fine for a while, but then begins to affect the sealing properties of the O'Rings.
Dont go against the manufacturers recommendation because getting the fluid is easier. If in fact there was a catastrophic failure, and you were using an unapproved fluid, the legal outcome might be disasterous.

Tom
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  #28  
Old 12-03-2017, 04:54 PM
F1R F1R is offline
 
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Location: ____
Posts: 525
Default No more leaks

Brake calipers that sit for several years have the o rings set up with a flat spot.
At least the o rings are not as live as they would be if they were new and just installed.

I once purchased an aircraft that had sat for a few years. On a concrete floor it could sit for a week with no leaks. Then I would fly it 1 hour, land and have no brakes. Check the reservoirs and they were empty. So I would re fill them, bleed the brakes nice and solid. Then I would sit and hold my feet on the brakes for 10 minutes. Get out and check ... no leaks and a nice clean floor.

A week later still no leaks so I would fly it for an hour or so and land with no brakes and empty reservoirs again. The slip stream made negative pressure by the calipers in flight, and that would drain the brake fluid before landing.

So I put in new buna N o rings and that solved it. The old O rings had flat OD's and look more like D rings than O rings.

In a different AC I did use Viton O rings with Mobil one and have had zero issues for 7 years now. If I had known about the Royco fluid (that Walt referred to) has the same higher flash point as the Mobil 1 ATF, I would have used the Royco.
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  #29  
Old 12-03-2017, 10:00 PM
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Mark Burns Mark Burns is offline
 
Join Date: Jan 2005
Location: Ruston, Louisiana
Posts: 852
Default I'd do Mobil 1 again without hesitation

Walt's a good friend of mine and he has some excellent points about using "unapproved fluids".

I'm an A&P but I don't have near the aircraft experience Walt has.
I only worked as an A&P for a few years back in the 70's :-)

Data points:

I put Mobil 1 in my brakes back in 2008 due to the good reviews right here on VAF. First flight was October that year.

1450 hours and 9 years with ZERO issues. Never even had to add any fluid.
Now I'm wondering if I should flush some new fluid through the system?:-)

Another silly reason I didn't go with 5606 was I never liked working with it.
The smell and the way it gets sticky when it "dries".

And as far as our experimental planes go I thought you could use coconut oil in your brakes if you wanted to. I just checked, coconut oil doesn't even start to smoke until 350 degrees! LOL.

Mark
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  #30  
Old 12-04-2017, 07:43 AM
Tomcat RV4 Tomcat RV4 is offline
 
Join Date: Nov 2007
Location: Jacksonville,Fl. 32246
Posts: 175
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Just another old wives tale that ATF is lacking something,and as a result certified keep using special fluid.It is slight possibility that very old car ot airplane it might not be compa6ible !
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