Brake Fluid

[ahramin]

I've always just used pink automatic transmission fluid in my brake system but it occurred to me the other day that this may not be a good idea. Does anyone know of any reason not to use ATF with Cleveland brakes? Specifically I'm wondering if the o-ring seals are compatible.

[SuperchargedRS]

I'd just use 5606.

also heard you don't want to mix fluids in these things.


I'd imagine ATF might not make the seals very happy, besides why not use the correct fluid for the job eh?

[GyvAir]

I've always just used pink automatic transmission fluid in my brake system but it occurred to me the other day that this may not be a good idea.

Can't help but think that you're baiting here..

[NeverBlue]

...try Vaseline...

[Heliian]

I use fresh blood or fruit punch, pretty much any type of red fluid should do. Some newer systems use purple stuff which I assume to be watered down cough syrup or a dark varietal grape juice.

[robertw]

All aircraft manufacturers will specify what type of brake fluid to use. Most GA aircraft will use Mil-H-5606G. Your maitnenance manual will tell you what to use.

[ahramin]

Thanks everyone. Guess I should have specified that there is no maintenance manual. I'll drain it and fill with 5606.

[GyvAir]

The same situation in a certified aircraft would require replacing all the o-rings, seals or other affected rubber components, flushing the system with the correct fluid and then refilling/bleeding.

[ahramin]

Thanks GyvAir, that's the plan. Just got off the phone ordering the new seals: 7 in stock in the computer ... none on the shelf . Oh well, weather looks better next week anyway.

[GyvAir]

Good to read. Replacing them all now may well save you some hassles down the road.

[ahramin]

Too late . The second round of hassles is what got me thinking down this road.

[crazyaviator]

If its an amateurbuilt or especially if its in owner maintenance, you can use DOT brake fluid, ,,,isnt it the brakes anyways? Just think of the $$$ you will be saving, enough for 1/2 a timmies !!

[ahramin]

I did wonder why so many homebuilders use ATF instead of 5606 because it can't be the price. Per liter ATF is $8-9, Aeroshell 41 is $11. The only thing I can come up with is that back in the day the proper stuff was hard to get so everyone got used to using whatever they could find at Canadian Tire that would do the job.

[Heliian]

Since it's a homebuilt I guess it's not too big of a problem but... If you are using an off the shelf brake system, they would at least give you a specification for what kind of fluid went best at the time. You will most likely find it's 5606. Royco756 is the cheapest one that I know of.

[CID]

Note to self: Never ever fly (or taxi) in ahramin's airplane.

[shaune]

Maybe the ATF is easier to obtain than 5606 or Royco, shouldn't be though as most airports will have the stuff. I was at a field in the U.S. (west Yellowstone) though that had only fuel, nothing else (we needed nitrogen).

[sportingrifle]

ATF and 5606 are very similar and have been substituted for years by operators that were too dis-organisd to keep from running out of 5606. ATF has much more detergent in it but the base oil is the same and hey, it is the same color! Not legal but I never heard of any issues. As was pointed out, there is no reason to do this other than availability as ATF costs about the same as 5606.

Automotive brake fluid in an aircraft brake system will destroy the seals - fast. Very non compatible.

Given the internet and economical shipping available today, I just don't know why every operator or owner doesn't have a quart of 5606, a grease gun full of Aeroshell 5, and a roll of lockwire on the shelf.

sportingrifle

[ahramin]

Thanks sportingrifle. Took the brakes apart and the problem is definitely not the fluid as the housing surface is very corroded, but going to flush it and change the seals anyway while I'm at it.