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6A Brake Lines

MWH265

Well Known Member
Greased my wheel bearings yesterday with my mechanics assistance. While looking at the brake lines where they circle around the lower gear leg then attach to the caliper, he suggested we might want to cut and flare the metal lines and replace with a length of flexible brake hose for ease of maintenance in the future. Has anyone done this? Is there any reason not to other than crating a place for potential leaks? Do the calipers need a hard line the full length? Thanks in advance for the input.

Mike
 
Greased my wheel bearings yesterday with my mechanics assistance. While looking at the brake lines where they circle around the lower gear leg then attach to the caliper, he suggested we might want to cut and flare the metal lines and replace with a length of flexible brake hose for ease of maintenance in the future. Has anyone done this? Is there any reason not to other than crating a place for potential leaks? Do the calipers need a hard line the full length? Thanks in advance for the input.

Mike

I don't understand what problem the mechanic is trying to fix. What maintenance issues are the hard aluminum lines going to cause? All you have to do to disconnect the line is to loosen a nut. Same as with a flexible line.

To answer your question, there's nothing wrong with terminating the hard lines early and replacing with a high pressure flex line. Just money, time, and another potential leak. This is a fairly common modification.
 
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Don't cut and add a flexible section.

Simply replace the entire line down the leg into the brake caliper with a flexible Teflon hose line. in most cases with a -6A this will not add any extra connections in the overall brake system.

You also have the option of using smaller -3 hose instead of -4 hose. The -3 hose also has the option of being fabricated with -4 end fittings.
 
Kyle & Az,

I think he is preparing for brake pads. I guess you wouldn't have to remove the calipers to change the inner pad if there is a flexible line there. Just a thought he had. We were always changing things that were allowed on my Skyhawk to ease maintenance. Now with the RV we can do much more. I don't thing I would spend the money to make all the lines flex unless there was a need to replace the whole line. Again, just a thought.

Thanks,
Mike
 
I replaced mine from the fuselage down to caliper. Reason is that I couldn't replace brake pads without disconnecting the hard line. With the flex line, I can remove the caliper from the wheel to replace pads without disconnecting the line. This removes the need to bleed the brakes again. I hate bleeding the brakes.
 
Just received my new Teflon / SS brake lines from Tom Swearengen at TSFlightlines. There extremely high quality and run from the fuselage to the calipers eliminating the aluminum tube altogether. I know a lot have gotten by for years with no problems using the aluminum tube but they just seem marginal and bare bones for such a important line. There?s a lot of movement and vibration in the gear. Just my 2 cents.
 
Brake lines

I started with -3 braided Teflon lines all the way down . They were made up buy the local race car shop to my specs with crimped on fittings. Race cars use aircraft fittings almost everywhere.
 
I've never disconnected the hard line to replace pads. Do you have a service loop down near the caliper like called for in the plans? That gives you the ability to pull the caliper loose to change the pads without disconnecting any hydraulics.
 
I've never disconnected the hard line to replace pads. Do you have a service loop down near the caliper like called for in the plans? That gives you the ability to pull the caliper loose to change the pads without disconnecting any hydraulics.

I do have the service loop, however didn't feel comfortable with the amount of flexing required of the hard lines to remove the caliper. Maybe I'm overly cautious...

Chris
 
Probably. My '91 -4 (1000+ hrs) has the looped hard lines that were installed when it was built. If the installation is done correctly, there's very little likelihood of issues fore the life of the plane. If you use non-teflon hose, you'll be faced with time-limits on the hose.
 
I've never disconnected the hard line to replace pads. Do you have a service loop down near the caliper like called for in the plans? That gives you the ability to pull the caliper loose to change the pads without disconnecting any hydraulics.

Ditto what Kyle said. Maybe a bit of exaggeration, but this seems like a solution in search of a problem.
 
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My 1978 C-152 had hard aluminum lines to the brake caliper's from the factory. Very similar installation as the Van's per plans method. Good enough for Cessna and 40 years of service, good enough for my Van's RV. Light and simple.
 
My 1978 C-152 had hard aluminum lines to the brake caliper's from the factory. Very similar installation as the Van's per plans method. Good enough for Cessna and 40 years of service, good enough for my Van's RV. Light and simple.

Maybe, but I bet they were 5052 aluminum rather than the softer 3003 tubing that Vans supplies. Not a good comparison. :)
 
Maybe, but I bet they were 5052 aluminum rather than the softer 3003 tubing that Vans supplies. Not a good comparison. :)

Maybe, but decades of good service history on thousands of RV's built with the supplied line material indicates that it doesn't matter......

In fact, for those always interested in doing what they think makes it better (whether there is a well defined issue or not), the softer tubing might actually be better in this location since it does have to be flexed when the calipers are disengaged for brake pad replacement.
 
Maybe, but decades of good service history on thousands of RV's built with the supplied line material indicates that it doesn't matter......

....................

Unless they were built with the original factory supplied plastic tubing that went down the gear leg all the way to the brake caliper. :)

That version didn't last too many years IIRC.
 
Unless they were built with the original factory supplied plastic tubing that went down the gear leg all the way to the brake caliper. :)

That version didn't last too many years IIRC.

I should have clarified that I was talking about comparing to the kit supplied aluminum line........:eek:
 
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"Unless they were built with the original factory supplied plastic tubing that went down the gear leg all the way to the brake caliper.

That version didn't last too many years IIRC.
__________________
Gil Alexander
EAA Technical Counselor, Airframe Mechanic
Half completed RV-10 QB purchased
RV-6A N61GX - finally flying
Grumman Tiger N12GA - flying
La Cholla Airpark (57AZ) Tucson AZ"


But that's not what we're talking about, is it? Why muddy the waters?
 
But that's not what we're talking about, is it? Why muddy the waters?

It shifted from specific tubes to customer changes to the original factory specified parts.

In the aluminum tube case there must be an engineering reason certified planes all use 5052 tubing rather than 3003.
 
It shifted from specific tubes to customer changes to the original factory specified parts.

In the aluminum tube case there must be an engineering reason certified planes all use 5052 tubing rather than 3003.

Again, muddying the waters. By that logic, there's an engineering reason certified planes all use certified alternators, etc, etc, and that makes *all* of Van's choices of non-certified parts/components invalid. Not to mention all the non-certified 'clone' engines being run on RV's.

The question was related to convenience of adding a length of flex line (strictly for changing brake pads) to avoid flexing the spec'd hard line, and whether flexing the hard line to service the brakes is an issue. The answer is, the Van's-spec'd tubing has worked fine in thousands of planes for decades, but other stuff (both 'certified' and non-certified) works fine, too, if that's what floats your boat & you don't mind the added weight and expense, or you don't trust your (or the builder's) hard line fabrication skills.
 
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