Truth about brake lines?

Hi Guys,

In my "show your RV7 progress post", Pierre asked a very good question. I wanted to move it here for discussion as not to clutter that topic.

pierre smith said:

I have a suggestion for the brake lines. I'd seriously reconsider using the plastic tubing which comes under pressure, e.g. the lines from the passenger side to the pilot's side and also down to the wheels.

My feeling is that high pressure black braided hose will be totally trouble-free down the road. It's a real pain to get to after the top cowl is in place. I'd appreciate hearing from others.
Regards,

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ww2planes said:

We replaced almost every hose that we could with Steel braided hydraulic lines form our local shop. Almost three years of flawless service to this point. More money? Yes but the security is worth it. Oh yeah, they look very nice as well.

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I have read a lot of posts on the brake lines, but still find it inconclusive, partly 'cuase the guys that post, dont post their real life experience or hours.

So here go my 3 Questions:
IF you have more than 500 hours on your RV you qualify.
1) Is the plastic brake lines that run between passenger and pilot a problem?
2) What about the Alu lines running down the mains to the wheels?
3) Would you do it the same again?

Thank you in advance, Kind Regards
Rudi

Kitfox with all plastic brake lines

For what its worth; I completed and am still flying a Kitfox with 660+ hours on 1/8" Nylon brake lines on both the low and high pressure sides, including down to the wheels. I've had no problems and no leaks except for one fitting that needed another 1/16 turn in.

That said; for my RV8, I plan to use braided hose for the high pressure side and nylon for the low pressure side - although as I write this, I just had the thought to consider 1/8" low pressure lines instead of the 1/4" to provide some additional flexibility at the bends.

I've been flying my -6 for over 13 years and almost 1000 hrs with the nylon brake lines on the low and high pressure, pilot and passenger side without any leaks or problems of any kind. I have aluminum lines from the firewall to the calipers, again with no leaks or problems. And yes, I would do the same thing again.

OVER 1000 HOURS RV-6

Stick with Van's method.

Another one..

My purchased RV4 was finished in 1989. Same setup as Mel. 1,000 hrs. 17 years and no issues to date.

That said, I'm thinking of replacing the entire setup this winter just due to age. I'm trying to go through the plane bit by bit and update items that have potential to fail with age.

John

RV-6A Total Time since 7/4/2000: 2482hrs

1) Is the plastic brake lines that run between passenger and pilot a problem? NO problem
2) What about the Alu lines running down the mains to the wheels? NO problem
3) Would you do it the same again? Definitely, no leaks, no problems! Rosie

Brake lines

I have an RV6 which has only 155 hrs on it with Van's brake lines. No problems. I rebuilt a wrecked RV4 with 1550 hrs over 20 years and Van's brake lines. Again, no problems. Would I do it again? Yes, with one exception.

While changing brake pads while performing normal maintenance, the aluminum line which loops around the axle seems to be flexible enough to be functionable, cheap, light and, in the case of the wreck, durable. But, you cannot remove the caliper far enough without removing the line from the caliper in order to replace the outboard brake pad. This means bleeding the brakes each time you replace pads which is a tough job on the 4 since the brake cylinders on the pedals are installed upside down due to lack of room. They bleed really poorly. The RV6 bleeds fine but it is still a chore that would not have to be done IF there was a short 12" or so of flex line forming that familiar loop around the axle. I am considering this modification.
Just a thought.

Dick DeCramer
N500DD RV6
Down for a C/S prop,
Should fly again next week
N149KC, RV4 Back in the air.

800+ hours, no nylon problems, no aluminum down the gear problems. I did use 3/16" aluminum down the gear, but I wouldn't think that would matter.

Brake Lines

Rudi:

I only have about 50 hrs on my-8 but: I help a friend of mine who is an aircraft mechanic (A&P with inspection authorization) do annual inspections on certified aircraft.

I don't recall seeing a certified aircraft with aluminum lines connected to the brake calipers. I believe most all have flex hose from somewhere on the gear leg to the brakecalipers. As mentioned above, this allows more freedom of movement when changing discs.

On my -8, I installed 12 in. stainless braided hoses inside the wheel pants. They allow the brake calipers to slide more freely on their guides where rigid lines might hold the calipers against the brake discs causing excessive wear.

Another consideration when using plastic lines would be ultraviolet degredation over the years.

Glad to see the great progress you're making on your pride and joy!

Mannan Thomason
RV-8 N161RL No. One Girl

Certified brake installations

mannanj said:

Rudi:
I don't recall seeing a certified aircraft with aluminum lines connected to the brake calipers. I believe most all have flex hose from somewhere on the gear leg to the brakecalipers. As mentioned above, this allows more freedom of movement when changing discs.
Mannan Thomason
RV-8 N161RL No. One Girl

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Mannan ... all of the small Grummans are certified with metal lines down the gear directly to the brakes like the RVs.

A bit earlier in design.... ...a certified Great Lakes biplane I made new brake lines for only had a flex hose at the pedals... the rest was solid tube...

gil in Tucson

cessna 150

mannanj said:

Rudi:

I only have about 50 hrs on my-8 but: I help a friend of mine who is an aircraft mechanic (A&P with inspection authorization) do annual inspections on certified aircraft.

I don't recall seeing a certified aircraft with aluminum lines connected to the brake calipers. I believe most all have flex hose from somewhere on the gear leg to the brakecalipers. As mentioned above, this allows more freedom of movement when changing discs.


Mannan Thomason
RV-8 N161RL No. One Girl

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how do i know ...cause they were leaking however im still using them ..its a 73 model

Hi Guys,

thanks for your input, if you have experience, please add below.

Kind Regards
Rudi