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Thread: Brakes, the continuing saga

  1. #11

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    Default Re: Brakes, the continuing saga

    Quote Originally Posted by t j View Post
    Just thinking out loud, did you receive pedals for the passenger side instead of pilot side?
    As I mentioned in a reply to another post, the picture I have shows the open end of the "E" to the right on the pilot's side. Mine the open end is to the left. I can't see the passenger's side in the photo, so I can't comment on that. Also the mounting point of the master cylinder is quite different than mine.
    Chuck Gruby
    Petal, Kit Fox III Flying

  2. #12

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    Default Re: Brakes, the continuing saga

    Quote Originally Posted by Slyfox View Post
    what kind of lines do you have
    They are the typical Nylon line which MATCO and KF sell for that purpose. Interesting enough, I just measured the hydraulic pressure at the right wheel cylinder and got 400 psi. I was looking fro 450, but that's considerably better than which the old master cylinders.
    Chuck Gruby
    Petal, Kit Fox III Flying

  3. #13
    Senior Member t j's Avatar
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    Default Re: Brakes, the continuing saga

    The rudder pedal torque tubes and brake master cylinder floor bracks on the model 4 are opposite as to pilot and passenger sides to what the earlier models have. It looks to me like Model 4 passenger side pedals would be needed on the pilot side of an earlier model.

    Here's a model 4 photo I snagged off barnstormers. This one has C pedals but the E pedals install the same directions on the model 4.
    Attached Images Attached Images
    Tom Jones
    Classic 4 builder

  4. #14
    Senior Member Slyfox's Avatar
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    Default Re: Brakes, the continuing saga

    Quote Originally Posted by cgruby View Post
    They are the typical Nylon line which MATCO and KF sell for that purpose. Interesting enough, I just measured the hydraulic pressure at the right wheel cylinder and got 400 psi. I was looking fro 450, but that's considerably better than which the old master cylinders.

    you got the clear lines, same as me. I had problems with mine years ago. could not get good braking from one side. I gave up, until I built my rv7. I used the same lines. to my surprise they had me put inserts at the end of the lines all of them. I thought what? you see to make the lines work you have to put inserts at the end, kind of hard to get them in there, but the reason, they have that compression thing on the outside that crimps the line for a seal. if there is no insert than the line crimps off the fluid to the cylinder. in my case I removed each connection for my brakes and found one end did not have this and was closing off the line. you can have pressure and all air out, but if it's closed off, no brakes. I fixed this by buying new inserts from vans and redoing my lines. than I got nice even brakes on my kitfox after that.

  5. #15

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    Default Re: Brakes, the continuing saga

    Hi Gents,

    It's been a couple of weeks since I posted my progress (or the lack of) on achieving a firm brake pedal and symmetrical braking power. Since the last post, I've done the following:

    1. added a lower bale to my brake pedals to change them from "C" types to "E" types.

    2. raised the pedals up and inch by cutting and splicing the risers and re-welding.

    3. closed off the lines to the wheel cylinders by closing the park brake valve. When doing this, both brake pedals are firm, suggesting that there was no air in the master cylinders.

    4. disconnected the supply line to the right wheel cylinder and connected a fluid catch bottle to it.

    5. removed both wheel cylinders from their mounting plate and hung them up vertically with the bleed valve down and the catch bottle up, the interconnect line was left attached.

    6. pumped fluid into the bleed valve until no air bubble could be seen entering the catch bottle.

    7. remounted the cylinders back on the backing plate, pumped a little more fluid thru the cylinders until the supply port was free of air, and then reconnected the supply line.

    8. opened the parking brake valve and continued to pump fluid up to the reservoir.

    9. At the end of all this, I felt as though I had improved on the pedal firmness significantly. The next thing to do was to go taxi test.

    10. The taxi test yielded brakes that were symmetrical, but still short of totally perfect, but nevertheless, adequate.

    11. Takeoff and landings were completely normal, with no hint of loss of directional control (thanks to the "E" type pedals).

    The airplane is much more manageable, but short of expectations, but I can live with it. The positive side is that I don't have to worry about nosing it over. I have exhausted all my knowledge and energy trying to solve this problem and unless I come up with some startling revelation, I plan to close this thread.

    BTW, I discovered there is a special connector that allows you to connect to the bleed valve that stays put, I have never seen one in all my years working on aircraft. I have ordered one and a brake bleeder from ATS.

    Cheers,
    Chuck Gruby
    Petal, Kit Fox III Flying

  6. #16

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    Default Re: Brakes, the continuing saga

    Quote Originally Posted by t j View Post
    The rudder pedal torque tubes and brake master cylinder floor bracks on the model 4 are opposite as to pilot and passenger sides to what the earlier models have. It looks to me like Model 4 passenger side pedals would be needed on the pilot side of an earlier model.
    I think you are right. The master cylinders mounted differently, but substituting the passenger side for the pilot's side looks workable. I just copied the dimensions and modified mine.
    Chuck Gruby
    Petal, Kit Fox III Flying

  7. #17

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    Default Re: Brakes, the continuing saga

    Quote Originally Posted by Slyfox View Post
    you got the clear lines, same as me. I had problems with mine years ago. could not get good braking from one side. I gave up, until I built my rv7. I used the same lines. to my surprise they had me put inserts at the end of the lines all of them...
    I notice those things, but didn't pay a lot of attention to them. I just thought they were just different type of fittings. I will definitely look at those.

    Thanks,
    Chuck Gruby
    Petal, Kit Fox III Flying

  8. #18

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    Yakutat, Alaska
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    Default Re: Brakes, the continuing saga

    You might take a look at your pads. It sounds like the one side may be or have been saturated at one time or are from different makers.
    Dave

  9. #19
    Senior Member Slyfox's Avatar
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    Default Re: Brakes, the continuing saga

    Quote Originally Posted by cgruby View Post
    I notice those things, but didn't pay a lot of attention to them. I just thought they were just different type of fittings. I will definitely look at those.

    Thanks,
    if you don't have those installed at the end of your lines you will crimp down the line when you tighten the nut. it crimps the outside compression ring and than closes the line. if you didn't install those you need to cut off the end and press the little insert in. the best way to do this is to take the whole line off. start the insert and push it against a hard surface and wiggle push it on while holding the line. I believe I took my heat gun and gave it some heat and mine went right on. a tough thing to do, but very important. you will also need to buy new compression rings.
    steve
    slyfox
    model IV 1200-flying
    912uls
    IVO medium in-flight
    RV7A-flying
    IO-360
    constant speed prop

  10. #20
    Senior Member jiott's Avatar
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    Default Re: Brakes, the continuing saga

    I agree with Slyfox; those inserts are mandatory. Without them the compression ring just collapses the plastic tube without getting a good seal, so you have to tighten (collapse the tube) them much more than ordinary to get a good seal. You may have a firm pedal now, but poor brake response-sluggish to apply and release.
    Jim Ott
    Portland, OR
    Kitfox SS7 flying
    Rotax 912ULS

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