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Thread: Sticking brakes

  1. #21

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    Default Re: Sticking brakes

    Quote Originally Posted by JPerkins View Post
    Steve is talking about a sleeve that fits over the axle tube. It looks like the axle has a shoulder for the bearing to butt up against st but its actually a sleeve, the axle is is the same dimension its entire length. I have seen where bearings weren't torqued properly, spun on the axle shaft and wore the end of that bushing sleeve. On your drawing where the axle tube enlarges, that is the bushing.

    Sent from my SM-G930V using ShortWingPipers.Org mobile app
    JP, thanks! I think that's the missing piece. I didn't see the axle sleeve (bushing) on any of the exploded drawings. I did put the shim (spacer) on yesterday, and test taxi'd it with no more dragging/sticking! I feel like I'm almost there! Now I'll look for availability of the axle sleeve, as I think that is what needs replaced or repaired. You and Steve are a great resource! Do you fellows know of availability of the axle sleeve/bushing, etc.?

  2. #22
    Administrator Steve Pierce's Avatar
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    Default Re: Sticking brakes

    If you have stock Tri-Pacer gear and brakes the bushing is welded to the axle.

  3. #23

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    Default Re: Sticking brakes

    Quote Originally Posted by Steve Pierce View Post
    If you have stock Tri-Pacer gear and brakes the bushing is welded to the axle.
    Ok, thanks Steve, I thought that might be the case! Hence, the reason why many have added a shim/spacer.
    Last edited by bubben24@windstream.net; 11-14-2019 at 08:32 AM.

  4. #24
    andya's Avatar
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    Default Re: Sticking brakes

    Might ck the other side to see what it looks like, ie spacer or other. Compare since it apparently is not squeeking?
    "Progress is our most important problem"

  5. #25

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    Default Re: Sticking brakes

    Quote Originally Posted by andya View Post
    Might ck the other side to see what it looks like, ie spacer or other. Compare since it apparently is not squeeking?
    Thanks! I did compare to the other side early on, and it looked identical. I've tried different brake-shoe cam adjustments. Since it's just 'grabbing' on the one side (left), I've ruled out the master cylinder, over-pressure issue. The return spring appears good. I've removed the shoes and cleaned the surfaces. The brake lines are steel, with no rubber sections, so ruling out debris in the lines, but still planning to flush that side.

    Thought I had it fixed, by adding the spacer washer, but went flying yesterday, and that same side, slightly grabbed again. Not nearly as much though. It's a brain-tweezer, but since it's improved with spacer, I think I'm on the right track.
    Last edited by bubben24@windstream.net; 11-15-2019 at 09:55 AM.

  6. #26
    Glen Geller's Avatar
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    Default Re: Sticking brakes

    You should note that there is a front and rear shoe at each wheel, they are slightly different and have slightly difference markings on the rib. To further complicate matters the shoes are mounted top and bottom so you need to skull it out carefully to make sure they are installed correctly.
    IF you do have them wrong, and you then install them correctly, be sure to readjust the cam for best performance.

    Other things to consider:
    * The springs could be weak on one side, so the brakes don't return correctly.
    * The NRBB is a pain to adjust correctly; it is not vented, so if air is trapped in the M/C and becomes hot it will expand and apply a bit of force to the fluid and brakes can drag (really a problem in '53~'55 where M/C is on the engine mount.)
    * Likewise a bubble in the brake tube exiting the M/C, thru the parking brake valve and down the left firewall, will be exposed to the heat of the muffler.

    Before I ditched my NRBB, my process was bleed the heck out of the system from bottom up, both sides alternately a few times, so all bubbles were pumped up and out, thru the parking valve and out the top of the NRBB M/C, using a kludge of fittings, hose and soda bottle;
    Fill the M/C all the way, install cap snugly with good washer, apply brakes firmly and set the parking brake;
    Put a lot of paper towels below the NRBB and with the parking brake applied, crack the M/C cap a ful turn or more and apply the brakes until a 1/2 teaspoon of red fluid escapes, then tighten the cap, making sure no air got sucked into the M/C;
    Apply the brake to release parking brake valve - the drum springs will backfill the M/C a bit.
    You might have to fiddle with this several times until you find that sweet spot where applying brakes holds at runup, and releasing brakes you can pull plane on the ground.

    I replaced my original drums with disk brakes and original Scott M/C, all those problems went away.

    GG

  7. #27

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    Default Re: Sticking brakes

    Thanks for all of that great info, Glen! I'm confident the shoes are in the right position, so I think I'm to the point of replacing the spring, and bleeding, using the steps that you mentioned, and if that doesn't work, biting the bullet and installing the disc brake upgrade. Those are spendy but I've already spent several hours on it and want to get it resolved asap.

    May I ask, which disc brake mod kit did you use? I understand the Stinson kit from Univair (199-08700CH), will work. I've contacted them for verification and price. It says on their website to "Call for price". Always makes me nervous!
    Last edited by bubben24@windstream.net; 11-16-2019 at 01:27 PM.

  8. #28

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    Default Sticking brakes

    My STC is for single puck Cleveland 199-46 wheels and brakes... Cost is $250 for the STC.. ACS has the conversion kits for $2245 and I know Univair and Sporty’s also carries them..

    I also have the STC vented master cylinder that replaces the Scott diaphragm.. retains the original pedal and frame.. the Cylinder is $420..

    I usually give a $50 discount to Tri-Pacer owners that order both at the same time..

    Brian


    Sent from my iPhone using Tapatalk
    Last edited by stevesaircraft(Bri); 11-16-2019 at 03:48 PM.

  9. #29

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    Default Re: Sticking brakes

    Thanks Brian. I'll think on that. May need to go that route.

  10. #30
    Jim's Avatar
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    Default Re: Sticking brakes

    Hi,

    Can you tell by the shoe rub pattern if one end hits first perhaps causing a drag? If you get a chance to check, drop a shoe in your drum and see if they're the same radius. Brake shops, in the old days, would re-surface the shoes to match the drum radius. I've filed off high spots to get maximum surface friction on new linings. I don't recommend testing on your stuff, just reminiscing years of fixin' things. Are your drums really round? I have a panel lift with a slightly bent brake drum that catches on the way up if the release handle isn't held just right.

    https://forums.aaca.org/topic/242058...g-brake-shoes/
    https://content.invisioncic.com/r277...3142698387.jpg
    Last edited by Jim; 11-19-2019 at 08:05 AM.

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