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Thread: brake booster for scott brake pedals

  1. #1

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    brake booster for scott brake pedals

    hello everyones

    finaly i got my bird in the air this weekend
    with my new alaskan 29" and the baby bushwheel very happy lost few mph down to 94 mph with a 0-235
    new gear extended with no fabric on i will cover them this winter as a project ,i found an other problem no more brake
    difficulty to jam a wheel everything is new rims ,disk,and brake caliper (double pucks) but with the old scott brake pedals i herd that poeples put a kit to convert those brakes pedals and its seem to work well ,i dont know theirs anybody on this forum have a kit and see a good difference

    let me know

    my bird is -12 with 29"

    thanks pelican -12

  2. #2
    PerryB's Avatar
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    The North River style master cylinders are a good high pressure system and relatively inexpensive. The down side is its a non-vented system and requires fairly constant topping of the fluid level to keep a firm, high pedal. These are sold through Airframes Alaska. Steve's Aircraft in Oregon makes a vented high pressure master cylinder kit that does not require routine filling, and always has a uniform pedal height. Its considered to be the best system by almost everybody who is familiar with them, but is also more expensive. I currently have the North Rivers and have gotten used to keeping them full. I can just about do it in my sleep. When the time comes to rebuild them I will probably convert to Steve's.

    I just looked up the prices.
    North River (Airframes Alaska) $ 408.00/pair
    Steve's Aircraft $ 800/pair

    -- That's not a knock on Steve's. I've been up to their shop and seen their work. Its an innovative design, the workmanship is perfect and you're not constantly maintaining the fluid level. Also, with either system you'll have over twice the braking pressure that you have now, but you MUST have high pressure brake line (such as Aeroquip 303 or hardline) from the masters down to the wheels.
    Last edited by PerryB; 08-10-2015 at 07:32 PM.
    After Monday and Tuesday, even the calendar says WTF !

  3. #3
    txfirefighter628's Avatar
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    I have a O-235 PA-12 with 8.50x6 tires with double puck brake calipers. It came with the stock Scott brake diaphragms and the brakes would barley hold for a run up. After asking and talking to everybody on this forum I bought Steves boosters. Well worth it, money well spent. Took about 4hrs to install from start to finish and the only extra part I had to get was 2 90 degree fittings to clear the bungee cords (these were originally designed for a PA-18 that does not have bungees). The stock Scott diagrams won't create enough pressure to make the double puck calipers work correctly but Steves has all the pressure you need and then some. Also Steves is a fairly simple install and can be done with out cutting any fabric.
    image.jpg

  4. #4
    geoaspen's Avatar
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    Steve's Boosters. When it comes to safety, get the best.

  5. #5
    RaisedByWolves's Avatar
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    Steve's or Dakotas. If you are going to go through the trouble, go with vented. It's a giant pain to keep them topped off. You will have no pedal or locked pedal depending on the temp change. It's really fun trying to let some fluid out as you are taxing into a big controlled airport at almost full power and the jets having to stop behind you. That's no fun, but I learned to carry a 5/8 wrench with me

  6. #6

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    North Rivers suited me fine. I wouldn't hesitate to use them again.

  7. #7
    Eddie Foy's Avatar
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    Quote Originally Posted by stewartb View Post
    North Rivers suited me fine. I wouldn't hesitate to use them again.
    If you enjoy having to constantly fiddle with them. Scrapped my North Rivers for Steve's and never looked back.
    "Put out my hand and touched the face of God!"

  8. #8

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    You're the same guy who on another thread tells of how poor his brakes are? Mine worked great. No "fiddling" required.

  9. #9
    Ken Kennedy's Avatar
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    Quote Originally Posted by Lefoy84 View Post
    If you enjoy having to constantly fiddle with them. Scrapped my North Rivers for Steve's and never looked back.
    We put Airframes/North Rivers in our cub back in the end of april instead of the the Steve's, mostly because of the ease of install and the price. Haven't had to put fluid in since the beginning of may (which is really easy btw), during that time I've done around 100 landings braking hard keeping the tail up with jut the brakes all through the rollout. Guess we just have really tight system.

  10. #10
    RaisedByWolves's Avatar
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    Quote Originally Posted by stewartb View Post
    You're the same guy who on another thread tells of how poor his brakes are? Mine worked great. No "fiddling" required.
    When you have more than a few degrees of temp change, you will always be messing with them. When you add fluid when it's hot out, and you fly across country to somewhere cooler (Texas to Idaho) now when you get there you have no brakes. When you head back home after you added fluid in the cool temp you now have full locked brakes. Sounds like a fun ride landing with the brakes locked and you don't know it doesn't it?
    I had north rivers and ditched them for Dakota masters when I had the floors out a couple months ago. I haven't added fluid sense and the brakes work great. Well worth spending the money, I like flying, not working on them. If you're adding boosters you are crazy not to go with a vented system.

  11. #11

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    I run Grove vented masters, and like them because the pedal is always, always in the same spot. Disc brakes require fluid every now and then because the pads wear out. I put a couple drops in the reservoirs every six months.

    I have flown lots of North River masters, and have thousands of hours using those old inner tube diaphragms. They all seem to work - we have one Cub with Seneca wheels and brakes and original diaphragm masters. They work fine.

    The choices now are simply great. You really cannot go wrong, so long as you know how to bleed them and fill them once in a while. The only folks I know who have brake lock-up with the closed systems are those who run with power and brakes continuously.

  12. #12
    mvivion's Avatar
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    Quote Originally Posted by bob turner View Post
    I

    The only folks I know who have brake lock-up with the closed systems are those who run with power and brakes continuously.
    Bob,

    Weve never met, but as the man noted, subject those North Rivers to a big temperature change and you might change your position. Been there.

    MTV

  13. #13

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    One solution to the NORTH RIVER NO RESERVOIR is to add a reservior and on-off vale on top.Remove the plug on top of the NORTH RIVER system:install 1/8 NPTF brass nipple manufactured by Parker Fluid Connectors p/n 215PN-2 ;add a 1/8 NPTF brass on-off valve Parker p/n 012-2F2F-BJ ;then add a Gravity-Flow Reservoir 1/8 NPTF,1&3/8 oz capacity,1&3/4 in body diameter,2&15/16 in height.This reservoir is manufactured by LUBE DEVICES INC P/n R152-01.Do a FORM 337

  14. #14
    wireweinie's Avatar
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    Jesse

    We've done a bunch here using a check valve from a Ford carburetor. Put the check valve in the inlet of the booster and plumb it to a remote reservoir. Or put the check valve in the nipple on the bottom of a reservoir attached directly to the inlet of the booster. The valve allows fluid to trickle into the booster if there is a leak but works as a trap when you step on the peddle. And I've never done a 337 on a single one (gasp!).

    Web

  15. #15

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    On the heat thing - perhaps it does not affect me because I use brakes sparingly. I will jump on them when trying for a 100 foot stop, but that is such a quick application of heat that the fluid does not get a chance to expand. I admit I do not go from 110 degree desert to sub-zero temps routinely, or vice versa, but I have done SAN-YKM in the winter, which is a 60 degree change in two days, with no adverse brake problems and North River stock boosters.

    I agree - I truly like the reservoir systems. They are bulletproof. If you have the bucks, or have a friendly PMI and can get the Grove units field approved, I say go for it. Or do what Wire says - that sounds like a winner.

  16. #16

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    Wireweinie,
    Last edited by jesse heard; 08-11-2015 at 05:55 PM.

  17. #17

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    Wireweinie, Got a FORM 337 approvel on 4/16/02 from the Spokane FSDO. This set-up has worked well,fitts under the seat on the Super Cub nicely and is easy to install.Also,does not cost much! On the HOT&COLD issue a person could open the valve to allow an expansion or contraction of the brake fluid.

  18. #18
    skywagon8a's Avatar
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    Quote Originally Posted by jesse heard View Post
    One solution to the NORTH RIVER NO RESERVOIR is to add a reservior and on-off vale on top.Remove the plug on top of the NORTH RIVER system:install 1/8 NPTF brass nipple manufactured by Parker Fluid Connectors p/n 215PN-2 ;add a 1/8 NPTF brass on-off valve Parker p/n 012-2F2F-BJ ;then add a Gravity-Flow Reservoir 1/8 NPTF,1&3/8 oz capacity,1&3/4 in body diameter,2&15/16 in height.This reservoir is manufactured by LUBE DEVICES INC P/n R152-01.Do a FORM 337
    Something like this:

    SMITHCUBPetes042.jpg SMITHCUBPetes044.jpg

    This is a North River installation with local hardware store valves and a homemade reservoir. The right master cylinder and pedal is completely homemade since the right hand assemblies are hard to find or are extremely expensive. This is so simple that they can even be adjusted while flying.
    N1PA

  19. #19
    Larry G's Avatar
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    Sky what did you use rod system for up to the front pedals and fittings.

  20. #20
    skywagon8a's Avatar
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    It is two ball end fittings like this on a length of 4130 tubing. The airplane is a Backcountry widebody -18 kit.
    04-02277.jpg
    N1PA

  21. #21
    mvivion's Avatar
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    Quote Originally Posted by bob turner View Post
    On the heat thing - perhaps it does not affect me because I use brakes sparingly. I will jump on them when trying for a 100 foot stop, but that is such a quick application of heat that the fluid does not get a chance to expand. I admit I do not go from 110 degree desert to sub-zero temps routinely, or vice versa, but I have done SAN-YKM in the winter, which is a 60 degree change in two days, with no adverse brake problems and North River stock boosters.

    I agree - I truly like the reservoir systems. They are bulletproof. If you have the bucks, or have a friendly PMI and can get the Grove units field approved, I say go for it. Or do what Wire says - that sounds like a winner.
    Bob,

    The "heat thing" has nothing to do with the calipers, it has to do with heating the brake reservoirs in the cabin. Firing up in very cold temps, then having a strong cabin heater blow hot air on one reservoir can ruin your day. Trust me.

    MTV

  22. #22

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    It seems like common sense would tell you to top the masters when warm.

  23. #23
    skywagon8a's Avatar
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    Quote Originally Posted by stewartb View Post
    It seems like common sense would tell you to top the masters when warm.
    The North River Boosters seem to have a wider usable temperature range when you leave a small bubble of air in the adapter.
    N1PA

  24. #24
    wireweinie's Avatar
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    Quote Originally Posted by jesse heard View Post
    Wireweinie, Got a FORM 337 approvel on 4/16/02 from the Spokane FSDO. This set-up has worked well,fitts under the seat on the Super Cub nicely and is easy to install.Also,does not cost much! On the HOT&COLD issue a person could open the valve to allow an expansion or contraction of the brake fluid.
    Not saying it won't work. Just the opposite, it's a cool idea. But I rarely have customers with issues with temp changes and the North River boosters. That and it's a minor alteration so I would never do a 337 on it.

    Web

  25. #25

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    Thank you for your feed-back.This was my first try to post anything on the site trying to be brief.Just wanted to point out for anyone thinking about the NR System that the temp issue is really not a problem. I too think it is a light weight system that works.On the 337 down here in the Lower 48 you can't be too careful.

  26. #26

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    I have had a pair of Grove masters including pedal and frame on the workbench for almost a year, and got a field approval for them signed in January. I have been meaning to install them for a while, but my Scott frames with the Grove attachment have been performing flawlessly, and my basic philosophy is kind of -" if it works, don't mess with it".

    On the other hand, I like Robbie's products, and enjoy seeing them work. So I put one in yesterday, and test-flew it today. Worked perfectly. My heel cannot tell the difference.

    The big advantage of buying the entire frame is that there is no side load on the piston rod. I have had some minor problems with Scott pedals, presumably those with inferior aluminum, where the piston would dig a cavity in the pedal and lock it up. Never happened on my airplane, and I do three landings a day, and have had the attachment type installed almost since the day the first ones popped off of the CNC machine.

    I only mention this because the Scott brake frames are becoming somewhat rare, and the entire setup may be competitive in price with the North River attachments. You would have to get a field approval or declare the installation to be a minor mod. My PMI wanted me to do them as a minor mod, but I figured that some other fed might not look at it that way in the future.

    And, yes, I can see that a plenum aimed at a master cylinder might do the same thing as overheating a caliper. Keep your foot away from that plenum, Mike.

  27. #27
    skywagon8a's Avatar
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    Quote Originally Posted by bob turner View Post
    ...... I have had some minor problems with Scott pedals, presumably those with inferior aluminum, where the piston would dig a cavity in the pedal and lock it up...
    Aluminum on aluminum will gall without proper lubrication. Hint hint! Don't blame the Scott pedals.
    N1PA

  28. #28
    Steve Pierce's Avatar
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    Texas can have a 40 degree temperature swing in a day. Not always convienent to top off when the temperature is just right. I think everyone has posted pros and cons of each. One thing to consider is the condition of those old Scott frames and pedals. Seen lots of them Crack and welded. Though the Dakota Cub brakes require replacing the whole unit you have a completely new system and some really nice adjustable brake rods going to the front brakes.
    Steve Pierce

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  29. #29

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    Hint? One of our Cubs had this happen twice to the same pedal. First time I resurfaced the indentation, making it perfect and mirror- smooth, then lubricated it with a long-lasting gear lube. Second time I did the same thing. If it happens again, we might go with the new frames, per my above post and Steve's post. I did not realize that Dakota is also supplying the entire unit. These are not cast; they are CNC out of good aluminum billet.

  30. #30
    Steve Pierce's Avatar
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    Yes. If on bigg tires get the high capacity reservoirs because of the angle of attack.
    Steve Pierce

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    Will Rogers

  31. #31

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    Note that the pedal is reversible. I wondered if the lack of an angle would be noticeable - it is not. I will try to get a shot of mine today.

  32. #32

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    Here are a couple shots of the Grove assembly. Note the way the pedal is pinned - the entire cylinder can move laterally to ensure that the piston rod always remains concentric, with zero side force:



    The bleeder screw is my addition - I find it necessary when the airplane is in the 3-point attitude.

  33. #33

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    Also note - as with the Dakota, the pedal has no slant where your heel goes. I find no difference at all in feel, at least with shoes on. I will try it barefoot and report back.

    The brass fittings are so I can use the original auto- style flex line, and so it comes out the same hole as stock. Aeroquip will do the same job, although at a significantly higher price. The auto stuff has a working pressure of 5,000 psi by regulation.

    The disadvantage of the Grove setup is some may need a Field Approval. I can see it as a minor mod, although I hold a Field Approval.

  34. #34

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    Which one will stop the the 35 inch Bush Wheels?

  35. #35
    Steve Pierce's Avatar
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    I have had no problem with any of the boosted brakes on 35s, North River (Airframes) and Dakota. Steve's would work the same I just haven't flown a SC on 35s with Steve's.
    Steve Pierce

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  36. #36
    RaisedByWolves's Avatar
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    I didn't notice any difference in 31's to 35's with north rivers in stopping power.

  37. #37
    skywagon8a's Avatar
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    Quote Originally Posted by RaisedByWolves View Post
    I didn't notice any difference in 31's to 35's with north rivers in stopping power.
    Don't the 35" tires use a 10" wheel? If so the difference is the same as the difference in tire diameters, so one would expect the braking performance to be the same.
    N1PA

  38. #38
    RaisedByWolves's Avatar
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    Pete that's correct.

  39. #39

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    I am usually wrong when I don't agree with Skywagon. However, I believe you still use the same rotor and caliper so there will be less braking ability when you go to 35" tires. Just as you would have more going down to a 26" tire. A good set of double puck brakes can put a cub on its nose in a hurry so I don't think the bigger tire really effects them enough to notice.
    DENNY

  40. #40
    skywagon8a's Avatar
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    Denny, I'm not very familiar with the 35" installation other than the word is that it uses a 10" wheel. I assumed that the disk diameter was also increased. If not then you are correct.
    N1PA

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