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brake booster for scott brake pedals

pelican-12

Registered User
Montreal,canada
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 :oops: 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
 
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.
 
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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.
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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
 
You're the same guy who on another thread tells of how poor his brakes are? Mine worked great. No "fiddling" required. :)
 
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.
 
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.
 
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.
 
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
 
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
 
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
 
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.
 
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.
 
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:

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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.
 

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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.
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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.

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
 
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
 
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.
 
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.
 
...... 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.
 
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.
 
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.
 
Yes. If on bigg tires get the high capacity reservoirs because of the angle of attack.
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