Brake master cylinder mountings

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Richard Roller
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Brake master cylinder mountings

Post by Richard Roller »

Good morning everyone. I'm sure most are aware that N34KP was damaged a year ago July. At that time it was the latest incident due to not having brakes, and there are many.

So, I'm putting brakes on the old bird this coming winter. I've bought a set of Matco wheels and brakes that will suit my needs.

I've taken many photos over the years of various master cylinder installations. I'd like builders/pilots to post pictures of your installations, tell me your thoughts behind what you did and maybe what you might change with experience.

I have ideas of my own, but I'd be a fool if I ignored others experiences.

Thanks.
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taildrags
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Re: Brake master cylinder mountings

Post by taildrags »

Richard; do you have any preference as to whether you go with heel or toe brakes?

Oscar Zuniga
Medford, OR
Air Camper NX41CC, A75 power
"Bill Rewey style" toe brakes
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Richard Roller
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Re: Brake master cylinder mountings

Post by Richard Roller »

No preference. I have toe brake actuators on hand, but I have no problem with heel brakes.
Last edited by Richard Roller on Mon Sep 14, 2020 8:03 pm, edited 2 times in total.
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Richard Roller
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Re: Brake master cylinder mountings

Post by Richard Roller »

What would be Bill Rewey style brakes?
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taildrags
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Re: Brake master cylinder mountings

Post by taildrags »

Richard; see photo of the toe brake setup on Bill Rewey's Piet. Mine were fabricated after the same fashion. They sit pretty much on each side of the passenger's thighs, on the sides of the fuselage. Simple and effective. Bill's actually have parking brakes, which are the metal tabs on top of the cylinder shafts. You apply the brakes firmly, then pull on the parking brake knob which lifts the tabs such that they 'jam' the shafts and hold the brakes. I had them on my brakes when I got the plane but they never held and never worked right, so I took them off.

I have some pix of one or two nice heel brake setups as well, one which uses the Matco masters laid on their sides. I'll try to find that picture.

-Oscar
Rewey_brake.jpg
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Richard Roller
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Re: Brake master cylinder mountings

Post by Richard Roller »

Thanks Oscar. The picture is similar to one I've taken of Lowell Franks Piet.
Spark6
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Re: Brake master cylinder mountings

Post by Spark6 »

I'll try to get a photo of 5TM's brakes next time I'm out at the plane (may be next week), but the guy who installed them did a pretty clever thing, in my opinion - and no, I'm not the builder! The master cylinders are under the box formed by the passenger seat, with the heel brake levers extending out from either side. It's a very neat packaging solution, and nothing gets hung up on the cylinders. The heel brakes took about a few minutes of taxiing to get used to, but I'm very happy with them.
- Barrett
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KenBickers
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Re: Brake master cylinder mountings

Post by KenBickers »

Richard,

Like the heel brakes described by Barrett, mine are located under the front pax seat. I used Airheart small master cylinders. I designed mine to as flag pole levers. The attached photo shows them from above with the front seat removed.

They are never in the way in flight. I have to pull my heels slightly under the front seat to actuate the brakes on the ground. They work fine for runups and for navigating in close quarters on the ramp.

Cheers, Ken
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heel brakes (top view).JPG
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taildrags
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Re: Brake master cylinder mountings

Post by taildrags »

Ken: what's the nylon braided hose running down and out the bottom of the plane?

-Oscar Z.
Medford, OR
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KenBickers
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Re: Brake master cylinder mountings

Post by KenBickers »

Oscar, I used the braided nylon hose as conduit for the wires from FWF to run up to the aft instrument pod. Not visible from the top-down photo is a small hole drilled in the hose at the low point when the airplane is sitting on the ground to act as a drain for any rainwater that might find its way into the hose. Cheers, Ken
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taildrags
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Re: Brake master cylinder mountings

Post by taildrags »

Ken; got it. So you used the TSO'd braided nylon electrical flex conduit from Aircraft Spruce for that electrical wiring? ;o) :lol:

-Oscar
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Richard Roller
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Re: Brake master cylinder mountings

Post by Richard Roller »

Ken. I'm not sure I could use your set up. I have the rudder bar. It is a sharp looking installation!
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KenBickers
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Re: Brake master cylinder mountings

Post by KenBickers »

Oscar, I'm pretty sure that came from the aviation aisle at Home Depot. I've found lots of certified-ish items there. :roll: Cheers, Ken
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Richard Roller
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Re: Brake master cylinder mountings

Post by Richard Roller »

wood piet brake master installation.jpg
This is what I've come up with for the brake master cylinders. These are Cleveland master that I happened to have, model #10-55. I bought these back in the 80's, for another project that never came off.

I got my wife into the rear cockpit and had her put her feet on the rudder bar so I could take measurements for the pedal location.
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taildrags
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Re: Brake master cylinder mountings

Post by taildrags »

Richard: I think you're getting it! If it would help, I'd be happy to take measurements of the triangulated fuselage framing space where my brakes are mounted, as well as where the mounting points are located on the diagonal, to give you a point of reference to see if we're close to what you've come up with. It's easier to erase and redraw it in a CAD program than it is to plug drilled holes in your fuselage framing and make new holes if it needs adjusting later ;o) My setup may not be perfect or ideal, but it works fine and has done so for quite a few flight hours, under the feet of various pilots since it was first flown. I have a rudder bar in the rear cockpit.

-Oscar Zuniga
Medford, OR
Air Camper NX41CC, A75 power
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Richard Roller
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Re: Brake master cylinder mountings

Post by Richard Roller »

I would appreciate the help Oscar. It is better to measure twice and drill once!
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taildrags
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Re: Brake master cylinder mountings

Post by taildrags »

Aha. I knew I had a thread going somewhere on this subject. Here are the measurements of my setup, as well as a photo of the starboard side brake showing the welded-on tab on the pedal to make it easier to reach with the toe.

-Oscar
brake_dims.jpg
Attachments
brake_stbd.JPG
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Richard Roller
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Re: Brake master cylinder mountings

Post by Richard Roller »

Thanks Oscar. I appreciate the help.
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taildrags
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Re: Brake master cylinder mountings

Post by taildrags »

Richard; not saying "do it this way", just putting additional food for thought out there. I'm a bit curious about your leg length. Looking at my brake pedal location fore-and-aft relative to yours, either our cockpits are differently configured by a couple of inches, or my legs are shorter than yours because my brake pedals appear to be about 2" aft of where yours are in the drawing. I wear pants with a 32" inseam. Are yours by any chance a little longer, like 33 or 34"?

-Oscar
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Re: Brake master cylinder mountings

Post by tom kreiner »

Oscar,

Have you thought of replacing the L shaped bracket that mounts the pedal with a U shaped bracket? There appears to be an eccentric load on the angled fuse member along with the bracket itself.

Tom
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Richard Roller
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Re: Brake master cylinder mountings

Post by Richard Roller »

We seem to vary from .5" to 1.0" between what you measured and what I drew. The drawing is of the Piet plans. I did put my wife in the rear cockpit to get the measurements that I used. I'm sure it will work out okay.
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taildrags
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Re: Brake master cylinder mountings

Post by taildrags »

Richard; I'm sure it'll work out OK... I just thought it might inspire confidence if you had some measurements off another airplane. Sounds like you and I are mighty close on ours so get busy fabricating those brake master mounts and actuators. You'll like having brakes.

Tom: looking at the geometry of the brake masters, the pedals where the braking force is applied, the brackets and their mounting configuration, there are of course a number of eccentric loadings in the picture. I haven't given it much thought because there are others out there flying with the same setup. The main thing I don't like about it are the 3/16" holes through the framing members to mount the brackets, but I had no choice in the matter so there it is. Corky built the plane; I just fly it, break it, and modify it ;o) Regarding the braking force applied by the pilot's feet, there is an unintended but definite restraint that prevents the application of too much force to the pedals: the front support for the front seat. I know this because I have twice broken it loose from its mounting point at the cabin floor when I pressed a brake pedal "energetically" a time or two. The last time it happened, I removed the entire front seat frame, scraped everything back to flush clean wood on the cabin floor, and reinstalled the seat support using a crossmember the full width of the floor, from longeron to longeron, and made it the full size of the longerons to give the seat support plenty of glue area to attach it so as to resist breaking loose if I overdid it with the brake again. The rudder bar has its own stops (a la Mike Cuy's blocks), but the brake pedals were hitting the seat support. Incidentally, when I took the existing seat support framing apart to rework it, I found that it had apparently broken loose before I had the airplane and had been 'repaired' using Gorilla Glue. I hate that stuff! It foams up and fills the gap alright, but it's not structural... the hardened foam glue snaps like peanut brittle. I know why it was done that way... out of convenience and to get a feeling that a poorly-fitted joint could be gooped full of stuff that foamed up to fillet across an ugly gap and look like a real glue joint when it dried, but it wasn't. I think it is now though.

-Oscar
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Richard Roller
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Re: Brake master cylinder mountings

Post by Richard Roller »

I'm ordering extrusions for the brake installation. I have considered putting restrictions in the brake lines, to slow down the application time a little. The reason is that I don't plan on reworking the landing gear V's at this time and N34KP is built to the plans. Which means the wheels are to far aft for normal brake application, I'm pretty sure I could put it on its nose with to much brake application. I plan on using them only while taxiing on the ground.

Any comments?
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KenBickers
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Re: Brake master cylinder mountings

Post by KenBickers »

Richard, restrictors might be prudent. You might wait, though, until you've had a chance to do some ground testing. Depending on the mechanical advantage (or lack thereof) of the pedal assembly, you may find that things are okay without adding additional bits to the braking system. Good luck with this. Cheers, Ken
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Richard Roller
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Re: Brake master cylinder mountings

Post by Richard Roller »

Thanks Ken. I have done something similar in the past on another project for a friend. We just used a steel fitting (brass would work) out of the master cylinder, soldered shut, then drilled a hole through with a #50 drill.
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Richard Roller
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Re: Brake master cylinder mountings

Post by Richard Roller »

brackets.jpg
I made a set of brackets for the master cylinders. The piece of 1" key stock is the drill guide from the tail longeron repair. I added an extra hole to match the hole spacing for these brackets. It'll be clamped in place and the holes back drilled through the station diagonal.
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taildrags
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Re: Brake master cylinder mountings

Post by taildrags »

Looking good! Progress photos are good for those who might be considering the same setup.

-Oscar
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Re: Brake master cylinder mountings

Post by tom kreiner »

FWIW — The use of a restrictor will not reduce the braking force, but it will slow down the rate at which the force is applied.
Last edited by tom kreiner on Thu Jan 14, 2021 5:29 pm, edited 1 time in total.
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Richard Roller
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Re: Brake master cylinder mountings

Post by Richard Roller »

Very true.
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Richard Roller
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Re: Brake master cylinder mountings

Post by Richard Roller »

I've cut out all the pieces for the actuators foot pedals. I also have hooked up my tig welder. So...., after I get some practice welds in I'll try assembling the pieces. Wish me luck.
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20210307_181406.jpg
20210307_181416.jpg
Spark6
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Re: Brake master cylinder mountings

Post by Spark6 »

Luck! Looking forward to seeing how they come out!
- Barrett
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Re: Brake master cylinder mountings

Post by doug bryant »

here is how im doing my brakes; just one hand brake under the deck. this will be for stopping the airplane for safety and hold for run-up
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1F2E559E-1022-4D47-B78E-6C030327BBAC.jpeg
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Re: Brake master cylinder mountings

Post by tom kreiner »

Doug, Prior to completion, you'll be swapping the bolts that don't protrude from their nuts for some longer lengths, right?
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Re: Brake master cylinder mountings

Post by doug bryant »

those are just on finger tight at this point so i dont lose parts
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Re: Brake master cylinder mountings

Post by tom kreiner »

After my reply, it occurred to me that like others have done, these were the Ace Hdwre version of hardware while your next package with proper A/C hardware arrived...
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Richard Roller
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Re: Brake master cylinder mountings

Post by Richard Roller »

I was going to post pictures of the brake pedals, but I just realized I didn't take pictures of them. So here is a photo of the adaptors for the brake torque plates. They will bolt over the trimmed 1-1/2" axles and the 1-1/4" axles will slide inside.
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20210331_143220.jpg
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Richard Roller
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Re: Brake master cylinder mountings

Post by Richard Roller »

20210409_141513.jpg
Torque plates for the Piets new brakes.
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Richard Roller
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Re: Brake master cylinder mountings

Post by Richard Roller »

Pictures of the brake pedals and the finished axles for the Matco wheels and brakes. I will drill the axle attach bolt holes when in place.
20210425_095039.jpg
20210425_095050.jpg
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Richard Roller
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Re: Brake master cylinder mountings

Post by Richard Roller »

A test fitting.
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20210424_165347.jpg
20210424_165408.jpg
The new axles and wheels in place. They are not drilled and bolted yet. The axle stub is the existing 1-1/2" axle after being trimmed.
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Richard Roller
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Re: Brake master cylinder mountings

Post by Richard Roller »

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Richard Roller
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Re: Brake master cylinder mountings

Post by Richard Roller »

Left main on the ground. It looks so strange with a 6:00 x 6 tire instead of the 8:00 x 6 that was on it! I may have to go back to the old tires. Time will tell.
I haven't ran the hydraulic tubes yet, or installed the master cylinders.
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20210505_172615.jpg
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taildrags
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Re: Brake master cylinder mountings

Post by taildrags »

Richard; I'm right there with you. Pulling annual on my Piet and next on the list is to pull the wheels and brakes for cleaning, servicing the bearings, and swapping my 6.00 tires and tubes for 8s. I just think the plane will look better and will give me just a bit more deck angle in the 3-point landing attitude. The 6s probably look more like the Army Air Force trainer that the paint job reflects, but I've just got to try 8s for awhile.

I think you'll be happy with brakes on your Piet. I am.

Oscar Zuniga
Medford, OR
Air Camper NX41CC
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Richard Roller
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Re: Brake master cylinder mountings

Post by Richard Roller »

20210513_132744.jpg
20210513_132019.jpg
N34KP is standing on two new main wheel and brake assemblies now. Master cylinders and plumbing next.
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Richard Roller
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Re: Brake master cylinder mountings

Post by Richard Roller »

Still plugging along.
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20210523_142203.jpg
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taildrags
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Re: Brake master cylinder mountings

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Don't stop now, Richard! (pardon the pun ;o)

-Oscar Z.
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Richard Roller
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Re: Brake master cylinder mountings

Post by Richard Roller »

Hey Oscar. How'd you like those fancy reservoirs? Just for grins I weighed the master cylinder assemblies. Everything including hardware (no fluid) is 1 lb. 2 oz. each side.
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taildrags
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Re: Brake master cylinder mountings

Post by taildrags »

Yes, I noticed those reservoirs. I like your brake pedals, too. What brake line tubing are you planning to use? I used Nylaflo on mine after reading up on the pros and cons. It's not recommended for brake lines where the wheels and brakes are inside of tight-fitting wheel pants or on planes that operate at higher speeds with smaller wheels and brakes where things get pretty hot in a hurry. The end at the brake fitting can get hot and either slip off, melt, blow out, or otherwise fail. In my case, with big Clevelands off of a C172 with a gross weight about twice that of my Piet, my brakes don't ever work very hard or get very hot and I don't have wheel pants or fairings to hold the heat in close to the brakes. Outside the cabin, I tried to run the lines tight to the backside of the gear leg tubing without loose loops or slack, just enough at the brake to make the sweep into the fitting on the brake cylinder. I like to operate off of grass and don't want to be afraid of unimproved fields where weeds or grass could grab at a brake line that's out where it can snag on something. I guess I could have used aluminum tubing but I don't like that stuff very much.

-Oscar
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Richard Roller
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Re: Brake master cylinder mountings

Post by Richard Roller »

The tubing I bought is from McMaster-Carr. It's nylon rated at 430 psi. The brakes are open, with no wheel pants. I intend to use the brakes only when taxiing on the ground, not for landing. I didn't move the wheel locations, fore and aft, they are to the plans. So I could probably put the old Piet on it's nose easily enough on landing. One of the projects of this last winter was installing 8 drains (using seaplane grommets) in the front of the Piet. They are forward of every wooden cross piece in the cockpit area of the Piet. Drainage has been a problem in N34KP, Ken didn't put any in the cockpit areas. I plan on running the tubing out of one set of the drains and down the landing gear vee's. Probably similar to your setup.
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Richard Roller
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Re: Brake master cylinder mountings

Post by Richard Roller »

We have operational brakes! I haven't been able to taxi test yet, the propeller is still off, but I've bled the system and they are nice and firm with no leaks. So far no leaks, anyway!
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taildrags
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Re: Brake master cylinder mountings

Post by taildrags »

Looking good, and they will no doubt work just fine for you. Nice closeup of those fluid reservoirs on the brakes... from the plumbing section of the aero supply store ;o) It looks like your tires are McCreary Aero Trainers. Same as what I fly except mine are 6.00x6s right now; going to 8s one of these days.

-Oscar Zuniga
Medford, OR
Air Camper NX41CC, A75 power
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