BRAKE SYSTEM

 

I started the brake system on September 4, 2005.

Brake system parts Close-up of a brake pedal

The photo at left above shows the brake system parts for a single brake installation laid out on the drawing.  I ordered the "Dual Brake Option" when I ordered the kit.  This package consisted of two more pedal assemblies, two more brake cylinders and ....... that's it.  No more hardware and no more brake lines.  The drawing does show detail on installing the second set of brakes and I will probably be able to fabricate lines easily enough.  The photo above right is a close-up of brake pedal parts.  The edges are rough and need a little work.

Smoothing and de-burring brake pedals Making the F-6117C angles

In the photo above left I can be seen smoothing a brake pedal on a belt sander.  At right is a photo of the F-6117C angles in the process of being cut from .063" X 3/4" extrusion.  There was not enough extrusion in the brake pedal kit to make eight of these but there was still an entire 12' section of this angle that I haven't used yet.

Warped brake pedal Trying to straighten it with a mallet

When they stamped the brake pedals out of a large aluminum plate they warped every one of them.  You can see in the photo above left that one of the pedals is warped in comparison to the work bench.  In the picture at the right I can be seen trying to straighten a pedal with a hammer.  This process did not work very well. 

Straightening with an adjustable wrench Match drilling the F-6117C's

What did work was using a "Crescent" wrench.  I managed to get all of the pedals fairly straight.  Next I began to match drill the F-6117C angles to the brake pedals on the mini-mill (above right).

Brake pedals attached to the F-6117C's Match drilling the F-6117A's to four F-6117C's

Above left is a picture of all four brake pedals with the two F-6117C's attached with clecos.  The next step was to drill the F-6117A to one F-6117C on each pedal (above right).  I did one pedal at a time so that I would not get confused.

Drilling a 3/16" bolt hole 3/16" bolt hole in the opposite F-6117C

One hole in each F-6117A/F-6117C assembly gets enlarged to 3/16" for one of the bolts that attaches the brake pedals to the rudder pedal assembly.  I used a #12 drill bit in the mini-mill to enlarge this hole (above left).  I then drilled a 3/16" hole in the same place on the other F-6117C on each pedal (see arrow above right).  I actually clamped the F-6117A to the opposite F-6117C to locate the hole (not shown).

Countersinking a brake pedal Left inboard pedal

Next, I countersunk all of the attach holes for AN426AD4 rivets (above left).  Again I had to be careful that I did not countersink the wrong side.  I wrote on each pedal where it belonged and on each F-6117A which pedal it belonged on.  I then merely had to countersink the side with the writing on it.  The picture above right shows an example of a pedal countersunk.  My selection as to location was arbitrary.  The pedals are identical.

Trimming the F-6117C's All pedals are trimmed

Next it was time to lighten up the pedal a little per the plans (drawing 37).  I really only did this for looks.  I don't think it would be possible to tell how much weight was saved unless you had a scale that measured in tenths of an ounce.  At left above I am in process of trimming the F-6117C's per the drawing.  At right all four pedals are trimmed.

Arrow showing area to be trimmed  

The photo at left shows the F-6117C's after four of them were trimmed (arrow).  The photo at right shows the other location where all eight F-6117C's get trimmed (arrow).

Rudder pedals, all 3 bearing blocks flat on table Pedals aligned

the next step was to drill the hole where the brake master cylinder attaches to each pedal.  The first thing that I did was to put the rudder pedal assembly upside down on the workbench.  I made sure that the blocks all were flat on the table.  I then aligned the rudder pedals (above right).

Scale clamped to brake pedals Rudder pedals held with two aluminum strips

Next I installed the two left brake pedals temporarily.  I used my 24" scale to align the two pedals with each other.  I clamped it to the brake pedals (above left).  The significance to using the scale was that it was handy.  To keep the rudder pedals in alignment, I clamped a strip of aluminum on each side of two rudder pedals (above right).

#12 drill bit in angle drill Left side master cylinders attached

Next I reamed all of the bolt holes with a #12 drill bit (above left). I then attached two master cylinders temporarily (above right).

Using master cylinder and #12 drill bit as a compass Intersection where #12 hole was drilled

To mark the hole for drilling I inserted the #12 threaded drill bit through the master cylinder bolt hole and used the master cylinder as a compass (above left).  I applied very little pressure because I did not want a deep gouge, just a light scratch (above right).  I then drew a line perpendicular to the scratch in the center of the F-6117A.  I drilled a 3/16" (#12) hole at this intersection.

Gap between master cylinder and F-6117A Spacers

The picture above left shows the gap between the F-6117A and one of the master cylinders.  The gap was approximately 1/4".  The drawing says to install several washers to remove the gap.  That was the easy way.  I decided that the installation of the master cylinders was not taking enough time so I would make four spacers to fill these gaps.  The picture at right above shows a bunch of spacers I purchased from a vendor at The Arlington Fly-In a couple of years ago.  I don't remember the name of the vendor.

Spacer marked for cutting Two spacers approximately 1/4" high

Above left is a spacer with a 3/16" hole and a 3/8" O.D.  I marked it with two lines 1/4" from each end.  I then used the band saw to cut the spacer into two 1/4" sections (above right).

   

I then chucked these spacers in the lathe one at a time and finished the rough end (above left).  The picture above right shows the pilot side brake pedals with the spacers installed.  I made two more fro the co-pilot side out of the material that remained (not shown).