Differential Toe Brakes (15)

15 Hours

While I wait for my new wing to show up, I'm going to do something about the stock brake setup.  The factory's stance is you don't need differential brakes with the directly linked tailwheel, but after my experience I no longer agree!  I also want to move the brakes to my feet so I don't have to divide my left hand's attention between the brakes and throttle on the ground anymore.

My plan was to mostly copy the setup shown in this forum post.

Here's a look at the stock rudder pedals and the hand brake with single master cylinder.

Some dimensions for reference.

I started by copying the post above and getting some steel pedals cut out and welded together.  I paid a guy at a scrapyard to make these and they're alright but they definitely don't look as nice as what I'm copying!  After some grinding and painting though they looked fine.

I bought two of these Matco MCMC-5A master cylinders and a PVPV-D parking brake valve, some straight and 90-degree fittings, and like 20 more feet of plastic brake line.  From there I was pretty much on my own!

I did a lot of head scratching and mocking-up of parts to try and decide how and exactly where to mount the master cylinders.

This is close to the final answer.  For the pivot I used a 1/4" rod that was threaded on the ends.  I used a slim nut on each inboard side because there isn't much space between the rudder pedals, and I cut the outboard ends to length eventually so they wouldn't stick out too far.  I also used some bronze bushings that I already had laying around.

Next I pondered where to place the parking brake valve.  Initially I thought I'd mount it on the firewall or perhaps the floor, and then use a push-pull cable to actuate it.  I realized I could put it on the left sidewall though, near where the original brake handle was, and then I could reach it from the seat without any extra cables or parts.  It's still low enough that the build in reservoirs on top of the master cylinders are the highest point in the system!

I used my hangar neighbor's pressure bleeder to fill the brakes from the calipers, which was a little messy but otherwise extremely easy.  All done!!