Emergency brake

The assembly of the emergency brake, itself, was quite straightforward— until I decided to do a modification.   Below are the parts after I painted the bare metal pieces with Rustoleum black enamel.

The hand brake mechanism attached to the chassis is shown below.  There are two issues: 1) the handle needs to be sufficiently far enough away from the cockpit aluminum sides so that I can operate the handle without hitting the Al; 2) the routing of the cables to the calipers is problematic.

Two things constrain the location of the handle: 1) the bolt holes and ‘L’ brackets determines the rotation to the left and right; 2) the ‘slot’ in the e-brake mechanism just below the ratchet teeth:

e-brake 1
e-brake 2

The two photos above show the slot (indicated by the red arrows) and how it ‘locks’ the e-brake to the chassis mounting bracket.  While the slot helps with the mechanical advantage for immobilizing the e-brake relative to the mounting bracket, it also determines the vertical position of the e-brake.  Note that, per the F5 instructions, the rear L bracket is on top of the chassis mount and the forward L bracket is below the mount (see detailed photos in e-brake album).  The problem with this configuration that the passenger-side of the e-brake handle hits the cockpit aluminum thereby keeping the handle, itself, from extending far enough into the cockpit.  Some builders have put both of the ‘L’ fitting on top of the chassis bracket thereby raising the handle and allowing the bolt head seen in the photo below to clear the Al.  However, this also seems to cause some impingement with the handle on the upper part of the opening in the Al panel.  My solution was to cut out a section of the Al to allow the handle to rotate into the passenger compartment a bit more and therefore clearing the vertical part of the cockpit floor.  The outline in black marker shows the footprint of the ‘boot’ that will go over the e-brake mechanism and handle.  I needed to keep whatever modifications I made to the Al within this boundary.

February 2018:

The ‘normal’ path for the e-brake cables to travel from the handle to the cable bracket is to go under the 4” round tube that is transverse mid-cockpit.  There are a couple of problems with this in my opinion:

1.  The cable, under the tube, is potentially subject to abrasion.  Although many F5s have been built this way is just doesn’t appeal to my engineering instincts.

2.  The angle to the inner cable to the bracket holding the outer sheath is rather sharp, coming from under the 4” tube.

Edwardb, a contributor to the Factory Five build site, proposed a modification using a Lokar brake clevis (Lok-S-8078) and pulleys from McMaster-Carr (3434T24).  In this modification, the Lokar clevis replaces the cable attachment from F5 because in this set-up the cable needs to be shortened and the F5 clevis won’t work.  A problem as I see it is that the Lokar clevis will hit the bottom of the e-brake handle bracket.  Carlewms (another forum member) extended the clevis attachment bar length by fabricating a new set of handle brackets (two photos above showing the shorter bracket with the bar extension hanging from it. I don’t have the machining set-up to make a new set of rachet bracket handles as Carlewms did (below):

My solution was to make bar extensions using 1/8” x 0.5” steel stock:

and then attaching them to the ratchet mount:

The above photo shows the clevis mounted to the ratchet handle.  The photo below shows the ‘raw’ materials:

Note that the Lokar clevis was modified by cutting off the original attachment point.

I also included spacers that are in compression between the extension bars.  Finally, the photo below shows the new routing with the pulleys in place:

Note that the clevis doesn’t hit the bottom of the e-brake bracket.

Modification parts:

     Lokar clevis: (Lok-S-8078)

     Pulleys: McMaster-Carr (p/n: 3434T24)

    A longer ‘shoulder screw’ for the pivot point: McMaster-Carr (p/n: 91259A622)

    Steel tubing: 3/8” O.D., 1 ft. long; for spacer material (McMaster-Carr (p/n: 8910K393)

    Steel stock: 1/8" Thick, 5/8" Wide, 1 ft. long; McMaster-Carr (p/n: 9922K15)

   Various bolts, washers and nuts.