SonexBuilders.net

I'm converting to the Sonex hydraulic brakes, from the machined drums. For anyone who has installed these brakes, did you do anything about the wimpy tab on the bottom of the axle assembly? It bends as easily as a piece of cardboard, and has been incapable of not doing so with my standard brakes, leading to brake assemblies that grab the drums because they won't stay square to the drums.

Mike Smith
N439M

When I installed mine, I emailed Sonex a similar question about that tab. They stated that they are using the tab without issue, but if I had concerns to weld a larger tab in place. For now I'm going to see how the factor tab works out.

I re-aligned the tab several weeks ago, but it quickly bent out of alignment again on the left axle. The whole plane shudders and jerks when I use the brakes taxiing. It's so bad everyone on the ground comments on it.

Mike

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Hi all, I think the hydraulic brake upgrade is the way to go. Tracy obrien makes some nice products for the sonex line of aircraft. They make some steel backing plates that we welded onto our original axles, we now have 4 holes to take up the load and torque, instead of one single tab. The holes line up with the sonex brake calipers. Also we put in a longer aluminum angle that mounts to the floor to hold the master cylinder, hence no more floor flex. Other sources of brake products to take a look at are matco , hegar, and Great Plains.

WaiexN143NM wrote:Hi all, I think the hydraulic brake upgrade is the way to go. Tracy obrien makes some nice products for the sonex line of aircraft.

When I built my airplane the Sonex hydraulic brakes were not yet available so I installed Tracy O'Brien brakes. I'm using the stick mounted brake handle/master cylinder that works much better than I had anticipated. Many have noted, as I did at first, that the O'Brien setup fades fairly quick under hard braking. But after some time with the plane I've learned to slow it down on landing and actually use very little braking at all.

Dale
N319WF

WaiexN143NM wrote: They make some steel backing plates that we welded onto our original axles, we now have 4 holes to take up the load and torque, instead of one single tab. The holes line up with the sonex brake calipers..

So are you saying the Sonex hydraulic brake calipers would bolt straight on to the Obrien axles?
I was wondering about that a while back as they looked pretty close, but couldn't find any dimensions of the caliper holes.

I currently have the O'Brien axles with azura brakes/machined drums and was looking to upgrade to haydraulic later

Cheers
Tony

Hi tony,
The steel backing plates that Tracy obrien sells we welded onto original axles, line one of the holes up with the tab hole to index. The center hole on one side of the backing plate will need a slight chamfer with a large unibit, to allow for the radius on the axle. The hole pattern will line up with the sonex brake calipers. The sonex supplied axles using the mechanical brakes had a axel spacer , which is not used with the sonex hydraulic set up. The Tracy obrien axles have a steel tube welded in with the same distance as the spacer would provide (outside of the backing plate) . That portion would have to be cut off and filed flat to let the brake caliper sit flat against the backing plate. The backing plates u can order separate are the same ones they use on their welded up axles. Boring out the brake calipers center hole is not an option, the internal oil galleys run close to the center hole. Any more questions please feel free to ask. That's what's so great about the sonex pilots, online or at air shows, everyone shares lots of knowledge!

Michael RADTKE
Waiex 143NM
Jab 3300
STD Gear
Switching to Rotec carb and ignition

mike.smith wrote:I'm converting to the Sonex hydraulic brakes, from the machined drums. For anyone who has installed these brakes, did you do anything about the wimpy tab on the bottom of the axle assembly? It bends as easily as a piece of cardboard, and has been incapable of not doing so with my standard brakes, leading to brake assemblies that grab the drums because they won't stay square to the drums.

Mike Smith
N439M

When I built mine .. I also put on hydraulic brakes. I used Great Plains brake
setup. For the axles I used O'Brien ones for the sonex because they go right
on and have a beefier backing plate for mounting the calipers.

RT

Has anyone on here used the Matco setup? I am planning to use that with 5.00x5 wheels/tires and my own design of wheelpant.

I am also planning to have hand actuated brakes, but with a split handle for differential braking. Mounted in the center under the throttle. I saw a picture of this early on in somebody's Sonex and it seems like a good compromise between complexity of toe brakes and no differential braking.

Gordon