SonexBuilders.net

Noel,
This post was a big help today. We got our brakes assembled and we actually bent up the cotter pins on the axles this session. Thanks!

Glad it was helpful!

And thanks for the nudge; I’ve gotta get back to my bird... My new job kept me out of the shop quite a bit this fall and I’ve lost all momentum. :-P

Take care,

—Noel

I installed the sonex disc brakes on my waiex, found the plans a bit misleading but worked it out still using the single lever but am keen to go to differential. A little disappointed with stopping power better than drums but pulling effort is greater. Checked for grease on the discs seems to be clean, Used bolts instead of cleavis pins ground of part of head so they couldn’t foul the disc, then cut heaps out of the spat to make it fit better plans would have been appreciated :-

Agreed,

Installation was a little challenging, but after some head scratching it all went together reasonably well. Stopping power is slightly better than the mechanical drums, but will not hold the plane on tarmac with Jab 33A at wot ground run. Even the mag check at 2000 rpm is a challenge. I have degreased the discs with brake cleaner several times, and can detect no external leaks.

I have purged the system for air several times with the help of an assistant as suggested by Sonex. Still I have to ‘pump’ it on final to make sure there is some stopping power at all on roll out, so I feel there might be some air left in there. Can anybody point me in the right direction to get this fixed?

Thanks
Kai

Kai -- I have a trigear Onex and after filling the hydraulic cylinder (from the bottom) whenever I pumped the handle, I kept getting a small air bubble in one of the brake lines coming out of the cylinder/reservoir. After numerous tries at getting rid of the air finally in desperation talked with the local John Deere dealer's hydraulics mechanic. He pointed out that they pre-loaded their cylinders (not practical at that point) and then suggested that if I could change the angle of the resting reservoir it might release whatever air was trapped in the system. I put a couple of sand bags on the tail and brought the tail down on the skid. Pumped in a little more fluid and the bubble problem disappeared. Don't know if this will work for you but it solved my problem.

Tom Jones
Onex 0133

After about 60 hours, the parking brake feature stopped working due to wear.


I cut out the damaged area and made a stainless steel wrap.




I really like the brakes and the parking brake design is simple and easy to use. There is a stop you can pull past and it holds the lever, as per the Sonex plans. I am hoping the stainless will solve the wear problem.