Wheel Pant Bracket Failure and Brake Failure

[JonJay]

Dan hit it on the head.
As mentioned, the bracket runs very close to the brake disk. I discovered some minor scoring on my brackets very early on. I had to adjust the spacers to give the bracket more clearance.
I would do a run out check on your brake disks. There is a possibility of warping due to the excessive heat build up from the friction.

Wheel pant brackets, brake lines, brake disk, calipers, etc... should be inspected every time you take your wheel pants off. This probably didn't happen over night.

[bullojm1]

While my setup is slightly different (Sam James Wheelpants attached with the Van's bracket), I noticed a lot of play in the wheelpants bracket that I wasn't happy with. My solution was to rivet a piece of 0.090" 4130 steel to reinforce the wheelpants bracket:

[Wayne Gillispie]

Originally Posted by JonJay

Dan hit it on the head.
As mentioned, the bracket runs very close to the brake disk. I discovered some minor scoring on my brackets very early on. I had to adjust the spacers to give the bracket more clearance.
I would do a run out check on your brake disks. There is a possibility of warping due to the excessive heat build up from the friction.

Wheel pant brackets, brake lines, brake disk, calipers, etc... should be inspected every time you take your wheel pants off. This probably didn't happen over night.

Yes, wonder what the tire pressure was?

[JonJay]

Originally Posted by Wayne Gillispie

Yes, wonder what the tire pressure was?

Good point, and it looks like those might be new tires, or new retreads.

[Wayne Gillispie]

How much clearance between wheel pant and tire? I have 7/8". Check tire pressure as often as possible to prevent contact from a not so greaser of a landing. I try to check mine every three months. I also inflate 5 psi over Van's numbers. Not saying that is proper, just what I do on my -10. It takes about 90 min for me to disassemble, inspect everything, reinflate and reassemble. It makes it easier to move too.

[Bavafa]

Also, the way the brake hose is connected, leaves little room for flexing. I believe if not using a flexible hose, one need to put a full turn/circle to make the line flexible enough for all the movement.

[JonJay]

Originally Posted by Bavafa

Also, the way the brake hose is connected, leaves little room for flexing. I believe if not using a flexible hose, one need to put a full turn/circle to make the line flexible enough for all the movement.

Correct - which is exactly how the plans have always shown. It does not appear these lines where ran per plans. Good catch.

[BillL]

Originally Posted by DanH

The bracket was pushed against the disk. The disk cut through the bracket. Note the perfect semi-circle, and what appears to be a chunk still hanging.



Now look at the other photo. See how much bracket material is missing?

The brake disk is blue, and the caliper label has been heated. Both have been quite hot, either due to brake use or because the disk was wearing through the bracket. Either way, there's a high probability that the standard nitrile caliper o-rings are baked hard, thus the fluid leak.

Yep, from the fracture pattern on the other picture, I bet it broke loose first then drooped to the disk. The missing tube loop is already noted, and the caliper bolts are missing safety wire.

I will be mounting brakes next few days, so this is good information. Thanks for sharing.

[mmcmanus]

Thanks to everyone who looked at this and for your ideas. The caliper and all have already been fixed and reinstalled. We did not do the safety ties since we're waiting for the new bracket to come in. The brake line IS steel braided, flexible line.

I think the suggestions about something getting into the bracket, forcing it into the rotor, and that causing the failure are probably correct. And, the idea that the caliper and O-ring got hot (and hard) and allowed the brake fluid to escape makes sense too.

Also, I was remiss and did let the tire pressure get low. I didn't have time before I left on this trip and planned to take care of the tire pressure this weekend when I returned. Maybe my own procrastination bit me this time

Thanks again for your ideas and help.

[Beancounter]

During phase 1 and taxi testing I had a similar failure.
In my experience a dragging brake and numerous hi speed taxiing, heated up the rotor. The rotor heated the middle area of the pant bracket, causing it to warp and physically contact the brake rotor and wear a groove. I had to replace all of the seals, flex lines and pads due to overheating. I suggest that a dragging brake maybe the initial cause of your problems. Since you indicated you were going to add a flex loop, consider using a rubber flex hose, either automotive based or from a grease gun.