Slight Rotation of Brake Assemblies
 

Folks,

My A&P and I replaced a set of brake pads yesterday and he noticed the brake assembly on each wheel rotates slightly (I'd guess 1/16" each direction). Is this normal / ok? His concern is it will eventually wear through the bolt or elongate the hole necessitating a new axle. Also concerned if a brake malfunctions steering is lost.

Happy New Year and appreciate any guidance.
Tim

Not sure if it's normal, but you're unlikely to require a new axle. More likely, a new brake bracket. Probably not a safety issue (if I understand correctly what you are describing) at this point, but worth replacing the bracket at the next opportunity.

greg

Tim, I'm not sure I understand exactly what you are talking about, but there should be no slop in the assembly except where the caliper anchor pins go through the anti-rotation bracket (normal for the caliper to free float a bit).

The Anti-rotation bracket is bolted to the axel and there should be no slop in that hole. If that bolt is loose in the hole than you need to be looking to step it up to an oversize hole for a nice tight fit or perhaps replace the bracket like Greg mentioned above.

Slight Rotation of Brake Assemblies
 

Thanks Greg and Walt,

Is the bracket you're referring to the sleeve that goes around the axel with the bolt going through it or another component?

Tim

Yes, the one that the caliper pins go into.

In my experience, it's the Brake Flange (WD-4??) mounting holes that are becoming slightly elongated. You will see this on almost all mid-time RV's. It can be replaced with a new one and mounting bolts during your next brake pad/tire changeout.

Probably not a huge safety issue (unless you are seeing abnormal bolt wear), but it will result in a small amount of play in the brake assy and wheel fairing...

Brake Assembly Rotations
 

Thanks Walt and Joe. My A&P says it's definitely the axel / sleeve bolt and hole with the play. I'll call Vans tomorrow to see what size bolt we can go up to and put it up on stands to get a better look.

Tim

I noticed slight play - just enough to feel - at my second annual and around 70 hours. I'll see how it progresses at the next inspection. Thing is in an RV - unlike a car - you only brake going forwards so there is no reverse load cycling on the holes to open them up faster.

Sounds like a design mod to include a thicker walled axle sleeve is needed.

Jim Sharkey
RV-6

This attachment method is very common on this type of landing gear leg/axle. Because of the high torque loads and thermal cycles, it is really tough to keep the bolt from working the hole. This is one of those situations that requires a reamed (perfectly round) hole, and an interference fit fastener. If you can put the bolt in place without a hammer and drift, it's too loose.

You might be able to save it by reaming slightly oversize and going with a specialty fastener.

Tighten the bolt