Axle nut torque and pinning

billnaz · #1 10-03-2006, 09:20 AM

I'm finalizing my wheels, and cant find guidence on torque of the axle nut. I've heard that "tighten untill the wheel spins 2-3 times" works, but my brakes add some residual friction which won't allow a good spin. Any hints?
Also, any wisdom on how to drill the holes for the cotter pin? I'm planning to use a 12'' drill from both sides to clear the wheel/hub.

Thanks for your collective knowledge!

Bill

rv969wf · #2 10-03-2006, 08:06 PM

Some might not agree with me on this ok. What I do is make first that the wheel bearing races are seated correctly. When you install the brgs. wheel etc.... Tighten the nut firmly around 10-15 ft lbs. while spinning the wheel to make sure brgs and races are seated. If you tighten it to tight without spinning the bearings you can indent the bearing rollers into the race and make small indentions in the race, not good. By turning the wheel brgs. as you seat everything you will not do this. After you have found the happy spot back the nut off 1/8 turn, drill your cotter key hole and install the cotter key. With disc brakes you need the brgs to have a slight amount of loosness so that the brake rotor will wobble / push the brake pads away from the rotor during rotation. If the nut is to tight the brake pads will be dragging against the rotor everytime you takeoff and land. Hince less drag on the brake shoes / rotor creates less rolling distance on takeoff. Does this make since??? All automobiles are like this with disc brakes btw. Yes the wheel pants will pivot slighty by doing it like this. If you want the brakes to drag on takeoff then take all the clearance out of the brgs but only bring the nut up finger tight then the wheel pant will not move around as much. I myself don't like the brake shoes dragging on the rotors all the time. This is how I do it but others might have other opinions so do as you please. Just don't over tighten them. That's my 2 cents. Whatever you do the plane will fly just fine. One thing to remember is airplanes don't travel 50,000 miles on there wheels so I really don't think you'd be hurting anything if you run the nut finger tight and take all of the clearance out. AJ

Rene Bubberman · #3 10-04-2006, 12:59 AM

Hi Bill,

I have a description with pictures on http://websites.expercraft.com/PHVII...ry&log_id=2615

billnaz · #4 10-04-2006, 08:54 AM

A.J. and Rene,

Thanks for the help. I'm good to go. And pictures even! Love this forum.

Bill

cytoxin · #5 10-04-2006, 09:17 AM

Quote:

Originally Posted by rv969wf

All automobiles are like this with disc brakes btw. AJ

i dont believe this is correct, tighten spindle nut to 12 ft lbs while turning back off untill just loose, then tighten by hand till snug if pin will go in fine if not back off no more than 1/12 a turn ( half a flat) and install pin. disc brakes are self adjusting. caliper piston seals are designed to retract pistons just enough to allow brake lining to lightly brush disc without any drag. sliding caliper design compensates for any pad wear. looseness in wheel bearings will add to low pedal and sponginess.and increase side stresses on the rotors then leading to warped rotors and vibrations. the final end play of the rotor after wheel bearing adj is .001-.005

brianwallis · #6 10-07-2006, 05:41 PM

Simply unbolt your wheel brake pad and then tighten your wheel nut untill it turns 1-2 times after a good spin and then re attach your brake pad..
Thanks
Brian Wallis
A&P/IA