left hand thread on rear axle

[nattyphysicist]

Why does one rear axle on my Festiva have a left hand thread? Can I replace the axle with one that has a right hand thread without problems?

Thanks,
Nat

[fastivaca]

Why, I don't know. I have thought about doing what you suggest. Personally I can't see any problems with the idea. It will be interesting to see what comes up in this topic.

[Dave G]

It's so that the spinning of the wheel does not tend to loosen the nut. Really bad idea to switch it...

[fastivaca]

It's so that the spinning of the wheel does not tend to loosen the nut. Really bad idea to switch it...

If you think about that it doesn't make sense because the nut on the passenger side spins OFF in the same direction that the wheel spins when moving forward :shock: Same on the driver's side! Go figure....

[jglutz]

The Left hand thread (passenger side) prevents the nut from becoming to tight while the car is rolling and causing the wheel to lock up. This does not explain rolling in reverse but then again who drives at 55mph in reverse. Also, it not untypical in many spindle designs to use a LH thread to control failure mode of failure. most industrial application just use a second nut. The main reason kia did it is to keep manufacturing cost low. The machines that make the parts are indifferent to the thread. The only cost to the manufacturer is having two different parts to stock. Also the staking method is integral to the nut (free). Also the assembly cost in the plant is cheap, the torque is ver accurately applied and the nut is staked, no cotterpin to align with a castle nut (my prefered method). Anyway putting a opposite spindle on with a new nut (readily available anywhere for a couple of $) properly staked should not be a problem. Personally i hate this design, every year when my 92L goes thru inspection, They either screw up the torque, contaiminate the grease, or charge me for a new nut.

[kzbill]

I used two right hand spindles on my old axel I drilled and cotter pinned them. like the old fronts on rear wheel drives.

[elcamino1]

Mine came with castle nut and cotter pin.

[nattyphysicist]

The Left hand thread (passenger side) prevents the nut from becoming to tight while the car is rolling and causing the wheel to lock up. This does not explain rolling in reverse but then again who drives at 55mph in reverse. Also, it not untypical in many spindle designs to use a LH thread to control failure mode of failure. most industrial application just use a second nut. The main reason kia did it is to keep manufacturing cost low. The machines that make the parts are indifferent to the thread. The only cost to the manufacturer is having two different parts to stock. Also the staking method is integral to the nut (free). Also the assembly cost in the plant is cheap, the torque is ver accurately applied and the nut is staked, no cotterpin to align with a castle nut (my prefered method). Anyway putting a opposite spindle on with a new nut (readily available anywhere for a couple of $) properly staked should not be a problem. Personally i hate this design, every year when my 92L goes thru inspection, They either screw up the torque, contaiminate the grease, or charge me for a new nut.

Great info, thanks!

Regarding the bearing preloading process, are you suggesting to torque the nut and then imediately stake? I thought that after torquing, the nut should be loosened and then finger tightened, but I don't really understand why.

[freshtiva]

When I bought my red car it came with two righty tighties. Its never been a problem.

[FB71]

Regarding the bearing preloading process, are you suggesting to torque the nut and then imediately stake? I thought that after torquing, the nut should be loosened and then finger tightened, but I don't really understand why.

tighten, spin, loosen, tighten, spin... do this 2 or three times, it seats the bearings. Then torque to 25 lb/ft, then stake.

[jglutz]

To All: The finger tight method is typical where the outer races of the bearings are a slip fit, (the festiva is a press fit). This method ensures that the races are fully seated. What I do....when replacing bearings (ever 36 months or so)...is install the drum and hand tighten the nut....put the wheel on.... then proceed to spin the wheel and tighten....you will know if you are to tight....i also wiggle the wheel to see if I'm two loose. I lightly stake the nut. When I service the brakes only....I return the staked part of the nut to the keyway and stake it a liitle deeper. The rear wheel bearings on the festiva are simply.....touchy...the biggest trick is to keep them clean and add alot of new grease evertime the drum is put back in place. Also make sure the spindle is wiped cleaned or sprayed with Brake Kleen. The onleyrear end propblem i have is finding replacement dust caps. Help appreciated.

[FB71]

Taper roller bearings require preload to operate correctly. If set correctly and lubed properly, they shouldn't need to be addressed again for 60k-100k miles. Preload = 25 lb/ft torque.

[jglutz]

If the bearing are never over heated and not contaminated, they will hold up as long as the lube and inner seal hold up. Factory torque is 25-29 Newton Meters (18-22 ft-lbs). Factory instructions go further yet...something similar to the fron wheel bearing bench test....If interested....I will post copies....please let me know.

[FB71]

yup, I'm very familiar with the factory specs and service pubs... been reading (and re-writing them) for 15 years. 5 of those at a Ford dealer, 7 with Ford corporate. Trust me, 25 lb/ft works best.