Over tighten a loose axle nut

[sagaboy]

It started when I notice grease all over the outside rim of the tire that looks like brown mud, clean it and it build-up again after a few days driving, the process keep repeating over two months but I couldn't find what is causing it (brown mud that looks like grease, I keep assuming it is mud). The rear wheel appears normal except when rolling down a slope the wheel sound like faulty bearing but when I jack-up the car and slowly turn the wheel it is as smooth as can be.

Finally, I got fed-up and remove the axle nut--it simply pop-out--the only thing stopping it was the pin, I got the shock of my life, can you imagine that the only thing between the entire while coming out is just the pin.

At this moment, I couldn't find a replacement axle nut and so... I just over tighten it one more turn until I find a replacement, so far, no more grease are coming out.

Is it safe to drive with an over tighten one of the rear wheel axle nut?

[Ol'fogasaurus]

How much torque is one more turn? It sounds like you may have several things going on and just re-tightening the axle nut may or may not be solving the problem (if you are talking about a lug nut then don’t over tighten). There is at least one grease seal in there (you didn’t specify swing or IRS) and axle spacer(s) that need to be taken into consideration. On the swing axle there is a weep hole at the outer seal and the seal itself could be leaking axle grease.

The pin (cotter key) is there to keep the axle nut from backing out; if it isn’t a cotter key in there replace it! If the axle nut is not torqued to proper values it can back off. My Haynes manual (maybe not the best but it does suffice) says that swing axle torque should be torqued to 217# and drive axle (commonly called IRS) should be torqued to 253# but a lot of people like to go to 300# and higher (IRS only). It is common practice to take a ½” breaker bar and put a 4” extension on it and put all your weight on it, assuming you are not a 95# weakling (no insult meant to 95# weaklings) as you will not put enough torque into the nut. This way of doing it also destroys a lot of 1/2” breaker bars as the pivot pin usually breaks. If you plan on going this way then get a ¾” breaker bar and 36mm socket. There is also another tool you can use that can be hammered on and will accept a breaker bar; I do not recommend this as you are going to shock the axle/stub axle and not get a good torque to the nut that way. They might be OK for removing things (not a safe way to do it though) but there are better and safer ways to do it.

If you are serious about VWs then I would suggest that you invest in a torque dude (http://www.ebay.com/itm/Torque-Dude-Too ... 0303693961)/toque meister (http://www.ebay.com/itm/TORQUE-MEISTER- ... 5086826%26) which is a gear driven tool for installing gland nuts (unless you are using an aftermarket unit which has a bigger head on it) and axle nuts. It has a 9:1 gear ration so 30#s of torque values out to 270#s of torque on the nut. Both of the tools have stuff to allow for work with both 6 & 12 volt flywheels and wide and narrow bolt pattern axle nuts.

My first recommendation is to take the drum off and look at the seal area and fix it if that is the problem. Pictures might help.

Lee

[sagaboy]

Its a IRS slotted axle lug nut that I re-tighten. First, I tighten it as much as it can go with a 15" wrench then uses a 2 feet bar slotted into the wrench and tighten it one more turn (not possible or wise to force turn it further) until the slotted lug nut 'Hole" matches to put-in the cotter pin. My opinion is that the slotted lug nut has weaken over 40 years of usage and unable to grip well.

Thank you for the "torque dude" suggestion, will look into it ASAP and then inspect the seal area.

[Ol'fogasaurus]

I suspect that you are low on your torque reading.

The castellated (the base of the word is the comparison to the towers on a castle. The funny thing about the towers/turrets on a castle is that they were often the heads/toilets of the time and the moat was often a cesspool. I seem to remember that at least one King was assonated by and arrow up via the toilet hole [that is a funny pair of words in a sentence) nut is not the weak spot, if there is a weak spot than it would be the threads on the stub axle.

If my memory is OK (I doubt it), 300#s of torque is 300#s of weight applied to a 1 foot long bar or something like that (too early in a weekend morning for this kind of thinking) to make the object move (I took the easy way out: http://en.wikipedia.org/wiki/Torque).

If you think about it; the mechanics of torqueing and nut and bolt together could be compared to the latters A and V (threads; e.g., AV) jammed together in contact with each other (the two surfaces of the treads of the nut and bolt with only one surface of each of the threads [working surfaces] being in tight contact). As you apply a load, the nut is trying to walk up the threads of the bolt which causes the bolt to want to eventually stretch and fight back. The interference of the two threads and the stretching of the bolt is measured in the amount of work needed for the two surfaces to continue getting tighter. Of course this is way overly simplified as there are other surfaces that are in play but it is pretty much true.

Lee

[Marc]

The axle nut's probably still serviceable, although if you were to remove it and inspect the underside you'd probably see that it's no longer perfectly flat. The nut, stub axle, bearings and spacers are all steel but the drum is made of grey-pearlitic cast iron which is considerably softer. I can guarantee you that if you've been driving around with a loose axle nut the splines on the drum are damaged and the drum needs to be replaced. There'll be wear on the splines of the stub axle too, but usually it'll still be serviceable with a new drum. Inspect the axle splines closely near the inboard end; the drum doesn't contact the last part of the splines so they'll be the original width there, if there's a perceptible step in the thickness it means the splines are worn. On the drum, it's the outboard ~¼" of the splines that'll be unworn. Slide the tip of a slender screwdriver along the side of a spline from the inside, if there's wear you'll feel the screwdriver contact the step as it nears the outside end. Inspect the face of the axle spacer - it should be perfectly flat too. New spacers aren't available from VW anymore, although there are aftermarket parts available (the cheapest are $30 a side, you can pay at least twice that much for the better, hardened ones).
A drum with worn splines will continue to work back & forth on the axle, causing more wear...tightening the nut is only a temporary "fix". Even the inner & outer faces will wear away, shortening the length of the drum which causes a loss of torque on the axle nut. Simply put, the looser it gets the looser it gets. Eventually the splines are completely stripped (reduced to powder, a constituent of the "mud" you observed) and the car will no longer drive. By catching the problem when you did you at least avoided a towing bill, but you're still in the market for a drum (at least).

[SCOTTRODS]

You could use the 2 foot cheater bar (need to mark and put your weight at exactly the 2 foot mark), and stand on a bathroom scale and apply enou of your own weight to remove 150 lbs from the scale reading..... That would equal 300 ft lbs of torque.

Other than that, Marc has offered up some valuable info on he actual wear and damage..... Your car.... Your standards.

[Ol'fogasaurus]

Nice post Marc, I only address the tightning you covered it all.

Lee

[sagaboy]

The axle nut's probably still serviceable, although if you were to remove it and inspect the underside you'd probably see that it's no longer perfectly flat. The nut, stub axle, bearings and spacers are all steel but the drum is made of grey-pearlitic cast iron which is considerably softer. I can guarantee you that if you've been driving around with a loose axle nut the splines on the drum are damaged and the drum needs to be replaced.

There'll be wear on the splines of the stub axle too, but usually it'll still be serviceable with a new drum. Inspect the axle splines closely near the inboard end; the drum doesn't contact the last part of the splines so they'll be the original width there, if there's a perceptible step in the thickness it means the splines are worn.

On the drum, it's the outboard ~¼" of the splines that'll be unworn. Slide the tip of a slender screwdriver along the side of a spline from the inside, if there's wear you'll feel the screwdriver contact the step as it nears the outside end. Inspect the face of the axle spacer - it should be perfectly flat too. New spacers aren't available from VW anymore, although there are aftermarket parts available (the cheapest are $30 a side, you can pay at least twice that much for the better, hardened ones).

A drum with worn splines will continue to work back & forth on the axle, causing more wear...tightening the nut is only a temporary "fix". Even the inner & outer faces will wear away, shortening the length of the drum which causes a loss of torque on the axle nut.

Simply put, the looser it gets the looser it gets. Eventually the splines are completely stripped (reduced to powder, a constituent of the "mud" you observed) and the car will no longer drive. By catching the problem when you did you at least avoided a towing bill, but you're still in the market for a drum (at least).

Quite a mouth full!
Took half an hour of slow-thinking-repeat-reading to digest it all
OK, got it, thank you Marc It is appreciated.