TheSamba.com :: View topic

Wed Oct 02, 2013 11:01 am

I had a 'break' shop replace my '84's rusted-through rear backing plates with a fresh new set. Everything's back together fin, but my right rear castle/axel nut won't stay tightened. I took it back to the shop and they impacted it down which seems to be more than sufficient for driver side, but it just keeps coming loose on the passenger side. Each time it gets loose it sqeaks. Just like the one in this post http://www.thesamba.com/vw/forum/viewtopic.php?p=5819098.

Everytime I tighten it's quiet for a few days. The wife's driving it and she 'forgets' to tell me about the noise.

I tightened it to one turret space more than the 360ft/lbs speck with a giant torque wrench last time. Do I need a new nut? Is something broken? Or do I just need to put a bunch more torque on it? If so, how much?

I know driving with it loose nut is bad, so I'd really like to figure something out.

Thanks.Peet

Wed Oct 02, 2013 11:02 am

The torque rating for that nut is very high and it should have a cotter pin installed so it will not back out.

Wed Oct 02, 2013 11:12 am

Time to pull off the nut and inspect the threads to determine if the nut or stub axle needs to be replaced. The torque spec and cotter key should hold the nut in place without issue.

Wed Oct 02, 2013 11:38 am

there is supposed to be a pin thru a hole in the shaft that goes thru the castle nut. that pin is then bent so it cant come out. this pin is called a cotter pin. if pin is missing that may explain why the nuts keep getting loose.

if you have the pin installed, then the nut can't turn anymore. if the pin is in place and still you get looseness, then the threads could be pulling out on the nut or shaft, or the wheel bearing is starting to fail, or something was not installed right at the shop, maybe the stub axle was not fully seated in the bearing becuase the axle was damaged, or some foreign object got between the shaft and bearing, or hub and bearing. the bearing may not have been fuly seated, and it is getting squashed when you drive. you also may have failing splines, which would allow the hub to rock back and forth, which will allow the surface on betwen the hub and bearing and / or hub and nut to wear frm teh rocking back and forth motion.
(I had this happen on a Bug, the drums splines (no hub on a Bug, splines are on the drum) where worn, this allowed the drum to rock back and forth when driven, even though the castle nut was tight and pined, after a short time of dring the drum would be loose again. the solution was a new drum with nice fresh splines. the rocking motion was not detectable when on jack stands, but the drum did rcok when driven. so take a look at the hubs splines when you remove it. fortunatly the drum or hubs splines are made of a softer material tha that on the shaft, so the shaft was not damaged in myBugs case, only the drum. cast iron verse steel, the steel axle is stronger than iron hub. also look for particles of metal indicating wear on the splines

take the hub off next time and inspect there. for teh spline to wear it only takes one time that the nut is not torqued right. if torqued loose, things start moving, the splines get worn, then if the nut is torques correctly later it dont matter, the worn splines will still allow movement and further loosening. solution is a new hub.

so make sure the cotter pin is installed. if it is, investigate the other items.

dont drive with this coming loose, as bearing damage can occur, and at worst case you can loose the whole wheel. that can be very dangerous.

good luck

Wed Oct 02, 2013 11:48 am

bluebus86 wrote: if pin is missing that may explain why the nuts keep getting loose.

I'm not a Vanagon person so forgive me for chiming in, but my experience on the Beetle has been that the cotter pin is not sufficient to keep the nut from loosening. At least as far as the Beetle is concerned, the nut must be tight enough to stay on without the cotter pin. I think the cotter pin is there to slow down the nut from coming off. If the nut loosens, the cotter pin will hold it for a while, and you will definitely feel the effects of the loose nut so you will have a chance to fix it before the nut comes off completely.

If any of this is inapplicable to the Vanagon I stand corrected and would like to know how it differs. Thanks. :)

Wed Oct 02, 2013 11:51 am

My experience with tightening the castle nut is that you torque it to specs first and then continue to tighten until the cotter pin hole just aligns with a set of slots on the castle nut. Insert cotter pin and it will now resist any movement by the castle nut due to there being no slack available between the slots and the pin for unturning...

Wed Oct 02, 2013 12:12 pm

The impact gun will not do it. You need 360ft lbs and then some. Find a shop with the right tool and good luck.

Wed Oct 02, 2013 12:41 pm

Alaric.H wrote: The impact gun will not do it. You need 360ft lbs and then some. Find a shop with the right tool and good luck.

A 3/4" impact gun will easily do it.
My Snappy spins them on and off with ease.

I snug the nut and than use a 3/4" torque wrench to set the proper torque.

Same as any big truck shop.

Wed Oct 02, 2013 5:09 pm

Thank you everyone for your replies. Bluebus, you were especially through and probably spot on. The only plus side here is that it'll be easy to get the nut off to have a look. :) / :(

The redneck in me wats to douse it in thread lock and try one more time without disassembling it. Luckily the redneck rarely wins.

And just to be clear, it has been torqued to spec and a bit beyond so I could get the pin in. And no, the cotter pin will not keep it from loosening in its current state.

What do you all think? Should I ask the break shop to deal with this? It was quite a while ago that they did the work, but it wasn't an issue until they took it off.

Wed Oct 02, 2013 5:19 pm

peet1 wrote: the cotter pin will not keep it from loosening in its current state.

Than something is not right.
The threads of the stub and the nut need to be examined.
It should not be able to loosen itself.

Safety first, take it to a pro with tools.

Wed Oct 02, 2013 5:29 pm

peet1 wrote:

What do you all think? Should I ask the break shop to deal with this? It was quite a while ago that they did the work, but it wasn't an issue until they took it off.
I doubt there is any warranty on their part. Plan on getting new bearings, new seals, a new spacer, new castle nut and cotter pin. May as well pull the axel and clean, inspect and repack the CVs at the same time.

Wed Oct 02, 2013 5:33 pm

I recently had one that did the same, torqued to 360#, and a little more to get the cotter pin, then it backed off through the pin.

Examination showed hammered splines on the stub.

In the pic you can see the shiny freshly made chop of the pin, with the remainder of the pin in the center.

Wed Oct 02, 2013 6:46 pm

Quote: Time to pull off the nut and inspect the threads to determine if the nut or stub axle needs to be replaced.

Wed Oct 02, 2013 7:08 pm

levi wrote: I recently had one that did the same, torqued to 360#, and a little more to get the cotter pin, then it backed off through the pin.

Examination showed hammered splines on the stub.

In the pic you can see the shiny freshly made chop of the pin, with the remainder of the pin in the center.

You tightened it to spec and it backed off through the cotter pin? :shock: Was the spec wrong?

Wed Oct 02, 2013 7:39 pm

yes, here's the post:

page 3 of this thread
http://www.thesamba.com/vw/forum/viewtopic.php?t=4...p;start=40

Wed Oct 02, 2013 9:46 pm

Once the splines get loose there is nothing you can do but replace the hub and shaft. Each time you apply load and then back the load off the hub will move just a tiny bit in relation to the shaft and the nut will quickly wear and loose its preload as it does so.

It is likely that in the past someone failed to tighten the nut sufficiently which allowed the initial wear to occur and from that point on it has all been downhill. :cry:

Thu Oct 03, 2013 6:24 am

This has been very interesting to me. So I learned that putting the correct torque on the nut won't help if the splines are worn already, which happens when the nut is not torqued correctly in the first place. A slippery slope. Thanks.

Thu Oct 03, 2013 7:58 am

Don't they usually recommend replacing the castle also?

Or I saw it somewhere..

Thu Oct 03, 2013 9:03 am

samscholz96@gmail.com wrote: Don't they usually recommend replacing the castle also?

Or I saw it somewhere..

They recommend replacing the front "peen" nut, but not the rear castellated nuts, at least to my knowledge.

Tue Nov 19, 2013 10:14 pm

I'm finally getting back to this a month later. I thought I'd give tightening the nut one more go, but it started to back off after a day of driving. I've ordered a new nut just incas it has something to do with this ancient rusty castle nut.

That said I've removed the hub and inspected the splines. I'm not exactly sure what perfect splines look like, but besides the rust on mine, I really don't see any crazy wear. There's a bit on the stub axle, but I think that's from the little bit of running with the loose nut. There doesn't seem to be any play on the stub axle between the bearings. I slid the axle back and inspected the the bearings and spacers. There's no shavings or signs of wear.

The only thing that I'm curious about is there is a little bit of play between the hub. I'm not sure if this is abnormal, but it seems like 360ft/lbs of torque would tighten it up, but please look at the video link below and tell me if it's not normal (I'm sorry, but I couldn't get the youtube embed to work). I really don't think it's the case, but do I need a new hub? A new axle? Both?

I'm going to take this opportunity to teach myself about the rear wheel bearings and re-pack them.
http://www.youtube.com/watch?v=2P1oXpig09I

http://www.youtube.com/watch?v=2P1oXpig09I