King pin bearing numbers

[Dikfrik]

How the thread was stripped i do not know! However that costed me a new CV which i installed using the method a described in the manual, test drived it for about 20km and made sure there is now excessive heat. All was fine! (I did not replace the bearings since it all seemed fine, but maybe that was short sighted!) Every time i drove the car after that i would feel the heat on the hub and it was always fine.


What is not to hot?

Mine at the moment when I feel with the finger on the shaft itself - I can hold for 10 counts maybe a bit longer??

Riaan

Remember when you do the test you must use the brakes as little as possible - i drove during low traffic and use the handbrake where possible. On my bearings i could touch indefinitely - i remember using a laser temp gauge in the beginning to see what the difference between the two was and the colder one was around 45degrees if i remember right

[Riaan Harman]

Riaan

Remember when you do the test you must use the brakes as little as possible - i drove during low traffic and use the handbrake where possible. On my bearings i could touch indefinitely - i remember using a laser temp gauge in the beginning to see what the difference between the two was and the colder one was around 45degrees if i remember right

Freek

I shall do that test also just to make sure but mine is running to hot to my liking.

Mine also tend to come loose a bit after about 5000km, I thought I'm tightening them too little

[Dikfrik]

Just a wild thought. Perhaps your hub is not centred properly and this causes two different centres - one the half shaft in the tube and two the stub around the wheel bearings causing an eccentric rotation between them. This could put in a high axial loading in the nuts

Andrew, i sincerely hope your thought is too wild! I have taken care to place the shims exactly as it was taken out. Also would the seal in the tube not leak quickly - mine is still ok?

Alan i will send the hub to engineering shop to check for squareness - i agree is could be a problem.

[Alan]

Alan i will send the hub to engineering shop to check for squareness - i agree is could be a problem.

Hi Freek, this was definately a problem on my failed hub. It is easy to fix by an engineering shop but a new hub is unfortunately very expensive.

[Dawie Louw]

Not hi-jacking the thread, just giving tribute to a respected "G"-man, Dirk Wentzel.

Andrew wrote: "Dirk is here right now and my fingernails are still clean. Cool."

Dirk normally use those throw-away neopreme gloves so I am sure his nails are clean too!

My wife thinks Dirk is the neatest working mechanic she has ever seen. I agree, he is a pleasure to watch, doing front hub work: Changing CV boots, kingpins, etc. He did my 460's six years ago with no hassles since.


I too cannot understand how a nut secured with the locking tab, can wotk itself loose. Must be very strange forces at play.

[Dikfrik]

Feedback time on the issue of the loosening CV/hub nuts:

Considering that the history of the issue is recorded under this thread i kept the answer here.

After stripping the whole swivel joint / CV assembly and not finding any seized bearing or other issues which could explain why the nuts came loose so soon after installation i decided to check the fitment of the splines between the hub and stub axle since that is the only place where relative movement between the hub and the CV stub axle nuts could take place. After all the nuts do not exert a significant clamping force on the hub face and the only thing which prevent the CV stub from turning in the hub is the splines - and voila! my worst fear came true - the female splines in the hub tube are so worn that the hub will turn about 1mm or more relative to the stub axle and also has significant lateral movement (ie you can move the hub up and down by a few mm with the stub axle fully inserted)

In my opinion this has to be most important reason for the two failures i have experienced. The play in the splines will result in constant backward and forward movement between the hub face and the locked nut which have exert a significant force on the tab washer key, resulting in eventual shearing of the tab washer key and loosening of the nut. Then, with the hub moving outward on the stub the lateral movement will result in the nut starting to get an uneven loading on its edge which will concentrate the force on one side of the thread only which could result in the stripping of the thread i have experienced twice now. Also it is possible that not tightening the nuts as specified will improve the situation by reducing the friction between the hub face and the inner nut resulting in lower forces on the tab washer making it last longer.

No this 280 is now nearing 28 years and has done probably between 300k and 400k km's so some wear could be expected i think?

So the solution for me is to look for a new hub or finding a good second hand one! Bummer at about R7k each through MB..

Therefore my advice to all the members of the "loose nut brigade" is to go and check those hub splines..

I hope this helps a bit..

Regards
Freek

[Dawie Louw]

Freek

Thanks for sharing.

I am no expert but surely the splines should have been a tight fit and the only way to achieve that, the nut(s) must pull the shaft tight into to hub? The only other explanation may be incorrect tolerances between the male and female splines but hey, I know the Germans and Austrians are not perfect but their engineering and the quality of their steel is something to behold.

Just an aside, today I was cutting a hedge (as I have to do every few months) with a pear of shears, bought at least 40 years ago, at the OK Bazaars. No discernable wear. The hardest steel you can imagine, not found in any of the newer tools now available. Made in West Germany.

In your opinion, what would have caused the wear in the splines? Perhaps not pulled tight, not being fastened properly in the first place?

[Andrew]

Loctite makes a product called BRG with which you can secure loose bearings into a housing. It works. I am sure it will work in this situation.

[Dikfrik]

I think that when the hub is new the splines will fit relatively tight, but over a few 100 000km it should wear a bit. I do not know how many km my 280 has and the odo is not counting for the last 4 years, but i estimate closer to 400k km than 300k km. Also consider that there is no oil in there but only the grease fitted with the bearing and maybe that will aggravate the problem - so to me wear and tear there is not unexpected. If i get new ones i will check the fit - since my hub is also relatively new

I also owned two LR Defenders and both had problems with especially the rear side shafts due to the stripping of the splines. On my first one the rear side shafts had to be replaced on 80k km and once again before i sold it at about 240k km. On the second one work had to be done after only about 100k Km. At that stage the LR dealer welded the shaft to the hub to reduce the stress on the splines. Just look carefully at the rear hub some defenders with relatively high km - chances are good that the hub is welded to the shaft.

Andrew, regarding the Loctite product - does it actually build up the splines to improve the fit - if so can you get it out again?

[Andrew]

Ja it fills in all the voids and dries rock hard. To release you need a sharp blow which breaks the bond.

Try it with the parts on your workbench