945 front hub retaining nut re-use?

[Ian Fife]

I am considering regreasing the front hub bearings of my 1991 945 (2 litre manual UK spec.). These are the original bearings but seem a little sticky.
My question is about the nut holding the bearing on the stub axle. This is a special Volvo nut, slightly tight fitting to prevent it coming loose. Volvo recommend single use only - replace every time.
Does everyone always do this? Or is reassembly with some thread lock an acceptable practice? It seems wasteful to discard these nuts which are not easily bought and expensive.
What do you all do?
Ian F

[Familyman 90]

You can get them less than a tenner each! I doubt even the dealer would break the ten pound barrier for a new one.

Considering how inexpensive these nuts are, and the potential for considerable damage or pain in the - unlikely - event one should come loose, I can't see any reason why one would consider re using them.

[griston64]

Originally Posted by Ian Fozzard

I am considering regreasing the front hub bearings of my 1991 945 (2 litre manual UK spec.). These are the original bearings but seem a little sticky.
My question is about the nut holding the bearing on the stub axle. This is a special Volvo nut, slightly tight fitting to prevent it coming loose. Volvo recommend single use only - replace every time.
Does everyone always do this? Or is reassembly with some thread lock an acceptable practice? It seems wasteful to discard these nuts which are not easily bought and expensive.
What do you all do?
Ian F

Do the nuts differ from the later 945 hubs that are sealed units ?

[Ian Fife]

It's the nuts I am asking about. The bearings are integral with the hub, but I believe they can still be greased from the inside - please correct me if I am wrong!
Ian F

[Laird Scooby]

Originally Posted by Ian Fozzard

It's the nuts I am asking about. The bearings are integral with the hub, but I believe they can still be greased from the inside - please correct me if I am wrong!
Ian F

The bearings can NOT be regreased without dismantling them. If they are sticky and/or have excessive play, you need to replace the hub complete with integral bearings and a NEW EVERY TIME retaining nut. Those threads are pretty fine and tightened to quite a high torque level, the nut is designed to be sacrificial in the case of thread damage so re-use is NOT recommended.

Unless you know the nuts are relatively new (e.g. you fitted them recently) and the threads are clean, don't gamble with your life and those of others and renew the nut.

On the upside, new hubs/bearings usually come with a free nut.



Mark - i'm pretty sure the nuts are the same on the later 940s, the early ones with the integral bearings in the hub are the same throughout the 9xx range and (from what i've worked out) first appeared on the facelift 760 in 1988, were adopted by the rest of the 7xx range during its 1990 facelift and i believe all 9xx had the same.

[Ian Fife]

Many thanks folks, that's very helpful. I will leave well alone for now. For info: I did remove the hub about 15 years ago to allow fitting of new brake shields, and I did use new nuts that time. Just wondered if re-use was something people did now that we have good thread locking products.

Ian F

[Ian21401]

940, 1992.
I removed the front hubs when I replaced the rotten brake back plates.
The nuts were VERY tight. Prior to starting the job I checked whether I would be able to loosen the hub nuts. I managed to loosen the nearside with my breaker bar and a heavy hammer but the offside would not budge. I took the car to my local friendly tyre fitter who freed it very easily with an impact gun, without removing the road wheel. I then retightened it to take the car back home to do the job.
I had obtained replacement flange nuts from my main dealer ( part no. VO1387624, I think.) but for some reason, rightly or wrongly, I decided to refit the original nuts with thread locker. They were then tightened as per Haynes. ( 100 Nm. then angle tighten 45degrees.) In effect that was as tight as possible using my breaker bar. That was several years and several thousand miles ago with no issues since.

[Laird Scooby]

Originally Posted by Ian Fozzard

Many thanks folks, that's very helpful. I will leave well alone for now. For info: I did remove the hub about 15 years ago to allow fitting of new brake shields, and I did use new nuts that time. Just wondered if re-use was something people did now that we have good thread locking products.

Ian F

It's not about the thread locking properties per se, it's more about pre-loading the bearings. Also you wouldn't want any stray threadlock working it's way into the bearings.

Are you sure it's the bearing that's sticky and not the caliper and/or pads? If the car was laid up during lockdown for a considerable period of time, it's possible they may have Brinnelled as a result so your only option will be to renew the hubs or they could in fact just be worn out. Worth checking all the other options on what is quite an unusual query.

[Ian Fife]

Dave - everything is stripped down to replace calipers, discs etc. so the hub is the next thing to look at. I've never had noises or any problems with the hub bearings but the hubs don't spin very freely, BUT they do move round with light finger pressure. No play/no noise/smooth as silk.
Ian F

[griston64]

Originally Posted by Laird Scooby

The bearings can NOT be regreased without dismantling them. If they are sticky and/or have excessive play, you need to replace the hub complete with integral bearings and a NEW EVERY TIME retaining nut. Those threads are pretty fine and tightened to quite a high torque level, the nut is designed to be sacrificial in the case of thread damage so re-use is NOT recommended.

Unless you know the nuts are relatively new (e.g. you fitted them recently) and the threads are clean, don't gamble with your life and those of others and renew the nut.

On the upside, new hubs/bearings usually come with a free nut.



Mark - i'm pretty sure the nuts are the same on the later 940s, the early ones with the integral bearings in the hub are the same throughout the 9xx range and (from what i've worked out) first appeared on the facelift 760 in 1988, were adopted by the rest of the 7xx range during its 1990 facelift and i believe all 9xx had the same.

That's what I thought Dave but I had a funny feeling early 740's etc had separate front wheel bearings that you could regrease and replace

I wouldn't use threadlock either. When I replaced mine recently the SKF hubs came with new nuts and once tightened to spec they deffo aren't going anywhere