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johnfranklyn

One Shot Wheel Nuts

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I remember setting up the wheel bearings on my old van and fitting a new split pin to the axle. I just wonder why the bearings on my new van now require a one shot high torqe nut to keep the wheel on the axle when a simple split pin managed the same duty in the past? As I remember the outer tapered bearing in the past actualy encouraged a wheel to fall off in the past if the split pin failed. I beleve the modern bearings are not tapered and should tend to remain on the wheel rather better than the taper bearings. Perhaps a technical caravaner can explain why one should not just drill a split pin hole through nut and axle and use the old one shot nut again.

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Without going into the technicalities of it, the nuts are about £7 for a pair, is it worth the hassle?

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I wouldn't do it !

1 if you drill through the axle it would weaken it and it would therefore be thicker in design to allow for this

2 you would still need to torque to the same spec as before and if it did come loose the wear created on the bearing/shaft would affect your handling

3 for the sake of a few quid why risk itsmile.gif

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Hi, What type of chassis are we talking. Alko, BPW or Knott?

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if the split pin failed.

 

Taper bearings of pre-1994 were not tightened fully. The nut was tightened and then backed off to allow some end float. Instructions were always to use a new split pin. If these bearings were maintained, they would outlast the vehicle. IMHO one-shot nuts are engineering at its worst. The driveshaft nuts on my towcar are torqued to a slightly higher figure than the Alko nuts, but then they are secured by a castelated ring and a D clip through the stub axle.

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the thread streches some debate on other forums about the re use off on shots but for the price i would not.

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Hi

best of luck if you decide to alter the nuts----- they are tough !! took a tungsten carbide lathe tool to machine.

Cheers david

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If you are looking to drill why not try to purchase some crown nuts to suit your axle as they are far more suited to split pin application. Wouldnt worry about drilling the axle, when i used to prepare my race bikes, i used to drill and wire every single nut & bolt on the bike never had one break on me

 

 

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Sorry about my one shot wheel nut query. What I wanted to know is why we now need a high torqe wheel nut when before they started to fit them a castlated wheel nut under the very slight pressure needed to set up the bearing and securing with a split pin was all that was required to prevent a wheel coming off? Indeed it would be simple to turn up a couple of nuts suitable, castlate them then drill the axle for a 3mm split pin, but my questions has not yet been answered. My personal experience in the towing world is limited, but having worked on machine tool and diesel engine for some years I just want to understand why the high torqe nuts have to be fitted. ? Perhaps its our old friends, Health and Safety?

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It is probably to cut the cost of manufacture and parts.

 

No hole to drill. No split pin reqd. No castellated nut to make.

 

The one shot is made by a cheaper process probably. A castellated nut needs more processing to manufacture.

 

The whole assembly is therefore quicker on a production line.

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It is probably to cut the cost of manufacture and parts.

 

No hole to drill. No split pin reqd. No castellated nut to make.

 

The one shot is made by a cheaper process probably. A castellated nut needs more processing to manufacture.

 

The whole assembly is therefore quicker on a production line.

 

I'm sure this is the real answer - cut the cost of production and move those costs further down the line out of the factory either to the bloke who installs it, maintains it or owns it. The end customer still pays somewhere.

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I think these nuts are slightly oval to grip the Male thread of the axle.

Once used the interference fit is reduced so you need to replace them

As already said, a production line cost saver.

I wonder if they are cheaper than nyloc nuts to produce?

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I do know a fitter who used this material.

 

http://www. bondloc. co. uk/#/b262/4544520889

 

I am not suggesting I would use it or recommending anyone else either.

 

I felt he was taking a risk with other peoples caravans though.

 

I crossed him of my list of trusted tradesmen.

Edited by Lefthand Down

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The high torque is to pre-load the bearing which is a different type to the earlier versions with castellated nuts. The "one shot" is a reference to the method of 'locking' the nut by using an oval section of the thread which, with some types of nut, cannot be used more than once and retain the built in locking quality.

 

Regarding re-use

 

BPW nuts post 1998 can be re-used indefinitely according to the Approved Workshop Service Guide:

 

BPW Axle - there are two types of hub nut in use. The first (1996-1998 approximately) is a large flange nut used in conjunction with a secondary circlip within the hub, this allows the nut to be used as the hub puller. Due to the possibility of thread damage when removing tight hubs, this is a “one-shot” nut and must always be renewed and torque to manufacturers settings. The second (post 1998 approximately) is a smaller flange nut without a secondary circlip. These nuts are reusable, subject to no visible damage and there being resistance felt when screwing the nut by hand onto the spindle end.

 

However, BPW's own guide here, whilst at odds with the above, does not actually preclude re-use!

 

Knott nuts can be used twice according to the Knott maintenance guide

 

Refitting unitised bearing hubs with high torque nut.

 

Fit the drum to the axle shaft and tighten the nut to the correct torque 280 Nm as specified

NOTE. The nut may only be used twice so if the history is not known it must be replaced.

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Hi

Anyone thinking of using locking liquids on the nuts--- most break down when heated ( hot brakes ! )

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I don't understand why we are charged seperately and at extra cost per wheel nut when replacement wheel nuts are mandatory if the axle has one-shot nuts. It dosen't matter that they may be re-usable, the service agent will not accept liability if he does not fit new. So we are charged the "industry standard" charge for service (actually it's an inspection) and then we are charged extra for the unavoidable inclusive essential consumables. The cost of which should be included in the "industry standard" menue service charge.

On a tandem axle van, there is an ad-on of £40. 00 for the 4 nuts, installation of which requires less work thatn the correct fitting and adjustment of castellated split pin locked wheel nuts.

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On a tandem axle van, there is an ad-on of £40. 00 for the 4 nuts, installation of which requires less work thatn the correct fitting and adjustment of castellated split pin locked wheel nuts.

 

I think you'll find that's a case of the manufacturing industry making things cheaper to produce and the maintenance industry seeing an opportunity to make a few extra quid off the back of it. Everyone's a winner, apart from the poor consumer of course.

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Hi

I find the issue over one shot nuts cofusing. The guy who serviced my van, says it is not a reccomendation by Alko that the nuts need to be removed and replaced at every service. He says he can do a visible inspection of the hubs and brakes without removing the drums. Another service company in Teesside refits the original nuts with liberal amaounts of locking solution. When I asked him about this he said he builds and services racing cars and always uses the solutuion and he has never had any problems.

Sandy

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I don't understand why we are charged seperately and at extra cost per wheel nut when replacement wheel nuts are mandatory if the axle has one-shot nuts. It dosen't matter that they may be re-usable, the service agent will not accept liability if he does not fit new. So we are charged the "industry standard" charge for service (actually it's an inspection) and then we are charged extra for the unavoidable inclusive essential consumables. The cost of which should be included in the "industry standard" menue service charge.

On a tandem axle van, there is an ad-on of £40. 00 for the 4 nuts, installation of which requires less work thatn the correct fitting and adjustment of castellated split pin locked wheel nuts.

 

The reason the one shot nut is not usually included in the standard service price is that there are 6 different nuts depending on the axle manufacturer and axle type and so 6 different prices also a 7th possibility is a castellated nut in which case a replacement is not required at all, just the cost of a split pin.

 

James

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Sorry about my one shot wheel nut query. What I wanted to know is why we now need a high torqe wheel nut when before they started to fit them a castlated wheel nut under the very slight pressure needed to set up the bearing and securing with a split pin was all that was required to prevent a wheel coming off? Indeed it would be simple to turn up a couple of nuts suitable, castlate them then drill the axle for a 3mm split pin, but my questions has not yet been answered. My personal experience in the towing world is limited, but having worked on machine tool and diesel engine for some years I just want to understand why the high torqe nuts have to be fitted. ? Perhaps its our old friends, Health and Safety?

A castellated nut will only fit in a fixed number of places, fine when with the older taper bearings there needed to be end float. Different bearings require different fittings and they require pressing onto the shaft which is done by requiring a particular torque on the nut to achieve a correct fit. As it was described to me the one shot nut when torqued to the correct torque will distort slightly gripping the shaft which is why it does not require any other fastening to hold it in place, it is this distortion that means that on each occasion the nuts be replaced with new ones.

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Hi

I find the issue over one shot nuts cofusing. The guy who serviced my van, says it is not a reccomendation by Alko that the nuts need to be removed and replaced at every service. He says he can do a visible inspection of the hubs and brakes without removing the drums. Another service company in Teesside refits the original nuts with liberal amaounts of locking solution. When I asked him about this he said he builds and services racing cars and always uses the solutuion and he has never had any problems.

Sandy

 

To service and clean out the brakes the drum needs to be removed, if the drum is removed the one shot nut is replaced.

 

If a nut is reused and locking solution applied, this will probably stop the nut from coming off but when the nut needs to be removed, this could loosen the bolt securing the stub axle to the swinging arm on the axle. As the position of the stub axle changes the wheel angle & geometry then Alko say that the axle should be returned to them to be set up again! We charge out Alko one shot nuts at £4. 80 inc VAT as part of a service so is it worth taking the risk? I think caravans and racing cars are very different so I stick to what I know and don't get involved in racing cars.

 

James

Edited by G W Caravan Services

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Well said James!

If you really feel so bad about paying for the nuts, leave them alone, and dont have it serviced. For anyone with so little engineering knowledge to ask such fundemental questions abour axle nuts, and then suggest modifying it - is beyond belief! You want to experiment with a 1500Kg/90KPH misile? to save a Tenner? How pleased would you be if a wheel/tyre/hub flew through the front window of your car because some caravanner wanted to save a Tenner?

 

To service and clean out the brakes the drum needs to be removed, if the drum is removed the one shot nut is replaced.

 

If a nut is reused and locking solution applied, this will probably stop the nut from coming off but when the nut needs to be removed, this could loosen the bolt securing the stub axle to the swinging arm on the axle. As the position of the stub axle changes the wheel angle & geometry then Alko say that the axle should be returned to them to be set up again! We charge out Alko one shot nuts at £4. 80 inc VAT as part of a service so is it worth taking the risk? I think caravans and racing cars are very different so I stick to what I know and don't get involved in racing cars.

 

James

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I remember setting up the wheel bearings on my old van and fitting a new split pin to the axle. I just wonder why the bearings on my new van now require a one shot high torqe nut to keep the wheel on the axle when a simple split pin managed the same duty in the past? As I remember the outer tapered bearing in the past actualy encouraged a wheel to fall off in the past if the split pin failed. I beleve the modern bearings are not tapered and should tend to remain on the wheel rather better than the taper bearings. Perhaps a technical caravaner can explain why one should not just drill a split pin hole through nut and axle and use the old one shot nut again.

.

They are not tapered bearings any more?

 

Gra.

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I don't understand why we are charged seperately and at extra cost per wheel nut when replacement wheel nuts are mandatory if the axle has one-shot nuts. It dosen't matter that they may be re-usable, the service agent will not accept liability if he does not fit new. So we are charged the "industry standard" charge for service (actually it's an inspection) and then we are charged extra for the unavoidable inclusive essential consumables. The cost of which should be included in the "industry standard" menue service charge.

On a tandem axle van, there is an ad-on of £40. 00 for the 4 nuts, installation of which requires less work thatn the correct fitting and adjustment of castellated split pin locked wheel nuts.

 

this is how i do it, the nuts cost me between £5 to £9 each,

 

if its alko nuts they are included, as the amount i get through i can stand the cost, bpw and knott ones cost alot more so are chargable, so i offer them at cost,

 

now pete, if your being charged £40 for 4, if its not on a alko chassis fair enough, but if it is i think you need to ask your dealer why, or go else where

Edited by newarkcaravans

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as we all know one shots are oval in shape so when they are used they close on the stub bpw will use the split pin and castle nut as gone full circle with there design the vast torque setting will show that it is important.

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