15 replies to this topic

[chuee]

Concerning 8.4" front disc set ups: I had a snapped wheel stud. Method of  Replacement  is not mentioned in Haynes. Various forum  posts cover the topic.

 

There is frequent advice of the following sort:

 

 

 

(If it doesn't come out this way it's remove caliper, loosen four flange/disc bolts, undo castle nut, remove (disc/flange) assembly, knock out stud, tap in new stud, and rebuild, making sure you tighten the four bolts before the castle nut, and then only refit the caliper once everything else is on).

• You don't need to remove the hub, tap the old stud out after removing the brakes. The new one can be fiddled into place and then pulled through using a spacer and wheel nut.

•  
• if you can knock the remaining stud through, it might come out between the flange and the disc.

 

 

 

Other posters state:

 

 

The correct way to replace them (assuming here you have 8.4" Discs) is to separate the Disc from the Drive Flange. If you rotate the Disc around, there's usually one point where you'll get enough separation between the Disc and the Drive Flange to slip the new one in.

 

 

 

 

I have this to say: 

The proper way was the only way for me, with 8.4" disc brakes  and definatley to seperate the drive flange ffrom the Disc by removing the four nuts, after unding the hub nut. Neither The disc nor the caliper  need to be removed, and may be left in position.

The flange may be taken to  and held in a bench vise and the stud knocked out, (apply penetratin goil foirst and allow to saok, if in any doubt about rust) and replaced, with a little copper silp, tapping it in with a suitable puch, after aligning the splines on the stud. You will hear when the stud is sitting snug against the flange.

 

I could not wigggle a stud in, the new studs being  flat headed. Part number is given now as NAM465 (35mm long, same as the ones they replaced).

 

Furthemore, as the head of the stud touches the disc boss, it will not go in straight until flange is removed, and there is great danger of misaligning the splines of the stud. I read people who coul dget the stud in but not all the way, and thus had compromised the stud hole, and cause further unnecessary work.

Perhaps the boss of the discs varies between batches, by enoug hto make a difference, but I would not bet on it.

 

You cannot tap the stud in with a punch if you slip it in by wiggling.. you'd have to pull it in with a nut and washer... but the stud is likely to be tipped at an angle if it doesn't slip straight in.  So, dont attampt it. Perhaps it is different for 7" brakes, about which I cannot speak.

 

 

 

It could be possible to flatten part of the stud head, to help it slip in.. but, do you really want to do that, unless as an emergency and temporary measure.

 

Also, if a stud breaks, it is a sign that all all studs have been compromised by overtightening wheel nuts at some point. Therefore I replaced all four studs nicely and with ease.

 

The correct  wheel nut torque is 40 - 44lbs/ft.

Edited by chuee, 06 September 2023 - 10:21 PM.

[nicklouse]

Is it a 7.5 set up or a 8.4 set up. Different applications are needed.

[Coalhod]

Also draw the stud in by hand only!  I made the mistake on a 7.5" disc/flange using a 3/8" cordless Dewalt impact driver to get the stud to seat against the flange.  When I tightened the wheel nut to the specified torque the stud snapped off.

[Spider]

Yes, with standard 7.5's it's a snap to replace the studs (pun intended !).

 

I modify my 8.4's so that with the wheels I run, I don't even need to jack it up to replace a stud, otherwise, it can sometimes be done by removing the Brake Caliper, the separating the Disc off the Drive Flange while leaving the CV Nut done up, but this is not a given and more often the Drive Flange needs to be removed.

 

My preferred way to fit the Studs in though, is to press them in from the back, though, that's certainly not always possible.

 

 

[chuee]

Is it a 7.5 set up or a 8.4 set up. Different applications are needed.

True NIck, I state the set up  in the post, straight off under "I Have This To Say" 

You are reading to fast for the good    but nontheless, your comment is appreciated, because it's concise  and confirms the question raised, Is there a difference permitted in technique with 8.4" and 7.5" set ups? Spider also confirms that yes, there is.   

I myself have no experience with the 7.5".

Edited by chuee, 06 September 2023 - 10:17 PM.

[chuee]

Yes, with standard 7.5's it's a snap to replace the studs (pun intended !).

 

I modify my 8.4's so that with the wheels I run, I don't even need to jack it up to replace a stud, otherwise, it can sometimes be done by removing the Brake Caliper, the separating the Disc off the Drive Flange while leaving the CV Nut done up, but this is not a given and more often the Drive Flange needs to be removed.

 

My preferred way to fit the Studs in though, is to press them in from the back, though, that's certainly not always possible.

 

 

 

Very interesting stuff here in your reply Spider.

 

Thanks for confirmning the 7.5/8.4  are different, for the sake of all.

 

Your modification is quite lovely, and yet I wonder because I agree in preferring to press the studs in from the back,

- Why you bother with such a mod,    AND also,

- because given that you are obviously well practised, learned anfd thourough, with good techniques and ideas,  how often is it you ever break a stud!    AND,

- I even imagine you service brake with a new aquisition as a matter of course, and probably replace all the studs whilst at it! Am I wrong?   

 

The intended pun is delightful. Thanks. 

Edited by chuee, 06 September 2023 - 09:41 PM.

[chuee]

Also draw the stud in by hand only!  I made the mistake on a 7.5" disc/flange using a 3/8" cordless Dewalt impact driver to get the stud to seat against the flange.  When I tightened the wheel nut to the specified torque the stud snapped off.

Quite right. I myself prefer hammer and punch, because there is no undue force on the threads in order to get the stud to seat by pulling in what I find to be very tight splines. I imagine they are similarly pressed in at factory, and that racing teams etc would do the same in preference. Not that using a nut and washer to draw it in ( if that's what you mean ) is so very bad at all... just a wee bit, perhaps? Just my feel for things.

- Nah after contemplation,   I suspect I am being to wary here. not sure.

 

But if you  remove in the flange, waste of time to bother with a drawing in method; only necesary if you try without removing the flange. I am warning this is likely to be dangerous, I warn against it with 8.4" discs. But I have not tried rit by removing the calipers and seperating the flange and disc without removing the driveshaft nut, I.E. in situ... but as Spider above says this only sometime works - so why even bother trying and failing and swearing because I lie when I  said I like spanner work, but avoid it every inch of the way. Then its wheel back on the ground, caliper back on  to remove the shaft nut when my laziness failed me.

 

Of course, I am in no hurry, and waste no time.

Edited by chuee, 06 September 2023 - 09:51 PM.

[Spider]

 

 

Yes, with standard 7.5's it's a snap to replace the studs (pun intended !).

 

I modify my 8.4's so that with the wheels I run, I don't even need to jack it up to replace a stud, otherwise, it can sometimes be done by removing the Brake Caliper, the separating the Disc off the Drive Flange while leaving the CV Nut done up, but this is not a given and more often the Drive Flange needs to be removed.

 

My preferred way to fit the Studs in though, is to press them in from the back, though, that's certainly not always possible.

 

 

 

Very interesting stuff here in your reply Spider.

 

Thanks for confirmning the 7.5/8.4  are different, for the sake of all.

 

Your modification is quite lovely, and yet I wonder because I agree in preferring to press the studs in from the back,

- Why you bother with such a mod,    AND also,

- because given that you are obviously well practised, learned anfd thourough, with good techniques and ideas,  how often is it you ever break a stud!    AND,

- I even imagine you service brake with a new aquisition as a matter of course, and probably replace all the studs whilst at it! Am I wrong?   

 

The intended pun is delightful. Thanks. 

 

 

Hehehehehe,,,,,

I do this mod with all 8.4" Discs that I fit.

I do it because back in 1982 I was caught out when I broke my first wheel stud while on a trip and I just thought it madness / crazy to need to strip the assembly back so far for what I see as should be a straight forward operation.

How often do they break ? On my last trip a few weeks ago, I broke 2 studs, though, I'll add that's unusual. It'll generally do about 3 - 5 trips on a set before breaking any - time I'd say for a complete new set here. Yes, I so check them carefully between trips and am very fussy about what studs I use.
 

 

[stuart bowes]

I had no idea such a job could need any overcomplicating at all

 

I just figured, disassemble, punch out old ones with with a hammer, punch new ones in from t'other side until fully seated, reassemble 

 

saying that I also had no idea these things broke as often as they apparently do ?!   is this really a serious common issue or are you talking about when driving really hard like across the outback or on severe rally stages

Edited by stuart bowes, 06 September 2023 - 10:01 PM.

[chuee]

 

How often do they break ? On my last trip a few weeks ago, I broke 2 studs, though, I'll add that's unusual. It'll generally do about 3 - 5 trips on a set before breaking any - time I'd say for a complete new set here. Yes, I so check them carefully between trips and am very fussy about what studs I use.
 

 

 

 

Thanks for kind reply, which begs more questions, as Stuart also finds.

 

I thought studs would rarely break, or ever   even 40, 000 miles if not over or under-torqued.

3- 5 trips? That could be only 50 miles only! How long are your trips. 4,000 miles or more?  That'd still be worryingly poor performance with studs).

 Is it that they are more prone in the mini  geometry?

Is it the way you drive at all, and your horsepower?

Edited by chuee, 06 September 2023 - 10:29 PM.

[stuart bowes]

I was working on the assumption that the worst thing for fatigue on the studs would be constant wheel removal and refitting, i.e. gradual stretching on the bolts ?

 

so in the case of someone who does exciting desert safaris and so on the lieklyhood of punctures / repairs, wheels on and off a lot, would go through studs more often.. I don't think he was talking about trips to the shop or the beach surely

 

but I'm intrigued to know what the answer will be

 

also just as a side note are these studs high tensile, or would that make them more likely to snap or corrode

Edited by stuart bowes, 06 September 2023 - 10:32 PM.

[chuee]

I was working on the assumption that the worst thing for fatigue on the studs would be constant wheel removal and refitting, i.e. gradual stretching on the bolts ?

 

so in the case of someone who does exciting desert safaris and so on the lieklyhood of punctures / repairs, wheels on and off a lot, would go through studs more often.. I don't think he was talking about trips to the shop or the beach surely

 

but I'm intrigued to know what the answer will be

 

also just as a side note are these studs high tensile, or would that make them more likely to snap or corrode

Good point, ref frequent wheel removal.

Does SPider do desert safaris? 

Yes they are high tensile. IMO less corrosive in some sense,  less prone to stretch and so snap in that way, only within limits.  70 lbs/ft would severly weaken these studs i would say.

 

High tensile studs do have more than one standard. 

I also am led to  believe, and do beleive, some are  produced of inferior quality. 

 

This is the first wheel stud on a mini I have ever broken, and I've run and owned them since 1980, including 2,000 mile round trips to Europe, Scotland,  bumpy Roads in london and Lake District. One fairly powerful  mini clubman van was laden with workmates and  tools on 200 mile runs along  twisting A roads.

 

Perhaps drawing the in the bolt, rather than punching them in significantly  shortens their life - like over-torques them?  Or can we rule that out?

Edited by chuee, 07 September 2023 - 07:50 AM.

[stuart bowes]

perhaps 'desert safari' wasn't the best wording on that what I meant was Australian outback roads are notoriously harsh on even modern 4x4 type cars (from what I'm told hire car companies don't cover you on them for example) and that's in the places where people actually bothered to make tracks, if you go properly off road I'm sure it can destroy mini parts very quickly 

 

this is all just supposition of course I don't know him personally and haven't been on journeys with him, I'm just going by pictures and the fact he lives down under and drives mokes..  I'm sure at some point he will clarify by himself 

 

anyway on 'regular road' driving it's not something I've heard people constantly going on about having to replace

Edited by stuart bowes, 07 September 2023 - 08:31 AM.

[chuee]

this is all just supposition of course I don't know him personally and haven't been on journeys with him, I'm just going by pictures and the fact he lives down under and drives mokes..  I'm sure at some point he will clarify by himself 

 

anyway on 'regular road' driving it's not something I've heard people constantly going on about having to replace

Ah thanks Stuart, I see now. Agreed about the studs normal longevity.

Edited by chuee, 08 September 2023 - 01:18 PM.

[stuart bowes]

..Steve..

 

close enough 

 

I've been called worse to be fair