50 replies to this topic

[CharlesK]

Hello,

 

A couple of weeks ago i was driving down the road at about 60mph/100kmh in my 1988 Red Hot (straight road). suddenly i heard a loud ticking noise and before i knew it *snap crunch wobble* i managed to get it onto the side of the road without a major accident happening (this was during rush hour). I called the ANWB (dutch AA) and they came and rescued me. now the guy removed 2 studs from the left wheel (good wheel) and put them in the disc on the right wheel on which 3 of the 4 wheel studs broke clean off and the 4th was still attached to the wheel but totally bent since the wheel had twisted into the wheel well. The guy said just drive home carefully and you should be fine. i drove about 1km until i heard the dreaded clicking noise again. i limped back slowly to the parking lot and called them again and they had me towed back home.

 

My car has been in storage since then because it scared me and i no longer trust my car. It could have ended a lot worse.

 

I've searched the forum to what could be wrong but i found no similar problems. The only thing that could be related is for the MOT the steering tie rod end had been changed and maybe caused the alignment to be off. however I wound't suspect a wrong allignment to cause the wheel to snap off.

 

Just to be clear, the part that broke is the studs that the wheel nuts turn onto that are pressed into the brake disk.

 

About half a year ago i was driving on ventilated 4 pots brakes but one of the bleeding valve threads broke so i went back to stock discs+calipers at the front.

 

Thanks, any help is appreciated

 

quick edit: i've had the car on the bridge to check for any play but everything seems solid, nothing has broken off or has excessive play

quick edit 2: Except for the wheel

Edited by CharlesK, 02 February 2015 - 04:26 PM.

[Carlos W]

Who fitted the brake conversion? 

 

Are they the correct stud length and from a decent reputable supplier? 

 

Are you using the correct nuts for the wheels?

 

Were they torqued correctly?

[Gr4h4m]

Did they pull the studs through all of the way, and re torque the wheels after?

[CharlesK]

Who fitted the brake conversion? 

 

Are they the correct stud length and from a decent reputable supplier? 

 

Are you using the correct nuts for the wheels?

 

Were they torqued correctly?

 

The car came with the 4 pot brakes on the car and with the orginal brakes in a box of spares, the studs in the ''spares'' discs were already in so i assume they were original. i used the same nuts as were used on the car before. nuts were tightend using an impact wrench

[CharlesK]

Did they pull the studs through all of the way, and re torque the wheels after?

 

Yea, well they hammered them in and used an impact wrench to tighten them (I also use an impact wrench for the wheels)

Edited by CharlesK, 02 February 2015 - 04:32 PM.

[littlemissmagic]

My bf had a similar incident driving along the M4.

 

On his mini they were incorrect studs (too small) and had been overtightened.

We had just bought the car and were driving back. It has since had correct studs fitted and tightened correctly and hasn't had a problem since. Same as yours, 3 snapped off completely and the only one left was holding which bent.

[Alex_B]

Sounds like you have over torqued the nuts using the impact wrench and stressed the studs. 

The torque value for mini wheel studs is much lower than other cars and they are known to fail if torqued to "normal car standards" and it is quite likely that a impact gun would over torque them.

[Fast Ivan]

Is their any sign of copper slip or other lubricant on the studs?

[CharlesK]

My bf had a similar incident driving along the M4.

 

On his mini they were incorrect studs (too small) and had been overtightened.

We had just bought the car and were driving back. It has since had correct studs fitted and tightened correctly and hasn't had a problem since. Same as yours, 3 snapped off completely and the only one left was holding which bent.

 

Problem sounds identical. thanks for the reply.

 

Sounds like you have over torqued the nuts using the impact wrench and stressed the studs. 

The torque value for mini wheel studs is much lower than other cars and they are known to fail if torqued to "normal car standards" and it is quite likely that a impact gun would over torque them.

 

what would be the correct torque spec? i do have a torque wrench so that'll be the first thing i try would it be a good idea to change the nuts too? I think so. should i also do the back wheels at the same time since i did those with the impact gun too

 

Is their any sign of copper slip or other lubricant on the studs?

 

Nope, everything was dry (except for some oil coming from the diff)

Edited by CharlesK, 02 February 2015 - 04:41 PM.

[Carlos W]

 

My bf had a similar incident driving along the M4.

 

On his mini they were incorrect studs (too small) and had been overtightened.

We had just bought the car and were driving back. It has since had correct studs fitted and tightened correctly and hasn't had a problem since. Same as yours, 3 snapped off completely and the only one left was holding which bent.

 

Problem sounds identical. thanks for the reply.

 

Sounds like you have over torqued the nuts using the impact wrench and stressed the studs. 

The torque value for mini wheel studs is much lower than other cars and they are known to fail if torqued to "normal car standards" and it is quite likely that a impact gun would over torque them.

 

what would be the correct torque spec? i do have a torque wrench so that'll be the first thing i try would it be a good idea to change the nuts too? I think so. should i also do the back wheels at the same time since i did those with the impact gun too

 

 

Yup, change the nuts too.

[Alex_B]

40 - 45lbft IIRC but I would double check that with something like a haynes manual as it is a safety critical part. 

Edit:
 
I would also be changing all studs and nuts for safety considering they have all been subjected to this treatment.

And incidentally the main issue with using an impact gun on wheel nuts bar the obvious chance of overtorquing the nuts is the fact you don't know the torque you have applied, all four wheel nuts should be torqued equally, by using a rattle gun you have no way to gauge this. 

Edited by Alex_B, 02 February 2015 - 04:47 PM.

[Fast Ivan]

I would also look at the quality of the studs and how much thread engagement you had

[CharlesK]

Thanks for all the answers guys, I'll go to my local mini spares shop soon and buy all the parts, try it out and report back.

 

also...

 

My car needs alligning and i found the allignment specs online but the mini place said a normal alignment shop wouldn't be able to do it. is this true or did they just want my business?

 

Thanks again!

[Alex_B]

Thanks for all the answers guys, I'll go to my local mini spares shop soon and buy all the parts, try it out and report back.

 

also...

 

My car needs alligning and i found the allignment specs online but the mini place said a normal alignment shop wouldn't be able to do it. is this true or did they just want my business?

 

Thanks again!

You can have issues if you have 10" wheels, some laser alignment setups cant do wheels that small. But they may just want your business anyway 

[Cerberus]

A lot of places can't do it as some of the modern systems won't fit onto 12" wheels.  You've just got to ask/check whether the place can go down to whatever size wheels your running.

Edited by Cerberus, 02 February 2015 - 04:59 PM.