Rear disk thread failing.

[Sam Linssner]

So I've got a bit of a weird one. Checking my bolts with a torque wrench yesterday on track and found that one wouldn't do up. Took the wheel off and the stud has come out a bit. Try to do that up with no success and then find that the thread on the disk has perished. This is the second time this has happened to me and it's always the rears. Any ideas why? Using pure stud kit with locktite and genuine rear disks. Maybe try some different disks?

 

[JamesBryan]

Perished as in stripped?

 

[Sam Linssner]

2nd time the thread failed. First time the collar or countersink of the hole had cracked and a piece of the disk had come away. Only done up hand tight

 

[JamesBryan]

I wonder if they're coming loose and the movement is damaging the threads...

 

[Sam Linssner]

Using locktite on them. Only had two come loose but obviously is ruining the disk so need to take them out and reinstall them all

 

[Ads29]

What are you torquing the studs up to?

 

[Sam Linssner]

105nm

 

[Ads29]

105nm

For the studs? That could be why then. I'm pretty certain my studs were 30nm and the nuts to 105nm.

I'll have a look now and double check for you

 

[JamesBryan]

20Nm for the actual studs themselves with red loctite.

 

[Ads29]

In fact PMS recommend 20nm on their website for the studs

 

[Sam Linssner]

Sorry meant hand tight for the studs and 105 for the nuts

 

[Knuckles]

Sorry meant hand tight for the studs and 105 for the nuts

It could be that if they're only hand tight they're coming loose, and when you're tightening up the nuts it's slowly dragging the thread out.

 

[JamesBryan]

It could be that if they're only hand tight they're coming loose, and when you're tightening up the nuts it's slowly dragging the thread out.

This is also my thinking.

 

[Knuckles]

This is also my thinking.

Great minds

 

[Sam Linssner]

Is 20nm not about hand tight? I'll have to go get a smaller torque wrench to check

 

[Knuckles]

Is 20nm not about hand tight? I'll have to go get a smaller torque wrench to check

I don't know actually, but hand tight could be a nip to 100+nm

20-100nm torque wrench

I got my 1/2" one from here, seems to be cheapest on the market for the tent wrenches.

http://www.screwfix.com/p/teng-tool...-8/49363#product_additional_details_container

 

[STEVE.M]

Sorry meant hand tight for the studs and 105 for the nuts

I cannot think that the OE discs are the problem.
As long as you were supplied discs with part number 77.
https://partsouq.com/en/catalog/gen...E01XRCtV$&vid=1247&cid=2041853161&uid=3285&q=

 

[Sam Linssner]

I cannot think that the OE discs are the problem.
As long as you were supplied discs with part number 77.
https://partsouq.com/en/catalog/genuine/unit?c=Renault&ssd=$BQoJQHMFBwYESkECVzkBAAEDAwoCBF8bCVNBUVtGc3kFWBsMW1d0BUxaWVErVUkCCwMEAgVKWw4LDFFcUFByfgcFWFQ7TF5RW0dQW1IONxZdR3R4AQAHBykbDFFcUFByfQcFX1ZIAk1rdQcAeAcqC0p3d31aE01XRCtV$&vid=1247&cid=2041853161&uid=3285&q=

Def correct Genuine disks

 

[barnesautos]

These were Micky mouse studs before I purchased the PMS ones , never had an issue .

I can relate to you guys saying that the studs undo and then the nut needs retightening and in doing so eventually pulls the last bit of the thread out .
My studs have an Allen key in the centre , so I guess the 20Nm can be achieved with ease .
I just hand tightened mine with locktite , I'm assuming mine will be tighter than the 20Nm's.
No issues to date [emoji1303]