Fun with Tim and Claudia or How to Cure rattly discs

[timbox2]

Ok, I know plenty has been said and done about this before but maybe for new trixters I thought I would post a step by step photo manual for the said problem.
Mine started after I had replaced all the bobbins, bolts and washers for new ones, I then had masses of movement in the discs, side to side as well as in and out so to speak, really noticeable at slow speeds over bumpy ground.

The procedure here relates to my bike, a 2000 model, later models may be slightly different as in fact they should already have the disc stops (washers)installed.

Oh and not forgetting my Get Out of Jail clause, if you make a hash of it, DONT BLAME ME, if your not confident doing this get someone else who is, if your close to South Wales I might be persuaded to help you for certain favours

1) First things first, take your time, dont rush or you will regret it as you strip all the Torx heads on the disc screws.

2) After removing wheel and laying it on a couple of bits of wood( So disc is clear of ground) make sure all the torx heads are clean of any debris, like this one below.


3) Make sure you have a nice Torx socket of the correct size( TX40 ) and remove all bolts, this is where it pays to take your time and make sure the socket is well seated before applying pressure, the threadlock makes the bolts very tight, maybe you could apply some heat with a hot air gun to the posts, I didnt need to.

4) once all bolts removed take off the bobbins and curvy washers and inspect for any damage, no point putting back broken washers or badly worn bobbins( Mine were Ok as I replaced them all a couple of months back)Below is what they should look like.



5) Next step is CRITICAL. Run an 8mm x 1.25 pitch Tap down all the threads. Dont even think about going any further until you can screw all the screws back in with your fingers all the way.

WARNING: As pointed out by Mr Sandbar be very careful with the Tap, Ally is very soft and you could easily damage the Thread or cut a new one without realising, DO THIS AT YOUR OWN RISK, the alternative being to make a chaser from an old bolt, just cut a slot the length of the thread, still need to be careful though.



6) Ok, next get your shiny new disc stops, as BMW call them, washers they are, I got the genuine BM ones Part No: 34117670217, bloody quid each, but I thought worth it, think there are cheaper alternatives as some have found, anyway place a washer on each post,



7) Next carefully place the disc back on to the washers alighning the holes and pop the bobbins and wavy washers back on top, making sure they are seated correctly before puttng the screws back in by hand, to check nothing is out of line, you DONT want this situation below.



Once your happy everything is OK remove the bolts one at a time and coat in new threadlock( If youve bought new bolts you wont need to as they come ready threadlocked)



9) Snug all the bolts up then in a diagonal sequence torque them all up to 21NM, doesnt feel much I know but its enough, DO NOT OVERTIGHTEN.



10) Thats it, turn wheel over repeat for other side then replace wheel, not forgetting that you should torque the Axle first to 30NM, put the calipers back on and Torque to 40NM for 10mm bolts, 30NM for 8mm. Lower bike, apply brake and bounce the front up and down a few times BEFORE torqueing the axle clamp bolts to 21NM.

11) Sit back and admire work and revel in the nice quiet front end, yep not a sound.



Hope this helps some peeps, cheers Tim

[skiddy boxers]

Excellent post - well done

[sandbar]

Mine started after I had replaced all the bobbins, bolts and washers for new ones, I then had masses of movement in the discs, side to side as well as in and out so to speak, really noticeable at slow speeds over bumpy ground.

Interesting! I wonder if you had the bobbins for the 5.0 mm discs, but are actually running 4.5 mm discs. Just a thought!

Next step is CRITICAL. Run an 8mm x 1.25 pitch Tap down all the threads. Dont even think about going any further until you can screw all the screws back in with your fingers all the way.

Just a word of warning about using taps in aluminium threads. Here is a paragraph from a recent post of mine.

I was told - by someone who knows about these things - that here is no tool that is strictly correct for cleaning internal threads in aluminium. Taps are designed to cut new threads and that is what they will do. When you use one, there will be particles of aluminium on the tap at the end. That means that it is, in effect, making the thread slightly oversize. 'Thread chasers' are no better because they are designed to restore mangled threads and are even more severe. Both taps and chasers are usually made to be used in steel and it is very easy to f*ck up aluminium with them.

Just be very careful and if you intend to do the job more than once then think twice about using a tap.

Once your happy everything is OK remove the bolts one at a time and coat in new threadlock( If youve bought new bolts you wont need to as they come ready threadlocked)

You have used Loctite 243 and that may be much better than the Loctite 2701 as recommended by BMW. 2701 ( and the almost identical 270) is in fact a stud locker and is much stronger than 243 which is a nut locker. The heat ranges are similar so there does not seem to be a downside to using 243. It will make any subsequent attempts at removal much easier.

Well done that man

sandbar

[timbox2]

Cheers guys,

Sandbar, yes, I did wonder if I had the wrong Bobbins, but thickness wise they match exactly with what came out, I have 4.5 discs, which I believe are Std on the S, and I cant really explain why after replacing all the bobbins etc I should have had so much more play, maybe I didnt, and it was that bad all along I just hadnt noticed it.

Good point ref the Taps, think Ill edit my post to reflect how delicate the operation is.

As regards the Loctite, the only reason I didnt use 2701 was that my Engineering Suppliers only have 2701 in trade bottles at £30 odd quid a go, and I just dont use it enough to warrant it, so your observation is a bonus!!

As an update, I have just been for a 40 mile run around the B roads and the braking performance also seems to have improved, though maybe thats partly psychological, but the lack of the noise coming from the front end is the main thing, at one point I was convinced it was suspension or steering, it was that bad.

Anyway thanks for all the feedback, ride safe.

[Cobbster]

Hi Timbox,
RE the loctite. When I did my disc bolt last year I rang loctite to find where I could get hold of some 2701 as no one seemed to sell it. As with yourself they told me it was only available in a £30 bottle. When asked what was the difference between 2701 and 270 they put me through to the R+D department who told me next to non. I then rang my local BMW dealers who told they use 243.
In the end I used 270 cos I had some.

Cheers,cobbster.

[sandbar]

When asked what was the difference between 2701 and 270 they put me through to the R+D department who told me next to non.

According to the specification sheets there is no difference between 270 and 2701. They just have different standards approval.

sandbar