Front wheel / brake discs

nab 301 · Post by **nab 301** » Thu Mar 08, 2007 7:21 pm

I know it's been covered before but is the following pic what you would expect with the wobbly disc routine (r/h side.) Do I need a new wheel?
Anyone got a balaclava ,I just priced a wheel and discs (worn below the min) how thin can I go with the discs?

I fitted spacers and spring washers about 20k miles ago and the wheel seemed fine....... although as you can see the spacers are visibly worn.

Nigel B

r550s · Post by **r550s** » Thu Mar 08, 2007 7:33 pm

dunno what you mean by 'wobbly disc routine' but what you've got there is crap design - the slots in the brake rotor have mis-shaped the (soft ally) posts, leaving the rotor A: out of true & B unable to float properly. If you're careful, you can get a broad file and level them all back down flat - running the file across two at once to keep things level. Do it evenly to keep your rotors running true. Buy a new set of bobbins from Motorworks - yours will probably have flats bashed into them by the braking action. (edited) sorry didn't see the second photo - your bobbins are pooped aren't they (turning them through ninety degrees doesn't work!) If the posts are really really bad, and you can't guarantee filing them evenly, you need a mate with a big lathe to skim them up.

throttlemeister · Post by **throttlemeister** » Thu Mar 08, 2007 10:10 pm

Did you use the washers underneath the spacers? (flat ones, not the wiggly ones on top)

nab 301 · Post by **nab 301** » Fri Mar 09, 2007 10:22 pm

throttlemeister wrote:Did you use the washers underneath the spacers? (flat ones, not the wiggly ones on top)

Mine's a '99 with brembos , did they ever have washers between disc and wheel? certainly not in the 3 yrs I 've had the bike............

If the posts are really really bad, and you can't guarantee filing them evenly, you need a mate with a big lathe to skim them up.

Had thought of that although getting someone to do it in this neck of the woods,.....anyone else done this ,?

Nigel B

gus · Post by **gus** » Sat Mar 10, 2007 9:57 am

There was no washers between wheel posts and disc on early models.Later models had them fitted.Fit some very thin washers to take out the wear.You still want the discs to move/float slightly when fitted.If the inserts and wavey wahers are worn,then replace those to.
I had a interesting conversation with a BMW rep about why they had fitted washers on later mdels.This was after i had been told i needed a new wheel at 30,000 miles.I was pissing in the wind trying to get a straight answer.

Chris C went out on a mission to find some washers,second attempt we had a set that done the job.
gus

sandbar · Post by **sandbar** » Sat Mar 10, 2007 10:37 am

gus wrote:............about why they had fitted washers on later models.

I thought that this was so that they could use the same wheels for ABS and non ABS wheels. The washers are about the same thickness as the pressed tin ABS ring.

gus wrote: I had a interesting conversation with a BMW rep

sandbar

nab 301 · Post by **nab 301** » Sat Mar 10, 2007 8:02 pm

gus wrote:There was no washers between wheel posts and disc on early models.Later models had them fitted.Fit some very thin washers to take out the wear.gus

Thanks for that Gus ,I'll give it a try.

I thought that this was so that they could use the same wheels for ABS and non ABS wheels. The washers are about the same thickness as the pressed tin ABS ring.

Mine's the early one with the "substantial" abs ring

Nigel B

Jason M · Post by **Jason M** » Sun Mar 11, 2007 8:46 am

sandbar wrote:
gus wrote:............about why they had fitted washers on later models.
I thought that this was so that they could use the same wheels for ABS and non ABS wheels. The washers are about the same thickness as the pressed tin ABS ring.

gus wrote: I had a interesting conversation with a BMW rep

sandbar

The ABS ring is obviously only on one side of the wheel, and this problem occurs on both sides if you don't have ABS. I have ABS and this happened on the right but the ABS ring has protected the left hand side fine.

sandbar · Post by **sandbar** » Sun Mar 11, 2007 10:50 am

Yes you could be right. All the ones that I have dealt with have the washers on the side that does not have the ABS ring. On none ABS bikes the washers are on both sides.

The parts fiche shows that non ABS bikes have 10 washers - part number 34117661877 - but the ABS bikes have only 5. ABS and non ABS bikes use the same front wheel from 2001 on.

sandbar

nab 301 · Post by **nab 301** » Tue Apr 17, 2007 8:17 pm

Finally got bike sorted although couldn't find anyone willing to machine the disc posts

.
Rebuilt the calipers with new pistons ,and fitted the cast iron discs (luckily there's been a drought since

). Nearly ripped out the abs and fitted direct lines (must have taken 2 hrs to bleed the brakes) but perseverance and much use of my vacuum pump

finally paid off.
After over 1k miles first impressions were mmmm... silky smooth ,those old discs were shot , and that front wheel really does freewheel now......

Gromit · Post by **Gromit** » Tue Apr 17, 2007 8:52 pm

sandbar wrote:
gus wrote: I had a interesting conversation with a BMW rep

sandbar

Genuine LOL

Archie · Post by **Archie** » Tue Apr 17, 2007 8:56 pm

Well done getting it sorted.

Just a note of caution however. I rebuilt two sets of Brembo calipers recently, one BM and one old Ducati, and in both cases just one of the o-rings that seals the two caliper halves was too thin. The brakes worked fine, but when standing, brake fluid would seep past them. Maybe I was unlucky, but it might be worth keeping an eye on yours just to be sure. The symptoms are just weeping fluid at the bottom of the calipers.

nab 301 · Post by **nab 301** » Tue Apr 17, 2007 10:54 pm

Archie wrote:Well done getting it sorted.

Just a note of caution however. I rebuilt two sets of Brembo calipers recently, one BM and one old Ducati, and in both cases just one of the o-rings that seals the two caliper halves was too thin. .

The repair kit only supplied the pistons and the two seals per piston so I didn't split the caliper....

Nigel B