Front brake issue

[Bananas]

And finally I get back to this topic! Amazing what a little bit of snow can do - confined to the lock-up and still trying to sort this out!

Checked both discs and wheel with a dial gauge, and found about +/- 0.1mm on all of them - in other words no more than 0.2mm difference between the lowest and highest spots on either of the discs or wheel rims. To me that is negligable, especially as they are floating discs (EBC X-Lites).

Marked the measurements on the face of the discs, pulled the front wheel out, set it up on my front paddock stand with a long socket extension bar in place of the axle (which I know is true as it slides in and out of the forks with no effort at all). Measured again and results exactly the same, same high/low distance measured at the same point.

As you can imagine, now I am utterly tearing my hair out.

Just to recap this fault has been evident since I got the bike, and I have changed the following:

Fork seals, dust covers and oil
Front wheel bearings
Front Discs
Front pads
Front brake line setup - from 1 line from master cylinder to right caliper then looped to left caliper - to 2 lines from master, direct to each caliper
Front tyre (and balance checked)
Front brake fluid

Things I know are ok:
Axle straight
Discs straight (less than 0.2mm deflection)
Wheel straight (as above)
Headstock bearings ok
Frame straight
wheels aligned

So...where do we go from here?
I really don't think it's a disc problem, and I'm pretty sure all the mechanical stuff seems fine. Is it time to bite the bullet and replace the master cylinder (or the seals at least)? Do I send the calipers to the manufactures for a rebuild? Do I take the noose down thats hanging from the roof of the lock up before I really get tempted to use it?

Somebody come up with a radical "I hadn't thought of that..." idea cos my straw clutching skills are being tested!

[SouthendChris]

How was the condition of the mating face of the discs to the wheel? All torqued up good and even. You have checked the disc buttons to make sure none are tight? Tried swapping the pads from one caliper to the other?

I would have a go completley stripping down the right caliper remove and refit seals and plenty of red grease. Its nowhere nearly as hard as it sounds! Bleeding the brakes from scratch is harder, but a syringe can help you and do not bolt the calipers up tight as you may need to upend them a few times to move the bubbles.

Do you not have an original set of calipers to fit and compare? Alot of work but could eliminate either calipers or discs.

I would strongly agree with others when they say change the M/cylinder. I just picked up an '08 R1 brembo unit for £87 so they are out there for reasonable money.

A friend of mine had a similar problem to what you describe on a '99 blade and it ended up being a disc. Could you not contact whom you bought them from, show them the advisory, and ask if they could swap the pair for another? Just to try and eliminate the problem - they could return the discs after all.

Chris

[Stig]

omly thing I can think of thats not already been mentioned is the tyre not seated correctly on the rim or the wheel out of balance. You seem to have tried everything else

[Bananas]

How was the condition of the mating face of the discs to the wheel? All torqued up good and even. You have checked the disc buttons to make sure none are tight? Tried swapping the pads from one caliper to the other?

I would have a go completley stripping down the right caliper remove and refit seals and plenty of red grease. Its nowhere nearly as hard as it sounds! Bleeding the brakes from scratch is harder, but a syringe can help you and do not bolt the calipers up tight as you may need to upend them a few times to move the bubbles.

Do you not have an original set of calipers to fit and compare? Alot of work but could eliminate either calipers or discs.

I would strongly agree with others when they say change the M/cylinder. I just picked up an '08 R1 brembo unit for £87 so they are out there for reasonable money.

A friend of mine had a similar problem to what you describe on a '99 blade and it ended up being a disc. Could you not contact whom you bought them from, show them the advisory, and ask if they could swap the pair for another? Just to try and eliminate the problem - they could return the discs after all.

Chris

The original discs I had on it weren't OEM parts (there was no manufacturers mark on them so no idea what make they were). However they were solid discs (non floating in other words), yet had exactly the same fault as the new ones when I put them on. Have juggled the pads around, fitted new ones etc, still the same.
Thinking along the lines of sending the calipers back to Billet for a rebuild. Have done it plenty of times before myself, but the thought of doing 12 pistons doesn't fill me with joy. Probably a lot more hassle free (and the confidence that the job will be done properly for certain) might just sway me to spend the money!

Don't have original calipers, the Billets were fitted when I bought it.

Thinking that as I've pretty much swapped out everything on the front end bar the master cylinder that this might be the way forwards - albeit a not cheap option. Might take the MC of my NC29 trackday bike and try that to see if it changes anything. If it doesn't work though it'll mean changing the brake fluid again though incase of cross contamination...hmmm...may be worth a go none the less.

Thanks for the input!

[Bananas]

omly thing I can think of thats not already been mentioned is the tyre not seated correctly on the rim or the wheel out of balance. You seem to have tried everything else

When I had the fork seals and front wheel bearings done I got them to check the balance. Since then I've had the front tyre changed and they obviously rechecked it then too. Both tyres made no difference to the fault.

[fzr1991]

Hi mate, just the odd chance you may read my post,I'm having the exact problem as yours ,have changed everything you mentioned it's driving me insane, my question is had you ever found out what was the problem with your brakes. Kind regards Chris FZR 1000 '91

[Stig]

Did you manage to get this issue sorted?

[fzr1991]

Nah,not yet still working on it,i've replaced calipers with blue spot ones with new seal kit trhough'em,everything ''bananas'' has done but still no luck,The only thing yet to replace are stem bearings which by the way seem fine no play,maybe it's the rim i don't know ,i've put new tyre,wheel balanced ,i really don't ,any ideas mate?