Front discs and disc bolts

[Fazerider]

[quote author=Chris link=topic=11420.msg122899#msg122899 date=1390525864]
I'll do some basic testing like using the front paddock stand and spin the wheel but I'll still be replacing it all sooner rather than later anyway.

Chris

Just do things one at a time, it's always worth sourcing the problem anyway in case you ever have similar issues again in the future.
I've known people before to buy new parts and fit them all at once, and it's fixed their problem but they never actually knew what it was causing it, which is not really informative at all.
[/quote]

Spinning the wheel with or without a dial gauge won't indicate a warped disc, just a bent one. Put a straight edge across the disc to see if it's warped (i.e dish-shaped).
If a disc has warped then do everything at once. Chances are it's a sticky caliper piston responsible, in which case you need to clean the pistons and replace the seals to reduce the risk of it happening to the new one. Since you'll then have the joy of bleeding it anyway, it would make sense to change the lines at the same time as it's something you're planning to do.

[darrsi]

[quote author=darrsi link=topic=11420.msg122904#msg122904 date=1390542548]
[quote author=Chris link=topic=11420.msg122899#msg122899 date=1390525864]
I'll do some basic testing like using the front paddock stand and spin the wheel but I'll still be replacing it all sooner rather than later anyway.

Chris

Just do things one at a time, it's always worth sourcing the problem anyway in case you ever have similar issues again in the future.
I've known people before to buy new parts and fit them all at once, and it's fixed their problem but they never actually knew what it was causing it, which is not really informative at all.
[/quote]

Spinning the wheel with or without a dial gauge won't indicate a warped disc, just a bent one. Put a straight edge across the disc to see if it's warped (i.e dish-shaped).
If a disc has warped then do everything at once. Chances are it's a sticky caliper piston responsible, in which case you need to clean the pistons and replace the seals to reduce the risk of it happening to the new one. Since you'll then have the joy of bleeding it anyway, it would make sense to change the lines at the same time as it's something you're planning to do.
[/quote]

"...If a disc has warped..."

That's a different story if you've definitely sourced the problem, from experience it's not always that easy to tell though is it?
If you are certain that's the cause then go for it by all means.

[darrsi]

Correct me if i'm wrong Chris but i would've thought your calipers were in good shape from previous posts if i remember correctly, although the fact that you are surrounded by sea air could cause you trouble i'd imagine?

[Chris]

Darssi, My rear caliper is like new as I completely stripped it cleaned and put back together with new seals etc last winter. But my fronts have only ever just been cleaned out since I got the bike.

I'm pretty sure the pistons are all moving ok but I'm going to be changing the brake lines so while I have them off then I'm going to be replacing the piston seals and polishing up the pistons. After I've put that back together and tried it out then I'll see if there is still a problem, if there is I'll be changing the discs. 

Chris

[Chris]

Yeah, think I'm just being paranoid about the bolts but still something I'll do sometime..

Chris

[darrsi]

Darssi, My rear caliper is like new as I completely stripped it cleaned and put back together with new seals etc last winter. But my fronts have only ever just been cleaned out since I got the bike.

I'm pretty sure the pistons are all moving ok but I'm going to be changing the brake lines so while I have them off then I'm going to be replacing the piston seals and polishing up the pistons. After I've put that back together and tried it out then I'll see if there is still a problem, if there is I'll be changing the discs. 

Chris

I thought i recalled you talking about stripping down a caliper on here before, wasn't sure if it was front or back though.   

[Chris]

Yeah did the back end last year as it was in more need of it. I wonder if it's worth overhauling the master cylinder while the lines are off etc?

Good advice on the allen key front  8) I've got a really good set, not sure what make they are but they're like new and worked fine when I had the discs off to get the wheels powder coated.

Chris