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-   -   XT660Z new front brake discs needed !! ( https://www.xt660.com/showthread.php?t=26230)

kinioo 21-09-16 20:30
XT660Z new front brake discs needed !!
 
OK,

After my recent problem with front brake caliper/discs, bobbins etc.

I will need new set of front brake discs complete with new set of bolts!!

1) Where is the best place to buy them from ??

2) What is the best way to undo disc bolts - it wont be easy.

I understand the hub is aluminum so it should be done gently...

Is it better to try to do it with wheels on the bike or off the bike or just take the wheel to the garage ???

BTW, I cannot ride to the garage due to the brake problem.

Many thanks,

Chris

kinioo 22-09-16 09:14
Hi all,

Found this: https://www.ajsutton.co.uk/product/Y...FUefGwoduf4Gpw

Says Yamaha Genuine, so assume would be ok.

Are these left & right or it does not matter (judging by the diagram provided it doesn't matter)

Mine is non ABS version.

Still need some advise whats the best way to remove/undo old bolts ???

Thanks,

Chris

kinioo 22-09-16 14:00
Quote:
Originally Posted by Pepsi (Post 225109)
Can I ask why you need new discs? Was it that one was badly damaged when it contacted your caliper? It would be the aluminium caliper that would probably be damaged before the steel disc gave up, or is it that the disc is now badly warped? Just trying to save you a lot of money before you commit to finding out that the problem is still there after new discs are fitted.
Hi there,

The calliper is OK as I didn't use the bike once I noticed the disc was rubbing (which was literally when I wanted to ride my bike after it had sat in the garage).

Yes, the discs seem to be badly warped/seized. I tried to clean the bobbins but it barely made any difference.

The other thing I discover yesterday is something I don't know how to explain (may take some pictures later), but RHS (clutch side disc, which causes the problem) is bending/flipping when I press it with my fingers - what I mean is I can literally flip it to the left to slightly change its position (so its not rubbing the calliper) but once the brake is applied it gets back (flips back) to its original position and rubs the calliper.

C.

Well, if the discs from my link are suitable its �55 a disc, so not so bad and might be worth doing it and get them changed.

What I am worry about is the old disc bolts - they will be pain in the as* to remove.

Pleiades 24-09-16 21:28
Quote:
Originally Posted by kinioo (Post 225113)
The other thing I discover yesterday is something I don't know how to explain (may take some pictures later), but RHS (clutch side disc, which causes the problem) is bending/flipping when I press it with my fingers - what I mean is I can literally flip it to the left to slightly change its position (so its not rubbing the calliper) but once the brake is applied it gets back (flips back) to its original position and rubs the calliper.
That is the primary symptom of the seized and gummed up bobbins you've identified. The discs should "float" on the carrier with a fairly light touch. If they are sticky or stuck the disc will tend to get marooned in one position or other and move jerkily (if they move at all) as you have found.

OE discs are cheaper than decent aftermarket discs (EBC etc.) on the front, so buy OE. You can get cheap Chinese wave discs but they are more trouble than they're worth!

Interestingly at the rear, it's a different story - the OE disc is double the price of an EBC item!

Provided you can get the disc bolts out without damage then they'll be fine to re-use with a thin application of Loctite. If in doubt though - change them. Don't buy OE bolts though as they'll end up costing you as much as the discs! Go visit your local fastener shop.

Fitting new pads with new discs is always advisable even if you think they are fairly new/good; especially so if the discs haven't been running true.

kinioo 26-09-16 09:15
Quote:
Originally Posted by Pleiades (Post 225156)
That is the primary symptom of the seized and gummed up bobbins you've identified. The discs should "float" on the carrier with a fairly light touch. If they are sticky or stuck the disc will tend to get marooned in one position or other and move jerkily (if they move at all) as you have found.

OE discs are cheaper than decent aftermarket discs (EBC etc.) on the front, so buy OE. You can get cheap Chinese wave discs but they are more trouble than they're worth!

Interestingly at the rear, it's a different story - the OE disc is double the price of an EBC item!

Provided you can get the disc bolts out without damage then they'll be fine to re-use with a thin application of Loctite. If in doubt though - change them. Don't buy OE bolts though as they'll end up costing you as much as the discs! Go visit your local fastener shop.

Fitting new pads with new discs is always advisable even if you think they are fairly new/good; especially so if the discs haven't been running true.
Thank You Pleiades, you have been very helpful.

Yes, am thinking of new set of front discs plus pads (I have already asked for new pads, and (not surprisingly, you provided me with a source link) I already bought them).

I have cleaned the bobbins as you said (YT video), but it didn't help much, thus new disc time.

Will go for OE (the link I attached).

The bolts...I don't worry if the bolts get damaged when removing, I am worry about aluminium hub...?!

If the bobbins are badly seized probably the bolts will be even worst !!

C.

nikroc 30-09-16 11:54
I have previously struggled with disc bolts and found a relatively straight forward way of undoing them was to use an impact driver. Make sure you have a nice tight/good fit in the 'socket' of the bolt and initially give it a good tap turning it tighter..yes tighter. THEN REVERSE DIRECTION AND TRY...

kinioo 30-09-16 19:58
OK guys bit of update here....

Its never easy, isnt it ?

I manged to undo 11 bolts...there is 12 in total (6 a side),

and obviously there is always ONE!!!:

Allen key is turning now, so the bolt is fuc*ed!

Any ideas ?

Was thinking of welding a standard bolt/nut into it but am a bit nervous about temperature as the bolt seats n aluminum hub/body ?!

C.

http://i1217.photobucket.com/albums/...o/IMAG2626.jpg

Pleiades 30-09-16 20:51
Heating isn't really a problem. In fact a little gentle heating will help as the steel bolt and aluminium alloy carrier will expand at different rates and help release things. These bolts have thread lock applied on assembly and this is usually why the are sometimes hard to remove. Heat is a good way to release its grip. Even pouring boiling water over the offending area can do enough to get things moving.

Before going down the welding route, try knocking in a a Torx bit (that is slightly larger than the rounded recess) with a hammer and then use an impact driver to break it free.

Some people might suggest using a left-handed drill bit, but the bolts are very hard and if it doesn't bite and wind it out you're going to be left with a bigger problem because they'll be nothing substantial left to get hold of.

If all else fails, then tack on a bolt as you suggested which almost certainly will do the trick as the heat generated will probably be enough to free it off. Just don't go mad with the welder; a couple of blobs will do the job.

nikroc 30-09-16 20:58
Are you saying the bolt is now freely turning?..but not coming out?.ie thread is stripped?..

Pleiades 30-09-16 21:05
Quote:
Originally Posted by nikroc (Post 225314)
Are you saying the bolt is now freely turning?..but not coming out?.ie thread is stripped?..
He means the Allen key is turning inside the recess in the top of the bolt, but the bolt is still siezed. In other words, the bolt head is fooked.

Quote:
Originally Posted by kinioo (Post 225311)
Allen key is turning now, so the bolt is fuc*ed![/IMG]

nikroc 30-09-16 21:11
Ahhhh....my bad,sorry.

As said try a torx head or the old fave of cutting a slot in the head and use a large flat blade in an impact socket

kinioo 30-09-16 22:07
Quote:
Originally Posted by Pleiades (Post 225315)
He means the Allen key is turning inside the recess in the top of the bolt, but the bolt is still siezed. In other words, the bolt head is fooked.
Exactly.

Thanks man again!

My English is not that good!

C.

kinioo 01-10-16 16:05
Afternoon All,

Update again.

Managed to remove the last 12th bolt !!!

Tried to weld a bolt into it, however it snapped when I used the spanner, but immediately after this gave it another go with an allen key and it went!!

I think temperature did its job!

OK, now I am ordering new set of bolts and pair of front discs.

Am going for OM's from the link attached above.

Here is another question for you guys:

Are the discs directional and are they specific right / left ??

I noticed the hub is marked with two dots brake side and one dot clutch side - same marks on discs ??

See pictures below:
http://i1217.photobucket.com/albums/...o/IMAG2628.jpg
http://i1217.photobucket.com/albums/...o/IMAG2629.jpg

Many thanks again for your help,

Chris

Pleiades 01-10-16 16:45
Heat is usually enough in this situation with dissimilar metals - steel in aluminium alloy... and it was. Result! :023:

The discs are not 'handed' they can be fitted on either side. They are the same part number both sides. When the Z came out in 2008, they just gave it two LH discs from an XTR!

kinioo 01-10-16 19:04
Quote:
Originally Posted by Pleiades (Post 225338)
Heat is usually enough in this situation with dissimilar metals - steel in aluminium alloy... and it was. Result! :023:

The discs are not 'handed' they can be fitted on either side. They are the same part number both sides. When the Z came out in 2008, they just gave it two LH discs from an XTR!
Thanks Pleiades!

that what I thought.

I think the discs (not the hub) were marked by mechanics when I had the front stripped for hub re-spraying etc ?

C.


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