Rear disk touching the caliper carrier

[zx9landie]

Hi all,
A strange 1 here.
A damaged (partially crushed) rubber brake pipe caused the pistons to part company with the rear caliper as the pressure wasn't released after using the rear brake, so the pistons were fully 'pumped out' of the caliper body.
Fortunately, I was less than a mile from home when things started to go pear shaped so I didn't end up on my arse !
Things go so hot, I had a nice little fire of the rubber parts on the caliper when i rolled onto the drive !
The rear brake was virtually 'jammed solid' - I put the little fire out and had to wait for things to cool down before I could start to investigate.   
Anyway - replaced the caliper & mount with an 'as new' condition 2nd hand parts BUT......
The disc is now permanently binding on the caliper carrier at the very front edge of the mount, causing the disc to get warm/hot.
Obviously - not right & after (luckily) not dumping it previously, Mr Paranoid here is struggling to understand what's happening.
It is almost like the rear wheel isn't tracking straight (which it is near enough - the adjusters are 0.3mm different according to my Vernier).
I have a new disk on order as the old 1 is in a shocking state cosmetically but I'd be surprised if it's uniformly 'deformed/bent'.
All spacers etc are in the correct places as per the on line exploded parts diagrams.
I'm wondering if the heat transfer has caused a problem with the rubber seal on the rear bearings and will be checking when I fit the new rear disc but..... 
Any thoughts/suggestions as to why the disc has 'apparently' moved over a few mm within it's running clearance as it is no longer central.
Many thanks in advance.
 
It just occurred to me - please could someone post a pic of their re wheel setup, disk side, to show how much of a 'gap' they have between the space on the side and the rear wheel as this would show if my spacer is sitting 'too far' into the wheel, so by letting the caliper carrier more to far over.

Many more thanks in advance.
 

[Antares]

Originally Posted by zx9landie

Hi all,
A strange 1 here.
A damaged (partially crushed) rubber brake pipe caused the pistons to part company with the rear caliper as the pressure wasn't released after using the rear brake, so the pistons were fully 'pumped out' of the caliper body.
Fortunately, I was less than a mile from home when things started to go pear shaped so I didn't end up on my arse !
Things go so hot, I had a nice little fire of the rubber parts on the caliper when i rolled onto the drive !
The rear brake was virtually 'jammed solid' - I put the little fire out and had to wait for things to cool down before I could start to investigate.   
Anyway - replaced the caliper & mount with an 'as new' condition 2nd hand parts BUT......
The disc is now permanently binding on the caliper carrier at the very front edge of the mount, causing the disc to get warm/hot.
Obviously - not right & after (luckily) not dumping it previously, Mr Paranoid here is struggling to understand what's happening.
It is almost like the rear wheel isn't tracking straight (which it is near enough - the adjusters are 0.3mm different according to my Vernier).
I have a new disk on order as the old 1 is in a shocking state cosmetically but I'd be surprised if it's uniformly 'deformed/bent'.
All spacers etc are in the correct places as per the on line exploded parts diagrams.
I'm wondering if the heat transfer has caused a problem with the rubber seal on the rear bearings and will be checking when I fit the new rear disc but..... 
Any thoughts/suggestions as to why the disc has 'apparently' moved over a few mm within it's running clearance as it is no longer central.
Many thanks in advance.
 

 

Hey it's 99% possible the rear disc was warped from the heat of binding up as it's not a floating disc, The disc and the callipers are on the same axis so they should always be in line with each other regardless of wheel alignment.

[zx9landie]

Thanks for the reply Antares - the disc is defo my 1st thought.
The other thoughts are random but maybe/possibles.
I guess I have too much time on my hands as I cant ride me bike ! 

[RyanGTXR]

Firstly, do not set your rear wheel alignment by the swingarm marks or by measuring the swing arm, that is in no way accurate, 2 long straight edges are the best way to make sure it's correct.

Make sure the caliper mount is sat on it's lug properly,
as above something could be warped

[smithy]

Originally Posted by zx9landie

Hi all,
A strange 1 here.
A damaged (partially crushed) rubber brake pipe caused the pistons to part company with the rear caliper as the pressure wasn't released after using the rear brake, so the pistons were fully 'pumped out' of the caliper body.
Fortunately, I was less than a mile from home when things started to go pear shaped so I didn't end up on my arse !
Things go so hot, I had a nice little fire of the rubber parts on the caliper when i rolled onto the drive !
The rear brake was virtually 'jammed solid' - I put the little fire out and had to wait for things to cool down before I could start to investigate.   
Anyway - replaced the caliper & mount with an 'as new' condition 2nd hand parts BUT......
The disc is now permanently binding on the caliper carrier at the very front edge of the mount, causing the disc to get warm/hot.
Obviously - not right & after (luckily) not dumping it previously, Mr Paranoid here is struggling to understand what's happening.
It is almost like the rear wheel isn't tracking straight (which it is near enough - the adjusters are 0.3mm different according to my Vernier).
I have a new disk on order as the old 1 is in a shocking state cosmetically but I'd be surprised if it's uniformly 'deformed/bent'.
All spacers etc are in the correct places as per the on line exploded parts diagrams.
I'm wondering if the heat transfer has caused a problem with the rubber seal on the rear bearings and will be checking when I fit the new rear disc but..... 
Any thoughts/suggestions as to why the disc has 'apparently' moved over a few mm within it's running clearance as it is no longer central.
Many thanks in advance.
 
It just occurred to me - please could someone post a pic of their re wheel setup, disk side, to show how much of a 'gap' they have between the space on the side and the rear wheel as this would show if my spacer is sitting 'too far' into the wheel, so by letting the caliper carrier more to far over.

Many more thanks in advance.

Sounds like it's not been re-assembled correctly. Can you take a photo of the axle spacers etc for us.??

Smithy.

[Mareng1]

Is the caliper definitely from an XR?  Just wondering if there is a slight difference to the RR or the R - and you've bought one of them.   (not too likely - but you never know)

Otherwise - as above - I'd suspect that you have the washers or something not quite right.

The disc is unlikely to end up convex/concave throughout - with excessive heat.

[zx9landie]

Originally Posted by smithy

Sounds like it's not been re-assembled correctly. Can you take a photo of the axle spacers etc for us.??

Smithy.

Hi Smithy,
Will take a pic this evening but there are only 2 actual 'spacers' that can 'fall out' when removing the rear wheel. All the others are internal to the wheel or sprocket carrier.
As per the BMW parts diagram, the 'thinner' 1 goes into the wheel between the wheel & the caliper carrier (right hand side when viewed from the back of the bike) and the other 'Thinker' one goes between the sprocket carrier & the swinging arm (left hand side when viewed from the back of the bike).

Cheers   

[zx9landie]

Originally Posted by Mareng1

Is the caliper definitely from an XR?  Just wondering if there is a slight difference to the RR or the R - and you've bought one of them.   (not too likely - but you never know)

Otherwise - as above - I'd suspect that you have the washers or something not quite right.

The disc is unlikely to end up convex/concave throughout - with excessive heat.

Hi Mareng1,

From a visual comparison, both the 2nd hand caliper & the caliper carrier are the  same as the originals on my bike.

Cheers

[zx9landie]

Originally Posted by RyanGTXR

Firstly, do not set your rear wheel alignment by the swingarm marks or by measuring the swing arm, that is in no way accurate, 2 long straight edges are the best way to make sure it's correct.

Make sure the caliper mount is sat on it's lug properly,
as above something could be warped

Hi RyanGTXR,

The caliper mount is defo on it's mounting lug correctly.

I agree re something being 'warped/bent' but it's isolating the actual part.

Cheers

[zx9landie]

Pic's below