2013 RT - 1st MOT - FAIL

dr nosh

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Arghh. Disappointed customer. :mad:

2013 RT, just under 21,500 miles, failed 1st MOT today - Front disks warped giving 'Fluctuations of Brake Effort'.

Now the bike is immaculate (OCD here), serviced on the dot, returns 62mpg and I got 11780 miles out of the last pair of tyres, pads 2/3 worn so well on target for 24k miles, so not driven on the brakes.

So, why have discs on a premium product, at a premium price got to this condition.

I have motored for 40 years and replaced worn out discs but never a warped disc.

The only upside is BMW 'goodwill' on the parts, whilst I pay 1 hour labour.
 
Good job they picked it up on the MOT if you didn't notice it.
 
The only upside is BMW 'goodwill' on the parts, whilst I pay 1 hour labour.

IMO thats a result considering that disks are normally classed as wear items and cost a kings ransom.

If you contribute then they will effectively have a warranty on the new disks.
 
Don't get me wrong, it is good that they picked it up. Its related to preserving my life.:thumb

I know 2 other MOT stations that would have not spotted that.

The pads are being replaced. New discs with old pads would have been a more difficult argument in the case of future failure.

To be honest, the 'goodwill' came out fairly easily, I did not have to press very hard. They know something there is faulty.
 
I had a similar experience with my R12GSA. The problem was actually the rear disk being warped but due to the nature of the linked brake system it manifested itself as from disk warping. BMW even changed the front discs u Dee warranty only for the problem to persist which is when they realised and swapped the rear disc too. It's worth checking!
 
There is a theory ( I believe not proven) , that holding a hot pad against a screaming hot disk, can warp the disk.
I’m not pleased that I’ve just suffered mot failure 12,800mls, rear disk warped 2014WCGSA ( yes it’s not an RT ).I was not aware and I’m not a heavy braker who enjoys long pad life .
I habitually hold my bike still with gentle finger pressure possibly every time I stop and I’ll think about that . Do you ?
I’ve never warped any disk on any vehicle that I’ve owned until now .
 
May not be related, but when I bought my 2017 LC I was thinking about getting the BMW alarm system, then had second thoughts and said to salesman, I might get a disc alarm, he said careful you do not warp the disc, it only needs a little to fail inspection, I wonder what he already knows ???????
 
May not be related, but when I bought my 2017 LC I was thinking about getting the BMW alarm system, then had second thoughts and said to salesman, I might get a disc alarm, he said careful you do not warp the disc, it only needs a little to fail inspection, I wonder what he already knows ???????

Interesting, but think that is rubbish, how can a disc lock warp a disc. If they warped discs, BMW would not sell their own disc locks. Discs are a wearable item and are not designed to last for thousands of miles. Although 12k is not a lot, I have over 14k on my RT at the moment and the discs are fine, although its due an MOT in the next couple of weeks, so probably jinxed it now :)
 
Interesting, but think that is rubbish, how can a disc lock warp a disc. If they warped discs, BMW would not sell their own disc locks. Discs are a wearable item and are not designed to last for thousands of miles. Although 12k is not a lot, I have over 14k on my RT at the moment and the discs are fine, although its due an MOT in the next couple of weeks, so probably jinxed it now :)

Probably he did not know what else to say, to try and sell the alarm system, who knows, anyway been using the heavy ABUS 8008 and all seems OK.
 
I too have the same bike and at the last MOT it had an advisory for slight fluctuation on rear disc. Having bought the bike used, I stripped out the rear calliper and found it to be in very poor condition as were the pads. thorough clean and new pads all round.
MOT failure for this problem is quite common on the Kawasaki GT1400 . However, on the Kwacker, it is not a warped disc but sticking disc mounting bobbins preventing the disc from "floating". This was addressed on newer models by Kawasaki making the mounting holes slightly oval.
I regularly check my front discs to make sure they"rattle" and are free to float. On the rear it pays to ensure that the calliper is free to slide, else the pads stay in contact on one side of the disc and can cause overheating - check that the pads on the rear are wearing at about the same rate on both sides of the disc.
 
Is each of the discs a differing thickness around its circumference?

Or are the discs out of true on the wheel?

The former is possibly due to holding the bike on the brakes when the pads are very hot. The second may be due to the float rivets seizing.
 
Very common in motorcycles of all brands and can be caused by a number of reasons including warped discs, pad contamination, disc mounting hardware etc. A lot of riders don't even notice the symptoms. BMW are always quick to put this right but you have to pickup on it during the warranty period.
 
defo warped discs?

you can get the same fluctuations with shot wheel bearings.
 
defo warped discs?

you can get fluctuation with contamination on the studs that allow the disc to float (so it stops floating correctly).
 
Not the first time BMW have had discs wearing unevenly, last time I came across it the brake disc mounting pillars had been machined to uneven heights and this causes uneven wear in the disc. BMW came up with new bobbins with rubber in them, I don’t think it was always a good long term fix.
 


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