Brakes not right... Front makes a strange almost rubber on steel sound

[Gadgetsandwheels]

Not sure if anyone else has had this issue and I've tried searching but couldn't find it...  After about 4500 miles my brakes began to feel much less efficient, particularly the front ones.  The back brake doesn't have enough oomph to stop the bike at slower speeds unless I press like hell on it.  When I bought the bike new last Nov and until about 4500 miles, the brakes were excellent.  The front brake also makes a strange squelching rubbery sound when I come to a stop using it.  Sounds a bit like it is wet cork on steel or rubber on steel.  Now it's done 6000 and seems to be getting worse.  Still 3mm on from pads and 2mm on rear pads.  The dealer says "it's like all the other bikes".  Any ideas of what the problem might be?

[T6pilot]

My first thought would be a bit of glaze on rotors
I would try some 100grit wet/dry paper have bike on center stand with some one holding rear down
Rotate front wheel with sandpaper folded over inner and outer side of rotor, repeat on opposite side
With side case off, bike in nuteral hold front down and repeat process on rear rotor
I would then follow up on both wheels with some brake cleaner
On pads and rotors
Next step would be to replace pads if this doesn't help

[Gadgetsandwheels]

My first thought would be a bit of glaze on rotors
I would try some 100grit wet/dry paper have bike on center stand with some one holding rear down
Rotate front wheel with sandpaper folded over inner and outer side of rotor, repeat on opposite side
With side case off, bike in nuteral hold front down and repeat process on rear rotor
I would then follow up on both wheels with some brake cleaner
On pads and rotors
Next step would be to replace pads if this doesn't help

Many thanks for the reply.  When you say rotor, does that mean the disc?  I have tried brake cleaner and they do seem to work well for 10 minutes after that but then quickly return to the issue.  I've got a feeling that it is the pads that are poor.  They are the ones that BMW fit as standard.  I did have a similar problem though with a new GS Adventure I had last year.  Almost identical issue but not quite as bad as this one has become.

[T6pilot]

Correct, disc
Try a through cleaning, even simple green on calipers, disc's
Can help
Worst case change pads
And sand disc's

[guest2360]

Totally new issue for me.  if you are using your back brake regularly using the foot lever after 6000 miles its going to be well past its best. What do you use to clean the bike with, ie stuff added to water.

[Gadgetsandwheels]

Totally new issue for me. if you are using your back brake regularly using the foot lever after 6000 miles its going to be well past its best. What do you use to clean the bike with, ie stuff added to water.

I just use a little bit of fairy liquid. Always done it that way. The only other thing I can think of is ACF50 treatment. Wheels were covered but whether any subsequently dripped down into pads. Sounds unlikely but I suppose possible.  Odd though that it didn't do it for several months after that was done. I will try new pads and sanding the discs and see how it goes.

[guest2360]

I was once told that washing up liquid contains salt as well as a powerful de greaser so should never be used on vehicles.  Could have been told wrong of course. Not sure about sanding discs though.


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[Levisp]

Agree I would keep away from washing up liquid. Sounds to me you have contaminated pads. If you have cleaned your discs/rotors with brake cleaner and the brakes are good for a short time and then go off again, this would indicate the pads are the problem. I am presuming the brakes do not feel spongy, brake fluid OK. I would clean the discs again and replace the pads. Spray brake cleaner onto a clean piece of folded kitchen paper towel and wipe the discs until clean and then replace with new pads. I'm sure this would solve your problem. If it does then the question I would ask myself would be how have the original pads got contaminated.

[Gadgetsandwheels]

I was once told that washing up liquid contains salt as well as a powerful de greaser so should never be used on vehicles. Could have been told wrong of course. Not sure about sanding discs though.
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While possible, I would think on balance or probability that a substantially diluted small amount of WU liquid (never applied to brakes) would be the unlikely conclusion.  Not saying it is impossible.

[Gadgetsandwheels]

Agree I would keep away from washing up liquid. Sounds to me you have contaminated pads. If you have cleaned your discs/rotors with brake cleaner and the brakes are good for a short time and then go off again, this would indicate the pads are the problem. I am presuming the brakes do not feel spongy, brake fluid OK. I would clean the discs again and replace the pads. Spray brake cleaner onto a clean piece of folded kitchen paper towel and wipe the discs until clean and then replace with new pads. I'm sure this would solve your problem. If it does then the question I would ask myself would be how have the original pads got contaminated.

Thanks.  There is a certain amount of sponginess yeah in both front and back. They have just changed the brake fluid on 6000 service so I would hope they had blessed them as req. other than that I will go with the new pads all round and clean discs solution.

[guest3713]

Thanks. There is a certain amount of sponginess yeah in both front and back. They have just changed the brake fluid on 6000 service so I would hope they had blessed them as req. other than that I will go with the new pads all round and clean discs solution.

"Sponginess" is a little worrisome for air in your brake lines or water contaminated brake fluid...

You shouldn't get a "spongy" feel from worn pads or dirty discs. As long as you're changing the pads and cleaning the discs, I'd spend another few bucks on a sealed fresh can of DOT 4 and be certain lines are properly bled and system refilled with fresh brake fluid despite it being recently done.

Are either of the master cylinders, reservoirs, or calipers leaking?

[guest2360]

Who's the dealer who is telling you they are all like that.  As you are not new to Rs you know that's wrong.

[Gadgetsandwheels]

Who's the dealer who is telling you they are all like that.  As you are not new to Rs you know that's wrong.

I won't mention the dealer specifically but I do get a bit peed off with dealers given bulls__t answers.  The noise has got worse over the last few days on stopping and it is booked in again on Saturday morning for checks and replacement pads.

[guest3713]

I won't mention the dealer specifically but I do get a bit peed off with dealers given bulls__t answers. The noise has got worse over the last few days on stopping and it is booked in again on Saturday morning for checks and replacement pads.

When you have a moment, please let us know details on the outcome.

[Gadgetsandwheels]

When you have a moment, please let us know details on the outcome.

I had new pads fitted today.  Cost me best part of £250.  Problem completely gone away.  Whether something else was done at the same time or not I don't know.  The pads didn't appear contaminated to look at them and they still had plenty of braking surface depth.  They did have a shiny steel like surface to them.  So, I'm not entirely sure.  ...but for now with new ones it seems to work very well again.