GS1150 rear brake caliper and grinding feeling...

[BigyellowGS]

I've had my lovely yellow 1150GS (ABS) (02 reg)... for about a month now... And ive alreay racked up 2000+ miles (even though I took a week out from riding to visit scotland with some friends)...

Within the last couple of hundred miles (2 days commuting), I've noticed a strange grinding/vibration feeling coming though the pegs...

I've read a few threads on bearing failure in the bevel box and vibration caused by part worn tourances (shes probably done about 4000 miles on her current shoes).. But they seem fine with 8 to 10mm of tread left..

So today I've checked a few obvious things...

Tyre presure (its got tourances front and back) - pressure was 36front/42rear

There is NO play in the rear wheel what-so-ever!

I drained the final drive oil and checked for play again - nothing.. There was probably about a finger nails worth of fine silver gunk on the magnetic plug... but no worse than that ive seen on other bikes...

Refilled the oil and took her for a blat... Still the grinding..

It was only when I stopped and prodded about the rear wheel again, I noticed the rear brake caliper was "loose" on the disk... you could rattle it about 5mm side to side and a few mm front to back/up down... Also the pads are down to approx 1mm... So I'm guessing this could be the cause...?

Has anyone else had something similar? Or am i barking up the wrong tree?

 

[Dragon Master]

Check the road...

Hi Big Yellow,

Not sure about the brake thing causing the vibes, but 5mm free play is a bit scary, and at 1mm, the pads are leaving legal thickness...
As for the tyres, I run Tourances myself (1100), and they do seem to transmit vibes from the road once they start wearing to any extent. My front one is just about shot, and the bars buzz like hell on a bad surface. The rear has just started to show a flat; not sure of the miles it's done, I usually get about 11k out of them, I've had this on nearly two years, so I'm guessing about 7.5k. But it's started to 'buzz' as well. It's most noticeable on a badly worn surface, especially the gravel sprayed ones. Try having a look at the surface you're on when it buzzes, see if the buz changes with the surface...

Cheers,

Dave,

P.S. As for the rear drive/wheel bearing, mine went two years back, no warning vibes or anything, just a pool of oil by the wheel.

 

[ELIMINATOR]

The rear caliper is designed to "float", but 5mm is excessive. The pistons do not retract that much once the brakes are released. The fit is more of a "wobble", unlikely as you would have felt it, but is the disc warped? Or possibly the pistons are seized / stiff? Or the pad retaining pin has a goove worn into it?

 

[Gas'd Off]

Look closely at the rear pads. One wears faster than the other.

 

[Tarka]

Also the pads are down to approx 1mm...

 

[BigyellowGS]

Well... after about an hour of fiddling and soaking the pad mounting pin in WD40.. I got the pad out... cleaned the caliper, checked the pistons move freely... and put new pads in... And the caliper no longer wobbles...

But the grinding feeling is still there...

Road surface does seem to make a difference, so maybe it is just the fact im not used to riding with semi trail type tyres (having come from sports tourers)...

cheers for the thoughts...