Knackered Rear Disc

[DynaMight]

A few weeks back the girlfriend said her rear brake felt 'funny', So I had a quick look to find there was no pad, Just metal on metal, Nipped down to the shop, bought some new ones.

The disc looked quite scared, I am not sure how long it was down to metal.

Anyway I checked the rear pads yesterday and noticed that there was only a few mm of pad left, She's probably done about 300-500miles on them, Although she does use the rear hell of alot. I am not sure if she has been dragging the rear when riding also.

So my question is, would a knackered rear disc eat through pads quicker than a unknackered one?
____________________
My bikes are at https://www.bikepics.com/members/dynamight/

[Black Knight]

Yes it would. It will literally scrape the pad surface away.

My advise, replace the pad and the disc.

[Kickstart]

Hi

Will not help, but the pads have very little material on them from new (RS125 from memory?). A rear disk 2nd hand should be cheap and easy to find second hand. However the scores in the disk are not going to cut into the pad that much.

I would be inclined to check that the caliper is free. They normally are, those old Brembo (or the Grimeca clone) calipers are very good for resisting seizing up.

The front brake is far more effective.

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[DynaMight]

Her bike is a CBR400 NC23, I did have to move the piston back quite a bit to get the new pads in, It seemed to move pretty well.

She does pretty much use the rear brake for 90% of the stuff, Which I've tried to stop her doing. I think new rear disc's were about £40-60 anyway, So I cant see a 2nd hand rear being that much.

Thanks for your help guys.
____________________
My bikes are at https://www.bikepics.com/members/dynamight/

[Scotsman37]

Take the brake caliper off the disk but don't disconnect the brake hose. Get an old tooth brush or something similar to brush away dirt & grime from around the pistons while using silkolene brake cleaner as the pistons may not be moving back freely. Spread liberally some copper grease on the rear of the brake pads and the metal bars holding holding the pads in place too for giving it that final thorough service.

Remember to have a clean rag at hand to make sure no copper grease gets on the front of the brake pads themselves.

[Kickstart]

Hi

Does tend to suggest it is sticking a bit. Rear pads don't get much wear (just on the RS and the like there is not much there to start with). May also be worth bleeding the brakes through and checking that the brakes are not binding at the master cylinder end (eg, on my FZR the brake lever pivots on the footrest, and on mine this had started to seize up).

Bit worrying that she uses the rear brake that much.

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Reevo8]

Speak to Graeme France, i am sure that he will have a couple of second hand discs in stock. While the bike is out of ction, why not fit some braided lines too?

Show her how much you love her, and also that you dont want to have to buy a new(for her) bike for a while.
____________________
05 ZX10R, (**05 WKR)

[kenny]

Yes of course because it is more like sandpaper then a smooth disc now You should always replace you disc if you've let the pads go metal to metal aswell as if you get some new disc you should always replace the pads aswell.This is why people at garages say thats it cheaper to replace the pads earlier then to lem them run right down.

Also did you check that the pots where moving freely and not clogged up with dirt because if they are stick with dirt then the pads with be constanly rubbing on the disc, and check the brake fluid level aswell if there has been exess fluid in to compesate for the low pads in then when you have changed to the new ones the excess fluid will also make the pads rub which you will need to remove some of the fluid
____________________
KeNNy 100cc peugot speedfight 125cc Honda NSR125R 650cc suzuki SV650R 125cc suzuki GZ125 600cc yamaha YZF-R6