Rear disc brake weak

[mazdajason]

Afternoon,

Tuesday night I gave my MTB a wash. I took off the front wheel gave it a good clean and put it back on. Took the rear wheel off, did the same and put it back on. When i finished I took it for a ride to the end of the street and back and the rear brake was all of a sudden really soft. I had to pull the handle really tight to get even half the brake pressure I had before I took the rear wheel off. It has disc brakes on it but have I maybe bumped something when i've been cleaning it?

I haven't changed or messed with anything, just gave it a thorough clean.

Anyone know?
Jason.

[Kell]

Taking the wheel off and refitting it could have it off centre by a mm or so. Have you checked that's it's sitting straight in the mounts?

Also - cable or hydraulic?

[lufbramatt]

Sounds like it needs bleeding if it's a hydraulic brake. Maybe if you've had the bike upside down an air bubble has got into the system from the lever end. What sort of system is it?

[WinstonWolf]

Pad dropped out?

[Mr Gearchange]

Comtinated the disk/pad with something nasty?

I use brake cleaner - which I apply through a lighter flame, that generally gets rid of any contaminants.

[mazdajason]

Morning all,

It's cable brakes and the pads are definitely still in there. Maybe it's not seated 100%. I'll have another look this weekend. Cycled to work this morning (only a short 4 miles) and it was still the same.

Report back next week with hopefully a fix Thanks.

[Steve vRS]

My cable brakes were crappy when a load of muck got in the cable outer. The bike shop replaced the cables, inner and outer (internal cabling so I wasn't going near that!) and it was worse!

Turns out that 'normal' outers flex too much for disc brakes so at their cost, they replaced the outers with compression free outers and they have been fantastic!

Steve