Front brake calipers

[Silverlegacy]

Hi all,


Gave my bike a clean the weekend and decided to clean the calipers, not a full blown removal, just removing them off disc and taking pads out and cleaning dust and gunk out of them.
when i pumped the pistons out a little one came really far out and nearly dropped out, was sitting at an angle.
Now the front wheel seems to bind a little, i have removed that caliper and the wheel does spin a little more freely with it off, but its all nice and clean inside now, so i am thinking that maybe when the piston became unseated some air might have gotten in, so would you recommend bleeding the system.
I am pretty new to the whole bike maintenance thing (sorry) I normally just get my local garage to do it (now i know why)
thanks

[darrsi]

If you had popped it out too far it would've leaked fluid.


When i do mine i use 'G' clamps to hold the other 3 in place then just pump it out a little until you see a clean, shiny part of the pot, then give it a good scrubbing with a toothbrush and brake cleaner only, then i'll cover the exposed parts with Red Rubber Grease, then gently push it back in and move onto the next one.


If the brakes aren't spongy then i wouldn't worry about it, but if they are then bleeding them should be done anyway, you have to be patient though, you may need to do it a few times before getting them right.


A common reason for the brakes actually binding on reassembly is putting the pads in on different sides to what they were before, which makes them rub slightly against the grain of the pad on the disc, so will need bedding in again, but it won't take long for them to settle back down.


Don't use anything other than brake cleaner to clean the pots with as some other degreasers can leave a residue that could cause problems.

[Silverlegacy]

Hi
I don't think any brake fluid leaked out but can't be 100% sure as calipers were wet from cleaning them, so there is a slim chance a tiny bit could of escaped.
I did switch the pads over to balance out the wear so hopefully that's the main reason.
I will try and get some tubing to bleed them over the next few days, brakes don't feel to spongy but it does feel like I need to pull handle a bit more to get it to stop as well.
Thanks for the help.

[slappy]

As darrsi says if the pads have been put in different sides they will need bedding in again and that will be why you feel you need to use more pressure on the lever. Once they are bedded in to the disc again you should get the same feel at the lever as before, how long that will take depends on how often you use the brakes!

[darrsi]

Could always try tying your front brake lever back over night, it forces any air to rise to the top, it works quite well.

[Silverlegacy]

thanks for all the help and info guys :-)

[Punkstig]

As above really!
It doesn't sound like you've let air in, but just tie the lever back with a cable the over night.
If 1 pad is wearing quicker than the other then the pistons are clearly sticking slightly, next time you change pads make sure they're properly cleaned, if there's the same problem on the newer pads go for a caliper overhaul- new seals!

[His Dudeness]

I'd guess you disturbed the dust seal. They get a bit chewed up and corrosion builds up behind them and forces them out against the pistons causing them to start sticking.

[Deefer666]

When I clean calipers I put a spanner or a screw driver down the centre and then put an elastic band over each end and over the back or the caliper, this means you can pup the pistons out to clean them without fear of them popping out.