Just bought myself a proper bike stand. Got it from Merlin, seems good value.
So I've decided to attempt my first bit of bike maintenance. 🙂
Going to bleed my Shimano brakes. My back one seems to be dragging on the rotor. Not sure if a bleed will sort it but worth a try eh?
Has anyone got any advice before I attempt this?
More likely that you've either got a sticking piston or the caliper needs re aligning, doubt that bleeding will achieve much.
Oh great. 🙂
Should have asked question on here before I went and bought a bleed kit. Doh!
Anyone know how to free a sticking piston if that's the problem?
work it in & out, holding the non stuck one in so the sticking one has to move. clean & lube the sticking one when it's pumped out as far as you dare with either proper brake lube or brake fluid.
I would re-align the caliper first. This is the easiest way.
Loosen off the caliper so its floppy. Pull the brake leaver to clamp the caliper on to the rotor. Tighten the bolts and release the brake. The caliper should now be perfectly aligned.
If it still rubs you could have a sticky piston or the rotor is bent.
The brakes are only a couple of months old, and I remember when I fitted them one of the pads was rubbing on the rotor, I tried to move the caliper over as far as it will possibly go, but it still rubs. The Rotors are brand new so I don't think that they are bent.
So it looks like a sticking piston maybe?
Loosen off the caliper so its floppy. Pull the brake leaver to clamp the caliper on to the rotor. Tighten the bolts and release the brake. The caliper should now be perfectly aligned.
Doesn't always work. Correct way is to loosen off the mounting bolts, adjust so the rotor sits in the middle of the caliper & re tighten. Check the gap by eye.
If when you've done that the brake starts to rub again, then it does sound like a sticking piston.
How much drag is on the wheel when it turns? If its fairly free then bedding in the pads a bit more will help.
You might have a sticky piston if the leaver throw is very short and theres no brake modulation.
Take the pads out, and use a flat bladed screw driver to move the pads slowly back into the caliper. You might need to spray some light lube to free them up. Reinsert the pads and try a few high speed stops to rebed the pads.
What shimano brakes are they?
There isn't loads of drag, just enough to stop the wheel when it's spinning really slowly.
The brakes are deore 595.
When you say "light lube" do you mean wd40 or is that really bad? Suppose I can use the mineral oil from the bleed kit that I've just bought.
Just ordered a work stand myself from Ribble, £54.78 inc P&P. Bargain 😀
Think I paid about £60 for mine from Merlin. Got fed up with bike hitting me on the head whilst adjusting stuff. Stand makes things a lot easier from my limited experience, can't believe I put buying one as as long as I did.
WD40 would be fine just to unstick the piston.
Things to check:
1. Wheel is sat in the drop outs properly.
2. Rotor isn't bent
3. Rotor is mounted to the hub correctly
4. Caliper is mounted properly.
It doesn't sound as if you have a lot of drag, which would indicate a stuck piston, so perhaps you just need to bed in the pads properly.
Ok thanks for that.
I'll check those things that you mentioned. Maybe I should just ride more.
😀