Disc brake adjustment

[Paul_L]

Have a hybrid with Hayes MX4 mechanical disc brakes.

Over the last few weeks the braking power on the rear wheel has deteriorated. This could be due to age, but i doubt it. I think it's more due to the fact that after a couple of visits from the p****** fairy the rotor is probably in a slightly different location between the calipers that it previously was. The rotor is not rubbing at all, but i have to pull the brake lever pretty much to the bars to get any significant braking power, and an emergency stop on rear brake alone would not be possible.

The information in my bike manual is less than helpful and there doesn't seem to be any useful information on the hayes web site.

Any clues?

 

[fixedfixer]

Adjust the pads in with a 5mm allen key till they catch then back 'em off a bit.

 

[rusky]

I have Hayes MX4's on my bike & have to adjust them every couple of weeks.

TBH, the manual is crap & IMO the adjustment method doesn't work!

 

[rusky]

The best way I found to adjust them is to wind the barrel adjuster out a couple of turns, loosen the mounting bolts a little, wind the inner pad in until the disc is clamped, tighten the mounting bolts, back off the barrel adjuster then the inner pad so they don't catch.

 

[Paul_L]

i've sorted the rubbing problem but the brake performance is still crap (IMO). The front brake is really solid but the rear brake stopping ability is poor. Could it be the discs need replacing (odd as they're only 4 months old) or could it be there is some grease on the rotor?

 

[rusky]

MX4 Manual

 

[rusky]

There could be contamination on the pads.

 

[Paul_L]

thanks rusky, i wonder if you're right.

i've adjusted the pads so there's no rubbing. i've adjusted the brake lever so the pull on the lever is better. If i push the bike along and apply the brake the wheel locks up as you'd expect. But then test it with a rider and the brake performance is poor.

I cleaned the rear mech earlier and sprayed degreaser on it. I thought i was pretty careful to keep it away from the brake, but if this is the case will it "burn" off with use.

 

[rusky]

I have sprayed muc-off bike spray which has p.t.f.e. on the frame & got it on the discs.

Takes a few miles to get that off I can tell you!

these people are good for replacement pads DiscoBrakes <br><br>Don't get teh sintered ones as the centre of the backing plate has a hole in it &amp; the magnet in the calipers has nothing to stick to!<br>