Brake drag thoughts

M

motopsycho87

New member
I'm still experiencing a bit of brake drag on my bike, so far I've replaced;

Hose
Caliper seals
Master cylinder rebuild kit
Disc
Pads
Wheel bearings

I can still spin the wheel, but it only gets a few rotations before it stops, the carrier is dead straight, I've greased the slides etc, I can't find anything physically wrong, is there anything anyone else can suggest?
 
Which end?

Rear has more drag due to the drive chain etc, but you already know this so I'll say its been checked. My back brake drags some, but I care less. Its not chewing through pads or discs and only noticed when turning it on the stand.

Quick check to confirm its the brakes is to push the caliper off the disc completely and spin err up. If its greatly improved you've isolated some of the issue. I'll assume this has been done too.

So from your list, whats been done with the caliper pistons? how do they look? do they push in easily?
 
Front end, spins very freely when pistons are pushed back. There is reasonable resistance when pushing the pistons back but they do go...
 
This may sound silly but make sure the lever can fully return. Sometimes they hit bark busters or the rubber boots get in the way.
 
Yeah looked at that already. I was going to look for the lesser spotted bleed hole in the morning, but I figured surely if the pistons can go back they would dislodge whatever may be blocking it?

My other thoughts atm are

- use a thinner washer behind the circlip on the master cylinder piston
- machine off something like 0.5mm from the rear of the piston
- drill the return hole slightly larger

Clueless, really!
 
Check the caliper slide pins, the ones that mount on the caliper bracket. They may be binding.
 
gasgasman said:
Check the caliper slide pins, the ones that mount on the caliper bracket. They may be binding.
Click to expand...

Good thinking. You can buy replacement pins and also the rubber bushings through the local Honda dealer. Bit of quality ruibber grease and the caliper floats nicely.

The actual pad pins (and also holes in the pads themselves) can easily groove and stop the pads returning freely too.
 
One of my buddies suffered with this on his newer Polaris snowmobile. After replacing several parts with no change, what he did was add springs on the caliper slide pins in between the pads to help keep drag off the rotor. Worked like a charm!
 
dANbOT said:
One of my buddies suffered with this on his newer Polaris snowmobile. After replacing several parts with no change, what he did was add springs on the caliper slide pins in between the pads to help keep drag off the rotor. Worked like a charm!
Click to expand...

Now that is an excellent idea! Shame only one side has a pin, but I will give it a go!!
 
Does anyone know the piston sizes at all? When I changed the seals I didn't change the pistons, wondering if maybe the plastic may swell over time due to the fluid...?
 
how free is the brake pedal pivot?remove,clean,grease.make sure its returning fully freely(no sticky spots),then check that you have a small freeplay between pushrod and master cyl piston.if the pedal is a little sticky or binding slightly it will hold mcyl piston just off resting position.also if you set the pedal too high it may be hitting the stop/frame before fully releasing mc piston
 
Last edited:
Had a good snoop on the net and found a few studies and a lot of anecdotal evidence of plastic pistons swelling, replace with steel! Or aluminium bronze in my case!
 
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