Brake caliper adjustment!!

Plodder82

Replaced my Mechanical Tektro front disc caliper,for new/take off Hydro Avid 3's.
Cannot, in a million years, adjust the caliper pads from rubbing against the front disc.It really feels like the caliper is closed against the disc whist riding.
....I should add. I've been commuting ( for over 20 years).I assume I maybe need to bleed excessive fluid from the master cylinder .

cooldad

Or just ride for a bit and let the pads self adjust. Have you tried forcing them apart? Are the brakes actually on or just rubbing a bit?

Although I'm not sure what 'new/take off' means.

compuwiz_uk

as above, how much use have the new caliper/pads seen so far since been fitted.

it may just need a few rides use to bed the pads in ( wear off the top layer of pad as the pistons cannot be pushed any further back into the calipers. ( i had that on a new bike once, could not get the brakes to stop rubbing so just stopped trying & wore headphones for a few rides ( not my smartest move but it did the trick of stopping me hearing the brake rub )

now the brakes hardly ever make a noise unless in use & only time i hear em now is due to flex in the wheels/bike when hard cornering or really putting some welly into the pedals on a hill etc ( so not often at all as hills kill me lol )

JBA

Have you used the correct washers for mounting the Avid caliper, including the dished tri-align washers.

JGTR

How are you aligning them? Loosen bolts and pull brake and tighten bolts?

Never works on mine, I line them up by eye

LimitedGarry

JGTR wrote:

How are you aligning them? Loosen bolts and pull brake and tighten bolts?

Never works on mine, I line them up by eye

Pull brake, tighten snug. Undo one bolt, align by sight, tighten snug, undo the other, align, tighten snug, examine if alignment is perfect, then tighten strong.
Typically takes about a minute per brake, but sometimes I have this screwed up situation where I'm struggling to get it right for five minutes.

Rightarmbad

LimitedGarry wrote:

JGTR wrote:

How are you aligning them? Loosen bolts and pull brake and tighten bolts?

Never works on mine, I line them up by eye

Pull brake, tighten snug. Undo one bolt, align by sight, tighten snug, undo the other, align, tighten snug, examine if alignment is perfect, then tighten strong.
Typically takes about a minute per brake, but sometimes I have this screwed up situation where I'm struggling to get it right for five minutes.

Most people overtighten the bolts and distort the aligning cups, then when you tighten them after adjusting the caliper moves and you have to do it again.
Replace them and don't overtighten the new ones and things will be much more consistent.
Also check for bent bolts.

figbat

I recently replaced pads and fluid in mine and found a lot of drag afterwards. I thought "meh, it's just a little bit, I'll ride it off" but that first ride damn near killed me - I was essentially riding with the brakes on for 20 miles; when I finally finished the discs were warm to the touch. So I set about aligning the calipers (again) but the thing that really fixed it was taking a couple of drops of fluid out.

larkim

Just curious - by taking fluid out of the hydraulic system, what are you making space for? Are you implying that the pistons were limited in how far back they could return because of the fluid in the system behind them, so you've just made space for a little more movement? I thought that they way that they worked there was some form of non-return system which allowed the pads to be pushed back to their full extent (presumably by returning fluid to the reservoir?). I suppose if the reservoir was over-full that might limit things.

Asking genuine question as I have no real good understanding of the way that hydraulics auto-adjust themselves.

The Rookie

You only have to let fluid out if they are overfilled, which is clearly what he'd done.

Plodder82

I've followed typical brake caliper alignment procedure,slacken bolts squeeze lever,etc..
I've done over 50 miles on the pads and the pistons have been forced as far back as possible,even re-attatching the wheel afterwards is a pain.Also tried a genuine Avid rotor as I believe there discs are slightly narrower than the current Tektro...didn't make any difference.
As figbat said,I'll remove some fluid as the symptoms are the same.
Also, new/take off usually means somebodys upgraded parts brakes,wheels,etc.Without actually using the original part.
Cheers everyone!

cooldad

Remove fluid from the reservoir not the caliper.

figbat

The Rookie wrote:

You only have to let fluid out if they are overfilled, which is clearly what he'd done.

This.

Plodder82

Let a few drops of fluid out,brakes operating normally.Thanks chaps!!