14 replies to this topic Post Order

[ebenvn]

Hi guys,

My front brake doesnt "bite" when I brake... It only slows down gradually. It also squeals when braking. I had a quick look at the pads and they seem fine. What can it be?

Tx

[Mojoman]

ebenvn, on 10 January 2012 - 09:55 , said:

Hi guys,

My front brake doesnt "bite" when I brake... It only slows down gradually. It also squeals when braking. I had a quick look at the pads and they seem fine. What can it be?

Tx

Are they new brakes? Or have you had some work done on the wheel? Sometimes when I have done the front wheel bearings and a bit of grease gets on the disc it can take several stops before the brake pads feel as though they are doing there job. You can also check the pads for glazing if they have had some use.

[LeTurbo]

It does sound like there's grease or something slippery like silcon on the wheel. I find it useful to rub them down ocassionally with thinners (carefully, not getting it on the tyre). Also check the toe-in on the pads - put a sheet of paper behind the pad when you tighten the bolt, so the front of the pad touches the wheel a smidgeon before the rear of the pad. That should cure any squeal.

Edit: Just saw the Shimano XTR mountain bike bit now ... silly me. I have a roadie's one-track (ironic, that) mind and discount that anyone else rides anything different.

Edited by LeTurbo, 10 January 2012 - 10:16 .

[ebenvn]

They aren't new, and there wasnt any changes. Just one day stopped working 100%.

I will try and clean the rotor (or try another rotor) and see if that helps...

[Jacquers]

Perfect timing for Tech Tuesday

[ebenvn]

Jacquers, on 10 January 2012 - 10:19 , said:

Perfect timing for Tech Tuesday

Awesome!

Thx, will try it

[Guttersnipe]

I suspect you won't get much joy out the procedure Jacquers has linked to - that's designed to cut out squealing, not loss of power.You have both symptoms, which sounds to my crap home mechanic's ear like a classic case of rotor/pad contamination - you probably got some oil or grease on the rotor which will have gotten into the pads. Cleaning the rotor won't fix it, because the pad compound is all gunked up, and keeps depositing new muck at its interface with the rotor.
The quick and easy fix is to clean the rotor, and install new pads.
The cheaper, messier, fix for sintered pads is to pull them out and heat them up for a few minutes on a hotplate. Use an old frying pan, get it nice and warm, and put the pads in with the working surface facing up. They'll start to smoke and smell after a minute or two - take them off the heat when the smoke stops, 2 to 3 minutes later.
I tried this recently on holiday, after a joburg shop delivered my new bike with precisely the symptoms you describe the day before I flew out of the country with it. Worked a treat.
Sanding the pads down probably won't work, because the oil can work its way all the way through the compound.

Edited by pistadex, 11 January 2012 - 07:57 .

[Cavendish]

First time i've heard of cooking your brakepads LOL

[Pain or Shine]

LeTurbo, on 10 January 2012 - 10:06 , said:

It does sound like there's grease or something slippery like silcon on the wheel. I find it useful to rub them down ocassionally with thinners (carefully, not getting it on the tyre). Also check the toe-in on the pads - put a sheet of paper behind the pad when you tighten the bolt, so the front of the pad touches the wheel a smidgeon before the rear of the pad. That should cure any squeal.

Edit: Just saw the Shimano XTR mountain bike bit now ... silly me. I have a roadie's one-track (ironic, that) mind and discount that anyone else rides anything different.

Ha ha, that sux. All those words, for naught!

Hmm, thinners on the disc will help though, takes off any oil based contamination, just be sure to wash the disk when done. I have sometimes had a bit of luck with a light sanding of the pads, It has worked on occasion taking glazing off.. worth a try.

Edited by Pain or Shine, 12 January 2012 - 02:06 .

[sias]

My brand new XTR brakes do exactly the same, front and rear! Changed discs and pads (all brand new) and still no luck. I heard and read that the XTR brake system is one of the best there is, but at this stage, I'm not convinced. Also, I have to pull the lever right up to the handlebar before I even start to slow down.

[geecee]

sias, on 02 February 2012 - 08:39 , said:

My brand new XTR brakes do exactly the same, front and rear! Changed discs and pads (all brand new) and still no luck. I heard and read that the XTR brake system is one of the best there is, but at this stage, I'm not convinced. Also, I have to pull the lever right up to the handlebar before I even start to slow down.

sounds like you need to check the fluid levels
and run your brake pads in

[King_Crispy]

ebenvn, on 10 January 2012 - 09:55 , said:

Hi guys,

My front brake doesnt "bite" when I brake... It only slows down gradually. It also squeals when braking. I had a quick look at the pads and they seem fine. What can it be?

Tx

So put new teeth in (resin pads)

[Sawdust]

I tried cleaning with alchohol and sanding paper etc. At the end what worked on my metallic pads was to heat them gently over a gas flame until the smoking stopped. They work fine now. You still have to remove the glazed surface with some fine sanding paper.

[ebenvn]

I replaced the pads and switched to my others wheels, and it seems to be a lot better. Will see if I put the originals on what happens!

[divernick]

Sawdust, on 02 February 2012 - 11:02 , said:

I tried cleaning with alchohol and sanding paper etc. At the end what worked on my metallic pads was to heat them gently over a gas flame until the smoking stopped. They work fine now. You still have to remove the glazed surface with some fine sanding paper.

What you did there was burn off any contaminants that were on the pads......