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Disc brake pads

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 the sheep 15 Jun 2017
A complete numpty question, I need to replace the rear pads on the bike but have never done this for disc brakes before. Are the size and shape uniform or do you get different pads for different brands.
Cheers in advance.
 gethin_allen 15 Jun 2017
In reply to the sheep:

Some brands overlap but most are unique to each brand/model.
 Chris the Tall 15 Jun 2017
In reply to the sheep:

I tend to get my pads here http://www.discobrakes.com/
In reply to the sheep:
In case it's important to you depending on your usage, remember not all pads are equal even from the same brand - different compounds give different braking effectiveness, longevity, and running costs.
 nniff 15 Jun 2017
In reply to the sheep:
You'll probably need to take the pads out to see the model number that's written on them as the model number of the brake itself is less than useful. Be aware that the differences are often not apparent until you've got the wrong packet open. For example, Shimano J02A and L02A look the same but the former is a bit wider. You might well ask how I know such trivia. Ask away if you want to rub salt into the wound, but by the time I'd finished faffing I had acquired pro-level proficiency and was offered a Saturday day job changing brake pads

There are also so many variations on the theme that finding the right ones is easier said than done, although no doubt the internet will help if you can wait a few days.
Post edited at 16:14
 Run_Ross_Run 15 Jun 2017
In reply to the sheep:

Also check your discs. It will probably specify whether you have to use resin pads or not (or at least my Shimano discs do).

Halfords can be pretty cheap for them, click n collect so no carriage.
 johnwright 15 Jun 2017
In reply to Run_Ross_Run:

> Also check your discs. It will probably specify whether you have to use resin pads or not (or at least my Shimano discs do).

> Halfords can be pretty cheap for them, click n collect so no carriage.

That make a change!!!!!!!!!!!!!!!!!!!!!!! They are not called Halfrauds for nothing.
 TobyA 15 Jun 2017
In reply to the sheep:

Once you've worked out which ones you need (Decathlon do their own brand ones to fit quite a few different makes and models of brake) actually swapping them is dead easy. A few minutes job.
 Kean 16 Jun 2017
In reply to TobyA:

> Once you've worked out which ones you need (Decathlon do their own brand ones to fit quite a few different makes and models of brake) actually swapping them is dead easy. A few minutes job.

Um..."should be dead easy". I changed my pads yesterday and could push the pistons back out with minimum hassle, but they would not stay put and within about 10 seconds they had moved back in again. There followed a frustrating hour or so as I tried to work out how the hell I could push the pistons back, insert the new pads, and get the bloody wheel in during the 10 seconds before the pistons moved back out and closed the gap between the new pads. Web searches didn't really clarify enough to make me confident that I knew what I was doing ...in the end I slackened off the "filler cap"(?) on reservoir on the handlebar before very gently and slowly pushing out the pistons back. A few drops of hydraulic fluid came out (which I feverishly and obsessively wiped of the bike, floor, skin etc (as it's supposed to be corrosive or summat?). Lo and behold the pistons behaved and brakes are fine. Could be that new pads were slightly thicker than original ones...?
 Wry Spudding 16 Jun 2017
In reply to Kean:

Depends on which brakes you have. Some such as Avid use 'brake fluid' and others such as Shimano use mineral oil. Brake fluid absorbs moisture so the problem is that when you need to change your pads, the volume of fluid in the system is greater so the pistons don't go back to the original position (and the Avid brake bleed kit is complete rubbish). Brake fluid is corrosive, dissolves paintwork and is a skin irritant but is cheaper.
 Kean 16 Jun 2017
In reply to Wry Spudding:
Nice one...mine's mineral oil so that's good news.
Thanks Mr Spudding...you're pretty switched on for a 1 year old...
So whilst we're "talkin' brakes", does that also mean that you can spray on a lubricant to help ease up piston movement? And without it "corroding the seals" as I've seen mentioned on some sites?
This sheds a lot of light...http://www.epicbleedsolutions.com/blog/dot-brake-fluid-vs-mineral-oil/
Post edited at 09:27
 nniff 16 Jun 2017
In reply to the sheep:

My way of pushing caliper pistons back in is to use a large flat bladed screwdriver. The new pads will usually go in, but won't have room for the disc. So, before you fit the new pads, push the screwdriver in between the old pads and push the pistons all the way back in. Take the olds pads out, put the new ones in and refit the wheel. If it still binds, take the wheel out again and push the new pads further apart with the screwdriver - the wedge-like profile helps in this regard.
 LastBoyScout 16 Jun 2017
In reply to the sheep:

I've got brake components from here: http://www.superstarcomponents.com/en/shop/mountain/mountain-braking/mounta...

They do bundle deals on sets of 4 pads - mix and match - and they also have a handy identify sheet to get the right ones.
 Chris the Tall 16 Jun 2017
In reply to TobyA:

> Once you've worked out which ones you need (Decathlon do their own brand ones to fit quite a few different makes and models of brake) actually swapping them is dead easy. A few minutes job.

Not when they're Avid Juicys, you're in the middle of a midge infested forest and it's pissing down......

To the OP: Might be useful if you tell us what sort of brakes they are. There are so many different types, brands and models that without that information you will get bombarded with a wealth of useful but possibly confusing advice.
 Root1 16 Jun 2017

In reply to..Kean .in the end I slackened off the "filler cap"(?) on reservoir on the handlebar before very gently andK slowly pushing out the pistons back. A few drops of hydraulic fluid came out (which I feverishly and obsessively wiped of the bike, floor, skin etc (as it's supposed to be corrosive or summat?). Lo and behold the pistons behaved and brakes are fine. Could be that new pads were slightly thicker than original ones...?

Thats because the system was overfilled. When you put the new thicker pads in they pushed the pistons right back increasing the pressure in the system. You did the right thing letting some brake fluid out at the handlebar allowing more space for the pads. Its stops the brake binding too.
Post edited at 11:13
OP the sheep 16 Jun 2017
In reply to Chris the Tall:

Cheers, they are TRP hy/rd
http://www.wiggle.co.uk/trp-hy-rd-cable-actuated-hydraulic-disc-brake-calip...
and a look around reveals they will take Shimano M525/M515 pads, although there is a wide variety of pads available http://www.discobrakes.com/?s=0&t=0&c=14&p=100&tb=001

Anyway any further advice gratefully received
OP the sheep 02 Jul 2017
Pads ordered from discobrakes arrived really quickly and fitted today with no fuss. Fantastic
 PPP 02 Jul 2017
In reply to TobyA:

It's worth to realign the brake itself as well. It took me more than few minutes first time I've done it since I didn't realise I don't have to remove the wheel first*.

* - I would have anyway since I needed to push the pistons back, though. If I inspected them earlier and didn't wear them out completely, I might have been luckier.

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