Workshop: How to remove and replace disc brake pads
By Justin Loretz & George Ramelkamp | Wednesday, March 3, 2010 9.00am
If your brakes are squealing more than normal, there's been a noticeable drop-off in power or you can hear a grinding noise when you pull the lever, chances are the pads need replacing.
This easy-to-follow guide will show you how to remove the pads from the brake calliper, check that they need replacing, and talk you through installing a new set. Ideally, pads should be checked every month to avoid damage to the rotors.
1 Remove calliper
Most brands of disc pads are easier to change if you can hold the calliper in your hand, especially the front ones where the proximity to the fork leg can cause issues getting your ﬁngers into the right places.
2 Remove circlip
Hope and Avid both use a circlip or safety wire to keep the retaining pin in position. Don’t lose this as, without it, the brake isn’t safe to use because the pin can retract and the pads drop out during a ride.
3 Remove the pin
Some of the retaining pins screw in (Magura, Avid, Shimano) while others are press-ﬁt (Hope). If the pin’s manky, give it a good clean, as the pad’s ability to slide easily along its length is critical to smooth brake performance.
4 Remove old pads
Some pads like Shimano and Hope slide out, Avids sometimes need a bit of a waggle to free them from the pistons, while the Magura Marta needs a slight rotation to free the L-bend tab (which has the retaining pin hole in it).
5 Inspect pads
Deciding whether or not to replace the pads is simple. Some manufacturers use a gauge of sorts, such as the little bump found on Magura pads (shown on right in picture below). However, most pads should be replaced just before the compound reaches the thickness of the return spring (shown on +left below). Inspect the pads’ contact surfaces. Partially worn pads can sometimes be improved with cleaning. Glazed pads have a shiny hard surface with curved wear ridges in the shape of the rotor. Revitalise them by roughing up the surface with coarse sandpaper or a file.
6 Choose replacement pads
If your pads are past it, you have to decide whether to buy resin (also known as "organic") or sintered (semi-metal) replacements. Resin pads provide good stopping and produce less heat but don't last long in dirty conditions. Sintered pads squeal and heat up more but bite better and last longer when it gets wet.
7 Calliper care
If you’ve ever wondered where the old brake pad material goes, look inside the callipers, especially the front one. Pick out any trail crud then use a cotton bud soaked in brake cleaning ﬂuid to clean the black brake dust off.
8 Use new spring
Always swap out the old spring for a new one because aftermarket pads may not be identical, and without a fully engaged spring the pad retraction could be compromised, leading to rubbing disc rotors.
9 Insert new pads New pads should slide straight in. Be careful the spring doesn’t slip out of position; if the steel arms of the spring slip the wrong side of the pad (Avids are prone to this) it ruins the action. Remove and reﬁt until correct.
10 Test action
With the retaining pin and safety circlip (if your brakes have them) ﬁtted and the calliper remounted, give the brakes a dozen good pumps to ensure that the pads are seated and retracting properly. Do this before riding.
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