How To: Service your Brakes.
April 02, 2007
In Issue 9 Lee showed us how to bleed the brakes, though that in itself is essential to the operation of the braking system (and the cleanliness of your underwear) you should really take the time and properly service the actual brake components which take the brunt of the abuse – the calipers. This is the business end of the braking system and due to them being positioned on the wheel they take the brunt of the abuse, not to mention the heat build up which bakes the crap on and the fact they’re normally full of old dirt – you really should do this every six times you ride, depending on dirt conditions and how fast you are. Lee and every other mechanic do this each week, and even though you may be thinking ‘they work fine, why bother?’ I can see your point, but believe me when I say you will be shocked at how much shite is packed in there. Take the time and clean ‘em out for happy braking:Over to you Leeroy.
With the brake calipers, there isn’t really that much involved in stripping them but if you leave it for any amount of time the floating aspect which allows the calliper to work both sides of the disc, even though it only has hydraulic pistons on the outside (unlike a car or street bike calliper which has hydraulic pistons on both) – by hindering this floating it really can affect the braking performance and it pretty much wrecks the disc in the process.
First things first…
Give the brakes a really thorough pressure washing, you shouldn’t really do this unless you plan on stripping and cleaning the calipers; then remove the brake hoses, the bolts are pretty tight so make sure you have a well fitting 12mm socket or ring wrench / spanner, and always have something to allow the fluid to drain into, brake fluid is nasty shit and you need to keep it off your hands if possible – it strips paint off cars so you don’t really want any part of that really.
Next is to remove the flat blade cap screws which cover the 5mm Allen bolts which hold in the brake pads, these are really tight if you haven’t had ‘em out recently you may need an impact driver though don’t go crazy, I have seen someone bend a disc getting these undone. And you have to get a really well fitting 5mm Allen for the brake pins, these are tight as well and you’ll be glad you left ‘em on the bike as opposed to wrestling them on the bench – and be sure not to round them off; it can happen quite easily and it will really spoil your day.
Make sure you remove the calipers from the bike; on the front you can just remove the 2 bolts holding the calliper to the fork and its on the bench, the rear means removing the back wheel. With the half disassembled calipers now on the bench you can pull the actual calliper off the carrier, make sure to remove the spring pensioners and lay it all out in an orderly fashion. (image 1)
Next is to scrape out the crap that is wedged in there; with that done and out of the way (you need to make sure the work area is well clean for this part) you can now remove the piston, the guts of the brakes if you like, on the front you can pull them out as the piston is hollow (image 2) but on the rear it’s a bit of a bitch and you have to use an air line to force the piston out (image 3) but make sure you put a flat plate on the calliper forks to stop the piston careering across the floor. Then draw the piston out, it’s a little tight on the seals but it’ll come out. (image 4)
Now remove the seals from the casting (5 front 5 rear), be very careful digging these out as they can mark and the brakes will never be the same again; there’s a thin and a thick seal in there and make sure to keep these away from any solvent as they will swell up like Pammy’s tits. Just wipe ‘em down with WD40 or similar and they’ll be fine. Give the calipers a really good clean and they’re ready for re-assembly.
Just start with a really light coating with brake fluid to help with re-assembly on the seals, then for the pins we use Nissan brake grease but any hi-temp grease will suffice; be really careful you don’t catch the seals on re-assembly, then re-grease the pins which the actual calipers sit on, don’t go crazy on the grease as I’ll squeeze out and possibly on the discs. I use a small paintbrush to apply the thin layer on the pins. (images 6 front and 6 rear).
Now you can replace the springs and the pads while it’s on the bench (image 7) and then they’re all built and ready to go back on the bike. (image 8) Replace the brake hose (you should use new copper washers really) and dig out issue 9 and bleed ‘em up.
Your brakes will be better for it.
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