Most new brake systems arrive in their boxes, fully assembled and ready bled. Whilst it’s nice to be able to fit a brand new brake straight away without having to go through the rigmarole of cutting and bleeding, you will probably find that the hoses are too long for your bike and that you will need to cut them eventually.
Fit the new brakes to your bike first and go for a ride, though – tape the hoses to your frame if you have closed cable guides. This means that you will at least know how the brakes are supposed to feel before you tackle the task of shortening them, and so will be able to recognise whether or not any air has got into the system in the brief period that you have the hose loose from the lever.
All brake hoses can be cut to length, though braided ones require some care and effort. A little bit of a graceful curve is fine and you need to make sure that hoses are long enough to allow the bars to turn fully without being restricted by the hose. It’s a good idea to allow a little extra, too, just in case you manage to have a bad enough crash to spin the bars round so far that you might manage to rip the hose from the lever. However, you want to avoid leaving the hoses so long that they snag on trailside hazards as you pass. If you’re cutting your hoses down, then work out how much you need to remove before you dismantle the hose and mark it securely with tape – and remember the workshop truism: it’s easy enough to take more off but you can’t add more on once it’s gone.
The most common connection between the hose and the lever is a soft brass ring called an olive. This fits around the hose and is tightened by the threaded shroud which covers it and joins it to the lever, making an airtight seal. The lever has a barbed fitting, which keeps the hole in the hose open so that the fluid can pass through. With patience and a bit of luck you can usually shorten hoses which use this system without needing to go for a full bleed, as they’re less disposed towards dribbling oil everywhere.
Some other systems require you to fit the barbed lever to the hose, before connecting it to the lever. This type usually need bleeding as it’s virtually impossible to fit the barbed fitting to the hose without displacing some of the brake’s fluid as you go. Follow the steps for shortening the hose and don’t forget to attach all the necessary fittings before connecting the hose.
If you’re trying to reuse a barbed fitting from the end of a hose, hold the fitting carefully with pliers and slice away from you, down the hose, with a sharp knife. Point the knife upwards, so it cuts the hose without scoring the fitting. You can’t simply pull the fitting out of the hose, no matter how hard you try; the more you pull, the tighter the barbs hold onto the inside of the hose.
You then have to fit the new or reclaimed fitting back into the new hose, which can be tricky as it’s a tight fit. The correct methodis to place the hose between two special guides and clamp it pointing upwards in a vice before tapping the fitting gently into the end. If you find yourself short of a guide or two and the bike shop can’t oblige, then make your own by drilling a hole the same diameter as the hose through a 2cm (1 inch) deep scrap of wood. Cut the wood in half down the centre of the hole to leave two pieces of wood, each with a long semi-circular groove in which you can safely clamp your hose without fear of crushing.
Disc-brake tools: replacing brake pads
- Depending on pad securing system, pliers (for split pins) or screwdriver 2 or 2.5mm Allen keys for threaded retaining pins
- For Hayes – 10mm ring wrench to push pistons back into calliper
Disc-brake tools: bleeding brakes
- Tool to remove reservoir cover – 2 or 2.5mm Allen key or Torx key or Phillips screwdriver
- Plastic hose to fit over bleed nipple – available in a manufacturer-specific bleed kit from your bike shop, or from hardware shops or car spares shops – often in the brake and clutch bleeding section
- Bottle to route the hose into
- Plenty of duct or electrical tape to strap bottle and hose to your bike
- Spanner to turn bleed nipple – 7 or 8mm
- The correct brake fluid for your bike – DOT or mineral oil
- Cloth to mop up spillage and to protect your paintwork
- Rubber gloves Tools to shorten brake hoses
- Tools as above, in case you need to bleed the brakes afterward
- Sharp knife
- Replacement olives
- Small screwdriver
- Spanner to remove shroud – usually 8mm
Source : BIKE MAINTENANCE TIPS, TRICKS & TECHNIQUES