How to bleed hydraulic Brakes/ change hoses

[rennie]

You will need:

· Longish clear tube

· Rags/tissues

· Container

· New brake fluid

· (Syringe)

· appropiate tools

Firstly, be sure to cover any areas that you think may come in contact with brake fluid (if this occurs, your paintwork will easily strip). Place some rags underneath your brake fluid reservoir and on the floor.

Take the cover off the bleed nipple and attach the clear tube to it. (Make sure the tube is clear or else you won't be able to tell when it's finished bleeding.) At the end of the clear tube place the container to collect the old brake fluid.

Un-do the nipple and let the old brake fluid flow out. NB: make sure your brake fluid reservoir is tilted so that all fluid flows out. If you wish, you may use a syringe to help draw the fluid out, it saves a lot of time.

Once this has finished, tighten up the nipple and do the other hose. (Assuming your bike has two callipers.) You may also want to take any excess fluid out of the callipers, simply tip them upside down and catch the escaping fluid in the container.

Once you've finished the other hose, you may then disconnect the hoses. Undo the nut, which holds the banjos onto the lever, and slide them off, noting how they go on. Do the same at the calliper end. Make sure you have a rag handy, as there may still be some fluid in the hoses. Have a look at the washers, if they are badly corroded then they must be changed, also note where they are in relation to the banjos. You should now have the hoses off.

Put the new (or old) hoses on, in reverse order. Make sure they're put on correctly and they don't affect the steering, or create pressure on the hose ends. You may also want to clear any dirt or corrosion off. Also remember that mixing alloy and steel can cause corrosion, so check the fixings before you buy.

Once all nuts are tight and correctly fitted, you may now fill the brake fluid reservoir with your new brake fluid (make sure it remains topped up for the following steps or you'll let air back in).

Attach the clear hose to the bleed nipple on one of your callipers and un-do it slightly (with container below), fluid should come through, then retighten the bleed nipple.

You need to repeat the sequence of: brake lever pulled, bleed nipple open, fluid comes through, bleed nipple closed, brake lever released. Do this until the fluid coming through the clear tube is free of bubbles.

Once this is finished, do the same with the other calliper.

Ensure ALL bubbles are out!

You'll find that pressure on the lever will increase. After doing the above, pump the lever several times to ensure the pistons are contacting the pads correctly.

If you have completed all of the above, then your brakes should be working properly.You may have to repeat several times before it's right.Test brakes while pushing bike first, then take your bike out for a slow test ride, being very careful.

A good tip if struggling to bleed brakes succesfully is to leave the lever tied back over night. Also remember that new pads need to bed in. You can buy bleed kits but they only consist of tube and a container as mentioned above.

[Guest]

or get a one way valve and insert about 2-3 inches from the bleed nipple, this way the lever can be pumped without closing the bleed screw.

alternatively, attach a syringe and pull the fluid through, if the fluid goes below the master cylinder (looks empty) then push the syringe, pushing liquid back up the hose and add more fluid... then pull through as before.. close the bleed screw before detaching the syringe and closing ready for repeat...