Ive got some PP tuning rearsets to go on and Ive just ordered a banjo bolt for the rear brake light. Ive fitted new pads/ discs on cars and bikes but never had to bleed the brakes before (always got away with just opening the reservoir cap to slide the caliper back) When I fit this banjo bolt I will need to bleed the brakes. Is it as simple as keeping the reservoir topped up whilst having the bleed nipple open (with pipe on into waste bottle) and keep pumping the rear brake pedal? How much fluid should you pump through it to make sure theres no air in the system? Thanks Dan
Yes, you open the nipple and pump the brake and hold the brake in, till the nipple is tight and then you release the brake. and never let the reservoir get too low with fluid
Get an assistant to give you a hand mate! 1) Remove the resivoir cap and make sure it's topped up to the max line with clean brake fluid, prefrably not old stuff because old brake fluid absorbs moisture. 2) Get your assistant to pump your brake pedal, about 10 times nice and slowly, get them to hold it down so you can undo the bleed nipple. When you undo the nipple brake fluid should come out along with air, also the brake pedal will sink slightly, when it does this TIGHTEN UP THE BLEED NIPPLE, DON'T RELEASE THE BRAKE PEDAL UNTIL YOU HAVE TIGHTENED IT UP OR YOU'LL LET AIR BACK INTO THE SYSTEM! 3) Repeat step 2 until all the air is out of the system, you should feel the pedal getting firmer as all the air comes out, DON'T LET THE RESIVIOR RUN LOW ON FLUID TOO, KEEP IT TOPPED UP OR YOU'LL LET THE AIR BACK IN. As stated loads of stuff on You-tube or folk on here who will help if you get stuck
cheers guys for the advice. I think Ill have to drain the whole system first though so I can take the existing bolt out and then re-fill it. Its an excuse to change the brake fluid anyways.....
you can get a kind of 'auto' bleeder which is just a one way valve fitted in the tube you use for your old fluid to exit the caliper from. makes the process much easier (i use one) ... you fit it to the bleed nipple, open it up and just pump the lever (whilst keeping the reservoir topped up) ... the valve stops air being sucked back into the master cyl. as you let off the lever. a little tip for bleeding the brakes if you're struggling getting a 'good lever'... sometimes it helps if you dismount the caliper and raise it above the brake pedal. this helps get any air out of the system because obviously the air rises. you are trying to do two things when bleeding the brakes. the first is remove any old 'dirty' fluid which will have absorbed some moisture which lowers the boiling point of the fluid. the other is to banish any air bubbles in the system which can create a 'spongy' feel to the brakes. hope this helps
to add to that, if you find it refuses to bleed and you are getting billions of tiny bubbles in the res, leave it overnight, as smithy says with the caliper propped up. bubbles will form together into one big one and will rise to the top, making it easy to bleed out once it's settled.
just an add on to all the above you can get a large shringe from a chemist and a length of pipe that fits nice and tight over nipple then just pull the plunger back with the nipple open once its full tighten nipple empty shringe and do it again you can see bubbles in fluid when they stop your done. i use either this or the 1 way valve type mentioned previous and i have a couple of specific brake bleeding kits but find other 2 more affective
