I have refilled the master cylinder with brake fluid about 5/6 times now and the front brake still will not tighten. i‘ve tried bleeding from the brake hose that connect to master cylinder and from the caliper bleeder and still no pressure. 98‘ suzuki dr350sew
A possibility: the brake hose could have a partial wall failure, and the outer cover is ballooning out under pressure which you haven't noticed. Fix: new brake line Another possibility: the bike is so filthy that you cannot see where the fluid is leaking. I agree with Nasty--brake fluid does not magically disappear. Step 1) clean bike. Step 2) find leak. Step 3) fix leak. Step 4) reverse pressure bleed. The easy way to change brake fluid without adding air is to suck out MOST of the old fluid from the reservoir with a rubber suction bulb, fill the res with new fluid, crack the bleed valve at the caliper (with a tube attached so as not to drain it onto the tire) and SLOWLY pump the new fluid down with the brake lever. Keep a wrench on the bleed valve and WATCH the res so that you do not pump it dry. Close the bleed valve. Fill the res to the line with new fluid. Presto, dude. New fluid. No air.
Try another simple trick. Fill a syringe full of brake fluid, and place the end of the syringe into the hole (Where brake fluid gets sucked down) in the master cylinder. Make sure there's a good seal, and push down on the syringe to let the fluid shoot down that hole. Before you do this however, open up the bleed nipple on the calipar. This will help get out any big air pockets. After this is done (Try a few times), close the bleed nipple and pump the lever to see if it regains pressure. As a tip, cover the bike up with a sheet or something so the fluid doesn't go on paintwork.
Probably the O-ring in the caliper !
