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Front brake Resevoir problem? Bleeding Brakes!!!!!

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Timbo45:
Clearance was ok so I'm back to the drawing board.

Left it now cos the swear box is full!

kent400:
It's fair to say the front brake is is a pig to bleed. The method I've used seems to work well. place a tube on the bleed nipple with the other end in a jar with a small amount of fluid in it. Open the nipple and just let the fluid run though without pumping it. Keep an eye of the fluid in the master cylinder of course. You will probably be surprised by the amount of air bubbles you will see in the jar as the fluid flows though the system.

I put silicone brake fluid in my front brake after resealing the master cylinder and caliper. Some suggest this should not be used as it has an adverse effect on the seals, well it's been in there for about 8 years and all is well. Silicone fluid does not absorb moisture and will not damage paintwork. The bike has just had an MOT and the tester commented on how little travel there was of the lever despite the fact it still has the original brake hoses. I'm not sure if the silicone fluid has any effect on the amount of lever travel but at the time the real advantage to me was there could be no damage to my newly painted tank should a spot a fluid drop on it using silicone fluid.

florence:
It is worth remembering that air bubbles can be too small to see easily with the naked eye and can remain in suspension in the fluid.  The idea with bleeding is to replace all the fluid in the system with new stuff which will not have any air in it.  Although it is tedious the only method I find to work well is to open the bleed nipple, pull back the lever, tighten the bleed nipple, release lever, repeat and keep repeating until it all feels firm.  Don't forget to keep checking the level in the master cylinder and replace the cap each time or fluid will squirt out, this is normal.  It takes a while but should work unless there is something wrong with your brakes.  Make sure you have adjusted the caliper as explained in the manual.  If you bleed lots and it still feels spongy you may have an air lock.  Try moving the wheel to a different angle to make sure the bleed nipple is at the highest point.  Do not reuse old fluid.

jcknapp:

Is the  nipple a newer one where you don't have to open the nipple? There are some newer nipples where you can bleed the brakes on your own which i actually have. I completely had to dismantle my front brake caliper unit. I examined it and it was pretty pitted. So I fought getting out the piston and seal. A bunch of nasty old rusty brake fluid and junk came out and I completely cleaned out the caliper unit, replaced the piston and seal and went to a braided cable with a new banjo bolt connection with a copper washer. I also replaced the master cylinder. Now to get brake fluid going through the line is pretty easy and also when you just bleed the brakes in general. If you don't have the nipple where you have to open and close the brake nipple then this is how you do it. You open the nipple quarter turn, squeeze the brake, close the nipple and repeat. you keep doing this till the air gets outa the line and no more air bubbles occur. You will know when this happens. As florence explained this is the way to do it. Also use the correct DOT 3 fluid and run a clear tube into a jar so you can see the air coming out. The toughest thing for me was to maintain a tight seal on the braided cable connection to the caliper. A copper washer did it good though. Hope this helps even though it was more or less said by others.

mickwinf:
Timbo did you get this problem sorted, i have tried all these methods with no success so bought a new master cyl from silvers, still no brake! the only thing i havent replaced is the top hose as the brake was working before i stripped it down. When bleeding i dont get much movement of the fluid in the pipe, it moves about an inch then flows backward to the same place. I have new master cyl, bottom hose, piston and seal.Caliper is adjusted correctly and free, i have tried suction with syringe and pushing caliper piston back manually all with no luck, the lever comes back to handlebars with no resistance although the brake does work enough to stop wheel rotating.Please help !!

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