front Brake system

wally · Posted: June 15, 2008, 2:37 am Post subject: front Brake system

I am fitting a new front disc brake system to café project
Have put fluid in & tried to bleed brakes but can’t get any pressure
There is fluid at the discs as I have undone the banjo bolts to see if I was getting fluid there

Brakes still not working?
Any tricks to bleed a system that’s not had fluid before in brake system brakes

Joseph · Full Member Joined: May 22, 2007 Posts: 767 Location: NY

maybee master cylynder. I had to rebuild 1 the 1st time i bled the breaks it got stuck open or closed?.

pops354 · Posted: June 15, 2008, 9:15 am Post subject: Re: front Brake system

Wally,

I don't know if you ever bled brakes before but, there are 2 things to remember. First if you are bleeding the brakes using the master cylinder you should close the bleeder screw before releasing the lever. If you don't do that you may be sucking air back into the system. So, open bleeder screw, squeeze lever, close bleeder screw, release lever.
The second thing to check is that the bleeder screw is pointed straight up. If it isn't you could be trapping an air bubble in the caliper. If that is the case you may want to take the caliper off and put a block of wood in it so that you don't blow out the pistons. Then attempt to bleed the system as I previously stated. When you are sure that you have all of the air out of the system reinstall the caliper and slowly squeeze the brake lever until the pistons push the pads to contact the rotor. Then you should a good firm pressure in the system.
I hope this helps you and solves any problems you may have.

Pops

wally · Posted: July 11, 2008, 4:56 pm Post subject: Re: front Brake system

I have now replaced the master cylinder & have pressure now but the brake callipers don’t release completely

These callipers have not been on a bike for a long time
Maybe they need the piston greased with something

rwreed · Posted: July 24, 2008, 3:32 pm Post subject: Re: front Brake system

I think you know the answer already. Rebuild the calipers!

yamaman · Posted: July 24, 2008, 8:42 pm Post subject: Re: front Brake system

when I fit new pads, I
1: remove callipers, remove old pads
2: put a piece of wood between the pistons (slightly thiner than 2 badly worn pads and a disk) this prevents pistons popping out
3: pull brake lever to push pistons out beyond there usual limit
4: clean and polish pistons-and calliper
5: spray pistons with silcone spray
6: push pistons back in, gently
7: apply anti seize to contact areas on new pads and pistons (dont get silicne spray or never sieze on any other bits!!!!)
8: put it all back together, check brake fluid, check calliper bolts tight!
9: pump up brake lever

works a treat, good luck

eb_xs · Posted: July 24, 2008, 10:43 pm Post subject: Re: front Brake system

you might want think about replacing your brake hoses too depending on how old they are. i had a problem with my front caliper locking up and it was because the fluid didn't want to travel back up the old crappy hose.

Cainacdc · Full Member Joined: Aug 16, 2008 Posts: 11

I am having the same problem. The calipers just don't want to release. My dad helped my clean out the system and after all this mess just tonight said, "oh, I guess that was what that tube of red grease was for!"

AGGHAGGAHHAGAHHHHG

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