C3 Brakes Question

[crazy wampa]

hi guys, a quick question for you, sorry if it has been asked elsewhere, i looked but couldn't see it.

 

i have changed the front brake pads on my 2003 c3 desire, i loosened the bleed nipple on each side before pushing the piston back in, re tightened the bleed nipple after replacing pads and callipers, now i cant feel any pressure on the brake pedal, if i drive slowly in 1st gear, when the brake pedal is fully depressed the car will stop, but as speed increased so does the time it takes to stop. have i missed something? before the pads were changed i only had to partially depress the brake in order to stop the car, any and all ideas advice would be gratefully received, thanks in advance.  

[Johndouglas]

Have you tried bleeding the brake lines?

[john h]

I have never touched the bleed nipples for a pad change, just force the pistons back and change the pads, no disturbance of the hydraulics

[Johndouglas]

There's a theory that if there's crud in the brake callipers when you wind the pistons back in, the crud may find its way into the ABS.   So by opening the bleed nipple, the fluid is displaced rather than being forced back up the line.

[coastline taxis]

ok from reading your post you have opened the bleed nipple pushed the pistons back replaced the pads the bolted the caliper on then closed the nipple. Youve let air into the caliper. You should of just slightly opend the nipple and closed it the moment you pushed the piston back anyway not to worry its easily put right.  Get acsess to both front bleed nipple then get someone to sit in the car and pump the brake pedal a few times till it goes hard and keep it pressed down. Next put your finger over the end of the bleed nipple and open it up just a littel till you hear the air coming out the brake pedal shoud creep down when doing this. get your assistant to tell you when the brake pedal is all the way down then lock the nipple up. You may have to do it a few times per side  and dont forget to keep  toping the brake resevoir up while your doing it.

 

There is a couple of reasons you open the nipple

1 pushing the fluid back up can damage the master cylinder and abs seals as ther designed to work one way only

2 brake fluid has a boiling point and the heat of the brakes boils it in the caliper. thats why its black when it comes out the nipple

 

Brake fluid should be change at least every  2 to 3 years

[crazy wampa]

thanks for the help guys, problem was solved by bleeding the brakes  :rolleyes: i can be a bit dim at times

[paul.h]

Thanks for getting back to us. When pushing the piston back with the bleed nipple open, I only have it open whilst the piston is being moved but also I make sure the nipple is at the high point (as when fastened to the car) so air should not get back in to the caliper and any that is already in the caliper will be pushed out.