Brake Bleeding - 2 Questions
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Joined: Nov 2001
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From: Atlantic Canada
Brake Bleeding - 2 Questions
I am rebuilding the front calipers.
Do I need to bleed the entire system or just the front ? I will bleed the whole thing when I re-install.
How long should the system be left "dry" ?
Thanks in advance.
Do I need to bleed the entire system or just the front ? I will bleed the whole thing when I re-install.
How long should the system be left "dry" ?
Thanks in advance.
Track Day
Joined: May 2001
Posts: 24
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From: Seattle, WA
Jim,
If you're careful about not letting the brake fluid reservoir empty so as to be sure no air enters the rear system, you only need to bleed the fronts.
I don't understand your question, "How long should the system be left 'dry'?" You rebuild them, you re-install them. There's no requirement to leave the system dry.
If you're careful about not letting the brake fluid reservoir empty so as to be sure no air enters the rear system, you only need to bleed the fronts.
I don't understand your question, "How long should the system be left 'dry'?" You rebuild them, you re-install them. There's no requirement to leave the system dry.
...and your car will like you a whole lot more. 
Thread Starter
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Joined: Nov 2001
Posts: 71
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From: Atlantic Canada
Bob, I am sending the units out for rebuild and they will off the car for about a week.
During that time, I can only assume the brake lines will be void of fluid and was just curious if I need to be overly concerned about deterioration of any components (namely the brake lines).
Thanks for your feedback.
Jim
During that time, I can only assume the brake lines will be void of fluid and was just curious if I need to be overly concerned about deterioration of any components (namely the brake lines).
Thanks for your feedback.
Jim
Instructor
Joined: May 2001
Posts: 111
Likes: 1
Jim:
No, they won't be void of fluid because you will have taken a 2x4 and used this between your seat and brake pedal to gently push the brake pedal in slightly. Move the seat forward or back to put that pedal in about 1/3rd travel - this prevents fluid from draining.
Remember to tell the rebuilder not to push the brake pistons in too far on reassembly. It is imperative that, when you put the caliper back on, you make sure that you have to push the piston back in a bit to get clearance to put your brake pads back in. Why? Because you will have a soft pedal if the piston/pad combo is not right up against the rotor.
To force a piston out that is too far in you can either bleed the system with old brake pads whose width is less than that of the pads you will finally put in. This cause the pistons to push out; then you pull some fluid out of the master cylinder resevoir and push the pistons in to make just enough room for the final pad set. Might also consider bleeding the system in this manner with only the pad pins in; without the cross-shaped "return and squeal prevention" spring. This spring has a face on it that contacts the pad, causing the pad to push back away from the rotor for improved retraction.
Bleed the whole system. Yeah, it's a pain but you should baseline the entire system with new fluid.
Jw
No, they won't be void of fluid because you will have taken a 2x4 and used this between your seat and brake pedal to gently push the brake pedal in slightly. Move the seat forward or back to put that pedal in about 1/3rd travel - this prevents fluid from draining.
Remember to tell the rebuilder not to push the brake pistons in too far on reassembly. It is imperative that, when you put the caliper back on, you make sure that you have to push the piston back in a bit to get clearance to put your brake pads back in. Why? Because you will have a soft pedal if the piston/pad combo is not right up against the rotor.
To force a piston out that is too far in you can either bleed the system with old brake pads whose width is less than that of the pads you will finally put in. This cause the pistons to push out; then you pull some fluid out of the master cylinder resevoir and push the pistons in to make just enough room for the final pad set. Might also consider bleeding the system in this manner with only the pad pins in; without the cross-shaped "return and squeal prevention" spring. This spring has a face on it that contacts the pad, causing the pad to push back away from the rotor for improved retraction.
Bleed the whole system. Yeah, it's a pain but you should baseline the entire system with new fluid.
Jw
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Joined: Nov 2001
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From: Atlantic Canada
I am majorly confused now.
Don't I want to get ALL the fluid out if I am replacing it and if I have pressure on the pedal, won't that mean the fluid will be pushed out towards the caliper ??
I know I am asking very basic questions, but am am somewhat, make that VERY, confused.
Don't I want to get ALL the fluid out if I am replacing it and if I have pressure on the pedal, won't that mean the fluid will be pushed out towards the caliper ??
I know I am asking very basic questions, but am am somewhat, make that VERY, confused.
