S13 Braking Issue

[louren]

Hey guys,

Looking for some help. I have a S13 240SX with SR20DET swap. Experiencing some issues with the brakes. The brakes felt a little weird, not slowing the car down like they have previously felt. When the rearend of the car is in the air and the car is in the gear, applying the brakes barely even slows the wheels down at idle. However applying the ebrake stops the rear wheels dead.

The one rear caliper was a little stiff, replaced it, no luck. The pedal feels great, despite that we have tried bleeding the brakes with no luck. The rotors are well above the wear limit, pads are almost brand new. Was worried the pads may have been glazed, removed them, scuffed them up, put them back in, still no luck. Checked the line from the intake manifold to the brake booster, looks good, doesn't look like theres any cracks or blockages in the line.

Any help would be greatly appreciated!

[AzS13hatch]

So the car in the air and just idling in gear, stepping on the brake pedal doesn't stop the wheels from spinning? Sounds like if you replaced one caliper, you should have a look at the other. If it all seems fine, I'd say the brake lines from master to caliper need to be looked over really good. Maybe disconnect and put a piece of wire through the whole line to ensure no blockages. If the ebrake works fine, it really sounds like its not getting fluid pressure. Maybe the master itself is bad? Jack up the front and have someone on the brakes, then try to turn the wheels and see how easily it moves or if its stopped solid. I know that is still a lot of different things it could be, but maybe something you haven't thought to check yet.

[erikforce1]

So the car in the air and just idling in gear, stepping on the brake pedal doesn't stop the wheels from spinning? Sounds like if you replaced one caliper, you should have a look at the other. If it all seems fine, I'd say the brake lines from master to caliper need to be looked over really good. Maybe disconnect and put a piece of wire through the whole line to ensure no blockages. If the ebrake works fine, it really sounds like its not getting fluid pressure. Maybe the master itself is bad? Jack up the front and have someone on the brakes, then try to turn the wheels and see how easily it moves or if its stopped solid. I know that is still a lot of different things it could be, but maybe something you haven't thought to check yet.

Makes a good point to check the other caliper. When u bled the brakes, did you just do that one caliper or all around? If just one, I would bleed all around and see if the brake fluid moves out. If there's movement like mention there's a possibility of pressure not going to the calipers. Check the master cylinder. Sometimes the brake booster diaphragm could have a leak causing lack of pressure, but that you be my last option.

[RickBlaine]

Air in the brake system due to improper bleeding.
Leaky master brake cylinder due to age or one of these two things: A) letting the fluid in the master cylinder get low when replacing the inoperative brake caliper, or B) someone stepping on the brake pedal - just once, when the fluid was low.
Bad brake caliper(s).