Brakes...what else can it be?

[benemorius]

'90 240sx - no ABS

My friend recently got this car and saw no problems, but I am not impressed by the brakes. From my limited experience, it feels very much like glazed pads. However, the pads, master cylinder, and booster have all been replaced and there is still no difference. (they need replacing anyway as the pads were in fact glazed, and the master cylinder had filled the booster with fluid) I have also properly bled the lines, and replaced the fluid while I was at it.

I have even tried new rotors and calipers just for grins, though I'm back to the old ones as that did no good. So, the only thing that I know of that is either not new or hasn't been made new temporarily is the brake lines. What can be causing this? Surely this isn't normal or something? I realize some cars just have different brakes, but I can push frightfully hard on the pedal and still not lock up the wheels.

I'm tired and aggrivated, so if I've left something out, please be forgiving.

umm...in case I wasn't clear: The brakes just don't feel as 'grabby' as most cars I've driven do. When I push the pedal down, it goes down a bit before the brakes kick in. I feel as though I must puch as hard to stop from going 40 as I normally would to stop from going 70. I would not call the pedal 'spongey', and applying constant pressure does not cause it to sink slowly, however I can push it all the way to the floor, given the aid of the booster.

[Altiman94]

I would rebleed all the lines again. It seems there still may be some air in the lines.

[benemorius]

They have been bled and rebled. I normally do them RR RL FR FL, but I've also done them RL RR FL FR as this is how Chilton says to do it...??

I was quite certain that all the air was gone, regardless of which order I chose, but is it really possible that there is still air somewhere? Can it not be anything else?

[Magnes]

Sounds like you're describing the clutch pedal. The brake pedal is the one in the middle.

hehehe ... sorry.

[NISTECH]

try bleeding the master cyl at the lines coming off of it. do your bleed process as you would at the wheels but instead crack the lines open at the master cyl when your partner is holding the pedal down. Do this a few times then retest the brakes. This car has rear disc brakes or drums?

[benemorius]

It has rear disk brakes. I'll try bleeding again later today, and I'll do the master cylinder thing too. Could someone explain about this master cylinder though? If it works, I'll be happy, but I'd also like to know why it works.

[droll]

If you replaced the master cylinder, you probably got air in it. Bleeding the brakes at the wheel cylinders will not neccessarily remove the air that is trapped in/at the master cylinder, at least not easily. It is a good idea to bleed a master cylinder before installing it in the car.

[nlzmo400r]

how would u bleed a master brake cylinder when its not on a car?

[KaDrifter]

Fill the master cly reservoir up with brake fluid cap off one of the ports and pump the cyl with a metal dowel or something simliar till fluid starts comeing out then do the second one the same way

[NISTECH]

they have cheap kits for doing this at sears and other tool places. it has adapters that screw into the line ports on the master. The kit comes with hoses you plug into the adapters and submerge the other end in the resivor. use a rod as Ka mentioned and pump away [I use a #3 phillips screw driver it fits perfectly in the booster rod port]all the air in it simply bubbles out in the resivor without drawing air back in. This is also alot less messy:D

[droll]

Yeah, the kits usually come with instructions too.

[nlzmo400r]

about how much do those cost?

[NISTECH]

less then 20 bucks

[nlzmo400r]

awesome, thanks nistedh

[benemorius]

Well I've bled the master cylinder and the entire system again to no avail. My friend is convinced now that it must be the brake lines. Sound likely? I guess that is the only part of the brake system that hasn't been replaced.

I might add that the calipers I tried were from a junk yard, so there's no guarantee that they were in great condition...

[1989coupe]

When I bought my master cyllinder from advence auto parts, it came with the bleeding lines.