300zx brake problem on a s13 help!

[Bumnah]

show pictures of your brake lines. i'm interested in seeing how they look.

everyone i know with z32 brakes has used conversion lines.

i suspect they may be causing your issues.

are any of the link bulging?

how is your reservoir fluid, as you losing fluid?

did you bench bleed the new mc?

have you bled in this order:

LR > RR > RF > LF

my s13 fsm actually has it listed like so:

LR > RR > LF > RF

if you did not bench bleed, you need to bench bleed!

[Flip240sx]

today i only did the two front ones but b4 i did em in a z pattern whis is right rear, left rear,right front ,left front, this is hows is done right ? and nope my fluid level is the same..

[Flip240sx]

ok i will do post pictures in the morning and yes the mc was bech bleed. im just mad having to drive my car like this..

[Flip240sx]

yes i did it something like that ...hey so i should keep my aluminum caliper and return the iron ones and get my money since its doing the same thing so my calipers are good ..i like how my aluminum caliper look better that the iron calipers..

[94_240sx]

today i only did the two front ones but b4 i did em in a z pattern whis is right rear, left rear,right front ,left front, this is hows is done right ? and nope my fluid level is the same..

No, that's not right. Left rear is the longest line, so you should start from that one. This could be the problem.

[Flip240sx]

passerger side drivers siderebuild calipers onsince the calipers werent bad im returning the iron calipers and putting my aluminum ones with the stock 240sx lines my friend has em like that in his s14 with no problems lets see if this helps..oh and my mc (rebuild)just in case you guys are curious how it looks
Modified by Flip240sx at 11:12 AM 2/1/2009

[Bumnah]

Are the rotors used or new?Is there any front end vibration?My issue was warped rotors, knocking the pistons back in the caliper. I don't see that being your issue, but used rotors.... Just an option.

It's been said, but I'm not sure if you've done it, but did you test the BMC to see if it's working properly?

If I were in your shoes I'd so the following:

Fill up reservoir

Remove one hard line at a time from the reservoir and pump the pedal a few times. You'll squirt out brake fluid from the BMC, so put a towel close by to catch it. Do all three lines that so.

Re fill reservoir.

Start at LR, and start bleeding. Bleed by putting a tube on the bleed nipple, and have the tube run into a clear bottle filled with brake fluid, so you can see bubbles come out. Keep bleeding until you're positive there is no air in the lines.

Then move to RR and do the same thing.

Then move to FR and do the same thing.

Then move to FL and do the same thing.

Then test drive the car.

If you really want to be sure, take the car to a shop and have them pressure bleed the system. I purchased the Motive pressurized brake bleeder and it really helped.

BLEED BLEED BLEED.

Look very carefully at all the point that can be open, and the slightest bit of air could be coming in. I suspect the brake lines are the issue. They look fine in your pictures (but it's hard to make out anything since they're low res, and small). They make conversion lines for a reason. I actually didn't know you could use z32 brake lines on a s-chassis. I'd suspect those after the bleeding and still no improvements.

Make sure ALL NIPPLES ARE FACING UP!

[Flip240sx]

thats what i did when i put the new mc exactly what you just wrote ..and yes there is front vibrations when im braking and also the rotors are used but they look fine to me nice and smooth... so i just put in the stock 240 lines on the calipers im just wating on my friend to come by and help me bleed the system once again thanks for all your help Bumnah im really thankfull i will keep you guys updated when my brake nightmare is finally over..

[KFL]

http://importnut.net/300zxbrakeswap.htm

Doube check everything, also I would ditch those hard lines and just get conversion lines.fit directly, better pedal feel. splparts.com 240sxmotoring.com etc.

[Bumnah]

You can't measure if rotors are smooth by looks. My rotor were smooth and looked perfect, but were warped .08 of an ich. To give you an idea. .003 is bad.

[94_240sx]

Bleeding should be easy and straight. It took 10 min for me to bleed all four with my wife pressing the pedal and that was it. No more bleeding.

You have 30mm calipers, right? Can you check how much gap you have between the rotor and caliper? This is mine and it should look like this. This way pistons will come out only a couple of millimeters and push the pads. I have 30mm aluminum calipers. I wonder if you got 26mm rotors by accident, so you have to press a pedal several times to push out the pistons further.

[Flip240sx]

yes i know the bleeding part is easy but it didnt work b4 ..but i got the set of a running 91 300zx NA and i compared the calipers with some info i found in importnut.net so i know i got the 30mm i may be wrong but i i double checked ..

[Flip240sx]

i dont own a micrometer or else i would check ..

[94_240sx]

yes i know the bleeding part is easy but it didnt work b4 ..but i got the set of a running 91 300zx NA and i compared the calipers with some info i found in importnut.net so i know i got the 30mm i may be wrong but i i double checked ..

Yeah, do that. I think you might have gotten 30mm calipers and 26mm rotors.

[94_240sx]

i dont own a micrometer or else i would check ..

30mm is 1.1811023622047243 inches and 26mm is 1.0236220472440946 inches. I just googled and used a converter.

Some tape measures have both inches and centimeter/millimeter.

[Bumnah]

Even if he put the 26 mm rotors in 30 mm calipers. it won't matter much. The pistons would come out far, but still wouldn't fall out of the calipers.

If you're putting on new pads, you should at least have the rotors turned so the pads bed in well. This is bare minimum stuff that SHOULD be done with any brake job.

I'm stressing bleeding because if he didn't bench bleed the first time around and just installed the BMC, and bled at the wheels, then there could be air trapped in the lines and with the "z" shaped bleeding he did he could be pulling the air bubbles corner to corner.

In either case. You need some some quality time bleeding. If it doesn't work atleast you'll know they've been bled well, and it's not air in the lines.

After that I'd look at the lines as being the root of the problems.

If i were you I'd have someone pump the brake pedal while you go from corner to corner looks for issues.

[Flip240sx]

what does this tell you??

[94_240sx]

Man, I don't know. It's not perectly sentered, but looks okay to me.

I didn't bench bleed my BMC and it worked just fine. If you search, you will see many people saying that z32 BMC doesn't require bench bleeding.

[Flip240sx]

Are the rotors used or new?Is there any front end vibration?My issue was warped rotors, knocking the pistons back in the caliper. I don't see that being your issue, but used rotors.... Just an option.

Bumnah so what was the problem when you had the warped rotors????i thinnk thats my problem cuz when i spin the rotors with out the calipers if you really look at it it rotates in wave form this is bad right but with the calipers on it only waves a little please let me know ASAP thanks

[Flip240sx]

bumnah?? i need your anwser

[Flip240sx]

bumhna???

[94_240sx]

Well, you should replace them or turn them I guess. That's the solution pretty much.

[Bumnah]

Of course the rotor is going to look wavy. There's nothing to keep it flush against the hub. Normally your wheels do that. I doesn't looks as wavy with the caliper on because the caliper helps keep it a bit more straight.

I ran ARP wheel studs with too wide of a Knurl for my Ichiba 5 lug hubs. My rotor was sitting on the studs. OEM parts will not give you that problem.

Have you gone out there to bleed until the break of dawn?

Replace those POS lines, and get some real lines. At this point you have to make a list of possible issues, diagnose and fix them. No one over the internet is going to solve this for you.