installed 300zx MC and 300zx brakes and the car stops like crap

[koukiKA240]

last night after work i finally installed my z32 mc just in time to drive down for the twi night autoX. The autoX i was at 2 weeks ago i competed with the z32 brakes and 240sx mc and complained that the pedal was unpredictable and squishy, so i upgraded.

The event last night the brakes felt AWFUL, the scariest part was i couldnt get the car to stop in the stop box, i couldnt MAKE it lock up. the pedal feel was good but the brakes were 100% unresponsive. I had a TON more stopping power with the 240sx mc than with the 300zx one but sacrificed pedal feel and consistancy.

This cant be normal. I filled the mc and allowed the car to gravity bleed for about 10 mins and then bled it with my bleeder bottle and a 1 2 3 hold bleeding method. I saw no air in the lines and then headed for the track.

what could be the problem? Is it possible to upgrade to the z32 brake booster?thanks,~Sam

[navysnail]

it sounds like there is still air in the system. make sure to bleed it good, the air would be all the way up in the MC.

[240SicknessX]

be sure to bleed the caliper furthest from the mc first, then work your way closer to the mc, be sure that the mc is bled first, and keep a constant eye on the brake fluid level, if it runs dry or low, you could expose the brake system to air, rebleed everything.

[koukiKA240]

i did blead from furthest to closest and i know no air made it back into the system from it running low on fluid, i watched that pretty close.~SAm

[Fenvy]

does it feeel like it's just 1 side?maybe due to failure of caliper/line, 1 or more piston isn't working?make sure you are not leaking brake fluid from mbc or using the wrong type of fluid. I am under the impression that you're not suppose to use dot4 for s13 (I am not sure about this)

brake booster is more than likely not your source of problem. I have q 45 upgrade, many people here have 300zx brake upgrade and we don't change it

[koukiKA240]

ive got dot3 in the system now and have had dot3 since ive owned the car for 4 years now.

I am not leaking anywhere, i have lost no fluid and cannot find fluid anywhere other than where it should be.~Sam

[themadscientist]

Gravity bleed? air travels up not down, do you mean leave the lid off the MC overnight? how big are the bores on the respective MCs, I had a similar problem when I put GT-R calipers on my T, the R MC was 1" the T was 15/16" and unable to generate the pressure. Did you overhaul the Z MC? It might be bad. It sounds like air in the system, it can be a pain it the *** sometimes.

[Fenvy]

gravity bleed?

um if you are bleeding brakes lines or any other lines, you need one of those bleeder where you can pump the fluid directly from the mbc all the way to each bleeding bolt

it might look something like this...

[koukiKA240]

its the 1 in mc, and i just opened em all up and let em sit and drain for 10 mins. im gonna go out here in a sec and bleed em further.

I could use something like u have pictured but i dont think it is 100% necessary.~Sam

[themadscientist]

there can still be are trapped in there. Any time you drain the whole system you run that risk. I remember one car it took several days to bleed out. I actually disconnected each caliper from it's mounts and shook it up , then bled it with a peice of wood between the pads. That car was cursed or something!

[Fenvy]

are you serious? so you been doing a gravity bleed?

you're right, you don't really NEED it if you are quick and plugged up the hardline asap while doing the brake upgrade. If you didn't and a lot of air got inside, some might still be trapped in a weird/awkward angle. Leacing the mbc cap off, personally, doesn't really do much. Ever seen cooking oil in a clear package? try to shake it up and down, the vicisousity of the fluid will make the air bubble travel very slowly, unlike water.

anyways, go out and buy one, it;s like 3 bucks last tim I bought it.

[themadscientist]

I say pick up the car and shake out the air bubbles.

[koukiKA240]

just finished bleeding them again and still no air comes out through the lines.~Sam

[cyrus240sx]

ive seen a problem on my friends corolla where when he bled his brake system, he pushed the pedall all the way to the floor, which caused the seals in the MC to become damaged (because there is rough spots in a MC at the ends), and it caused him to have a internal leak, he replaced his mc and it fixed it...

i dont see why so many ppl have 300zx brake problems.... i have 300zx brakes on my car with a the stock s14 MC and my brake pedal is just as high as stock and is the perfect stiffness...

[BryanGrigsby]

Cyrus do you have a manual trans? The brake booster on the manual is different than on the automatic(on an s14, not sure about s13).I just purchased the z32 17/16 mc to install as well but i have a manual and am beginning to wonder if I need it. I think I am going to try the calipers out before I swap the MC's.

[onosqv]

I had a similar problem.

Check your brake booster bolt, it may be too far into the m/c, which will not let the pressure release as well - will feel stiff, but less fluid is running through the lines - i.e. less air (if any) is coming out even from bleeding.

Or, might be the other way around if your pedal feels sluggy, which I don't think it does from your description, but that would be the bolt is too far into the brake booster & you are not getting full pressure.

Well that was my experience at least, hope that helps somewhat.

[koukiKA240]

i found time to bleed the brakes properly at every corner fora bit yesterday and the problem has gotten better. so i am going to bleed them once a day untill the problem goes awaythanks for ur help guys.~Sam

p.s. i do need to adjust the pedal from the inside some thanks.

[themadscientist]

you can adjust it to what feels right to you. Unless you set it so low it hits the floor before fully compressing the MC piston it's just personal taste.

[mirra32]

i didn't read every response here but here are my two cents

not to sound stupid but instead of that gravity bleed stuff...just sit you dad or younger siblings in the drivers seat tell them to push the petal 3 times then hold it down and then bleed you lines yourself and do it real slow do that like 4 times or so...on each side.....always worked for me.....

[koukiKA240]

i guess u didnt read my entire post, cause thats what i did, except insert girlfriend wher u said dad or brother.

thanks though~Sam

[bruinbear714]

It has to do something with your setup... bad calipers maybe? I know a few folks with the exact same setup and they say its much better than the 300zx caliper + stock mc.

One thing you can try... is to use some super blue racing brake fluid and bleed out the system with that. The fluid's blue, so you will know for sure when the clear stuff is out of the system.