Spongy Q45 brakes

[JohnJohn86]

I swaped to Q45 brakes in the front and the spongy since the swap and I have changed everything and it still spongy.

things I tried:
New remanufactured caliper, tired 2 different sets
New Bembo rotor
Stainless steel lines
New Master cyclinder
Bleeded at least a quart of brake fluid and I am pretty sure that's no air



What else could it be wrong? Will a 300ZX master cyclinder help?
I am getting at least 1" of travel in the brake padel before it feels firm.

I am so fustrated and wanting to get 300zx brakes already. Can you guys help me out?

[joshchewuhh]

thats how its suppose to be

since the calipers are 2 piston rather than one it takes more brake fluid

its normal and youll get used to it

[Tearlessj]

I've read on here that your supposed to use a 280z Master Cylinder. Dont hold me to it though.

[JohnJohn86]

I am used to it. I have been driving like this for almost a year but I just don't like it.

I drove my friends 300ZX brakes and I love the feel. Can I run 300Zx master cyclinder on Q45 brakes? How will it affect the feel and brake balance?

[joshchewuhh]

nope you can use the stock one thats the one im using and my shit stops

[theslows13]

just put a z31 master on my buddy's hatch today. q45 fronts, oem rears. balance is nicer than mine with stock mc... altho thats on a car with stock suspension and shit.... mine is PBM everything... so idk if thats a fair comparison.. my shit locks the fronts no prob tho. all stainless lines, syn fluid, and a heavy foot

[JohnJohn86]

my brakes lock up ok and the car can stop. I just don't like I have to press the padel more than 1" to stop the car

My car sees a lot of track time and it is affecting my confidence in braking somewhat

[240sxaddict]

Automatic S-Chassis BMC's are larger and supposedly pick up a good deal of slack on the q45's

[aznrib]

upgrade the bmc to 1 inch for q45. Theres less slack

[98s14inaz]

That is a weird symptom. I did this on my non-abs s14 and the q45 fronts are rock solid. Such a drastic improvement over the oem crap. No spongy feel here. Perhaps try bleeding again or have a shop flush your lines and refil with fresh fluid.

[JohnJohn86]

That is a weird symptom. I did this on my non-abs s14 and the q45 fronts are rock solid. Such a drastic improvement over the oem crap. No spongy feel here. Perhaps try bleeding again or have a shop flush your lines and refil with fresh fluid.

Is yours automatic?

[FaLKoN240]

I'm putting the 1 1/16" BMC on my S13, with Q45 brakes, I'll let you know how it goes once I get the car out on the road.

[MELLO*SOS]

^ I'm doing the same, 17/16+q45 fronts+z32 rears... Car is still in the air and probably will be for weeks... Let us know how it works out

[pbcstylez]

do a better job at bleeding ur brakes

[onehundredoctane]

make sure the correct caliper is on the correct side. You can bleed and bleed all you want to, but if you have them reversed you'll never get all the air out.

bleeder screw should be higher than the brake line going into the caliper.

[SilviaSR20DET]

what bmc do you guys suggest for q45 fronts and stock oem rears? Mine has a bit of travel too.

[trevor34]

There is an adjustment behind the BMC it takes a 6mm and u can extend it so it takes less pedal travel to engage the brakes, also when u get bigger calipers they take more fluid therefore harder u have to push and more flex in the fire wall, I made this L bracket thing and bolted it to the side of the shock tower on my buddies car and it helped a lot. I will try to get a pic up if you guys want.

[JohnJohn86]

There is an adjustment behind the BMC it takes a 6mm and u can extend it so it takes less pedal travel to engage the brakes, also when u get bigger calipers they take more fluid therefore harder u have to push and more flex in the fire wall, I made this L bracket thing and bolted it to the side of the shock tower on my buddies car and it helped a lot. I will try to get a pic up if you guys want.


Please get pic, i was looking for that adjustment
I was adjusting my clutch the other day but I couldn't see it

[FaLKoN240]

I'd like to see a pic as well, although I probably won't need it.

[clark]

have you tried adjusting your rod???


also do this..

http://www.zilvia.net/f/showthread.php?t=31732

[JohnJohn86]

I'm putting the 1 1/16" BMC on my S13, with Q45 brakes, I'll let you know how it goes once I get the car out on the road.


Any update on your install?

[SoguRacing]

I use the q45 brakes on my stock 7/8 bmc and it's fine. there's probably 1/2 inch of pedal movement before full engagement but other than that it's fine and better than the stock brakes. maybe you have the nipples upside down??

[FaLKoN240]

^ I'm doing the same, 17/16+q45 fronts+z32 rears... Car is still in the air and probably will be for weeks... Let us know how it works out

Any update on your install?

Cliff notes:

Q45 brakes + Z32 BMC 1 1/16" = NO PROBLEMS, NOT TOO STIFF AND IT WORKS.

YEP YEP! I drove my car for the first time this weekend.

Car felt fine, I didn't really notice a PROBLEM with the brake travel, but then again it has been about 4 months since I've even driven an S13.

Not to mention the set up on my car is completely different so the brake feel wasn't exactly the biggest thing on my mind... (KA-T, Super Drifts, etc.)

[SoguRacing]

good job. the z31 bmc should suffice. i would think the z32 bmc would be too stiff.

[ILoveMyRHS13]

I run J30 brakes with a Z31 master and yes it does feel "spongy" but it's a good thing because it's a smoother engagement than what you're used to.

[eye-5]

I'm sick of flat spotting tires on my stock brakes (S14). They lock way too easily, almost instantly on hard braking. I have all the parts for the Q45 upgrade and hope to get it done in week. I hope it helps for a smoother engagement. Tires are getting kinda pricey. I'm on set # 3 for the season.

[FusionR240sx]

mine are STIFF as HELL!!!

[JohnJohn86]

Cliff notes:

Q45 brakes + Z32 BMC 1 1/16" = NO PROBLEMS, NOT TOO STIFF AND IT WORKS.

YEP YEP! I drove my car for the first time this weekend.

Car felt fine, I didn't really notice a PROBLEM with the brake travel, but then again it has been about 4 months since I've even driven an S13.

Not to mention the set up on my car is completely different so the brake feel wasn't exactly the biggest thing on my mind... (KA-T, Super Drifts, etc.)

Thank you, I will try the Z32 BMC too and see how I like it on the track.
+rep for you

[SilviaSR20DET]

what kind of stock oem bmc is good? where can i find them?

[Mtndrifter14]

I also have q45's and my pedal is spongy, Ill adjust the MC and get back to you.

[JohnJohn86]

I finally got my new master cyclinder from a Automatice S14. It's is larger than the stock one but smaller than the Z32 one.

The padel feel is much better than the stock and the travel is just right. I took it to the track and the brake balance is great.

Q45 brakes + Automatic MC = GOOD!

End Thread!