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Z32 brake upgrade issues. Spongy brakes.

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Old 12-04-2007, 05:49 AM
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Z32 brake upgrade issues. Spongy brakes.

I recently upgraded to z32 brakes. Having some issues; the brakes were really spongy. I found out what some of the issues were.

What was wrong: The front passenger caliper was actually a front driver side. I mounted it upside down unknowingly. The bleeder sitting at the bottom caused air to be trapped inside no matter how much I bled. So I mounted it right side up and bled and then closed the system and remounted the caliper. Figured since the system is closed it shouldn't matter if it's upside down or not.

Does it matter if the caliper is mounted upside down even though the system is closed?

I just can't get this last bit of air out of the system.

I replaced all my bleeders with russell speed bleeders, I was affraid of stripping more of the bleeders from the calipers.

They are leaking but I am tightening them more and more slowly (again affraid to strip more of these calipers). Anyone with experience want to tell me of their experience with these things?

Any more tips on how to get the damn air out? I'm ultra frustrated.
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Old 12-04-2007, 07:13 AM
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Dunno about the calipers being mounted upside down sounds weird?
Order some bleeder stops, you can bleed the lines yourself, and use atleast DOT4
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Old 12-05-2007, 09:55 PM
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so i picked up a new front passenger caliper
bled the system again.

stopped being a woman and muscled down the bleeder screws
hopefully all is well and i finally solved my brake issues.
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Old 12-06-2007, 02:49 PM
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do u just have z32 calipers up front and stock rear? if u do u need to upgrade the stock BMC to a Z32 BMC.

http://importnut.net

im running 26mm Z32 calipers up front stock rears and stock BMC and its spongy till Monday when i upgrade.

Last edited by CusCo_S14; 12-06-2007 at 02:52 PM.
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Old 12-06-2007, 03:49 PM
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Just as stated above. Yes you will need to upgrade to the Z32 brake master cylinder to take care of the spongy brakes. It's not just the air problem. This is pretty common.
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Old 12-06-2007, 04:31 PM
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system has a 1 1/16 mc on it


i drove it today. the brakes are better. less spongy. perhaps there is still more air in the lines. i'm going to take it to a shop tomorrow and have them bleed it.

i just don't have time to work on it anymore. if all that's left is to bleed the system, some one else can do it. if they can't fix it, i'm going to bench bleed and rebleed all the calipers. when i bleed each caliper i'm going to bleed each caliper until it reaches the minimum line twice. if that doesn't take care of it. i'm blowing the car up!


while i'm posting. could it be a faulty mc/caliper in my system? how can i check to see if the mc or the caliper is bunk, without actually having a second piece of everything on hand.
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Old 12-06-2007, 07:57 PM
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You don't need to upgrade to a master cylinder just for z32 calipers in the front, who ever told you that is full of B.S. I install the Q45/J30 calipers and there is no upgraded cylinder. When ypou upgrade the front and the rear, then you need to upgrade the master cylinder...
When you use z32/q45/J30 calipers on the stock cylinder you should upgrade to DOT4 or 5, do not use DOT3 or it will feel spongy.
Just get the bleeder stops from SPL parts you will be fine bleeding the air out your self.

Also if you want to get rid of the spongy response you will want to use steel braided brake lines. stock lines can expandbefore applying enough pressure to the calipers.

Last edited by BigVinnie; 12-06-2007 at 09:04 PM.
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Old 12-06-2007, 09:29 PM
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i've already got the russell speed bleeders, and they seem to be working fine.

I'm running Motul RBF 600. which is DOT 4 & 5. I'll double check, but i'm pretty sure it is.

I'm not sure where all this should i upgrade the mc talk came from. But to clarify the swap is z32 brakes front and rear with the 1 1/16 MC.

The way the brakes are acting i really suspect the air is in the front lines somewhere. If it were in the rear it wouldn't be so evident.
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Old 12-06-2007, 09:46 PM
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im running r32 GT-R front brakes and rear stocks all 4 steel braided lines and Honda DOT 3 brake fluid and its been running great never felt spongy (dont knock my honda fluid i used to work for honda so it was free lol)
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Old 12-06-2007, 10:16 PM
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Originally Posted by Bumnah

The way the brakes are acting i really suspect the air is in the front lines somewhere. If it were in the rear it wouldn't be so evident.

There is a bleeder located in the hard lines. You may want to bleed from the hard lines rather tha n the brak calipers. You could of gotten air as far back as the rear brakes, that can make the entire brake system feel spongy.
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Old 12-06-2007, 10:23 PM
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the only place i can think of that may still have a break bleeder would be the splitter in the rear where it goes to the left and right rear calipers.

Is that the location you are talking about?

I looked at the box briefly when I was taking everything apart; I did not see a bleeder on it. I could be mistaken.

If I do bleed from there, do I have to bleed from the calipers as well?
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Old 12-09-2007, 10:27 PM
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Originally Posted by battosaii930
im running r32 GT-R front brakes and rear stocks all 4 steel braided lines and Honda DOT 3 brake fluid and its been running great never felt spongy (dont knock my honda fluid i used to work for honda so it was free lol)
I also run R32 GT-R brakes in the front w/ stock rears... No wonder why Vince asked me on saturday LOL

But yeah, when I first got them on, I had to bleed the brakes all day long. But the only reason why I had to was because I drained the whole system out prior to refilling with that Euro blue brake fluid (DOT 4) I forget the name of it, but really good stuff, better than Motul (as to what all the Euro guys say).

Even after I bled the brakes for so long, they felt spongy for the first 2 weeks. The way I got it to stiffen up, every once in a while, when theres no traffic, and your in WIDE open space, brake HARD. Doing that a few times helped out. Now my brakes will make me stop on a dime... literally. Even with them heavy 350Z 18's...

And no, you do NOT need to upgrade to the Z32 BMC unless you upgrade the rears to Z32. In your case, you were already planning to upgrade the rears right Bumnah? If you were, then yes, I would recommed the Z32 BMC.
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Old 12-10-2007, 07:23 PM
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So I did the following:

Problem 01: Ebrake just doesn't want to work.

The king pin was too short to sit properly. Causing my ebrake assembly to not work properly. So I went to lowes picked up some washers. They were too large in diameter to fit properly, so I cut some ends off, and slid them on, and re assembled the brakes. Easy as pie and I've cured 98% of the ebrake problems. It engages properly and a solid feel on the lever when you pull on it. It just rattles a little when you get on the car really hard.

Problem 02:The sponge that is my brake pedal.

So I bench bled my master cylinder. Made a cheap bench bleeder and pumped the pedal 15 times. Only the first pump produced any bubbles. the other 14 did nothing. So i'm very certain that is bled properly.

Next I started bleeding at the calipers. Pattern: RR>RL>FR>FL. I have russell speed bleeders in each caliper. I ran a line from the bleeder to a bottle with brake fluid in it. I pumped the rear calipers until the master cylinder went to the minimum line 3.5 times, each caliper. If your mc is at the MAX lines it takes around 12 pumps to get it down to the minimum line. So each of the rear calipers got 42 pumps of the brake pedal. I figured that would flush anything out.

Front calipers; same procedure, but I took it down to the minimum line 4 times per caliper. So each caliper got 48 pumps. Now each corner has the proper caliper on each side as well. So the caliper being upside down has been taken out of the equation.

Results: Ebrake i'm happy with it. Few minor minor issues, but nothing I can't live it, and something that is very minor and i can probably fix.

Brakes. I drove it this morning to work. Brakes worked well, but spongy. I was really upset. I get to work around 9:40. Left work around 3:40. I get in the car and the brakes are working perfectly! WOW?! Too good to be true? Well I drive the car for a good 20 miles, no issues. EXCEPT. When I'm pulling on to the street where my home is. Now i was going down hill and turning right slightly when i braked with the car in neutral. I brake and it's more spongy then before. But nothing huge. So I get home and park it. Later on I go to test drive the car. i get on it pretty hard, and it seems to be working well still. Hopes rising. Could that f'ing thing finally be working properly? I thought maybe it was residue of some grease on the rotors causing my issues this morning? Brake pads weren't up to proper temps this morning? What was causing the issues this morning? Who cares! It's working fine.

Either way. I go run my errands and I take one of my favorite back roads as the proving ground for these brakes. DEF. some more sponginess in the brakes. Not nearly as bad as before, but def. not rock solid as I want it. So wtf is up with this **** now?

I'm planning on taking the car into a decent shop near my business. They have a pressurized bleeding system, and that should take care of any and all issues. IF it is indeed air in the lines still. How there could be air still, I do not know.

Brake info for those who don't know.

Z32 1 1/16 brake mc.
z32 30mm aluminum front calipers
z32 aluminum rear calipers
z32 ebrake assembly
Motul RBF 600 brake fluid
Forodo DS2500 front and rear brake pads
Z32 conversion lines (stainless steel).
Russel speed bleeders on all calipers
Powerslot rotors front and rear.

So. any more input from anyone?

Could having it neutrel and braking be causing any issues since there is less vacuum? I dunno. Doesn't sound right to me, but I'm coming to end of my list of things to check out.

I'm ready to light this ***** on fire.
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Old 12-10-2007, 08:40 PM
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orginal brake booster? if it is the check valve could be bad my friend had to replace his brake booster from his s13 cause it was bad its not hard to do though
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Old 12-10-2007, 09:08 PM
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Since you upgraded the rears, I honestly think you need the Z32 BMC IMHO. I would rather see you upgrade to the Z32 BMC and be safe then have it go sponge bob no pants while giving it a good run.
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