Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Go Back   Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum > General > Tech Talk

Tech Talk Technical Discussion About The Nissan 240SX and Nissan Z Cars


Reply
 
Thread Tools Display Modes
Old 07-30-2015, 07:25 AM   #1
lusos
 
Join Date: Dec 2014
Location: Barnesville, Georgia
Posts: 17
Trader Rating: (0)
Feedback Score: 0 reviews
S13 with Z32 brake swap, brake bleed problem

Hi guys,

I have searched a few dozen threads and it seems like this is a common problem. However, I can not find any resolution to this issue so I'm putting up a new thread asking for help. I have a track day in 48 hours and I've been working my these brakes easily for a week now with no resolve.

I purchased my S13 from a fella who did the Z32 swap on all 4 corners. No ABS and stock master cylinder. Two weekends ago I wanted to do a brake upgrade. I rebuilt the front two calipers because one was sticking, then replaced all rotors and pads, upgraded to speed bleeders, and I bled all of the old fluid out of the system in exchange for Motul 600.

After about 3 hours of bleeding I had moved a good 3 pints of fluid through each wheel. Yet the pedal pressure was still lax to nonexistent. I could close the bleeders, then pump the pedal. After 5-6 pumps the pedal would get hard and hold. However, if I let off of the pedal then came back in a few seconds the pedal would go down almost to the floor with only a little resistance. (this is all while the car is off)

Fast forward a few days and I decide it's my master cylinder. I replace the master cylinder, bench bleed it thoroughly, then put it on the car. I spent 3 hours last night bleeding each wheel and moved easily 3 pints of brake fluid through each bleeder. I pumped and pumped and pumped; fast and slow and made sure that each piece of tubing was bubble free and clean.

However, I am STILL having the same problem. Again, I can close the bleeders and pump and pump and pump and the pedal will get hard. Yet when I let go of the pedal and get back on it, the pedal goes almost to the floor.

If I crank the car up and try to drive it then the pedal immediately goes to the floor. You have to pump super fast to get the brakes to work and even then they just barely seem to work.

When I put the car up in the air I can press the brakes and each corner grips the pedal fine. I have no leaks whatsoever and I have honestly spent 5-6 hours bleeding the brakes on my car. The calipers were rebuilt correctly, the bleeders are on TOP of the caliper, and as far as I can tell I'm not leaking a drop anywhere on the vehicle.

Any thoughts? I'm using speed bleeders and the only doubt I have about the whole system is that the LR bleeder weeps a little bit of fluid when I first crack it open for a bleed. None of the other wheels do that, as they will only start to weep when I open them then push the pedal.

It's ****ing frustrating. I've done brake jobs on dozens of other cars and this is by far the worst experience I've ever had.

HELP.
lusos is offline   Reply With Quote
Sponsored Links
Old 03-19-2017, 12:52 PM   #2
Blue55
 
Join Date: Oct 2016
Location: Los Angeles
Posts: 8
Trader Rating: (0)
Feedback Score: 0 reviews
What did you finally do? I'm having similar issues.
Blue55 is offline   Reply With Quote
Old 03-19-2017, 01:02 PM   #3
bataangpinoy
Zilvia Addict
 
Join Date: Nov 2010
Location: caves
Age: 24
Posts: 821
Trader Rating: (7)
Feedback Score: 7 reviews
try adjusting the clevis for the brake pedal. if that makes no difference, your BMC is toast
__________________
Quote:
Originally Posted by GTR-Garage
Handling, power and style must be in harmony.
bataangpinoy is offline   Reply With Quote
Old 03-20-2017, 12:20 PM   #4
lusos
 
Join Date: Dec 2014
Location: Barnesville, Georgia
Posts: 17
Trader Rating: (0)
Feedback Score: 0 reviews
Awesome,


I'll adjust the clevis this coming weekend.

I believe the LR caliper is just so old that the gap around the bleeder thread is causing air leak. I've tried using grease and teflon tape but to no avail. The vehicle stops fine (scary enough is that I track it) but the pedal just feels very soft all of the time.

I'm pulling the car out of storage next week and plan on buying new calipers to see where that gets me.
lusos is offline   Reply With Quote
Old 03-20-2017, 02:14 PM   #5
ANDY black s13
Leaky Injector
 
Join Date: Mar 2012
Location: erith kent england
Age: 49
Posts: 116
Trader Rating: (0)
Feedback Score: 0 reviews
you may well need the larger bore z32 300zx BMC to match the larger fluid volume
of the 300zx calipers and get rid of the long pedal travel
the stock smaller bore BMC can only deliver so much fluid,so has to over stroke to
get the pedal firm and working the pads onto the disc's
there are three z32 BMC bore sizes 7/8th,1",and 1 1/16th
(and not sure what you can got on the USA spec cars)
I went with the 1 1/16th version to match my 8 pot K sports and z32 rears
you may be better with the slightly smaller bore sizes as can over do it
and end up with a sharp and hard to modulate pedal (easy to lock up)
the K sports are for my 13 but tried them on my 14a as a test
with stock rears+ stock BMC
and pedal needed a rapid second dab to keep it from sinking away
the UK 14a has 4 pots and a bigger bore BMC than a 13 on single piston/sliders
but not enough for the extra fluid volume of 8 pots
just stuff I found when searching on what others have done
ANDY black s13 is offline   Reply With Quote
Old 03-20-2017, 02:52 PM   #6
lusos
 
Join Date: Dec 2014
Location: Barnesville, Georgia
Posts: 17
Trader Rating: (0)
Feedback Score: 0 reviews
Thanks Andy, I will definitely look into these options.

Cheers!

Quote:
Originally Posted by ANDY black s13 View Post
you may well need the larger bore z32 300zx BMC to match the larger fluid volume
of the 300zx calipers and get rid of the long pedal travel
the stock smaller bore BMC can only deliver so much fluid,so has to over stroke to
get the pedal firm and working the pads onto the disc's
there are three z32 BMC bore sizes 7/8th,1",and 1 1/16th
(and not sure what you can got on the USA spec cars)
I went with the 1 1/16th version to match my 8 pot K sports and z32 rears
you may be better with the slightly smaller bore sizes as can over do it
and end up with a sharp and hard to modulate pedal (easy to lock up)
the K sports are for my 13 but tried them on my 14a as a test
with stock rears+ stock BMC
and pedal needed a rapid second dab to keep it from sinking away
the UK 14a has 4 pots and a bigger bore BMC than a 13 on single piston/sliders
but not enough for the extra fluid volume of 8 pots
just stuff I found when searching on what others have done
lusos is offline   Reply With Quote
Old 03-20-2017, 04:41 PM   #7
Nissan2nr22
Premium Member
 
Nissan2nr22's Avatar
 
Join Date: Aug 2008
Location: USA
Posts: 1,273
Trader Rating: (26)
Feedback Score: 26 reviews
Did you upgrade your master to 1" or 17/16?
Nissan2nr22 is online now   Reply With Quote
Old 03-20-2017, 07:29 PM   #8
lusos
 
Join Date: Dec 2014
Location: Barnesville, Georgia
Posts: 17
Trader Rating: (0)
Feedback Score: 0 reviews
Quote:
Originally Posted by Nissan2nr22 View Post
Did you upgrade your master to 1" or 17/16?
No I never did the master cylinder upgrade.

The previous owner did the brake swap and before I changed pads and rebuild the calipers, the pedal was much better. Would there be any reason why the rebuild could have messed up my brake bleeding abilities? Again, I think it's leaking from around the bleeder threads on one caliper when I'm bleeding the brakes.

I've tried to bleed them with and without speed bleeders (Mity-Vac) but the results are still the same with a spongy pedal.
lusos is offline   Reply With Quote
Old 03-20-2017, 07:34 PM   #9
Juantwo3
Zilvia FREAK!
 
Juantwo3's Avatar
 
Join Date: Sep 2011
Location: DTFullerton
Age: 26
Posts: 1,025
Trader Rating: (18)
Feedback Score: 18 reviews
Make sure the bleeders are on the top sides of the calipers not the bottem
__________________
GO DUCKS!!!!!!!!!
Juantwo3 is offline   Reply With Quote
Reply

Bookmarks

Tags
brake bleed, s13, z32 brake


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -6. The time now is 06:33 PM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
vB.Sponsors
Copyright © 1998 - 2015, Zilvia.net™