s13 brake master cyl w/ nissan 4pot calipers

[badbiki]

heya,
i have a nissan silvia (s13) with all the suspension components from an s14 in the front, lwr arms, nuckles, hubs, and brakes. is there any difference between the s14 and s13 brake master cyl? as pedal feel is quite sloppy as you can practicaly have your foot to the floor before really stopping at a bulk rate (a few pumps and its all good) yes i've bled my brakes quite a bit and i'm sure i have every last air bubble out of them now..

or is this the result of having those nasty rubber hoses instead of nice braided lines in the front?

my rear brake pads are almost totaly worn outaswell, would this affect pedal feel bulk?

:confused:

[Chris Rogers]

from my limited understanding of this (and by feel) the back brakes seem to affect feel. I know when I adjust the rear ones (drum) on the sherpa the brake feels different.

[dbasteve]

Originally posted by badbiki
heya,
i have a nissan silvia (s13) with all the suspension components from an s14 in the front, lwr arms, nuckles, hubs, and brakes. is there any difference between the s14 and s13 brake master cyl? as pedal feel is quite sloppy as you can practicaly have your foot to the floor before really stopping at a bulk rate (a few pumps and its all good) yes i've bled my brakes quite a bit and i'm sure i have every last air bubble out of them now..

or is this the result of having those nasty rubber hoses instead of nice braided lines in the front?

my rear brake pads are almost totaly worn outaswell, would this affect pedal feel bulk?

:confused:

If there is no air in the lines and the pedal drops to the floor it could be pad knock off from disc runout or worn bearings on one or more wheels. Especially if the pedal is firm again after a few pumps. Too small a master cylinder will feel spongy all the time.
You cab easily check rotor runout with a dial gauge. New rotors and good bearings should be less than 0.1mm runout. More than 0.25mm will start pad knock off.

[badbiki]

ye its more spungy than too the floor i mean... is the s14/s15 master cylinder a larger bore diameter?

[dattoman1000]

on the side of the master is a casting #
If it says BM33 then its too small.
You need to change to at least a BM44 or prefferably a BM50 if you've just fitted 4 spots.

Look at S14 or S15 wrecks or frontcuts or Z32 300zx's for second hand units

[badbiki]

okies thanks =) i'll take a looksi!... i may go source a s14 brake unit... *shrugs*

[Clint32]

i know a few people with the bigger calipers with the s13 master cyl with out problems. Thy checking everything else before doing any major changes.

[badbiki]

i didn't say it doesn't work, it does. but pedal feel is sloppy and very spungy in comparon to how it use to be with the single piston calipers.. the point from pedal out to braking begins is a fair distance.. and then its very spungy due to the small master..

I'm going to chase down a new bigger master next week some time..

[badbiki]

okies i just check my brake master. its leaking like crazy! i didn't see this before with my motor in, so its coming out to ber eplaced..

its a BM-33 unit. i'll have to find out what size master cylinders are on the s14, s15, r32 and z32's etc..

the r32 and z32 would have the wrong proportional valve tho ye? possible to have an asjustable valve put into the master cyl?

[dattoman1000]

Don't panic too much about proportioning.
The valve on the side of your looks the same on the inside to all other Nissan ones. Proportioning is done with caliper piston sizes and weight shift.
Its not a commodore after all.

BM33 = 13/16
BM38 = 7/8
BM44 = 15/16
BM50 = 1"
BM57 = 1 1/16

Some cylinders run a combination of these. Such as Exa's that can have a BM33-50 which is a stepped bore. Though this is of no consequense to you as your cylinder and the others I have mentioned are all straight bores.

When you find a cylinder make sure it has enough outlets. Some of the cars run ABS so only use 2 of the 3 outlets.

[badbiki]

k, so exactly what size would be best suited to the 4 piston fronts and single pistons rears? BM50?

[dattoman1000]

BM44 would be easiest to get as its fitted to Z31 300zx ,late V6 Pathfinders and Gazelles.
I'd think this would be fine.
You would hardly notice the difference between BM44 and BM50 but you'll definatly notice the difference between BM33 and BM44.

If it was my car I'd try to chase down a BM50 but they are hard to find. Failing that go the 44.

[badbiki]

cost of one new? as if i were to find a second handy it very well could be stuffed.. and how much would one expect to pay?

[dattoman1000]

I can't recall seeing a part # for BM50. So you might have to go to Nissan armed with model details for that one.
A BM44 is a JB1617.
Even if you find a stuffed one you can always have it reconditioned. Don't pay more than $20-30 for a s/h unit.
Ring around for new prices.

[badbiki]

yes thats what i was thinking.. rebuild wise. so buying new compared to running around having one rebuilt. thats all..

[badbiki]

mmm i found a s15 front cut with the master cylinder.. but i think all s15's come with ABS standard.. therefor i cannot use this can i?

[badbiki]

hang on, can't i just make a divider up? front output -> 2 outputs for the 2 brake lines? isn't that basicaly how it works anyway? no prop valve on the fronts...

[dattoman1000]

Yes you can run a t piece in the system to split your front brakes

[sillbeer]

Sorry to bring up an old post.

I'm in the same boat at the moment as Lucas was in 2003...I'll be running R33 GT-R Brembos on my S13 Silvia, but as yet I haven't chosen an appropriate brake master cylinder. My main problem is identifying a larger Nissan BMC such as the BM50 that has 3 ports for a non-ABS application.

I've heard/read conflicting specifications on what was available in the R32 Skyline range, some saying BM44 others BM50 - maybe it should be non-ABS was BM44 and ABS was BM50.

Does anyone have any suggestions around this? Maybe the R32 GT-R N1 that didn't have ABS holds the answer.

Cheers
Brendan

[dattoman1000]

ABS is BM57 which is 1 1/16
Non ABS is BM50 which is 1" (N1)

This is for R32 GTR and Z32 TT
They are marked on the side

[sillbeer]

The only BM50's I've been told about are ABS versions. Do you happen to have any Nissan part numbers for the BM50 non-ABS versions at all?

Cheers
Brendan

[dattoman1000]

Sorry I don't have a Nissan microfish

Just buy a 3 outlet and blank the back port off with a 10x1 blanking plug

[sillbeer]

Datto

Is the use of a T-piece or block illegal on road cars for this type of application if I was to use a BM50 2 port brake master cylinder? I need 3 ports as I have no ABS on the Silvia.

Cheers
Brendan

[sillbeer]

Found the Chassis designations for the R32 GT-R N1 which had no ABS from factory:

R32 GT-R V-SPEC N1 > KBNR32RBFS ZN
R32 GT-R V-SPEC II N1 > KBNR32RBFS8 ZN

Can anyone get the brake master cylinder part numbers for these?

[dattoman1000]

T pieces are fine

[sillbeer]

OK, I managed to track some pics down off of Yahoo Japan of a BNR32 N1 brake master cylinder (BM50) and someone else did a screen grab for me from the Nissan FAST application of brake master cylinders with numbers starting with #46010.

These photos relate to #46010-05U01 for RB26DETT.GT-R.17 N1 (which I think relates to the V-spec N1) which is number 5 on my list below.
http://www.ipixel.com.au/temp/bnr32n1bmc/bnr32n1bmc1.jpg
http://www.ipixel.com.au/temp/bnr32n1bmc/bnr32n1bmc2.jpg
http://www.ipixel.com.au/temp/bnr32n1bmc/bnr32n1bmc3.jpg

http://www.ipixel.com.au/temp/bnr32n1bmc/bmc-46010-range.gif

The Japanese next to 5 & 6 is as per the following:

(5) tokiko 1 bembutsu(?) confirmed N1 specification
(6) nabuko 1 physical count N1 specification

So a further translation would be

(5) #46010-05U01 | *RB26DETT.GT-R.17 | Tokico 1" N1 Specification
(6) #46010-05U21 | *RB26DETT.GT-R.17 | Nabco 1" N1 Specification

I can only deduce from the 2 versions listed on Nissan FAST to be relating to the first version of the N1 based on a standard GT-R (RB26DTT) running the Sumitomo calipers (#46010-02U00 & #46010-02U20 were 15/16" cylinders), and the 2nd version which was based on the V-spec and V-spec II models (*RB26DETT.GT-R.17) running the Brembo calipers (#46010-05U01 & #46010-05U21 were 1" cylinders).

So after all this, I'll be ordering in either a #46010-05U01 (Tokico) or #46010-05U21 (Nabco) unit depending on which one Nissan tell me to order. They seem to still be available ex-Japan for $445.00 inc GST and $440.00 inc GST respectively (trade pricing) through Nissan. When I receive the unit, I'll post pics and confirm size.

Stay tuned.

Cheers
Brendan

[dattoman1000]

The pictured one is for ABS

What do you actually need ?

[sillbeer]

Um, the pictured one is non-ABS, it has the 3 ports, two for front and one for rear. All the ABS Nissan master cylinders I have seen are 2 port only, one for rear circuit, and one for front circuit which feed directly into the ABS unit usually mounted on the passenger side of the engine bay. The item pictured is what is required in my situation as my non-ABS Silvia was originally equipped with a 3 port master cylinder only it was smaller, therefore this will do the job nicely.

Cheers
Brendan

[dattoman1000]

Correction
Yes your right
My brain hurts today

[sillbeer]

OK, ended up ordering the BMC from the R32 GT-R V-spec N1, didn't want to repeat myself about all the details so here's a link to a post on my blog about the Brake Master Cylinder information:

http://www.sillbeer.com/2007/04/brake-master-cylinder-upgrade.html