Brake master cylinder questions

[AIROCOBRA]

TRACK CAR --- ADM Sprinter with STD master cylinder & booster.

1. I 1st ran the car with RX7 caliper / Mini disc on the front ---- stock ADM Drum rear ---- under hard braking massive rear lock ups.

2. Then fitted JDM rear set up --- STD DISC & calipers , TRD 2 WAY diff ---- now the front brakes lock up , big time.

3. Just fitted Rear Nissan S13 disc kit --- using STD JDM rear calipers , have not used the set up in anger yet. But up and down the street if feels ok.

MY PROBLEM IS THAT I JUST NOTICED THAT STD MASTER CYLINDER IS LEAKING !

Did a search on MASTER CYLINDERS ----- lots of choices --- too much info --- the right one required seems to depend on what brake set up you have --- now not sure what to replace leaking unit with ?

So what will best suit my set up ???? Nissan r32 , PAJERO , STARION , TOTIKO , JDM STD ??????

ps --- Want to keep the STD booster !!!

Regard Bob

[Sam-Q]

there seems to be a lot of questions on master cylinders, I am thinking that maybe that I put them all into one thread

[Javal]

Go for something that's designed to operate a 4 wheel disc brake setup and has an integrated proportioning valve.

A quick google shows the R32 master suits these requirements.

Remember to fuck off your standard external proportioning valve.

[ke_70]

if you can get an r33 brake master snap it up
from what ive know and read the r33 non abs (bm44 written on it i think?) 15/16" bore which go's well with the rx7 calipers
and ive read they have the proportioning (sp?) valve built in unlike the r32 one. apart from the valve theyre the same though

and apparently most nissan brake masters bolt up to the standed brakes booster r32/r33 being two examples . about 90% sure on this so dont quote me but pretty sure they bolt

and to fix your locking up issues you need a brake bias adjuster. i wouldn't bother with finding different proportion valves as adm suits, adm front calipers and drums and jdm suits, jdm front calipers (i think their bore the same anyway) and disk rear end. so these arnt setup for 4 pot fronts and s13 rear disks. so you'll need a bias adjuster unless its stock to get the perfect balence front to rear.

(btw joel from spirited drive can get you these bias adjusters)

hope this helps

[oz_eight6]

from what i remember when i put disc setup in my 86 the ADM biasing setup has a restrictor for the rears, which can be removed making it the same as the JDM biasing valve, ie 4 wheel disc setup,

in answer to your question about booster and master cyl it truely depends on the required fluid flow to the calipers, and match this up with a master and booster that can deliver this. (dont ask me how to find the required fluid volumes, i usually take my brake setups to my local shop for one of the guys their to sort out)

just my two sents

[AIROCOBRA]

Thank for the reply's. So if have got this right ----- I need a Nissan BM44 15/16 M/C off a non ABS car ( 2 out lets only ) . This will bolt up to my ADM AE86 booster . I also need to pull apart my std ADM bias valve and open up the flow to the rear line.
And to fix the locking up issues I will need a brake bias adjuster.
Regards BOB

[AIROCOBRA]

I just pulled apart a STD ADM bias valve ------ attached is photo of the parts that came out of the end marked rear . So do I just take out the guts and put the brass nut back on or do I need to modify some of the parts in the photo.
Regards Bob

[Skylar]

ABS are 2 outlet, non-abs are 3. You need non-abs/3 port.

[Just Half Steppin]

simple solution is to contact ajps regarding the master cylinders i set him up with, is perfect for your application...

in the photo of the bias block, put the nut back on and thats it

[AIROCOBRA]

Sorry to be a nob , but the std ADM M/C has only two outlets ,one front -- one rear ----- I bought a Nissan 180sx BM44 as it had 2 outlets like the ADM . So if you are using std ADM PROPORTIONING valve , which has one inlet from M/C to two outlets to front brakes . And one inlet & one outlet going to the rear ( having pulled the bias valve out ) . Would this not wok ??????
If you use the 3 outlet MB44 non ABS unit then you will have to bypass std ADM VALVE UNIT and go one brake line to each front caliper ????

Regards Bob

[Skylar]

Yah. If you are keeping standard splitter, use 2 port. or you could plug the third port on the MC.

[Faceplant456]

go the Pajero master cylinder, they are easy to find and are already designed for large calipers, i have one and will be running Hilux 4 pot calipers and JDM T series calipers, steroid chickens also has this set up.

but you will need to get another piece from a ford laser linx to make it all work.
should look like this when its complete.
http://www.ae86drivingclub.com.au/forums/attachment.php?attachmentid=7800&d=1260446444
this is the MC on its own.
http://www.ae86drivingclub.com.au/forums/attachment.php?attachmentid=7799&d=1260446444
this is the bit from the ford.
http://www.ae86drivingclub.com.au/forums/attachment.php?attachmentid=7798&d=1260446444

[Sam-Q]

whats the bore of the Pajero?

[ke_70]

thats 15/16" sam i erection steroids beams 86 has em

[Jonny Rochester]

What I use is RX7 front brakes and standard AE86 master cylinder. When the AE86 master cylinder starts to leak, I get another one the same. I did the maths and find the stock 13/16" MC is well suited to the Mazda brakes, and I find it works well in practice also.

Currently I have no rear bias valve, and the rear brakes lock up too soon. Im installing a Wilwood bias valve this weekend in the stock position.

[ke_70]

what rear end are you running?

[Jonny Rochester]

I have the "JDM" disc brakes at the rear.

[Dom86]

Im installing a Wilwood bias valve this weekend in the stock position.

Ahh the stock position?? What do you mean by that please?

[jaz_ae86]

F:FC calipers on FC disc, using Ferodo DS2500 then DS3000 pads.
R: unknown pads then project mu on rear running new EBC rotors on T18 diff converted to AE86 disc brake.

I did run the original AE86 master and is usable with the FC caliper/disc rear set up and I ran this for 3-4 years without issue (inc stock proportioning valve), feeling that there was a little more brake available in the rear, but happy to rely on the front brakes.
When my master started leaking, and I wanted to upgrade to proportioning valve to get more rear brakes. I chose the Pajero 15/16 for a little better pedal feel as the stock pedal gets a little longer with the FC calipers.
The Pajero MC was about $130 brand new inc a little adapter similar to the bit on the ford laser.

Would highly recommend the proportioning valve, has made the braking that little bit more confident going into northern at Mallala. When the speedo is repeatedly pointing at 'kmh', you need to be confident with the middle pedal!

[Jonny Rochester]

Ahh the stock position?? What do you mean by that please?

The AE86 as sold to the public had a rear brake proportioning/bias valve, located on the right side of the engine bay, under the brake master cyl. The Wilwood and Tilton adjustable valves are about the same size and style as the Toyota one, only they have a handle coming out of them to adjust the spring preload. I plan to mount this in the same position.