Master Cylinder Upgrade For R32 Gtst, Bm57?

[Frosty]

abs or non abs R32?

if abs then you have a BM50 already and thus should be no issues. If non abs then i would recommend the BM50 or upto BM57. They are readily available in both ABS and NON ABS versions however

Holford have them on this site under the business traders section aswell for the NON ABS BM50 otherwise $500 from nissan (or there abouts)

[robbo_rb180]

this is similiar to the issue i am having, would going back down to a r33 bm44 or a bm50 solve this issue?

[Rolls]

abs or non abs R32?

if abs then you have a BM50 already and thus should be no issues. If non abs then i would recommend the BM50 or upto BM57. They are readily available in both ABS and NON ABS versions however

Holford have them on this site under the business traders section aswell for the NON ABS BM50 otherwise $500 from nissan (or there abouts)

Yep holford sell for $139 however it is a Z32 copy so different biasing.

[R.3.2.G.T.R]

i did the same upgrade as richard (sinista32, went from stock 32R to 33R brembo, initially BMC wasn't changed so BM50 was being used and i did not like the pedal feel, longer travel, so swapped out to bmc57, much better pedal feel, same as i had with original setup, no issues now

[Legionnaire]

Just thinking out loud here - could it possibly be that calipers are incorrectly centered on rotors? I mean, axial offset might cause that.

One pad touches rotor prior to the other, and therefore gives that mushy feel at the beginning pad engagement and longer than expected travel, and when opposite pad engages - solid deceleration.

[Rolls]

That is sort of what brake knock off is, the gap between pressing the brake pedal and when the brake pad actually touches, it is not adjustable though, both pads are connected to the same fluid line and everything is mounted solidly so I don't see how one could hit before the other, however if it did I doubt that is the issue, would probably add more modulation if anything tbh.

The mushy feel at the start is the knock off, eg no braking for a bit of the travel.

Cheers for the thought though!

[GTSBoy]

Yeah, you won't get uneven pads to rotor gap from side to side (except perhaps on the first application after putting it all back together) because after the pressure is released the wobble in the rotor and the springiness of the piston seals will pull/push the pads back approximately the same each side. The only time this might not be true is if there was a substantial difference in how springy the seals are on each side.

[discopotato03]

My take on all of this .

Brake type hydraulics work on a system of different size pistons in the master compared to the calipers . If the master piston was the same size as the calipers the pressure ratio would be 1 to 1 . You use smaller master pistons to get an increased pressure because 1 to 1 wouldn't clamp the pads on the disks nearly hard enough .

The smaller the master size is for a given caliper piston size the higher the pressure ratio goes , but because the volume the master moves is less the further it's piston has to move to get the same caliper piston movement .

Id say the best way to look at upgrading brakes , to a higher performance factory system , is the change it as a system meaning the four rotors calipers and master cylinder . Maybe even the booster too .

Assuming the pedal box is the same then everything is sized to work together and the only remaining question is brake bias front to rear . GTRs are front heavy compared to RWD Skylines and only some of the late ones got the larger rear discs .

Because of hydraulic differences between Skyline models it can be easier to go up a rotor size at the front and use caliper leg extensions to make them fit . I've seen this done to R33s to get 224mm rotors on but it may cause a bias problem and I'm not sure if there are extensions to do the same at the rear .

My 2c cheers A .

[StevenCJR31]

Rolls, probably too late a reply but ive got a r32 gtst type M. .(abs) I put r33 gts front rotors/pads on the front only as the backs were the same size from 32 to 33

Even allowing for the facts my 32 front rotors were scored and low on pad material the change in braking was quite noticeable, ive not changed the MC and every thing is working good

Hope this helps

[cobrAA]

i did the same upgrade as richard (sinista32, went from stock 32R to 33R brembo, initially BMC wasn't changed so BM50 was being used and i did not like the pedal feel, longer travel, so swapped out to bmc57, much better pedal feel, same as i had with original setup, no issues now

Is it something like that you bought ? https://holfordmotors.com/store/HFM-46010-30p02-1

It seems uncertains which BM57 ABS should fit on a BNR32.. it appears the R33 is different than the one form r34 and unsure if I need to buy R32 v-spec or could fit a R34 gtr ?

thanks for the help

[KiwiRS4T]

I can't remember where I got my M/C but it is a Nissan part. I don't know if the Z32 and GTR ones are in fact any different - someone with access to Nissan FAST may be able to tell. I do know I put a Z32 recond kit in it (new piston, seals and springs etc). It seems to work perfectly on my Nissan Stagea - AWD, 330mm 8pot D2s on the front and R32GTR 2 pots on the back - pulls up straight every time and my brakes get a hammering on the track - really, really hot when I pull in. My brake pedal goes about 1/3 way to the floor at most.

Markings on the M/C:

BM57 Nissan

1 1/16

NABCO Japan

850RF

The two lines are marked with a large letter F (nearest the firewall) and R

[cobrAA]

thankk you chief. Just looking to improve my braking feel here

[Rolls]

thankk you chief. Just looking to improve my braking feel here

it may make it worse depending on what "improve" means to you