In Cabin Brake Bias

[badhairdave]

Just wondering because i am about to get my BMC rebuilt on the track car.

can i get the master modified so there is no factory front/rear bias and run an in cabin adjuster for the rears or does it just not work? Is it worth it for a hack like me who will just set it and forget it?

If so, who can do this work in Sydney and recommendations on an in cabin adjuster brand.

[Risking]

Piss the whole master cylinder off and buy a brand new one from martins clutch and brake for a navara or patrol. They can be had in 15/16ths or 1inch.

They are also available in two or three port for abs or not.

The comercials have an external prop valve to varry bias according to the weight in the rear so they have no internal valve. To rebuild yours without a prop valve they will need to replace the pistons and re drill a relief port or th rear brakes will drag.

T the bias controller into the rear line and away you go.

Is it currently pinching rears or not using them?

My road GTR has that exact system with 997 cup car fronts and stock Nissan rears 1inch master.

It works really well.

It's worth while excersise even if you set it and forget, the GTR had tilton pedal box with bias bar and remote adjuster. Honestly on the odd occassion when grip was well down the bias may have got a tweak but otherwise it was set and forget as well, bias control was no better than the road car with the same brakes.

I have the part number at home for the master cylinder and use a willwood bias controller. I've tried a few brands in various cars and found the willwoods adjustment to be far less sensitive. The point of locking rears might be a full turn of the willwood but 1/8th turn on a tilton

You can either run -3 braided line into the cabin with dash fittings or use steel bundy tube with double flare fittings which is cheaper obviously.

Edited June 15, 2010 by Risking

[zebra]

Brad - is the Navara / patrol one a straight bolt on to the booster?

[juggernaut1]

Doesn't the s14 BMC also run an external proportioning valve too? Remove that and run the bias adjuster. Alternatively some guys in the US are (tediously) modifying the external stock proportioning valve to alter the bias.

http://nissanroadracing.com/showthread.php...er+cylinder+s14

[badhairdave]

it's an s15 abs bm50 so no external valve unfortunately

[juggernaut1]

Oh OK for some reason I thought you had an s14.

[badhairdave]

nah s13 chockful of random 14, 15 and r32 bits

and r34 too, forgot about the brakes...

Edited June 16, 2010 by badhairdave

[juggernaut1]

No wonder I was confused

[phunky_monkey]

Sounds like this could be a really good option if it's a straight fit onto the booster. I've been contemplating whether to go R32 N1 MC, which are very expensive and bias may still not be 100% correct for me, or go to a balance bar individual master type setup, but less hassle is the best option.

[Risking]

Those masters are a direct fit to the majority of Nissan boosters and the push rod lengths are also within mm of being perfect as well. You can change the pushrods if you want to or just loosen the jam nut and adjust it.

The lines may require some tweaking but nothing that's overly hard. All use m10*1 threads with double flare fittings as well.

[phunky_monkey]

Thanks for the info Brad. I might give the 1 inch a go if it's significantly cheaper than an N1 master cylinder.

[aleks]

Risking, any chance you can still get the part number for yours? Is it non abs? and who makes them if its not genuine.... going to see if I can find one locally.

Cheers, Alex.

Edited January 1, 2011 by aleks

[badhairdave]

I should probably update.

I finally got off my arse and started chasing this up and confirmed with risking.

1 inch (BM50 equivalent) 2 port master off a GQ patrol p/n JB1777, there are a few manufacturers around, i went with PBR for $110 delivered off ebay

1 1/8 inch (BM57 equivalent) 2 port again off a GQ patrol p/n JB1775, go for around $160 delivered

7/8 inch (BM44) 2 port master off an MQ patrol/D21 Navara p/n JB1731, $125 delivered

Wilwood proportioning valves go for 90-100 delivered off ebay depending on seller, or $92 from MSCN

you need an m10-1 tee, which i have already from MSCN for $22.50

And a bunch of lines, whether hard lines or -3 braid is up to you, big difference in price. I'm not sure how to run a hard line to the prop valve as it has 1/8npt fittings and not inverted seats like regular brake lines, there are adapters for braid though.

Edited January 17, 2011 by badhairdave

[Beer Baron]

good info mate. The N1 masters are so fking expensive it's not funny. like a normal GTR master from nissan is about $250 and the N1 and R32 Vspec II are like $450. nuts.

[aleks]

Thanks for the info dave. Do you already have it setup in your car?

[badhairdave]

Nah, just collecting bits at this stage

[Legionnaire]

Hey guys, a little update on this with OEM P/Ns, that can be useful for non-AU readers here who can't order using the numbers above

After browsing FAST I was able to obtain following info:

1" BMC

P/N: 46010-01G00,

installed on European Patrol Y60 with RD28, Canadian D21 Pickup with VG30 and Jap Safari Y60 with TB42 engine only

17/16" BMC

P/N: 46010-02J00,

can be found in European Patrol Y60 with TB42E and AT as well as in Jap Safari Y60 with TD42 engine

15/16" BMC

P/N: 46010-41G00,

Canadian and Asian WD21 Pathfinder and Japanese WD21 Terrano with TD27

The list of models may be incomplete and somewhat inaccurate, as it was put together based on various catalogues available online. Part numbers are accurate though, as I took them directly from FAST.

I'm also very curious to see results of external bias adjuster vs. in-built prop. valve, preferably with some pics.

[«Cyph3r»]

Interesting read, looking at using a BM57 on my S14 when I change over to 350Z brembos all round.

Also looking at the proportioning adjustment seeing as I'm thinking the patrol bias will be quite different to what would be ideal on an s14.

[Risking]

I'm also very curious to see results of external bias adjuster vs. in-built prop. valve, preferably with some pics.

what sort of results are you wanting to see exactly??

The external proportioning valve allows quick easy bias trimming without the need to remove and refit master cylinders

The only downfall is the need to run more lines and slightly complicate the system.

Various weather conditions, tires, heat etc etc all have an effect on brake bias, something that you cant do anything about with an internal proportioning master cylinder

Here is a few photos of one I have in my road GTR with 997 cup brembos and stock rear GTR calipers. It used to grab rears all over the place but after trimming the bias it now works okay with a 1 inch tandem master.

Obviously a proper dual master pedal box is the real solution but to keep the booster this works well.

If there is interest I can organise to buy semi bulk of the PBR master cylinders in 1 inch, Wilwood or preferably tilton proportioning valves, all the braided teflon line and fittings required to get it working.

[Risking]

And like all good GTR's it currently has no engine in those photos.