Brake Bias Valve
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Thread: Brake Bias Valve

  1. #1
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    Brake Bias Valve

    Fitted discs to the rear of my corsa and want to reduce rear brake pressure.

    1. Can i do this with the setup i have as standard.

    2. Would i need an in-car brake bias valve, how is this fitted, is it road legal?

    Any other suggestions appreciated cheers,

    JJ

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    On non ABS cars you have four outputs from the master cylinder,the two rear ones allready have restrictors on the rear two lines,you can get different values of restrictors,on a nova i know the GTE/GSI allows the greatest pressure to the back brakes,and the 1ltr's the least pressure,so depending on what car and model you have you may be able to change them.
    If not,may-be you could put two restrictors together to make one bigger restrictor.
    Thats the cheaper way of doing things anyway.
    Dave

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    Corsa 1.5 TDS 99 bhp
    dont think the 1.2 8v have brake bias valves, so lowering it wont effect the brakes.

    its only the diesels and sport models etc.. whcih have them and need to be adjusted.
    1993 corsa 5 door 1488 cc TD 99 bhp 132 ib/ft torque soon to be a lot more ;)

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    KrisTD-we are talking about how to prevent his new rear discs from locking up,the restrictors i mentioned are hexagonal shaped things screwed into the the rear outputs of the master cylinder itself.
    Dave

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    Corsa 1.5 TDS 99 bhp
    ah yes so we r, lol, serves me right for not reading it properly.

    you could try fitting one of the brake bias valves from one of the sport models. they can be adjusted quite a lot.
    1993 corsa 5 door 1488 cc TD 99 bhp 132 ib/ft torque soon to be a lot more ;)

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    How do they adjust?
    I thought they were preset at the factory,thats why there is different values,theres about four different values for different model nova's!
    Dave

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    Corsa 1.5 TDS 99 bhp
    its got 2 ways of adjusting it, there is a nut which u undo which is connected to one end of a spring, u adjust the bolt by sliding it until the spring is only just in tension. if the nut goes all the way to one end then you can undo another screw and it makes it move back and forwards and so forth, this is on corsas not novas.
    1993 corsa 5 door 1488 cc TD 99 bhp 132 ib/ft torque soon to be a lot more ;)

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    nova 2ltr 16v
    Im having the same problem my 2 litre 16v nova with disc brakes at the rear,Does anyone know what valves i know they have numbers on the side is this how you identify them?

  10. #9
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    effin hell jj cymru.

    u were really good fitting all that between dinner time 2day (25th) and now (8pm).

    last time i checked u had crusty rusty drums

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    2.0 Nova, Astra Mk3
    Originally posted by novavalver
    Im having the same problem my 2 litre 16v nova with disc brakes at the rear,Does anyone know what valves i know they have numbers on the side is this how you identify them?
    You identify the valve by the value on the side, yes It should say something like 3/45.
    Apparently, the most restrictive valves on Novas are fitted to the saloons. The code on these is something like 3/25 or 3/27. It seems the lower the second number, the more restrictive the valve is. The smaller engined, hatchback models seem to have the least restrictive ones fitted (maybe due to the lighter engine/box up front?), these are the 3/45 valves.

    Cheers,
    Kieran

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    Definitely no spring on the rear beam for brake adjustment!!

    Followed the brake circuit from the MC all the way to the back and its just solid copper pipes and nothing attached which means theres no restrictors.

    Any pics what these restrictors look like jst to make sure?

    Any gen on incar bias valves?

  13. #12
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    2.0 Nova, Astra Mk3
    Originally posted by jjcymru
    Any gen on incar bias valves?
    Mine cost 44.63+VAT from TAS. The valves can reduce rear fluid pressure from 0-57%.
    You'll need a couple of T-piece brake pipe joiners to build the valve into the system and ideally an ABS (2 outlets) master cylinder. For the front brakes you bring the brake pipe from one of the outlets on the MC, run it through the T-piece (to split the 1 pipe into 2 - obviously ) and then through to the 2 front calipers as usual. Bias valves only have 1 inlet and 1 outlet, so, with the rear setup, you run the single brake pipe through the bias valve, before sending it through the T-piece and then to the rear brakes.

    Hope that helps
    Kieran

  14. #13
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    Cheers kieran, will prolly need one of em, doesnt sound like too much of a ballache to fit either, just setting it up needs to be delicate.

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