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Brake Proportioning Valve?

Discussion in 'Stop, Drop & Roll' started by JspeXAE102, Nov 28, 2005.

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    JspeXAE102 Active Member

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    Brake Proportioning Valve?

    I've keep hearing people recommending swapping out the brake proportioning valve when doing a drum to disc conversion. I recently spoke to a guy who recently did a rear disc swap on his 95 celica and he claims that toyota told him both the rear disc and drum models had the same parts no. for BMC and proportioning valve. One of the reason I downloaded a Toyota EPC (Electronic Parts Catalogue) were to check that fact and sure enough it checks out. And not only that, the 93-97 corolla also has that same parts no. for the valve as well as the 88-92 models.. I've been told that when using a gauge to check brake pressure on a disc brake ae92 corolla vs. drum brake model the pressure on the drum models were significantly higher... Am I missing something here?
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    Dr Tweak Mad Scientist

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    There is no rear disc on the '95 Corolla. I don't know for sure if there is a difference with the AE92 GTS with rear disc though.

    You can just use a valve from a mid 90s Celica GT.

    -Doc
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    JspeXAE102 Active Member

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    .
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    Dr Tweak Mad Scientist

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    I just checked. It appears that the Celica GT and ST brake proportioning valve is the same.

    Very interesting.

    *edit* It looks like the one from the Corolla, Tercel, Camry, and Paseo might also be the same one.
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    JspeXAE102 Active Member

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    part no. 47150?
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    Dr Tweak Mad Scientist

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    Do you have the whole part number?

    Check this out, taken from the '94 Celica BGB:

    On the ST (rear drum), if the front brake pressure is 1138 psi, then the rear should be 604 psi.

    On the GT (rear disc), if the front brake pressure is 1138 psi, then the rear should be 690 psi.

    So, at least on the '94, it's different, but the drums get LESS brake pressure than the discs, so swapping to discs should NOT cause rear wheel lockup.

    Okay now on the '98 Corolla: if the front brake pressure is 1138, then the rear should be 605 psi. So it's the same as the Celica ST, and in either case, the rear is getting less pressure than it would with the GT part. Which means that rear disc lockup is NOT an issue.

    This is interesting: on the '97 Celica ST, if the front pressure is 1138 psi, then the rear should be 551 psi. The '97 Tercel is the same.

    Here are some part numbers:

    '97 Celica ST 4715020280
    '97 Celica GT 4715020240

    '94 Celica ST with no ABS: 4715020280

    '91 Corolla Wagon: 4715012250
    '98 Corolla 4715012240

    '97 Tercel 4715012230

    So, they are different, but the pressure is the same.

    Well, that's a little confusing. For one thing, your buddy is wrong, the valve for the '95 GT and ST is in fact a different part number, and the pressure is different. But, the bottom line is that the whole "you need to swap your proportioning valve or your rear brakes will lock up" issue is way overrated.
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    JspeXAE102 Active Member

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    Oh ok, I just figured out how to get the full part number from that EPC program and it does list a couple of different parts numbers. So the brake pressure is actually less on cars with OEM drum setups? Weird indeed. Thanks for the effort.
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    cBass buffalo bell lover

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    Milky, get in here!!!
    Added: Oct 2, 2013 5:33 PM
    after reading this now im really confused.:confused:
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    MacktasticSlick TRD whore with 36,000 posts, bitch

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    Confused how? If the pressure on the rear discs isn't as high as it is stated in a Toyota catalogue, just get the valve that came on the car that the brakes did, a 90s Celica. Problem solved.
    1nicetrd likes this.
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    cBass buffalo bell lover

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    MacktasticSlick TRD whore with 36,000 posts, bitch

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    Exactly. Milky was probably being over protective. It would make sense to me to just use the valve that matches the brakes.
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    James Bullshit Police

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    Shit, you figured this out like 4 years before me. Good on ya mate.
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    MacktasticSlick TRD whore with 36,000 posts, bitch

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    Milky Enlarged Member

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    this. i believe i doing it right the first time so i dont have to come back and redo it later. i had never seen this thread before.
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    1nicetrd Well-Known Member

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    I ran my car with both BPV's and the 8th gen one NEVER locked up actually never really made the pads bite. Swapped to a ae92 gts BPV and the rears came to life, you actually saw on the disk(well the pitted ones i had) it was bitting more.

    Make sure you have a good BPV some from junkyards maybe seized and may not deliver optimum performance.
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    James Bullshit Police

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    MacktasticSlick TRD whore with 36,000 posts, bitch

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    Bro feels to everyone in here
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    James Bullshit Police

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    Goldy Well-Known Member

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    I don't know anything about BPVs but I know lots about brofeels!
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    James Bullshit Police

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    This is my current brofeels sentiment also.
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    cBass buffalo bell lover

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    well my bpv works great, i can feel all 4 wheels stopping much better

    best mod ever, until i fix the parking brake tho:weep:
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    Goldy Well-Known Member

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    I'm only here for the brofeels anyway!
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    James Bullshit Police

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    That's what she said! :naughty:
    Added: Oct 23, 2013 3:04 AM

    ****** :please:
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    cBass buffalo bell lover

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    best Brake mod:ashamed:
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    Goldy Well-Known Member

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    Wait, she is here for brofeels?
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    James Bullshit Police

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    Goldy Well-Known Member

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    Exactly! :please:
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    James Bullshit Police

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    WHO ARE YOU!!

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    Goldy Well-Known Member

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    James Bullshit Police

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