Brake Proportioning Valve

[Confused]

Hi all,

Over the weekend we swapped out our teeny 256mm discs/single-pot calipers for some 296mm twin-pot VR-4 ones

One thing I potentially overlooked, is the brake bias valve.

I've finally got ASA up and running, and have done a search for a PFL Legnum, and a PFL Galant V6-24, and it's showing up as the same PNC (55876), but different Part Numbers.

They are:

PFL V6-24 - MB669555
PRL VR-4 - MB669554


Neither are listed as being superseded by the other, so are they going to be different?

Should I swap out the original with the one that came from the VR-4?

Rear calipers are identical across the lot of them.

Anyone know what the differences between them are, or should I not change it due to the weight difference between the two vehicles?


Cheers!

Garry

[steelie600]

To be fair Garry, if youve now got the vr4 system on there, i personally would also fit the vr4 bias valve. I would imagine the valve would be different mainly due to the fronts on the vr4 being bigger than the v6 ones. Are the rears different too??

[Confused]

The rear calipers are identical anyway (checked via ASA), so they've not been changed.

[steelie600]

yeah put the vr4 valve on mate just to be on the safe side

[Gly]

ive had vr4 brakes on the st now for 4 years, using the stock v6 bias valve,
no issues at all,

the v6 bias valve only becomes an issue if you want to fit brembos.

[bradc]

There are 3 different jdm ones, and yes the standard V6's are different to VR-4's. I wouldn't bother too much at the moment as I've done the same as Carsten, upgrading my ST-R to VR-4 brakes and I haven't had a problem. Note though that the ST-R has 5 stud wheels and slightly larger front brakes than his 25ST did, so his findings are probably more important!

If a cheap VR-4 one came up though I'd probably grab it.

[Turbo_Steve]

Actually, the valve is more likely to be different due to the balance of the car more than the caliper size.

[bradc]

Indeed, the Galant and Legnum VR-4's have different valves and then ST-R's are different again. The other ones, 1.8's and such use the same ones as some of the other chassis' I mentioned above. I'll check out my list tonight.

[psbarham]

i never bothered on either car and it was all fine

[bradc]

VX, VR-G, VR-4 Galants = split point of 22.5 to 27.5 bar
ST, 25ST 2wd, VR-4 Legnums = split point of 27.5 to 32.5 bar
20ST, 25ST, 25ST-R 4wd Legnums = split point of 32.5 to 37.5 bar