Brake proportion/bias thingy?

[arhTVR]

My apologies for the flippant title but my brain hurts from reading all the brake upgrade posts on here. I still can't decide whether to leave well alone, put 260 on the front and 25x on the rear or even 257 on the front. Enough of that, lots said already!

What I am really after is a Sierra brake proportioning valve as mine is in a very poor condition. Does anybody know where I can get one from?
Tony

[arhTVR]

glenrobbo said:

www.sierrasrus.co.uk ?

Won't it clean up with a bit of tlc?

Thanks Glen
I'll give them a try and see what they have. Mine is beyond repair unfortunately.
I'm considering a Chim/griff setup for the brakes which might mean that the available Griff (mondo) valve might work
Alternatively, perhaps just upgrade the front to Griff 260mm set up.
Cheers.
Tony.

[arhTVR]

I can make it look OK but one thread is no good. If push comes to shove I could try a helicoil fix. the outside is proper rusty and the bracket pretty much non existent, so I'm concerned that the the 'ball' and spring inside may not be OK - it has been stood for over 8 years. I thought it safer to get a new one but my mate Google was no help. I'm about to try the Guys in Glen's link. (Thanks again)

My (limited and amateur) understanding is that the kit car adjustable regulators reduce the overall pressure, in a 'static' sense.
The Sierra ones use inertia(?) to dynamically reduce the pressure under braking, and my assumption is that the Chim/Griff set up (which the larger rear discs and 260mm front emulate) use a regulator which reduces the pressure when the pedal is pushed very hard - again, more of a dynamic arrangement. I'm aware that I am messing with things I don't fully understand but the Chim bible suggests that its unconventional set up of larger rears works well in this particular case.

I'll update with some pics later - just making a few minor mods to the chassis repairs before getting it to the powder coaters.
Tony

[arhTVR]

OK. Those nice people at Sierras R Us had one, so no need for helicoils or any other worries I hope. If anybody still has a nice stainless bracket that would be great Thanks to Glen for a great link - they seem to have lots of second hand Sierra parts readily available.

I may just go for 260mm front discs and retain the rear drums, but as I have most of the parts for a 273mm rear disc set up that is also very tempting. This would be similar to the Griff 500 set up so fitting a Mondeo pressure regulator seems appropriate - I think that must be what Richard did (previous post). I now have both options and will make a final decision when I get to re-building the back end.

Thanks to everybody for their help.
Tony