rear disc prob..

[suzuki-rob]

hi everyone 95% complete my rear disc conversion on my Sammy I heard from a few people that I will have to fit a brake bias valve do i need one of these or can I just rigg the brake lines right up to the callipers

[Darrell]

I've read quite a few rear disc conversion write ups and some say to fit one, some don't. Bottom line is if you don't fit one the rear brakes may well lock-up before the front brakes do. This can make you loose control in emergency braking as your more likely to end up going sideways. It does depend on what pads and calipers you fitted as some are more powerful then others.
I'm not sure how people set these up, on a rolling road like at the MOT station would be ideal.
Quite a few of the guys have done this conversion so hopefully they can give you better advice.
Cheapest I could find on fleabay if you do go for one.....

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[dan_2k_uk]

I aint got one. Occasionally I feel a back wheel skip a bit during hard braking.

Never really any drama though I just notice it happens.

Dan

[Ladaman]

Isn't the valve thing on the drivers side of the chassis towards the rear a proportioning valve?

Or is it that you have altered the braking force per axle by adding rear discs that "may" need an additional one fitting, or a new one fitting and the original one removing!!!

We had a bias valve fitted to a rally car I used to compete in, and to set the bias up we just drove up and down a quiet road, breaking hard and adjusting it to either make it get the rear out of line intentionally, for forest events, or not for tarmac events.

The main thing is for the driver to know what is likely to happen when breaking hard.

[ScottieJ]

Well it's sort of a bias valve I think? It adjusts depending on how fast you are stopping or something like that? I would consider removing it and fitting it an adjustable bias valve on its own when fitting rear discs.

However from my experience I know people like my dad who's rear disc set up works well with the stock valve. Then another mate who fitted a wilwood adjustable bias valve and left the stock one in place; even with it set up to limit rear braking as much as possible he would still lock up the rear wheels before the front. Then again I run vit front brakes and stock 410 rear drums and I've still managed to lock up the rear under heavy braking.

Then again most of these valves are now 20 odd years old so who knows if they are all still working as they did originally so that could have something to do with people having different results.

[suzuki-rob]

ive been out and had alook at my mates Suzuki his done same rear disc conversion as me and he said your not aloud to use bias valves on the public highway there for track use and he has plumbed the brake pipes up the same as they where with the rear drums no bias valve and its braking is spot on would stop on the spot