Rear bias valve

[anto]

The rear bias valve (on my Phase 2) seems to have completely seized up now internally. I am getting a lot more braking from the rear these days.

Is there any issue with removing it completely and repiping the rear brakes like a Phase 1 that had no bias valve? Is there a difference in the master cylinder between a Phase 1 with no bias valve and a Phase 2 with bias valve?

Thanks,
Anton

[underground375]

Doesn't the bias valve work along side the ABS when you slam the anchor's on? What I believe. Ive took them off before and didn't feel any difference in normal breaking.

[puglove]

Im not sure it would pass an MOT without the bias valve .:/

[anto]

But would it not be the same setup as a Phase 1 without a bias valve?
How would they know as id be removing it completely and redoing the brake pipes in exactly the same position as a Phase 1.

PS no abs on my car, although there are the big drums rather than the normal small drums on a Phase 1.

[underground375]

Big drums normaly mean abs

[anto]

Definitely no abs on mine.... Its a late 97 Phase 2 so just after the switchover from PH1 to 2.

[silverzx]

Parts bin special. <3

[anto]

Id say so lol

[puglove]

If it doesnt have ABS it shouldnt be an issue. ...... I would think

[306Dan]

It'd pass the mot fine, take the 1.4 miami's their pov spec and don't have a bias valve

[mikey b]

It will pass mot ok but you may find that the rear brakes work to well and lock up now and again

[Andy!]

the early P1s without the bias valve has small rear brakes from what I have seen (I could be wrong).

If you have the larger rear drums it may well cause you problems. I don't think there is any relationship between having abs and having one or not, the confusion comes in because the later cars (P3) had a better version of the ABS with EBD which replaced the bias valve.

I would be very wary of removing it, try and free it up or see if you can get one. Although I appreciate how difficult either of those is going to be!

[welshpug]

the small drum setup without a load compensator had different wheel cylinders with integrated pressure limiting valves.

[Andy!]

^ that rings a bell. Amazing how much I've forgotten.

[anto]

the small drum setup without a load compensator had different wheel cylinders with integrated pressure limiting valves.

Any way of adapting those brake cylinders for a big drum setup?

[welshpug]

I doubt they would be large enough bore, I would get a load compensator fitted if you wanted the big drum setup.

[anto]

To be honest welshpug it is adjusted as much as possible and it is still always fully closed due to the level of the suspension at the rear. I dont think its actually doing anything at the minute anyway so the thought of brake cylinders with limiting valves would be a good option for all low 306 owners.
(Its not lying on its arse but its still quite low).

Im currently trying to get it raised up but the bloody shocks are seized on!

[darrenjlobb]

This is an interesting thread, as the ammount of cars ive driven which have dangerously lively rear brakes is rediculas... Yet my car has always been fine...no matter how low....and it does have a compensator, and altho ive adjusted it so it can still travel, its largely bottomed out most of the time tbh... So i find it weird that i dont get the problem. But i have driven so many cars that do, its its bloody dodgy when you need to stop for an oncoming car on backroads and your on a bend, as the only way to get enough stopping up th front involves letting the back lock / go sideways...just gotta prety you stop before you drag the arse in the hedge lol

[Rippthrough]

I doubt they would be large enough bore, I would get a load compensator fitted if you wanted the big drum setup.

I think the bore is the same but the width is different, although it's been a while since I was tinkering with 'em. And yes, the early cars have pressure limiters in the rear cylinders themselves.

[anto]

Well i eventually got the rear damper bolt unseized (it involved beating it for an hour with a lump hammer!) so i got the rear raised up so the bias valve wont be as much of an issue now.