Anyone got one lying around or know where to pick one up cheap? (apart from the scrappies).
Cheers,
Pat...

I know its not what you want to hear but I have only just given one to MikeR. Sorry.

GGB sell Fiat parts really cheap, they used to be in London but have relocated to Yorkshire I think, my old numbers do not work anymore!

Hi,
I got one from www.brakepart.co.uk for £13.95 brand new. Here are the details:

Fiat Uno adjustable rear brake compensator valve - £13.95 (P/N HRV1013)

At this price it's just not worth messing about at a scrapyard!
Cheers,
Craig.

Do they come adjustable, or do you have to adapt them? - any details?

Mark,
They are adjustable but you need to fabricate a bracket for the valve onto which a nut and bolt is welded. By screwing in the bolt you can increase rear brake pressure. It does this by preventing the plunger on the valve from moving as far as it would in the absence of the bolt. Once you have set the bolt to a suitable bias point it will need to be tack welded or held with a roll pin to comply with SVA regs.

There are a few pictures of this arrangement on the forum here and I'll try to dig them out. Watch this space.
Cheers,
Craig.

Couldn't find the one I was after but here is a picture from "bob" 's photo archive. Hope you don't mind Bob...


Close up of bias and adjuster

Note that the plunger sits down when there is no pressure in the system and then rises up when pressurised until it hits the stop bolt. This is just an evolution of the old mini type bias valve and I'm sure there will be a spring loaded valve inside which will require more pressure to close if the bolt is pushing the plunger farther down. I understand that it requires quite "fine" adjustment but once set it is reliable and consistent.
Cheers,
Craig.


[Edited on 10/4/2004 by craig1410]

£13.95 plus vat and £5 postage !!!!!!

Still way cheaper than the £39.95+vat I was quoted by Fiat!!
I got a whole load of stuff from Brakepart at the time so the postage became insignificant.

I still wouldn't entertain any second hand braking parts from a scrapyard unless I could source a repair kit to replace all the rubber seals and do a full rebuild.
Feel free to rub my nose in it if you can find it any cheaper.
Cheers,
Craig.

Cheers Craig,
Didn't mean my last post to sound ungrateful. My dad lives near the Bolton depot so will get him to pick one (and pay for it hopefully)!
Cheers,
Pat.....

quote:

---

Originally posted by Avoneer
Didn't mean my last post to sound ungrateful.

---

Craig,

Thanks for the help, there still seems to be a bit of debat if one is needed with rear drum, anybody got any commets?

I'm using discs myself but I'd have thought that you are better off having some way to limit rear pressure even with drums and at least you can optimise the rear braking force if it becomes a problem during SVA.
Cheers,
Craig.

I had better get one then! Thanks

Mark,

IIRC if you've got the escort master cylinder, cortina front (M16?) brakes, escort 8" rear drums with crossflow engine you should be fine. One of the guys from TOL days used to work for Girling and put the numbers through their computer.

Of course i've got 9" rears

Iv'e got M16's at the front, but Capri axle at the back, 9" I think

Mark,
You don't have an Escort master cylinder either do you? I thought it was Sierra?
Cheers,
Craig.

I am not sure the master cylinder has much bearing on the pressure, as it will be the same on both circuits, but yes, I am using a sierra master cylinder, and have just ordered a Fiat bias valve.

On the subject, where is the best place to fit it - next to the master cylinder is looking favorite at the moment

Mark,
Yes you're probably correct although I suppose it is possible that a tandem cylinder "could" have different bore sizes front and back. I've never seen this though and can't think why it would be done.

As for the location question, I would agree that the front bulkhead next to the master cylinder would be favourite and is where I intend to mount mine.

Cheers,
Craig.

I have just got to make sure there is enough room to get a lecky drill into the lock nut to fit a roll pin.

Does it have to be mounted vertically, I seem to remember from my Fiat days that that it was horizontal on the rear bulkhead?

Mark,
I don't know if it has to be mounted vertically or not but it seems to be the way most folk mount it. I agree it is probably not necessary though.

Make sure you make up some rollpins the correct length so that you can drill it and fit it during the SVA. You'll probably need to fit a new bolt at the same time.

Craig.

I will predrill the welded locknut before welding it on, hopefully set it up at SVA and drill the bolt in position through the nut.

GGB, brilliant service, I ordered it by phone yetserday at 1:00pm, it arrived today at 9:30am in the post. It was £22 inc vat and postage.

Just a quick question, which is the inlet and outlet?

Mark,
If you look closely there is an arrow between the hydraulic unions. I presume this is the direction of fluid flow from master cylinder to rear circuit.

On the price, I guess I was wrong about Brakepart being cheapest as they would have charged a whopping 27pence more at £22.27 inc vat and p&p. Also great service and they even threw in a few bleed nipples for me at no extra charge as I forgot to order them at the time.
Cheers,
Craig.

[Edited on 14/4/2004 by craig1410]

[Edited on 14/4/2004 by craig1410]

That would be this one then!!
Rescued attachment BiasValve.jpg

Yep, that's the fellow...

You'll notice that if you pull the plunger (no the one on the bias valve... ) then it will move outward. I "believe" that this is what happens when brake pressure is applied and you need to resist this movement by way of the adjuster bolt to increase pressure to the back brakes. If you allow the plunger to move unchecked then you will get minimum pressure to the rear brakes. I'd expect that if you completely stop the plunger moving then you will get 100% of available pressure to the rear.

It's quite a neat little device isn't it?

Cheers,
Craig.

quote:

---

Originally posted by craig1410

It's quite a neat little device isn't it?

Cheers,
Craig.

---

instead of welding and / or fitting a roll pin you could always drill the head and a hole in the bracket prior to fitting and use locking wire. just a thought.

Hi,
I don't think that will do for SVA as they require it to be "permanently" locked and locking wire doesn't qualify as permanent. I know, neither does welding or using a rollpin but these are explicitly permitted in the SVA manual... Go figure!
Cheers,
Craig.

I thought the mechanism only had to be locked if it was operable from the drivers position. When did the rule change?

Pete,
I think that unless it is locked then the SVA tester will adjust it to the "worst case" with the maximum rear bias and then test it. So you will then probably fail for having too much rear bias.

I don't know when/if this changed.
Cheers,
Craig.