Board logo

SIerra brake inertia valve...which way?
tegwin - 12/3/08 at 08:50 PM

Does anyone know which way around the sierra inertia brake valve is supposed to go?

Which is the inlet from the MC, and which is the oulet to the rear brakes?

And which ends needs to face fowards?

RichardK - 12/3/08 at 09:07 PM

Does this help, the pipe nearest the block goes through the tunnel to the rear where it's tee'd off. The other goes down to the MC

Regards

Rich

[Edited on 12/3/08 by RichardK]

stevec - 12/3/08 at 09:13 PM

Bin it, You dont need it.
Steve.

Mark Allanson - 12/3/08 at 09:15 PM

quote:
Originally posted by stevec
Bin it, You dont need it.
Steve.


I'll second that

graememk - 12/3/08 at 09:43 PM

i havent got one

onzarob - 12/3/08 at 09:56 PM

what does it do :confused:

tegwin - 12/3/08 at 10:11 PM

Its getting fitted to help me pass the SVA!

Enough said!


Chears for the photo, does the job

whitestu - 12/3/08 at 10:11 PM

Agreed - bin it.

It's supposed to limit brake pressure to the rear under braking to stop the rears locking.

stu

donut - 12/3/08 at 10:23 PM

If you have a proper sierra master cylinder then you don't need it.

indykid - 12/3/08 at 10:59 PM

quote:
Originally posted by tegwin
Its getting fitted to help me pass the SVA!

Enough said!


Chears for the photo, does the job


IT WILL DO NOTHING TO HELP YOU PASS SVA!

it's an inertia valve. it's a dynamic proportioning valve for when the car is moving. the sva test is a static test, so you will still get full pressure to the rear brakes.

tom

matt_claydon - 13/3/08 at 02:30 AM

^^^^ Spot on.

I understand it also works partially due to the dive of the vehicle under braking. i.e, the more the back lifts, the less line pressure to the rear. A seven will hardly dive during braking.

zzr1100rick2 - 13/3/08 at 07:27 AM

as i understand it if it is fitted mr sva only does a moving test of the brakes to measure front to rear ballance due to it been an inertia device

britishtrident - 13/3/08 at 07:32 AM

quote:
Originally posted by matt_claydon
^^^^ Spot on.

I understand it also works partially due to the dive of the vehicle under braking. i.e, the more the back lifts, the less line pressure to the rear. A seven will hardly dive during braking.


Only a tiny ammount of its action is due to dive it is as indykid pointed out a G valve it works on decelleration (and hence won't do anything in a roller test).

The gubbins inside the Girling G valve is very simple, just a ball bearing that rolls forward (up a slope) under braking, when it reaches the end stop it closes the port to the rear brakes, brilliant very simple and very reliable but not much use on a Locost or for passing SVA.
First application I encoutered this type of valve on was the Austin 1800 Landcrab.

James - 15/3/08 at 04:18 PM

Bit in!


Get a Fiat Uno adjustable one for £20 new.

HTH,
James

bob - 15/3/08 at 04:30 PM

I wouldnt even bother with the adjustable valve, i fitted the fiat type as james pointed out but left it wide open for SVA and it passed like that.

I thought i would need it with the rear discs but plenty others have gone through the test without.