Can it drop the pressure? Doesn't it just stop the pressure in the rear from increasing further? I think the rear is pressurised when the deceleration valve is closed, definitely enough for the switch. What do you think?

I don't know but good engineering practice says don't take the chance.
Enoch

Hi
Thanks for asking and your help. The car is comming along not badly work pressure is a bit too much but the car gets a little attention and does unwynd from work.

here is how it works

its fitted angled with the input to the top/front angled to the front of the car

when you step on the brakes hard there is a little spool valve that travels uphill by enertia preventing the rear brake lines form increaseing fluid pressure
stoping the rear wheels from locking as the back goes light

so the harder you push the pedel the rear gets no pressure rise
the steeper you set the angle the harder it is for the valve to work

when your stoped and level the back should get full pressure

hope that helps

This might be a really stupid question - but on the rollers for the IVA test will these deceleration valves work as the car is not actually physically decelerating :confused:

Same for any car thats on test, weather new or old.

So it would seem then that for our purpose of IVA there is no benefit in fitting one.

But! it will give you better braking benifits, I think :o

I would have thought that when braking all the weight transfer will be forwards so the majority of the braking will be done by the front brakes and you will then become traction limited. At the back of the car, the weight will reduce and you will also become traction limited because of the reduction in load on the tyre - i.e. the rears will lock because they are lifting off the road and have a neglibile braking effort.

I've heard off this before David and once the inspector has seen that the deceleration valve has been fitted he is confident that the rear wheels are not going to lock and will be okay with it.

Regards....AndyH