GRIFF/CHIM REAR BRAKE LIMITING VALVE

[wixer]

Can anyone shed any light on what was fitted to which model and year ? My pre-serp Griff has a valve mounted to a plate, on the rear offside chassis, between the diff and the wishbone inner mounts. It seems later cars don't have this valve, so what do they have as a pressure limiter and can you update the earlier versions ??

(Morning Del, you all ready for Le Mans yet ??)

[seasider]

wixer said:

Can anyone shed any light on what was fitted to which model and year ? My pre-serp Griff has a valve mounted to a plate, on the rear offside chassis, between the diff and the wishbone inner mounts. It seems later cars don't have this valve, so what do they have as a pressure limiter and can you update the earlier versions ?? (Morning Del, you all ready for Le Mans yet ??)

Morning

I dont recall seeing anything in that area on mine Phil, 97 Serp..

Cant wait !! you sorted ?

[wixer]

seasider said:

wixer said: Can anyone shed any light on what was fitted to which model and year ? My pre-serp Griff has a valve mounted to a plate, on the rear offside chassis, between the diff and the wishbone inner mounts. It seems later cars don't have this valve, so what do they have as a pressure limiter and can you update the earlier versions ?? (Morning Del, you all ready for Le Mans yet ??) Morning I dont recall seeing anything in that area on mine Phil, 97 Serp.. Cant wait !! you sorted ?

Yeh, we got the tickets through last week, Houx this year. See you there for a few 's ??

[seasider]

wixer said:

Houx this year. See you there for a few 's ??

Take a fridge

[v8sag]

Have a 95/97/98 here and the only thing in that area is a T junction for the left and right brake lines.
Having srtiped 2 of these cars iv'e never come across a limiting valve anywhere.

[GreenV8S]

v8sag said:

Having srtiped 2 of these cars iv'e never come across a limiting valve anywhere.

There better had be a bias valve somewhere, otherwise the brakes are going to be dangerously out of balance.

[chassis 33]

Mine has a limiting valve infront of the rear T piece, M-plate 4litre. I'm planning on removing it shortly and adding an adjustable bias valve.

Regards
Iain

[petea]

my 94 chim 400 has one of these valves - it was leaking and i had to get another from a breaker - sorry, cant help with the spec on later cars.

[v8sag]

So in front of the tee (at the rear)the nut in front is the valve?certainly does'nt look like a valve.
I thought the dual system did its balancing bit at the master cylinder?

[wixer]

v8sag said:

So in front of the tee (at the rear)the nut in front is the valve?certainly does'nt look like a valve. I thought the dual system did its balancing bit at the master cylinder?

The valve's quite large, you wouldn't mistake it for a T piece, it's about 3-4inches in length. I have seen later cars that don't have the valve and there is just a T piece.

[GreenV8S]

wixer said:

The valve's quite large, you wouldn't mistake it for a T piece, it's about 3-4inches in length. I have seen later cars that don't have the valve and there is just a T piece.

Presumably (hopefully!) on these cars the valve is further forwards somewhere. You definitely need the valve, I doubt that even TVR would have simply left it out!

[wixer]

GreenV8S said:

Presumably (hopefully!) on these cars the valve is further forwards somewhere. You definitely need the valve, I doubt that even TVR would have simply left it out!

Exactly, so how do the later cars do it ??

[GreenV8S]

wixer said:

Exactly, so how do the later cars do it ??

Don't know, but at a guess the valve is simply positioned somewhere else. Perhaps inside the sealed wing area at the front, where the reservoir is?

[v8sag]

GreenV8S said:

wixer said: Exactly, so how do the later cars do it ?? Don't know, but at a guess the valve is simply positioned somewhere else. Perhaps inside the sealed wing area at the front, where the reservoir is?

Nope not there.

[GreenV8S]

In that case, if you've followed the brake line all the way from the master cylinder to the slave and not seen the valve, I guess there isn't one. That's a rather alarming thought!

[wixer]

GreenV8S said:

In that case, if you've followed the brake line all the way from the master cylinder to the slave and not seen the valve, I guess there isn't one. That's a rather alarming thought!

Unless the master cylinder compensates somehow.

[GreenV8S]

wixer said:

Unless the master cylinder compensates somehow.

It doesn't.

[else]

Perhaps the later cars with bigger front brakes didn't need a limiting valve in the rear circuit. Perhaps the earlier cars had too much of a rear bias with those smaller front discs and calipers.

[wixer]

else said:

Perhaps the later cars with bigger front brakes didn't need a limiting valve in the rear circuit. Perhaps the earlier cars had too much of a rear bias with those smaller front discs and calipers.

Mine has the bigger brakes and the valve.

[GreenV8S]

else said:

Perhaps the later cars with bigger front brakes didn't need a limiting valve in the rear circuit. Perhaps the earlier cars had too much of a rear bias with those smaller front discs and calipers.

All those things affect the static brake balance. The pressure limiting valve corrects the dynamic brake balance i.e. it changes the brake balance to compensate for weight transfer under braking. You fundamentally can't do that just by changing the static balance.