As I understand from the gurus on the site the IVA needs 30% efficiency from each side of the split brakes (how do they measure it?). So front/rear
split will not give the rears 30% of the brakes.
Can I re-plumb to put the two front Sierra master cylinder outlets to go one side forward and opposite side rear, tee the rear m/c outlet to do the
other front/rear?
If not can I still use the Sierra m/c?
I have RS200 drums (9"
on the rear but still doubt it will suffice, and if it does I suspect it will lock the rears before the fronts!.
Any advice welcome.
brake bias valve?
Didn't someone mention that brake bias valve are not allowed any more?
Brake bias valves are still allowed, but they have to be permanently fixed in place. ie. the old measure of drilling and using a pin is no longer
allowed - they suggest welding the bar to lock it.
I'm currently using a sierra m/c, and am preparing for IVA. The way I look at it is this; the front/rear brake proportion is split 60/40. With
the twin fronts, they should be equalling 30% each as a rule of thumb. Thus, is either one of the front pipes fail, you should still get the minimum
30% from the other front brake and rear units.
Dickboy, the way you are suggesting splitting the braking would not create equal force. My understanding of the Sierra m/c is that the front
section/2 outputs has a smaller bore than the rear, allowing for the bias itself. If you did it how you suggested, one diagonal would technically put
more braking force than the other, something I think you'd not be too keen on! If anoye wants to correct me, please feel free.
Someone who has a copy of the IVA might be able to give us the technical definition, but I don't intend to split my brakes diagonally in a
specific manner, other than that of the standard sierra setup!
quote:
Originally posted by Charlie_Zetec
Brake bias valves are still allowed, but they have to be permanently fixed in place. ie. the old measure of drilling and using a pin is no longer allowed - they suggest welding the bar to lock it.
Sorry, mis-read that!
My understanding is that bias valves and bars are both acceptable, as long as they are fixed in place.
Again, someone who has passed IVA or has a manual might be able to shed more light than I.
You can lock a bias bar
but a valve??
Hard to believe that this can be done.
Straight from the horses mouth.
quote:
Note 4: Hydraulic valves that only operate automatically and react to vehicle loading or braking forces are permitted (Load Sensing and Gravity valves) Manually adjusted valves (other than to permit presetting the automatic function of a valve) are not permitted to be fitted even if they are rendered un-adjustable.
Note 5: Bias bars and other mechanical adjusting devices fitted to twin master cylinders must have no means of adjustment. However they will be deemed acceptable if the all nuts etc are fully welded to their relative threads and all the threads originally intended to provide adjustment are welded along their length i.e. permanently rendering them un-adjustable.
Charlie_zetec, just checked my master cylinder, the front two outlets are both into the same chamber, one pipe/brake loses pressure then both are dead!
quote:
Originally posted by Dickyboy
Charlie_zetec, just checked my master cylinder, the front two outlets are both into the same chamber, one pipe/brake loses pressure then both are dead!