Is it possible to swap out the balance valve with a union or section of pipe as a test to see if that is the problem, I know it sounds like a bit of a faff but you've swapped master cylinders a time or two so should be no worse and at least it would save you trying to track down a difficult to find part only to find it's not the problem.DaveEFI wrote: ↑Wed Aug 04, 2021 11:05 pmMy mechanic neighbour was available today. And after trying conventional bleeding, he came to the conclusion the balance valve is faulty. After we swapped master cylinders once more. The flow from the rear bleed nipple is tiny compared to the fronts. And we agreed the only thing that could cause this is a faulty balance valve.stevieturbo wrote: ↑Wed Aug 04, 2021 9:14 pmThe pipes are too small for air locks to be an issue.
However....control valves etc can cause issues. What is the nature of the balance valve ?
There is a problem there. Rimmer list two - one for all SD1 except the Vitesse. Vitesse one NLA. No mention of my EFI which has the same brakes as the Vitesse.
Alternatively you could even terminate the line where it enters the valve and bleed air out at that point this would at least eliminate anything downstream as the issue.
Bear in mind that for a given pedal pressure the valve will restrict fluid to the rear line, that's its job, although it's possible that the restriction is dependent on input pressure they are not a device I'm too familiar with.
I think the non-level nature of the car could cause an issue if it is severe enough. If the outlet from the brake calipers is not at the highest point and there is air trapped in there then it will not come out, presumably the calipers are designed for this to be the case when the car is level. Could you stand the low end of the car on axle stands to level it out?
It's also possible to get a similar thing if the car is not level side to side (in roll), this is worse if the caliper pistons are extenced I generally retract the pistons which is the case if fitting new pads but if I'm not then I wedge the pistons back.