Brake booster issues on FC

Yep got a tank. Once it got down to 20"HG it pretty well stayed there even at idle. That gave the 1500 psi on the front. As you say it weighs over 5 ton and the 900,s on it give more resistance to stopping than the 7.50,s would.
The pressure in the disco dropped faster with each application.
Asked around about the VH90,s but seem to be like Rocking Horse Poo:(
On that table their max pressure is 1460 like the VH40 but with a much lower input pressure. I understand the master has to be bigger in the bore for more capacity hence the lower pressure.
I dont really want to change the master yet.
I can get a high pressure VH40 for the front discs then put that standard VH40 on the back. That should give me higher pressures all round.

I wont hijack your thread any more Murray but just for comparison I put the gauge in the 1954 86" I am rebuilding.
With about the same pedal pressure I was using before I got just on 1000 psi unboosted, std SWB master.
Thats more than the VH44 gets:o
Keith

Quote:

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Originally Posted by 123rover50

I wont hijack your thread any more Murray but just for comparison I put the gauge in the 1954 86" I am rebuilding.
With about the same pedal pressure I was using before I got just on 1000 psi unboosted, std SWB master.
Thats more than the VH44 gets:o
Keith

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Hi keith

Was discussing this with cookey who's just started manufacturing a disk brake conversion for the front of the series LR. He suggested that you need at least 1200 psi to have reasonable braking.

Maybe you could migrate the VH44 to the clutch line and have a soft clutch pedal!

In regards to the actual setup for the FC, I've been considering making a pivot and crank arrangement on a six cyl pedal box to turn the mastervac 90 degrees to the pedal direction, the booster would be bracketed off the LHS off the clutch pedal box and the master cylinder beyond that above the radiator. The idea came when I looked under the bonnett of an XF Jaguar, where in the RHD models there is a cross shaft across the top of the engine with the mastervac sitting on the LHS in front of the passenger.

Diana

That sounds a good idea. Something that I had not considered at the time.

Hi Keith,

Have a look inside the dash of a bus or forward control truck. Often the brake master cylinder / vacuum booster assembly is at 90 degrees to the pedal inside the dash. My old Coaster was like that and I thought that may be adaptable to a LR Forward Control.

Bob