Transbrake/line pressure issues

904 in the Demon, Tranzact brake. Completely rebuilt at the beginning of the season

Seems lately having a harder time to get the brake to hold without running up the RPM some at the line. Once locked it holds fine. Also notice I need a little more RPM to get it into reverse. Been told the pump could be weak. Tried checking the line pressure with a gauge, and getting no movement at all. Obviously has some sort of pressure since it's still functional. Any ideas where else to look?

Most transbrake VB's shut off the fluid to the accumulator where the line pressure is normally checked, hook a gauge to the front servo and check the line pressure in 3rd gear.

Perfect, thank you!

Survey says on a cold transmission at about 850 idle it's right between 135-150psi. Goes over 160 at maybe 1100-1200 rpm, so I'd say the pump is doing it's job. Any suggestions why I need to get more RPM to lock it? It's cost me a few races by creeping after I've got it staged.

Perform the same pressure check at the rear servo in 1st with the transbrake applied, should be very little difference in pressure between the front and rear servo.

The instructions on some VB's state that it may take 2000 rpm or so for a consistent brake lockup.

I'll check that later this week.

First year running a brake so may just be a learning curve for me. It seemed like it locked right away at the beginning of the season. I can adapt to it if needed. Just need to make sure it stays locked and doesn't accidentally deep stage me!