Brake pedal going solid

[Turbocharger]

A mate has a Series IIA which he uses as a mechanical wheelbarrow and mobile winch around the farm and environs. He recently stacked his daily drive, so the LR has to step up duties.

He took it out for a run, and all was well. After stopping at the shops, he got back in and the hydraulics seemed to have gone 'solid'. He doesn't think it's a problem at the pedal end, it feels 'hydraulic'. The brakes didn't seem to be locked on (although he'd had a lack of power climbing a hill earlier that might have been dragging brakes?) but obviously he's not confident about driving it.

It's not servo-assisted and he's recently replaced the master cylinder to attempt to cure this problem, without success.

[Phil Hancock]

Check the master cylinder pushrod for clearance, the symptoms sound like lack of clearance and the heat of driving/braking is applying the brakes as the fluid heats up and expands but due to lack of clearance cant equalise back to the resevoir.

[ciderman]

Also check the hose condition , they swell internally with old age restricting the flow back and causing brake bind

[SteveRK]

I've experienced this type of problem - albeit on a motorcycle. The small (tiny) vent hole in the master cylinder reservoir adjacent the 'supply' hole blocked up preventing the return of fluid back into the reservoir when brake pressure is released.

I'll stop here as I'm starting to confuse myself trying to put into words!

[Turbocharger]

Thanks chaps - simplest explanation has hopefully solved it - he says:

Thanks for that. Just been out for a look and concluded I must have been thinking aircraft flying controls when I set up the pedal. Have readjusted to agricultural clearances and not expecting the problem to recurr.