Soggy brake pedal

[PaulAA]

Chaps

I tried a search, but nothing quite matches this:

When I bought the TR, the PO had replaced the brake fluid with silicone .  The brake m/c failed and was replaced two years ago and the system refilled with silicone.  One or two numpty hiccups along the way (incl. educating my ex-mechanic that DOT 5.1 is not a better version of DOT 5) and all has been fine.

Until now.  For a week or so, the brake pedal has been soft, with much longer travel.  It doesn't build up pressure after repeated pumping at standstill, until the handbrake is applied.

Reservoir (both sides of the divide) is full and there are no obvious leaks.

Any ideas?

Paul

[JohnD]

Paul,

Has to be air in the system, or a leaky seal.

Can't be leaking from the brake ends, so internal, in master cylinder.

Air, some say that pressing down on the pedal and keeping it there with a stick, overnight, allows small bubbles to acummulate and then be bled out, but I can't see how that works.

John

[Nick Jones]

The effect of the handbrake is the clue I think - not a hydraulic issue.

Your rear shoes need adjusting, and if supposed to self-adjust.... they aren't...…..    When you apply the handbrake the excess movement at the rear is removed - a temporary adjustment if you like.

Nick

 

[PaulAA]

Thank you, both.

The odd thing is that it came on relatively quickly, from one day to the next.  The system was bled about two months ago, although I've found in the past that silicone has a tendency to retain air for longer than the mineral stuff.

I'll pull the rear wheels and see if the self-adjusters are sticking.

I sincerely hope it isn't the brake m/c again... two years is not much of a lifespan.

Paul

[Nick Jones]

If it was your M/C I don’t see how yanking on the handbrake would help.......