Once or twice a trip, my brakes suffer from a soft pedal - the pedal can be depressed to the floor with no effort. If you lift and apply again, normal function is restored - any ideas why?
The vaccuum hose from the inlet manifold has a soft patch on it, so that is being replaced at lunchtime, however is there anything else to look out for?
The car is a TR7 v8.
Cheers,
Seals in master cylinder shot assuming there's no fluid loss.
Fluid leaks.
When the fault occurs does the pedal feel spongy all the way down, or does it just sink further than normal but feel firm? If the latter, a worn front wheel bearing will cause the disk to push the pads further back in to the calliper. The next brake application pushes them back out so normal travel is attained.
Worth a check as it is so simple to do?
HTH
Chris
All the way down.
There's no play in the front wheels as far as I can tell - well with a good wiggling, anyway.
Cheers,
Master cylinder fault I'd expect.
Change the fluid.
Sourced a new master cylender, so it will get changed on the weekend anyway.
Cheers all,
The fluid is your problem though. Brake fluid is hygroscopic, it absorbs water. This reduces its boiling point, and if the fluid boils, you get the same symptom you have there - the pedal goes right down without resistance. It happened to me a couple of times in a LWB Landcruiser towing a caravan through High Peak. That's scary!
That is scary, but it's not relevant to the problem the OP described, ie the pedal goes to the floor once or twice during a journey when the fluid is cold, we're not talking about boiling fluid here, it's knackered master cylinder.
Steve
If it was a fluid leak, the next press of the pedal would push more fluid out of the leak and the pedal would go down to the floor again. The master cylinder is knackered.
Steve
A wheel bearing loose enough to cause the pedal to go all the way down to the floor would already have manifested itself as a wheel bearing problem long before it became a brake problem. The master cylinder is knackered.
Steve
I was hoping someone else would say that - the thought had occurred, but it's always nice to get a second opinion.
Cheers,
Aye! Since the clutch master cylender is weeping slightly as well, I'm swapping them both at the same time, so there's only one saturday spent faffing with bleed tubes, SWMBO moaning about being stuck in the car pressing pedals on a cold wet afternoon, lying in the most god-awful position to get the bolts out from the footwell.... Ho hum!
Thanks for all the info :->
Which is what I said, assuming he notices no fluid leaks.
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