760 Intermittent Soft Brake Pedal

Hi John, Thankfully this model does not have wear indicating connection/cables, a previous old Ford Granada did and they were a bit of a pain! I should have a new master cylinder arriving this very dayish as I feel sure it may be the problem, I will let you know what happens. A cousin of mine runs a garage and his comment was: "If it's an intermittently soft pedal it's always the master cylinder as the sharp lips wear off the rubbers, HOW old did you say yours was?" Bob.

Hi John, Sorry to hear you're still in trouble. I finally got my new master cylinder fitted yesterday morning after a fortnights thinking about it. I now have a pedal that is much improved although as I only did a time limited bleed of the cylinder itself it still feels a bit spongy but crucially after a couple of days has yet to fade to the floor, we shall see what happens, it will get treated to a whole bleed/fluid replace in a week or so and then the real truth will be known. I have to say with regards to yours I still don't see how a booster that has a solid rod through it can produce a pedal that goes to the floor, I tried mine with the inlet valve blocked off so it was adding no boost and the pedal was rock solid. Maybe if the shaft was sticking in the cylinder piston it would slide further in as it cleaned up but it would only be able to do that surely if the master cylinder piston was already pushed in a bit to allow it to settle into it, and at that point you would have to be driving around with the brakes partly on all the time? If it was air in the system it would be the same all the time and not intermittent surely? If it was fluid bypassing a seal then it would only go soft when it bypassed, here we go back to the master cylinder again!!, .................... could you have fitted a duff one that has only worked for a while, could it have been old and had dried out rubbers in it. If the pedal only goes down occasionally it has surely to be fluid bypassing a seal somewhere, what's in the ABS stuff, don't ask me I haven't looked that deep as yet. Where's that Volvo expert Glenn when you need him, or perhaps these old wrecks are out of his remit? Bob.

"R G Green" wrote in message news:nLqdnW3 snipped-for-privacy@brightview.co.uk...

Hi John, Thankfully this model does not have wear indicating connection/cables, a previous old Ford Granada did and they were a bit of a pain! I should have a new master cylinder arriving this very dayish as I feel sure it may be the problem, I will let you know what happens. A cousin of mine runs a garage and his comment was: "If it's an intermittently soft pedal it's always the master cylinder as the sharp lips wear off the rubbers, HOW old did you say yours was?" Bob.

"John Robertson" wrote in message news:4e080595$0$13394$ snipped-for-privacy@news.optusnet.com.au...