Sorry, I wouldn't know how to test for brake fluid contamination, short of taking a sample to a lab which is likely to be prohibitively expensive. Might be worth inquiring if there has been any recent work to the brakes though.
My suggestion would be to completely drain the system, flush through thoroughly with the correct fluid, and then re-fit the new master cylinder. It's not a bad idea to replace your brake fluid every few years anyway. Brake fluid will absorb water from the atmosphere, which collects in the system and can cause corrosion. On the AX, we did this, and then changed both rear wheel cylinders, and put new seals in the front calipers. They would probably have failed sooner or later anyway, due to the contamination affecting the seals. But working from an unknown history? Tricky. One other thing I can think of. Some cars (not sure whether this applies to the Fiesta/Quantum) have a tiny vent hole in the brake fluid cap. This is to allow air into the master cylinder, to replace the fluid displaced from the reservoir when the pedal is pushed. (The air gets pushed back out again when the pedal is released and fluid returns to the reservoir - air shouldn't get into the system this way). If the vent hole is blocked, it's possible a slight vacuum in the reservoir might prevent fluid getting into the master cylinder properly. This could cause symptoms like those you're seeing. I can't remember how the Fiesta cap vents, but if it's been fitted with an aftermarket "fashion" cap, or pattern master cylinder, it may be missing the vent. TonyV. On Nov 6, 7:01 pm, shaun mcsorley <[email protected]> wrote: > thanks soo much for your replys, As i admitted my knowledge isnt the best > so can you advise how to check these things? > Really appreciate this > > > > > > > > On Sun, Nov 6, 2011 at 6:32 PM, TonyV <[email protected]> wrote: > > Possible use of wrong brake fluid, recently or at some point in the > > past? > > > For example, even a trace of Citroen brake fluid in the system could > > cause eventual MC seal failure. > > > We found this out the hard way, after we had to change the master > > cylinder in Louise's old AX several times in a couple of weeks. > > Turns out the Citroen AX doesn't use Citroen brake fluid. > > We'd bought a bottle of fluid at the same time as the new Master > > Cylinder, and recommended by the motor factors. > > The can of brake fluid just said "suitable for most Citroens" - no > > actual application list, so we'd taken his word (and catalogue lookup) > > that it was the right one. > > > TonyV. > > > On Nov 6, 4:39 pm, Jim Hearne <[email protected]> wrote: > > > Nothing that i can think of. > > > Why was it replace last time and what makes you think it's going again ? > > > If this is the one that cost you 350 i'd go back and make them replace > > it. > > > > Jim > > > > On 06/11/2011 16:33, shaun mcsorley wrote: > > > > > After having the brake master cylinder changed only a couple months > > > > ago and costing fortunes, i'm pretty sure its going again? does anyone > > > > know a possible reason that would cause the master cylinder to > > > > continuously break? > > > > Many Thanks > > > > Shaun McSorley > > > -- > > You received this message because you are subscribed to the Google Groups > > "Quantum Owners Group" group. > > To post to this group, send email to [email protected] > > To unsubscribe from this group, send email to > > [email protected] > > For more options, visit this group at > >http://groups.google.com/group/quantumowners?hl=en > > > IMPORTANT NOTE: All information presented herewith is provided on an "As > > Is" basis, without warranty or the implication thereof. Neither the Quantum > > Owners Club nor the individuals associated with the Quantum Owners Club or > > in the preparation of the above information shall have any liability to any > > person or entity with respect to liability, loss, or damage caused or > > alleged to be caused directly or indirectly by the instructions contained > > within this or related message(s). -- You received this message because you are subscribed to the Google Groups "Quantum Owners Group" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/quantumowners?hl=en IMPORTANT NOTE: All information presented herewith is provided on an "As Is" basis, without warranty or the implication thereof. Neither the Quantum Owners Club nor the individuals associated with the Quantum Owners Club or in the preparation of the above information shall have any liability to any person or entity with respect to liability, loss, or damage caused or alleged to be caused directly or indirectly by the instructions contained within this or related message(s).
