new bloke with brake problems

hello everyone

had an 03 ulysse for 3 years now fantastic car no major problems how ever yesterday i decided to change all the brake pads. front ones were half worn but warning was coming on about "worn pads" rear ones had about 1mm of material left, all was well but now the brake pedal just sinks to the floor, if i pump the pedal it will firm up but then goes bad again, never had this on a car before can anyone help please ?

thanks andy

Sounds like classic symptom of air in the system, probably a good time to replace brake fluid and bleed thoroughly, replacing any dodgy joints or seal anywhere, important to find the source of the air ingress if this is the case.

Edit :- air can be created in the system if the fluid is old, brake fluid is hygroscopic and retains moisture from the air.

thanks Ffoxy

will try out later thought this might be problem but it just seemed wierd that it coincided with pad change could be that i opened resevoir lid when changing them !
will let you know

thanks again

andy

No problem, Post back if a bleed doesnt fix it.

At its worst, if there IS water in the system causing air to be bled in, there is a chance of total braking loss as the water in there effectively can boil under heavy braking, the air is the steam. May be a stuck piston in the caliper after you pushed them back to get the new pads in tho, did you check for free movement and lightly grease the moving bits with HMP grease?

Worth checking the lips on the discs. As they wear they form a lip that actually catches the low pad warning wire before the pads are actually low.
I take an angle grinder and dress the lips back down to the disc surface. There's a minimum thickness marker on the disc to indicate whent he discs are at minimum thickness.
And yes sounds like air in the brakes.
Maybe pressing the pistons back in to take the new thicker pads introduced some air?
Try bleeding and see what that yields.

hi
thanks for your advice ,the brakes are bled and they work properly again.
interesting to here about the possibility of a lip on the discs catching the wires as the front pads were only half worn and there is a nice looking lip on the discs !
rear pads were well past it though.
i have driven this car to the south of italy four times now (with a trailer each time) and it has been fantastic.thats a 3000 mile round journey each time, with no problems, on the whole a really good car.

thanks

andy

I replaced our front discs just a month or so ago. Not too expensive and a simple job.
But still worth getting what life they have to give out of them first.
We've done a number of runs to the south of France and tow a folding camper.
Great car for long runs. So comfy and reliable.