No brakes after fitting new pads?

[tight fart]

I've fitted new pads all round and the pedal now goes to the floor, I can pump the pedal up but if I leave pressure on it, it sinks.
I expected to find a piston seal gone and a puddle of fluid.
On an older system I'd have said the master cylinder seals had gone.
Could it bu99er the abs pump by fitting new pads?
I've driven it up and down the yard and the brakes feel better in reverse.

(It's an Iveco daily van)

[justinio]

Tried bleeding the brakes?

[tight fart]

Not yet, one I was on my own and didn't have a pedal pusher,
but also I couldn't see how I'd introduced air into the system.

Also with air you tend to be able to pump up the pressure and it holds, this is.

[TooMany2cvs]

justinio said:

Tried bleeding the brakes?

Where's the air come from...?

How old's the vehicle, and how scrupulous has the brake maintenance been? If fluid changes have been slack, it's entirely possible the caliper bores have got a bit grotty, and the seals have ripped as they've gone back across a bit that doesn't normally get used. I've had that with a "perfectly good" clutch master on a fluid change, that turned out to be horrible inside...

Easy way to see if it's calipers or master/ABS is to clamp off the flexis, and see if the pedal firms right up.

[tight fart]

Thanks, good call on clamping them off, I'll try that, when it stops snowing here!

[GreenV8S]

tight fart said:

On an older system I'd have said the master cylinder seals had gone.

So would I. As mentioned below, pumping or bleeding the brakes can move the master cylinder outside the normal range of travel and damage the seals on a score or lip on the inside of the bore.

[tight fart]

Drove the van yesterday having blead the brakes and they are a lot better but,
White smoke filled the road for about a mile on my test drive.
My question
Could the servo have sucked oil into the manifold?

[TooMany2cvs]

tight fart said:

Drove the van yesterday having blead the brakes and they are a lot better but,
White smoke filled the road for about a mile on my test drive.
My question
Could the servo have sucked oil into the manifold?

Diesel will have a vac pump rather than use manifold vac.

But even then, it'd require both master AND servo to be shagged. More likely is that you spilt some on the exhaust.

[Fastdruid]

tight fart said:

Could it bu99er the abs pump by fitting new pads?

Short answer is yes.

It's advised to bleed the excess fluid out rather than to force it back via the ABS valves and master cylinder. Both due to the danger of damaging seals and also due to the risk of contamination.

[HughG]

If it still isn’t right have you checked the spring/clip is holding the pad into the disc, put them on wrong and they can pull the of away from the disc. Go on, ask me how I know...