Long pedal travel

[curious]

OK, so I give up.

I've bled the brakes and, I've bled the brakes again. I've pushed litres through the system trying to get to the bottom of this. No air bubbles whatsoever yet the brake pedal on my Vito (W639) feels as if it's almost at the floor before it starts to bite.

I've cleaned up the calipers to the extent the MOT guy commented that they were all very well balanced left to right for a 12 year old Vito (only 100,000 miles).

The long pedal travel started after I replaced the pads one time. I probably shoved the brake pedal too far whilst bleeding and possibly caused problems with the master cylinder. I replaced the master cyclnder and bled with lots of little strokes with a helper. I've also tried bleeding with a Gunson pressure system. I've bled it with the engine running and without.

No air comes out whatsover, yet the pedal travel is longer than it used to be and too long for comfort.

I'm hoping someone can help me with this?

Thanks

 

[Oldspanners]

All I can suggest is that you may have got the wrong master cylinder with a different bore and this is what's causing the long travel.
Or have a look at this faulty ABS

 

[bembo449]

Ive heard of this before on merc vans , cant remember fir the life of me what causes it thow

 

[Botus]

six usual things on most vehicles (no experience on Merc vans or exceptions they might have)

1) the master cyl had corrosion and conventional bleeding of the brakes has ripped the seal travelling in to the rusty area. But you say you swapped it out
2) the system is badly designed and an air pocket is loitering somewhere. reverse bleeding / moving a given component temporarily / knowledge / experience of this stupidity helps
3) heavy wear on the disc means the new pads are not bedded in and the long travel is basically forcing the pad against the disc, will settle with time and miles
4) sliding calipers are just a bit nasty with more slop leading to longer travel, should settle a bit as it all beds in
5) you have rear drums and adjustment is not right so the shoes have to travel a long way
6) handbrake via stupid combined brake caliper (where you screw back in the piston to fit new pads), and it needs to adjust up the slop with repeated use (or manual tweak once the disc and pads have settled a bit)

 

[D5meister]

If when pedal gets to the bite it is not spongy then not an air issue. Can you read part nos from original and new master cylinder?


I got in a mess once by bleeding the fronts then the rears.
My dad said do the long runs first then short and normal service resumed.