Dam rear brakes!!

[Quicksilver]

I've read all the posts on the subject and tried them all but I still have juddering from the rear brakes!!

I know their glazing up as I can see from the appearance of the disc, they look gray not a shinney grooved finish as I see on every V70 I look at.
The pistons are free, backs of pads and fitting kit all copperslipped, I can strip it all down, de-glaze the discs re-assemble, two weeks back to square one!!

My feeling is I'm not getting sufficant braking power to the rear brakes to stop them glazing over, when I press the brake pedel it always feels like theres air in the system sometimes I will double press to get a better feel.
I've bleed the brakes many times and no differance, so I'm thinking master cylinder? or is there a brake bias thingy somewhere?

Please help me! it's doing my head in! much as I love the way she goes sooner or later you have to stop and it's horrible!

[PHIL V70R]

just about 2 start the same job...replaceing discs pads shoes..same sort of thing as you but we think mine is a bad disc on the rear..will keep you posted on what we find.....

[T5frankie]

im having the same issue

[bubba_1986]

Have you tried bleeding the abs unit, ie: crack the nuts off a bit an tighten. How many times have you bled all the brakes ?

[Quicksilver]

Have you tried bleeding the abs unit, ie: crack the nuts off a bit an tighten. How many times have you bled all the brakes ?

Three, with a pressure bleeder.

[bubba_1986]

Try the abs pump. If not then me and wobblydave have a master cylinder for sale.

[bubba_1986]

Have you changed the standard rubber hoses or upgraded them. As thesse perish over time and can lead to a spongy pedal. I would invest in braided lines if u havent. Well worth it. You'll be about 50 odd quid for the 4. ATE blue racing brake fluid is also good. What I used when just done all my brakes after can was off the road. With it being blue helps you to see when old fluid is flushed out.

[Rogerb]

Hi,
Years ago when I had a 850r as a exdemo from Volvo, I had this problem.
They fitted FIVE master cylinders ,flexey hoses all round new callapers,
Even a set of 330mm front discs at £600 instead of £1800,
Turned out to be the ABS pump unit.
Thankfuly all under warrnty apart from £600 for the big front brakes-boy they were good
compaired to the standard ones.
Regards Rogerb

[bubba_1986]

Hi,
Years ago when I had a 850r as a exdemo from Volvo, I had this problem.
They fitted FIVE master cylinders ,flexey hoses all round new callapers,
Even a set of 330mm front discs at £600 instead of £1800,
Turned out to be the ABS pump unit.
Thankfuly all under warrnty apart from £600 for the big front brakes-boy they were good
compaired to the standard ones.
Regards Rogerb

There ya go, try bleeding the pump like i suggested. If not then change it

[Quicksilver]

Thanks guys, next job on the list then!!
I've decided to give the old gal a bit of TLC, she's just had two wishbones, new rear section of exhuast, just need to find a second hand cat to replace my rattling one and we'll be good to go!!

Many thanks again
Steve

[T5frankie]

let me know how this goes as mine is the same on the rear nearside

[Quicksilver]

So how have people bleed the ABS pump? Under pressure the same as doing the rest of the brakes?

[bubba_1986]

I would just crack the nuts at each exit pipe after pumping pedal 3 times and holding down.

Won't do you any harm to try it

[Quicksilver]

Thanks Bubba it worked!!!
Now have a consistent peddle, maybe still not as solid as I would like but way better than it was and the same every time I hit the brakes!

The bonus is my rear brake judder is greatly reduced, my thinking is the air in the ABS unit was in the rear brake circuit and has been reducing the efficiatncy of the rear brakes and coursing the discs to glaze up and judder, we'll see.

Anyway many thanks again to Bubba for pointing me in the right direction this is why I love this forum!!

[Quicksilver]

Just done a 500 mile round trip on motorway and across country and although the brakes are better their still not consistant.

So I'm thinking there is still a problem in the abs pump, I have no error lights so I'm assuming the ecu is fine so my question is do I need to match the part number on my pump with the replacement or are all the 5 pipe pumps the same but with differant ecu's?

[bubba_1986]

Glad I could help mate.