Brake bleed

[benx]

Hi all,

I have a 2003 V70 D5.

I've just got the car through this years MOT. It initially failed and as a result I had to replace the front discs/pads/hoses.

The brake system has been partially drained so I may have introduced some air into the ABS unit/master. I did a full pressure bleed. The new brakes feel great (even without bedding in) but I'm fairly sure there's still a bit of air in there somewhere.

My question is - is there a Volvo recommended (or maximum) pressure for bleeding? and is there a VIDA procedure (or other method) for bleeding/replacing the fluid in the ABS? - or do I just need to go out and do a few emergency stops

Thanks

[Dippydog]

What makes you believe there's still air in the system?For pressure bleeding 10psi seems to ring a bell-but I could be wrong on that.I know on Vauxhalls with the TechII system it can be hooked up to operate the valves in the ABS block to get any trapped air out of it so would imagine on Volvos the Vida/Dice can do the same thing?

[oragex]

These videos show how to 'home bleed' the master cylinder and the ABS unit. If you are lucky you will undo the line nuts without removing all the stuff above. But don't force on the nuts if it feels like the wrench starts to slip because the nuts are not made of steel, rather of a soft alloy

https://www.youtube.com/watch?v=FcwYnG6Fg9I
https://www.youtube.com/watch?time_c...&v=mGU-glkL2B0

.

[benx]

Thanks for that oragex. v.informative, will look into it.

Dippydog, the reason I think there is a bit of air in there is that the pedal seems slightly longer. It might just be the pads are spanking new/not bedded in so the pedal needs a bigger push. But with engine off (and after pressing pedal a few times to get rid of any vacuum) pedal is not quite as hard as it probably should be.

I did the bleed at 15 psi. What I find strange is that nowhere does it recommend what psi you should actually pressure bleed at.

My bleeder unit simply says something like "follow manufacturers instructions". The Haynes manual is completely useless - it recommends that you pressure bleed but doesn't offer any figure at all. I also took a look at VIDA which was also vague - it states "the unit must be capable of up to xxx psi" but did not say what psi you should actually use. Cant remember the exact VIDA figure but I can remember it sounded that high that I thought I was misinterpreting it.

[Dippydog]

As you say it could be the new pads etc that have not yet bedded in and not feeling as sharp as before that's leading to a harder push on the pedal.If you sit with your foot on the pedal does it sink slowly towards the floor?Or if you use the brakes while driving do you need to pump the pedal to get any feel?
FYI I have asked at a couple of garages what pressure they use to pressure bleed the brakes and they've told me that in general they use 15psi you can go higher[up to 2bar]but the higher you go the more danger there is that you'll blow the seals somewhere in the system.HTH.

[ITSv40]

I have a Sealy pressure bleeder. They recommend no more than 20psi. I generally use about 15psi maximum and find it does the job well.