Brake woe's.....any hints or tips please

**Harvey** · Thursday 17th January 2013, 22:52

Sounds like the master clyinder could leaking past a seal back to tank.
Try to get it pressure bleed first.

**V70 Graham** · Friday 18th January 2013, 04:29

Originally Posted by Harvey

Sounds like the master clyinder could leaking past a seal back to tank.
Try to get it pressure bleed first.

Will do, don't think there's a repair kit for my master cylinder.

**nobananas** · Friday 18th January 2013, 23:50

Had a similar problem once before. Checked all the brakes, replaced master cylinder and bled brakes god knows how many times but the fault remained. In the end I stripped all the brakes and removed the anti-squeal shims which cured it. Found out that some of the shims were acting like a weak spring and slowly pushing the caliper pistons into the calipers very slightly. First press of the pedal would go to the floor and then it would be fine unless the brakes weren't used for ten minutes or so (like on the motorway) then you'd get a long travel again, not saying it's causing you're problem but it certainly caused mine !

**JUDGENINJA** · Saturday 19th January 2013, 09:14

Rather than just bleeding, have you completely changed your fluid?
Flexi pipes would be a good idea if they are the originals from new.
Never heard of shims making a lot of difference.
When I change my pads I do spend a bit of time cleaning and polishing the pins and sliders to ensure the pads can move freely.
then the last thing could be Master cylinder/servo.. It's been a while since I looked under my 850 bonnet are there any Vacuum lines that could be perished with a small air leak?

**Saaamon** · Saturday 19th January 2013, 14:46

As above you need to completely flush the fluid out of every pipe which will require quite abit of fluid, also you need to start with the furthest away.

**V70 Graham** · Saturday 19th January 2013, 17:15

Right, braided hoses ordered, gonna try them along with a proper bleed/fluid change.

**V70 Graham** · Monday 11th March 2013, 11:26

*Update*

Right, I had the brakes bled and fitted new flexi hoses, result was a better pedal.....till today !
It's back to as it was, pedal travels a bit further down but not to the floor, if I release it and reapply pedal is great, lovely and firm.
The only other addition to my previous comments is that last time I drove the car, I was pushing along a bit and was using the brakes fairly hard (for me anyway).
Surely brakes don't need bleeding every 2 Months (I know they don't).
I'm now at a loss as to what to look at next, callipers (car doesn't pull under braking) or master cylinder, or could it be the servo ?

Any comments as always appreciated.

**M-R-P** · Monday 11th March 2013, 11:40

It's odd that a bleed cures it for a while. Maybe something's letting air into the system. There's definitely no fluid seeping from the master cylinder?

**V70 Graham** · Monday 11th March 2013, 11:56

Originally Posted by M-R-P

It's odd that a bleed cures it for a while. Maybe something's letting air into the system. There's definitely no fluid seeping from the master cylinder?

Nope, dry as a bone, each time seems to happen after I have been braking hard.

**Kingsford G** · Monday 11th March 2013, 12:48

So u have brakes on the 2nd pump of pedal.If u do 2nd pump and hold it does the pedal go down slowly?

**V70 Graham** · Monday 11th March 2013, 13:13

Originally Posted by Kingsford G

So u have brakes on the 2nd pump of pedal.If u do 2nd pump and hold it does the pedal go down slowly?

No, it stays firm.

**M-R-P** · Monday 11th March 2013, 13:15

Weird...

**stribo** · Monday 11th March 2013, 13:23

Originally Posted by M-R-P

Weird...

Enough about Graham, what about the car? Definitely sounds like air's getting in somewhere. Has the fluid level dropped at all?

**V70 Graham** · Monday 11th March 2013, 13:42

Originally Posted by stribo

Enough about Graham, what about the car? Definitely sounds like air's getting in somewhere. Has the fluid level dropped at all?

Not a bit, just wondering if Harvey was onto something with the seals in the master cylinder ?

**V70 Graham** · Monday 11th March 2013, 14:36

Just off the phone to a Volvo 'Guru' he recons it's 80% master cylinder 20% a sticking calliper.....

**nobananas** · Monday 11th March 2013, 16:21

Have you checked for brake fluid in the servo ? Easiest way is to pull the vac hose off and dip a cable tie into the bottom of the servo, any fluid and it's bye bye master cylinder. Another tip would be to clamp off each flexi pipe until the excessive travel stops though obviously this will only help if the fault is constant and you can't drive the vehicle like this.

**M-R-P** · Monday 11th March 2013, 16:23

I can see how a sticky caliper could cause that.

**oblark** · Monday 11th March 2013, 17:06

Originally Posted by V70 Graham

Just off the phone to a Volvo 'Guru' he recons it's 80% master cylinder 20% a sticking calliper.....

I`ve got a fully working master cylinder if you go down that route

**Kingsford G** · Monday 11th March 2013, 18:54

To change the master cylinder is an easy job.When was your brake fluid changed last?Do a quick master cylinder change,don`t have to bleed the whole system,just the 2 pipes that go to abs unit by undoing them on the pump will do the job.All gonna take 30-40 min max.