Poor Feeling Brakes

[stevekoz]

Got some Braking issues on the P1 V70 R.

When i first bought her i was aware of a warped front disc - brakes would feel like they were surging, they were spongy, and feel like they'd grip then not etc and i'd get a severe wobble at braking at speed (70mph).

So i got a set of front discs and pads and had them fitted and all seemed ok. However, i was still aware of a need to apply what i would consider to be heavier pressure on the brake pedal in order to stop. It seems to travel further than i have had on other cars in the past, didn't feel as sharp as i would like.

Anyway, the garage advised, on fitting the brakes that my o/s front brake hose was split and the front abs sensor was melted (previously heated during suspension work prior to my ownership by looks of it).

So set about buying a set of goodridge braided hoses and a new abs sensor and i have since had the system bled, lines fitted and new sensor.

Brake pedal still feels no better. It feels incredibly spongy. There seems to be a need to apply quite a lot of pressure. It is slowing down and stopping, but they don't feel "right". They some times appear to lock up if i apply too much pressure as the abs pops and i can feel a grinding at the very end of the pedal travel but only sometimes and if i have to apply lots of braking from higher speed and on those occasions the abs/tracs light has come on only to go off again.

So to clarify the symptoms. Spongy brake feel. Poor pedal travel (too much travel IMO). ABS sometimes seems to kick in towards end of pedal travel. ABS/TRACS light intermittently on. Brakes don't feel sharp in general. Work to date, its had new front discs and pads, new lines, new fluid, new abs sensor and a bleed. But they still don't feel very sharp, i want to feel like if i put my brakes on the car will stop when i want it too, at the moment i feel like the weight of the car is overcoming the braking.

I am not sure what it could be. Would the rear brakes have any effect to this scenario? I am a bit lost now. Any ideas would be greatly received.

Cheers

[RollingThunder]

My initial thought is that there is air in the system still, either that or you've got old brake fluid in there?

I'm about to have my discs, pads, brake lines and brake fluid changed because I have a similar issue - warped rear disc/s and spongy brake pedal. My 850R (with retro fitted 302s) had superb brakes, and the V70R has the identical setup so it should be very firm and progressive after that...

[graemewelch]

as above. flush the full system to get any boiled fluid out

[stevekoz]

So could still be air or bad fluid in the system.

i had to admit, id have imagined the braking to be a lot sharper than it is for such a car.

Well, i'll flush the system/re-bleed and put in new fluid.

Does anyone have any recommendations for the flush process to get the best results, likewise any particular type of brake fluid best or just get bog standard stuff from likes of gsf/euro etc.

Cheers

[partsforvolvos.com]

re bleed system first using a vacuum bleeder rather than just old fashioned pedal pump bleed.
can be diffiuclt to get all air out after changing hoses without one of these.

[M-R-P]

So could still be air or bad fluid in the system.

i had to admit, id have imagined the braking to be a lot sharper than it is for such a car.

Well, i'll flush the system/re-bleed and put in new fluid.

Does anyone have any recommendations for the flush process to get the best results, likewise any particular type of brake fluid best or just get bog standard stuff from likes of gsf/euro etc.

Cheers
Start from the rear passenger side then rear driver side, front passenger and finally front driver side. Don't forget to do the clutch (don't use a vacuum bleeder for that tho)
Volvo spec dot 4.1 but dot 5.1 won't hurt and probably last longer.

[stevekoz]

cheers all, thats the job for the weekend as well as paint correction and full detail. Hope the weather holds out! Will let you all know how it goes.

[merc85]

Start from the rear passenger side then rear driver side, front passenger and finally front driver side. Don't forget to do the clutch (don't use a vacuum bleeder for that tho)
Volvo spec dot 4.1 but dot 5.1 won't hurt and probably last longer.

Just to note, dot 5.1 you have to change sooner as it just has a higher temp threshold :)

[RollingThunder]

I use ATE Super Racing Blue on alternate fluid changes - you know you've got the last of the old fluid out by going clear > blue one time, then blue > clear the next

http://www.eurocarparts.com/ecp/p/car-accessories/engine-oils-and-car-fluids/auxiliary-fluids/brake-fluid/?130339010&0&cc5_179

[xllifts850]

Hi, I have the same problem as listed above, I am going to completely change and bleed my system through in the hope that it solves the issue .

Would I be looking at maybe a cracked bulkhead allowing master cylinder to flex excessively ?? Or even the cylinder itself?

Any help much gratefully received, thanks Dave.

[xllifts850]

Just a quick update, completely emptied the brake system today and re bled with new fluid, totally different car brakes are now top of pedal and solid feel.

Interestingly enough the rear offside bleed nipple was blocked solid, once cleared we got a good couple of seconds worth of air from system before fluid was visible at nipple. Possibly the reason car was put up for sale as now it is a completely different car to stop. The excessive movement in the master cylinder has also gone so happy days :)