2001 Volvo S80 T6 Spongy Brakes

VolvoS80Joe · Post by **VolvoS80Joe** » 30 Dec 2011, 15:11

My brakes are spongy but they stop... eventually. Firm when pumped up with engine off. Soft when engine is started.
I have replaced the following:

(1) Flushed and bled system with power bleeder - no change.
(2) New front rotors, pads, hoses - no change.
(3) New Master Cylinder and power bleed - no change.
(4) low mileage Booster and Master Cyliner and Power Bleed - no change.
(5) No leaks observed anywhere. Fluid level remains constant.

ABS works. DTSC On or Off. No defect indication on dash. Don't have reader for anything other than engine or transmission. No codes from Acton Scanner.

The only thing left is the ABS Motor and Controller?

Maybe the used Booster (2004 43K miles) is also defective?

System has been bled on 3 seperate occasions.

It is the right one for a DTSC System.

Any ideas?

Thanks,

-Volvo S80 Joe

shailey · Post by **shailey** » 10 Jan 2012, 09:38

Could be one ore more of the brake hoses.

Post by **fazool** » 10 Jan 2012, 09:44

If it was a brake hose/line it would lose fluid. You could have a pin-hole leak and get air into the lines.

But the fact that its firm when off and spongy when on suggests a boost problem.

I think you have a vacuum leak or a weak boost unit.

VolvoS80Joe · Post by **VolvoS80Joe** » 11 Jan 2012, 05:01

Thanks for the comments.

I forgot to list the Front Hoses are new.

I have a new (used) ABS Controller with the aluminum distribution block and plan to swap it out this weekend.

Will the ABS controller work or must I use my original one? If so, should I send it out for repair?

I do not have any light on the dash board.

BerniniCaCO3 · Post by **BerniniCaCO3** » 13 Jan 2012, 18:35

Hah! I am remembering when I was even more of a noob than I still am today, and had a spongy pedal after doing brakes and a brake flush. We even replaced the master cylinder in desperation, before it turned out, I'd put the little damping springs on the outside of the calipers on the wrong way!
They were prying the floating caliper body away from the rotor, rather than holding it against it, giving the caliper piston significant extra travel distance before it hit the rotor, and it manifested as a pedal that sunk awfully low before you got real braking power.
I was so humiliated!

So... not to condescend, but not to overlook something so simple either. Is it possible that when you put the retainer springs back on, you didn't do it the same way it came off?