Volvo Repair Questions? Ask a Mechanic for Answers ASAP
Front or rear?
caliper to caliper bracket - 30 Nm
caliper bracket to spindle - 100 Nm
rotor locating pin - 8 Nm
axle shaft nut -
lug nuts - 140 Nm
sorry, was offline yesterday for family events. if you still have this problem let me now I can continue to help out
yes thanks. A little more checking:
-With car off, press brakes, pedal low. Pump it twice and it firms up.
-With car running, stopped, pedal low. Half inch from floor.
-While driving, brakes work OK.
Bled the brakes twice.
did you disconnect the brake hoses from the calipers during the brake job?
did you open the bleeders when you compressed the caliper piston?
No to both questions.
Ok, there is a slight possibility that the fluid being forced back up into the master cylinder damaged one of the internal O-rings. Doesnt happen often, but I have seen this occur on enough occasions to be a concern.
Other possibilities is a twisted brake hose, caliper slightly cocked at an angle when bolted back up, pad sitting at an angle in the caliper, or rotor not flush to the hub, which any of these will cause your problem.
To save time in diagnosing, as well as being a highly accurate way to test, we need to do a brake line clamp test. You will need either 4 brake line clamps, or 4 vise grips for this. If you use vise grips, wrap some old cloth over the ends of them to protect rubber brake hoses.
On all 4 wheels, place a clamp or vise grip about midway up on the flexible brake hose, clamping it gently. Now, test your brake pedal. It should be nice and firm. If the pedal still sinks, then the master cylinder has an internal bypass of one of its o-rings and will need to be replaced. If pedal is good, proceed to remove one clamp at a time, starting at rear brakes, and test pedal after a clamp is removed. At which ever wheel the clamp is removed and the pedal sinks, that is the wheel with the problem. You will need to inspect the hose for kinks or twists, then check rotor placement and pads for being cocked. If all are ok, then the caliper piston is cocked at an angle and will need to be replaced
OK thanks. This will take some time for me to do, so it might be a few days before I follow up.
In the mean time, I read somewhere that the spring clips on these are touchy and if not perfectly seated will cause the pad not to stay flush on the rotor, which in turn will cause this phenomenon. I'll double check those as well.
Ok, if you run into any issues on the diagnosing or repairing it, let me know and I will be here to help out.