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Last year I R/R the rear brakes on wife's 2008 V70. Neat trick using a 9v battery to retract the electric P brake motors.
About 2000 miles ago I did the front, R/R rotors and pads. No problems. Checked the fluid level when finished and it was a touch over the max mark.
Today she calls that she has a low-fluid warning and "the pedal feels soft, maybe it's cause I'm wearing high heels."
I didn't open any brake line in either job, just pushed the caliper pistons back like I've done dozens of times when the caliper is in good shape. No sign of leakage, no torn boots.
Going to check it at her work today. Haven't noticed any fluid on the driveway but not inconceivable that a piston seal failed. Until I see it I'm just guessing.
Erwin
'88 745T 200,000+ miles
'95 855T (My favorite) 200,000+ miles
'01 945T 200,000+ miles
'07 C70 98,000 miles
'08 V70 3.2 (Superb highway muncher) 110,780 miles
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Can the "Neat trick using a 9v battery to retract the electric P brake motors" be basically explained.....before I Google it ?
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The parking brake is electric. There is a DC motor on each rear caliper. When the parking brake is applied, the motor runs a spiral slug (piston) into the pad and clamps the rotor. When released it only backs out a small amount to clear the pad, it does not retract completely.
When replacing rear pads the motors must be backed out to allow clearance for the new pads. Disconnect the wiring to the motor at the caliper, use clip leads and a 9V battery to run the motor backwards while pushing the slug or piston in with your hand. Polarity matters of course but I got it wrong initially with no ill effect.
Replace the pads, reconnect the motor and your done. First time you apply the parking brake the motors will run in and the working clearances reset.
You may know this but bleeding isn't necessary if the hydraulic system isn't opened. Loosen or remove the fluid reservoir cap, use the proper tool or a large screw clamp and push the piston back into the caliper slowly till it bottoms out. Displaced fluid will run back to the reservoir.
Install new pads, grease, etc, then work the pedal slowly to push the pistons out to engage the pads. Check fluid level. Done.
Erwin
'88 745T 200,000+ miles
'95 855T (My favorite) 200,000+ miles
'01 945T 200,000+ miles
'07 C70 98,000 miles
'08 V70 3.2 (Superb highway muncher) 110,780 miles
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Not much for us to go on either, except that she shouldn't be driving in heels :)
If the level looks good, check for corroded wiring.
Isn't time for a brake flush?
--
Keeping it running is better than buying new
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Klaus,
Checked the car at her workplace yesterday. The reservoir was below MIN and the pedal slowly sank to the floor. Checking behind the front wheels the lower control arm on the drivers side was soaked.
Towed it home on a dolly. Tomorrow I'll find out if it's a piston seal or brake line issue. Just glad it didn't happen on our 1,000+ mile trip to Kentucky a week ago.
Did a brake flush of the system when I replaced the rear pads last year.
Thanks,
Erwin
'88 745T 200,000+ miles
'95 855T (My favorite) 200,000+ miles
'01 945T 200,000+ miles
'07 C70 98,000 miles
'08 V70 3.2 (Superb highway muncher) 110,780 miles
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Wow, thank goodness for fluid level indicators and a good understanding of what brake pedal should feel like.
I'd be interested in your diagnosis of what failed and why. Brake lines don't often fail and neither do piston seals.
But the real pressing question is which of your fleet did you use to dolly the V70 home???
Stay cool this weekend!
-Will
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It was the rubber brake hose, just above the grommet that clips to the strut. A small split.
Which of my fleet? LOL. The 07 F150 FX2, 5.4L with 10,000 lb towing package and a UHaul towing dolly. I should put a Volvo emblem on the truck.
Erwin
'88 745T 200,000+ miles
'95 855T (My favorite) 200,000+ miles
'01 945T 200,000+ miles
'07 C70 98,000 miles
'08 V70 3.2 (Superb highway muncher) 110,780 miles
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Kudos to your wife for not driving the car!!
I suspect the line. If so, replace both before bleeding the system.
--
Keeping it running is better than buying new
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Klaus,
Both sides were replaced, system bled and a firm pedal restored.
Now there's a battery indicator. Time for a battery.
Thanks,
Erwin
'88 745T 200,000+ miles
'95 855T (My favorite) 200,000+ miles
'01 945T 200,000+ miles
'07 C70 98,000 miles
'08 V70 3.2 (Superb highway muncher) 110,780 miles
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