Activating ABS during brake bleed Topic is solved

CedBobKing · Post by **CedBobKing** » 30 Jul 2017, 08:04

I recently installed stainless wrapped Teflon brake lines, new rotors and brake pads on my V70. With the help of my 9-year-old daughter we bled the brakes, but they were still quite mushy but able to stop the car. So I broke down and bought a Motive Products pressure bleeder, which is an awesome little tool. Now the brakes are a little mushy, but certainly drivable.

I have read that bubbles can form in the ABS pump which can result in a soft pedal. The suggestion is to use my VIDA/DICE to activate the ABS while bleeding. Since I haven't forked over the money for one yet, my question is as follows....

Is there a known way to activate the ABS pump while bleeding the brakes without VIDA/DICE?

Thanks,

Cedric
2006 V70 2.5T

Post by **oragex** » 30 Jul 2017, 11:38

The pressure bleeder will indeed not be efficient with air trapped inside the ABS valve unit.

Some say take the car on wet/icy surface and brake to activate the ABS on all wheels. Not sure if really efficient.

Post by **precopster** » 30 Jul 2017, 15:31

I had a hell of a time with a spongy/low pedal on my 2001 XC70 just before sale. So much so that the mechanic wouldn't give it a safety inspection.

I had a replacement master cylinder fitted to try to locate the issue and I replaced the booster with a brand new one as my indie had tried 2 used boosters with small leaks. Also replaced the ABS pump and bled that from all the lines.

I had bled the system at the master cylinder and all 4 wheels extensively multiple times. The fluid was all new. I used Vida to activate the ABS while opening the bleeding valves and had no luck with that either.

I was desperate so I purchased a hand operated vacuum pump for $25. I bled it only twice and while sucking fluid from the front wheel (can't recall which side) I pulled some nasty old brown fluid with very fine bubbles in it just like flat Coca Cola. I feel it must have been lodged somewhere in the ABS distribution block. Immediately the pedal firmed up and it passed inspection.

Post by **oragex** » 30 Jul 2017, 16:48

Precopster, before using the vacuum pump were the brakes powerful enough (even being spongy) ? Were the rotors wearing as they should across the surface? I have my brakes lacking power and uneven rotor wear, trying to find the issue.

Post by **precopster** » 30 Jul 2017, 18:01

Oragex I didn't apply them for an emergency stop however upon normal low speed (under 60kph) braking they felt fine. The problem with the low pedal actually surfaced after it had been sitting for about 3 years. The pedal however was sometimes high and sometimes low. Also pads seemed to be evenly worn when I replaced them in the workshop however I don't believe the car had the problem until it sat for a long period.

Because the car was a long term project the first time I drove it properly was after it had passed all the safety inspections so it could get registration plates. Then it was sold.

Post by **jimmy57** » 30 Jul 2017, 21:23

The fact that rotors/pads were changed also brings in the caliper outboard anti-rattle spring being installed wrong. That tips caliper and makes pistons retract much more. It results in low pedal/mushy pedal.
A picture through holes in wheels would help here.

CedBobKing · Post by **CedBobKing** » 31 Jul 2017, 04:08

When I bought the car at 114K miles, the brakes were adequate. Rear rotors were pretty badly scored. However the car stopped okay. Decided to ignore it until the rear pads wore out, because the car had more important issues. Then did the lines, rotors and pads. The car will stop quite nicely now. However I still have the soft pedal.

I tried cycling the ABS on pavement before posting. However yesterday evening I found gravel roads and made sure the pump cycled. Soft pedal remains.

I will check on proper clip installation and post a photo later on today.

Post by **oragex** » 31 Jul 2017, 11:19

I ordered the vacuum bleeder, I'm curious to see if it makes a difference after using the pressure bleeder.

It's really inexpensive - at least this chinese model http://www.ebay.com/itm/263061559099 .

CedBobKing, as above the first thing to inspect for soft pedal upon a pad change, is the spring goes correctly

: CALIPER.jpg (125.1 KiB) Viewed 12459 times

Post by **vtl** » 31 Jul 2017, 12:59

Air/aerated fluid can be trapped in caliper too. Use C-clamp against inner pad to move piston into innermost position and push old fluid out.

Other things to check is how well caliper brackets are cleaned/lubricated, and if the piston is rusty and sticky.

CedBobKing · Post by **CedBobKing** » 01 Aug 2017, 11:42

So... about those springs.

Before

: IMG_4093.JPG (1.88 MiB) Viewed 12404 times

After

: IMG_4095.JPG (2.19 MiB) Viewed 12404 times

Pedal now feels okay to me. Now I'm just sad that I scratched some of my pretty blue paint.

Thanks so much for the assistance.