ABS brake bleeding

[entirelyturbo]

This probably isn't good practice, but when I change brake fluid, I usually just take off the lines to the calipers and let the whole system gravity-drain. It takes a bit of work to bleed the system after that, but it works for me.

However, I've only done this on cars with no ABS. I really, really, REALLY need to change the brake fluid on the wagon, and it has ABS.

Will I have any problems bleeding the system, simply because it has ABS, if I gravity-drain it?

[gt2.5turbo]

i believe the bleeding order for our cars is passenger front, passenger rear, driver front, driver rear if that helps

[entirelyturbo]

Thanks gt, but I know the bleeding order already.

What I mean is, is there a possibility that an air pocket could end up in the ABS system and necessitate more bleeding directly at the ABS pump or something like that...

[Legacy777]

After an incident with stubborn air....I wouldn't recommend doing the gravity thing you do. Plus it introduces moisture into the system.

[206er]

I think it might have been vikashs idea but
take a big pickle jar or the like
get 4 long lengths of 1/4" clear tubing at the hardware store
1 long length of a hose suitable for a vacuum port on your intake mani
put the vacuum hose on the jar lid so as to depressurize the jar
put all 4 hoses into the jar, sealed up
loosen the bleeders, put on the vacuum, and keep filling the reservoir as all the bleeding happens at once.

you can also do it with just one hose and do each corner seperately.

[entirelyturbo]

I might just bleed the brakes enough where I have to refill the reservoir. That should at least make the Brake light on the dash shut off.

[Legacy777]

My only issue even with vacuum pumps is the pressure. By utilizing the brake system/pedal to pressurize the system, you create a very large amount of pressure. This pressure is what helps force any air pockets to the calipers.

If you turn the car on, so the brakes are vacuum assisted, the pressure increases exponentially.

[vrg3]

I don't know how solid this advice is, but I would bleed the system, go out and do some ABS stops, and then bleed it again. That's what I have done each time. I've only dealt with Nippon ABS units, though, which have bleeders on them.

I also think you shouldn't gravity bleed. The idea of leaving the fluid exposed to the air so long just doesn't sit right with me.

Josh, you're right that my DIY vacuum bleeder doesn't create as much of a pressure differential as using the master cylinder to pressurize the system, but you don't actually need that much pressure. I filled a completely dry system (I replaced the calipers, ABS unit, master cylinder, and prop valve) using only vacuum bleeding.

[Brian Mau]

This probably isn't good practice, but when I change brake fluid, I usually just take off the lines to the calipers and let the whole system gravity-drain. It takes a bit of work to bleed the system after that, but it works for me.

However, I've only done this on cars with no ABS. I really, really, REALLY need to change the brake fluid on the wagon, and it has ABS.

Will I have any problems bleeding the system, simply because it has ABS, if I gravity-drain it?

The general rule of thumb for brake bleeding: further nipple goes 1st, closest one go last. ABS pumps would go very last after all wheels has been bled.....
I've done mine without ABS in order: RL, RR, FL, FR. (Yes it's a RHD) and on my mate's 300ZX I did the same except after all 4 wheels I also do the ABS pump. They all work very well and both were bleed from dry (I replaced my struts, he replaced all brake hoses). It's fine even engine's off as the aim is to displace the old fluid out and new fluid in. A transparent bleeder hose with one way valve works best as you can see if there're bubbles/old fluid from the nipple. As long as there're no bubbles and fluid is clean then lock the nipple and off you go. Keep engine running will not help you bleed better/faster - it just reduces the effort. Unless you nomally ride on a wheelchair otherwise it's totally unneccessary......

[vrg3]

That is the usual advice, Brian, but that is not what Subaru recommends for our cars. For example, for North American models with Nippon ABS, the recommended bleeding order is:

- Bleeder between left front and right rear fittings on ABS hydraulic unit
- Bleeder on right front caliper
- Bleeder on left rear caliper
- Bleeder between right front and left rear fittings on ABS hydraulic unit
- Bleeder on left front caliper
- Bleeder on right rear caliper

[Legacy777]

Josh, you're right that my DIY vacuum bleeder doesn't create as much of a pressure differential as using the master cylinder to pressurize the system, but you don't actually need that much pressure. I filled a completely dry system (I replaced the calipers, ABS unit, master cylinder, and prop valve) using only vacuum bleeding.

You may be right.....I'm just speaking from experience after having my system drip brake fluid for several days and it being a complete pain in the ass to completely bleed the system again.

I have since bled the system from almost dry several times after that incident without any issues, however I typically utilize the same/similar procedure that worked the first time.

[vrg3]

I don't understand -- what do you mean about the system dripping fluid for days?

[Legacy777]

The car sat on jack stands with the brake lines dangling and dripping brake fluid into pans.

[vrg3]

Oh. I thought you meant vacuum bleeding created that situation. But you're saying it didn't work for you after that situation?

When I did mine, I began the whole job (before removing a single bolt) by sucking all the fluid out the bleeders using vacuum. The system was dry and so disassembly was easier to do without making a mess. Then I put everything together and did two rounds of vacuum bleeding and everything was dandy.

[Legacy777]

Yeah.....I don't know....maybe it was a fluke.

I just know what I do works