Bleeding abs w/o expensive tools

[Talon1]

I have seen a lot of references to go to the dealer to have your abs bled, solenoids purged/cycled or whatever. NOT NECESSARY! It's easy to do. Here is my story.

I have a 2001 Explorer Sport. #My teenage sons wore the front brake pads down to the metal. #Drivers side pad actually came off and the metal backing got bunched up between the shield and rotor. #Pretty cool stuff. #He called me and told me there was smoke coming from the drivers front wheel. #Awesome! The piston rubber bladder completely blew out and brake fluid was running out. I limped it home using the parking brake only. I ran a red light because I couldn't stop in time. It was fun. No one got hurt.

Anyway, pads weren't my problem. #I replaced, both sides, pads, rotors and calipers. #Hmm, looks like a race car under the wheel wells. #Put it all back together, bled all four wheels and pedal goes all the way to the floor and there is only very little braking at the end of the pedal. #Sounds like a master cylinder, right? #The bleeding was doing nothing, by the way, so I did it again.

Replaced master cylinder, bench bled (I did the best I could, but realized I would have to be extra good on the wheel bleeding after the leakage during installation). #Still no brake action. #Exactly the same thing, no braking until the end, towards the floor after bleeding all wheels twice, again.

Was I supposed to pre bleed the calipers, somehow? #I did bleed the master cylinder after installation, twice. #I was having some problems bleeding the fronts, as they didn't seem to be flowing as well as the back. #In fact the passenger side wasn't flowing at all.

You can bleed the abs without the expensesive solenoid cycling machine. #It's pretty easy. #Focus on the calipers. #Remove them from the rotors and pump your brakes until the pistons come out. #I put some spacers in the caliper to prevent the piston from coming completely out. #Then remove the bleeder valve and the brake line. #Don't drain the caliper. #I stuck cotton balls in the brake line to reduce drainage. #MAKE SURE YOUR RESEVOIR IS FULL BEFORE DOING THIS! #Hold the caliper flat, so no fluid spills and proceed to pour more fluid into either the brake line hole or the bleeder hole, all the way to the top. #Might want to shake it a little to be sure as much fluid gets in there as possible. #Then reinstall the line and valve and take a c clamp and press the pistons down all the way. #I did this three times each side and fixed air in the abs system. #It is basically a reverse bleeding method and works great. I am sure I am not the only person who has done this, but I couldn't find it anywhere. A family friend and mechanic for us for the past 25 years suggested it to me. Thanks Mike at the Z Center in Houston!

 

[untrucker]

Sounds reasonable to me. Did you check for bubbles etc in the master as you compressed the piston in the caliper? Or just repeat until the fluid in the master starts to rise? This coiuld could be done with a pressure bleeder I think, even a cobbled together homemade one. Thanks for the idea!

 

[bb56]

Interesting approach. If normal bleeding was done, I would expect all the calipers to be full of fluid with no air. Only the ABS unit itself would have the air. So would it make sense to simply push brake fluid in from the bleeding nipple until air bubbled into the M/C? You'd have to do both fronts and one back wheel to get all three solenoids in the ABS HCU.
I'm going to be changing the M/C in my 96 Ex and have concerns about the ABS bleeding part. I'm hoping to get away without needing to as long as I don't cycle the abs unit or turn key power on.
I was thinking of wiring up a little harness for the ABS unit where I can turn on the pump, then activate the solenoids one at a time by grounding their input wire. That's what the special tool does. But I like your method and may try it first if I get into trouble. I think just pressing the piston back into the caliper at each wheel may provide enough fluid to push air out of the ABS back up to the M/C - it's only a 12" brake line. Either that, or I just have to figure out how to make a pressurized container connected to the bleeder port.
hmmm... Anyone have any ideas on that?

 

[crunchie_frog]

I see this is old thread and I have never had air in the abs but why not pull vacuum downstream of the master cylinder and upstream of the abs module while each of the brake lines are disconnected from the calipers with them submersed in brake fluid until there is no more air coming out of the abs?

 

[SoNic67]

Drive on grass or sand. Apply hard brakes until ABS kicks in. Repeat.
That will eventually eliminate the air.

 

[intelisevil]

Drive on grass or sand. Apply hard brakes until ABS kicks in. Repeat.
That will eventually eliminate the air.

And the Greenskeeper on your local golf course will love you forever . . .

 

[SoNic67]

Did I say golf course? There are plenty of other grassy areas. Or sandy.

 

[1998Exp]

Assuming that you can reach that grassy or sandy area without killing yourself (or others) driving with inoperative brakes....

Drive on grass or sand. Apply hard brakes until ABS kicks in. Repeat.
That will eventually eliminate the air.

 

[intelisevil]

Did I say golf course? There are plenty of other grassy areas. Or sandy.

Sorry, that was me trying to be funny . . .

 

[bb56]

Sonic's suggestion makes a lot of sense. After a bit of research, I found that the ABS test sequence using the special tool is actually cycling the abs unit while pressure is applied to the brake pedal. This is done several times for each solenoid. Of course, it does not take into account some of the posters' problems of having no brakes at all.

The ABS unit is really a straight through passage of brake fluid under pedal pressure and unless the M/C was fully bled, no air should get into the closed off sections of the ABS unit. The Isolation solenoid has to kick in to open passages from the brake line in each wheel to the ABS innards.
If an air pocket is big enough, the first time someone drives after doing brake work, the ABS may have kicked in and trapped air.

So those with no brakes at all can't safely use Sonic's suggestion. In that case, I would try the reverse flow that the original poster suggested. then if brakes are working well enough they can try Sonic's suggestion to firm them up.

A while back, one of my ABS wheel sensors needed adjustment because the ABS would go off with every brake application. It's possible to back off the sensor 1 turn or so so that the ABS kicks in all the time to get the same effect as the test tool (or driving in sand). So this may be a viable way to flush each ABS solenoid chamber when the brakes work but are still soft. The main priority during any of these attempts is safety of course.