How to bleed ABS brakes

[smokeandfire451]

I recently redid all the brakes on my '98. Bled them a bunch of times, but still get a bit of a soft pedal and I get into the abs motor. Is there a separate procedure for the abs? My haynes manual is missing some pages and I think that might be one of the pages missing! THanks!

[jimbosxj]

First what exactly did u do to the brakes? If say you did all the brake lines or other fluid work you may have gotten the abs pump to bleed down and it has air trapped in it. Other question is how did you bleed the system, manually bleeding may or may not work using a prussure bleeder is your best way to perform this job and with a bleeder bottle so no air and no splliage on the ground. If the abs pump is coming on I have has speed sensers pull out just far enough that the air gap for the senser will read the pulse signal but will cause the pump to come on with no codes for the fault Cheers

[smokeandfire451]

New pads and shoes, checked calipers up front, 2 cylinders and hardware out back. Do you have to specifically have to bleed the abs pump?

[jimbosxj]

It all depends on and if all the brake fluid came out most of the time no you don.t need to bleed the abs pump. But prussure bleeding usually resolves the soft pedal issue with the pump and if you have ever replaced a clutch slave cylinder it works great for both. Another thought I just had did you seat the rear shoes and readjust them that also can cause a soft pedal

[N8N]

Also check the adjustment on your rear drums. I swore I had the same issue - somehow I got air into the HCU while replacing my front brakes, even though I didn't replace the calipers or disconnect the hoses - and when I took it to a shop to have them rebleed for me with a scan tool the guy told me that my rears were "way out of adjustment" and that that was most of my problem. D'oh!

So I guess sometime after it warms up I will have to tear into the rear brakes to make sure that the self adjusters are working correctly and repair/replace as necessary

[smokeandfire451]

Well, the problems I had were these, Found a leaky cylinder, replaced that, noticed that the fluid looked pretty bad, so I flushed that. My "assistant" might have let the resevior run dry while texting...put in new shoes, adjusted and all that. Life was good! On the way to get my inspection, heard a POP and a grinding noise. Back in the garage found the retainer pin had broken on the driver side. Didn't look bad when I had it all apart, but anyway, brake stuff was everywhere. That plate that goes between the shoes under the cylinder got cocked funny and pulled the boots off the other cylinder. so i replaced that and all the springs and pins. didn't get a adjuster in that kit. Guess what broke, or at least came out in 3 pieces next time I checked the brakes...new pair of those. which brings me to where i am now. the pedal isnt "bad" but if i stay on it for any time at all, i can hear and feell the ABS kick in. Stops fine though.

[jimbosxj]

OK Long week Did u or did u not prussure bleed the brake's. It will have an affect on the pedal and that sinking feeling. Dealing with the ABS system the system should not activate if there are no wheel's turning. Also the system will do a system test depented on what year the Jeep is. Also Ck. the senser at each wheel that they are not dirty with brake dust/metal from the rotors or just from wheeling. Cheeer's

[smokeandfire451]

I did not pressure bleed, can't find anybody close that does that. The ABS kicks in while stopping only. Will check the sensors as soon as my wife brings it back.

[xj4life2]

first off did you remove any of the sensors? if not don't mess with them. Did you release the pressure on the ABS system prior to doing the brake job ? if not then you more than likely have air in the abs.

BRAKE BLEEDING (WITH ABS BRAKES)
ABS system bleeding requires conventional bleeding methods plus use of the DRB scan tool. The procedure involves performing a conventional bleed, followed by use of the scan tool to cycle and bleed the HCU pump and solenoids. A second conventional bleed procedure is then required remove any air remaining in the system.


(1) If a new master cylinder is to be installed, bleed cylinder on bench before installing it in vehicle.
(2) Wipe master cylinder reservoir and cap clean before removing cap. This avoids having dirt fall into fluid. Then fill reservoir with Mopar brake fluid.
(3) Perform conventional brake bleed as described in steps (4) and (5).
(4) Bleed master cylinder and combination valve at brake line fittings. Have helper depress and release brake pedal while bleeding cylinder and valve.
(5) Bleed wheel brakes in recommended sequence which is: right rear; left rear; right front; left front. Bleed procedure is as follows:

(a) Attach bleed hose to caliper bleed screw. Immerse end of hose in glass container partially filled with brake fluid. Be sure hose end is submerged in fluid (Fig. 3).
(b) Have helper depress and hold brake pedal to floorpan.
(c) Open bleed screw 1/2 turn. Close bleed screw when brake pedal contacts floorpan. Do not pump brake pedal at any time while bleeding. This compresses air into small bubbles which are distributed throughout system. Additional bleeding operations will then be necessary to remove all trapped air from the system.
(d) Repeat bleeding operation at each wheel brake unit fluid entering glass container is free of air bubbles. Check reservoir fluid level frequently and add fluid if necessary.
(6) Perform HCU bleed procedure with DRB scan tool as follows:
(a) Connect scan tool to ABS diagnostic connector. Connector is under carpet at front of console, just under instrument panel center bezel.
(b) Select CHASSIS SYSTEM, followed by TEVES ABS BRAKES, then BLEED BRAKES. When scan tool displays TEST COMPLETE, disconnect scan tool and proceed to next step.
(7) Repeat conventional bleed procedure described in steps (4) and (5).
(8) Top off master cylinder fluid level and verify proper brake operation before moving veh
Hope this helps

[smokeandfire451]

Thankyou! I think this is the info I was looking for! Now I am off to find this scan tool!