Bleeding the Kelesy-hayes ABS controller

Jeff B

Jeff B

Thanos was right
Joined
Dec 23, 2006
Location
Lincolnton N.C.
I have bled these brakes, taken it to dirt roads and locked the brakes to fire the ABS module to push out air from the module. Then bled it again. However still having issues with soft pedal till about half way down. I feel confident I am not getting all the air from the manifold.

I am considering a cheap scan tool that will fire the ABS module.

Can anybody recommend a cheaper scan tool?

Thanks
 
Autel Maxicheck Pro would likely work, it has automated ABS bleed capability but not sure about specific vehicle coverage for whatever vehicle you have. That's probably about the cheapest scanner that will do it that's worth messing with; it's usually less than $200.

I just checked, and my MD808Pro doesn't have bleed capability. I was going to offer that up to borrow if it could...
 
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Fabrik8 said:
Autel Maxicheck Pro would likely work, it has automated ABS bleed capability but not sure about specific vehicle coverage for whatever vehicle you have. That's probably about the cheapest scanner that will do it that's worth messing with; it's usually less than $200.

I just checked, and my MD808Pro doesn't have bleed capability. I was going to offer that up to borrow if it could...
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Thank you, I'll look that up.
 
Come by my shop, I can do the Auto bleed. (Ms908p.. cheap by tool truck standards, not cheap by my book) Chances are the master cylinder is giving up though. Usually don't affect too much on that application..
 
a_kelley said:
Come by my shop, I can do the Auto bleed. (Ms908p.. cheap by tool truck standards, not cheap by my book) Chances are the master cylinder is giving up though. Usually don't affect too much on that application..
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It's a new master cyl. Vacum booster, proportional valve,

I ordered new front rubber lines, cheap and my thoughts are maybe expanding.

That and gonna get it on stands, pull the wheels and have the wife run it up to 25mph and lock the brakes up, while I bleed them. Should be the same as the scan tool activating the ABS motor.
If don't get it figured out by the next time I go to Polk DOT. I'll holler at you to work that offer out.

Thank you
 
I don't think abs will activate unless all four tires spin at the same speed taking off and one or two lock.. it'll throw a rationality code.. But you should be able to get a stiff pedal regardless of abs. May try bleeding engine running though. Automated bleed is totally Auto, do not crack any bleeders in the process at all and is performed after traditional bleeding. I have gotten faulty masters before. Also check extension on the booster pushrod.
 
It actuated last time I had it on stands. I worked the ABS the shut it down and bled it. It helped, but didn't get it all. The push length is correct, I am a bit suspect of the master too.
 
I've learned that if you go with your gut feeling, chances are you're right. I've learned not to second guess myself.. usually if the pedal travels about half what it should, one side of the master isn't working properly. I've had them leak out the back when that happened last time on a NIB failure but chalked it up to it being assembly lube but I knew better. Had exactly the same symptoms. The auto bleed post getting a firm pedal only takes up maybe 1/4" of travel at most, and I've not ever had to bleed the brakes after an auto bleed.. I would try bleeding at the master cylinder before yanking it to defect it. Most the time changing a master cylinder I only have to bleed at the master FWIW (assuming the rest of the system didn't have air in it). Of course if it does, you have to follow up at the wheels but 9/10 can just bleed at the master a couple times and be good to go.
 
a_kelley said:
You might also try bleeding at the master cylinder in case there was air left from bench bleeding
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As soon as I can get a day to get back on it. I need 36 hour days..
 
a_kelley said:
Get a chance to try bleeding at the master? Or if you're like me, it stops so other things are more important.
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I ordered a new master. I'll install the new brake lines and master at the same time. I spent the better part of this morning porting the 4.0 head for my stroker this morning. Then mudding & taping a bed room I am remodeling. Now for beer and veal on the grill. Almost now.. wifey wants me to go to the gym for an hour of cardio first, ugh..
 
I finally got back to this. changed the master with no change in pedal.

I purchased a Vident ilink450 full service scanner. Capable of automated ABS bleeding & checking each solenoid. I performed the automated bleed and it was done in just a few seconds. So I started checking the each solenoid in the controller. With my foot on the brake I can feel when I turn them on and off. But a few had no response in the brake when I cycled them.

I am leaning towards a bad controller.

Any other ideas?
 
a_kelley said:
Are there any abs codes present? Does abs work properly?
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No codes abs or engine.

Its seems to, but it's difficult to get them to lock up. On Jack stands it will push the pedal back when activated. Rears lock up first and they are backed way off.

And as I stated, not all the coils would fire when I went through them one by one with the scanner.
 
Some of the solenoids are vent and some are seal, never really had many issues out of the solenoids/controllers except for the pump relay. I've got a abs hydraulic module (no electronics) here from a 3500, not sure if it's the same as the Tahoe though. Usually if the electric module is faulty, it'll show a failure code.

Did you try cracking the lines at the master while pumping? That worked on the 3500 I couldn't get a stiff pedal out of. Ended up going back and bleeding wheels again after I purged the crap out of the lines at the master cylinder.. almost like when I bled it that there was air trapped in the master. I used a half gallon bleeding that truck cause I did it at the wheels first, then at the master, then at the abs module, then again at the wheels.

You're welcome to pm/text me and we'll get it on my lift some time.
 
I'll try that tomorrow if I get time. Will start at the master then all the wheels again.

I may give you a shout in the next week or so. Thanks
 
Send me a pic of the abs module you have, if it fits I may want to purchase if it's for sale.
 
Fixed!!

First I bled everything, again. From master to rear wheels in correct order of course. LR, RR, RF, LF.

Then hooked up this cheap scanner I purchased off ebay iLink450 Full Service Bi-directional Scan Tool OBD2 Live Data ABS SRS EPB TBA 6971231354504 | eBay

Ran the automated bleed. nothing.
tested each valve, motor ran so I assumed all was good.
Tested each coil. A couple I couldn't hear. I should have do a magnetic test to see if they were working but I decided to just replace the damn thing.

Called the junk yard and they have several for $45 each. Went and picked one up. Got home & just wired it and checked the electronic module for codes and it had 2. I didn't write them down but the first said it would have the vehicle in limp mode. So I returned it and went back today and picked another up.

Installed it, Bled it and the wheels best I could with a 2x4 from the pedal against the seat. Then ran the auto bleed cycle several times with no positive results.

At this point I decided to run the auto bleed with the engine running. Rab it 3 times with better pedal each time. Turned the engine off and the ABS had sucked doen the reservoir past the 1/2 way point. (I think my vagina got a little wet here)

So, I bled the wheels again with lots of air coming out of the rear. very little from the front.

Ran the auto bleed another 3 times, this time the reservoir when down little less the 1/4.

One more time bleeding the wheels until there was no more air to be had.

Took it out for a spin and perfect brakes now.

This has been an incredibly long battle, 2 master cyl's, vacuum booster, ABS module, purchasing a scanner. about two gallons of dot3 fluid.

More aggravation then the shit box is worth. I guess now I'll keep it.

I believe the dump valve was leaking otr the internal accumulator had leaked down. never did go back to the coils..

Thanks for the help and suggestions.
 
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