tquinn

The ECBM of my ABS failed on a track day. I had it repaired by ABSFixer. When I went to reinstall it, I believed the factory service manual on the necessary torque sequence. It turned out to be too high for the newer version ABS that I have. One of the T20 screws broke on the second torque pass, leaving most of the screw in the ABS valve body.

I've been trying to extract the screw with the valve body still in the car. So far, no success.

Several have said to remove the valve body from the car and extract it or drill it/Easy-out it. If it comes to that, I'll have to disconnect the brake lines. When I do that, the ABS will need to be bled on reassembly.

From what I understand, it will require a GM Scanner or equivalent to force the automatic ABS bleed sequence.

According to the same flawed service manual, I should bleed the main brake system before I do the automatic ABS bleed sequence. That seems strange, because if there is air left in the ABS that has to be bled out, where will it go? It would seem like the air would go into the brake lines. If that is true, shouldn't I do the ABS bleed before the main system bleed? What am I missing?

Also, someone in another post said he had replaced his full ABS valve, and he used 8 gallons of brake fluid!? I've done a full pressure bleed of my brakes with less than 2 quarts of brake fluid. Where could 8 gallons have gone?

bobs77vet

8 gallons??? thats funny

maybe they meant 8 pints...still alot

Jurgen1

theres alot of screws holding that on tho if you leave that alone you should be ok .

tquinn

I've thought about that. It would be nice not to open up the brake lines. The guy who fixed the module says he tests them on his test stand without any screws. There are 6 screws in it, and the one that broke was in the middle front position (relative to the car).

On the other hand, I do track the car, and the ABS gets worked a lot on hard, high speed braking. So I'd sure like to get all 6 screws back in, preferably without breaking open the brake lines.

The screws are about 3.9 mm in diameter (M4), and there is a projection of the broken screw above the surface of the valve block of about 2.5 mm. It isn't much to get a bite on.

There is some resistance to turning of all the screws . . . it seems like they might have been installed with a patch lock compound.

So far, I've not been able to get a good enough grip with a needle nose pliers working from the side of the screw to turn the broken screw out.

My next step is to try a small vice grip, and approach the broken screw along its axis. I plan to grind two v notches in the end of the jaws, so that it makes 4 points of contact on the projected screw.

I also plan to heat the valve body with a hot air gun to about 160 F (similar to under hood temperature after a shutdown), and spray the vice grips with SuperCold 134 to create some differential expansion of both parts and make the screw grip a little looser. And I've already built a dam around the screw and filled it with penetrating lubricant meant for loosening stuck bolts, to try and get some of that into the threads.


If anyone has any other ideas on how to get this little turd out, I'd appreciate hearing them.

Jurgen1

I have had many of them off and on i know what ur talking about if it was my car i wouldt worry about it . Ur not gone leak any fluid but its ur car do as you please nothing anyone can say is gone take the screw out . If you were in Michigan id help or help you with my scanner to bleed the system .
good luck .

tquinn

I've still got a couple of ideas to take the screw out with the valve still in the car that might work. If they succeed, then all is well.

If they fail to extract the screw, then I'll need to decide what to do next. Maybe I'll just put in the 5 good screws that are left.

That might be better than opening up the liquid side of the system. Bryan, the guy at ABSFixer, recommended just putting 5 screws back in.

lionelhutz

Use Vice Grip brand locking pliers that aren't worn so they still have a good square jaw. Get the front face of the jaws up against the body and lock down on the screw stub as hard as you can. Lock and release it a few times tightening the adjustment each time. It always works better for me with the Vice Grips parallel to the screw, not perpendicular.

fuggles

if you can get a dremel wheel on it cut a grove for a screw driver. i haven't looked at the placement to see if this is possible or not.

I seem to recall seeing drill bits which are reversed so they cut while turning counter-clockwise. Might work.

tquinn

That is my plan, with a small vice grip. It was also suggested that I grind a V-cut in both jaws of the Vice Grip, a little smaller than the screw, to grab the screw from both sides. Have you had any experience with that?

Keep in mind, the screw (before being necked down from where it failed) is only 3.9 mm in diameter at the thread OD, and 3.3 mm diameter at the roots of the thread. So this puppy is damn small.

And there is only one turn of thread that is full size, the one closest to the aluminum block.

tquinn

I don't think there is enough room for a Dremel the exposed screw is surrounded by the support bracket for the valve, the valve rods, and a step in the aluminum valve block.

the idea of a backwards drill is good, but I'll only be able to do that if I take the valve block out of the car. I still hope to avoid that.

UM Rebel

My EBCM has been doing fine for many years with one broken screw.

tquinn

Now THAT is useful information. Do you remember which on of yours is broken? Mine is in the center location of the three screws closest to the front of the car.

DetroitPlac

Enough room to fit this over the stud (and/or enough stud exposed)?


I've had one of these for years and it's gotten me out of similar situations many times.

dproto09

when I took my EBCM off, two of my center screw head broke off. I removed all the brake line and took the abs pump off. They had to drill it and retap it. Then I used grey silicon around the gasket with new screws. I bleed the brake with a pressure bleeder motive brand. All is fine. I never used a tech tool, the abs works and stop great.

tquinn

That is interesting. I already have a Motive brand pressure bleeder. So you just hooked the lines back up and then pressure bled the system, and the ABS is working okay? Have you tried doing a very aggressive high speed stop, one where you knew the ABS was working to stabilize the car?

Your experience gives me confidence to at least try doing that.

Thanks,

tquinn

Thanks for the suggestion. Unfortunately the screw I'm trying to extract is an M4. The tool only goes down to 1/4 inch. The M4 is only about only about 60% of the diameter of a 1/4 inch tool.

dproto09

Don't waste your time, i was in your shoes. both center head broke off when i was trying to do the abs fix. People told me to leave it and just put the four bolts in. I'm very **** about stuff like that. I try my best to us vise grips in the car, nothing, then took the pump out still nothing. Then i try to drill it with left hand bits. The bits walked off.

short story
take it to a machine shop, they need to put it in a vise and use a machine drill press to drill and re tap the screws. They charged me $40 for two holes. i ended up going to a local aces hardware and buying all new six allen stainless steel metric bolts. I also use gray silicon around the old gasket to make sure that it was water tight. I haven't had any issues. I hit the brakes in the rain and the you can feel the abs motor pump working and the display says abs activated. Haven't had an issues so far with the brake, just an harmonic balancer.

If you don't want to go through all that trouble, I would buy new screws, anti-sieze, buy silicon to put around the gasket and tighten to spec. up to you.

sstonebreaker

Since it's sticking up above the surface, what about using a dremel to cut a slot in the screw and back it out with a screw driver?

tquinn

Thanks, that's good advice. What you ended up doing is about where I thought I might need to go.

apex26

Interesting thread. Because the car is a tracked Z06, I'd take it apart and take it to a machine shop to avoid breaking off a drill or easyout and making a real mess. When I needed to bleed my ABS, there was nobody to trust, so I used some wet grass. It's been fine ever since, and it gets tracked.