New disk pads dragging/locking up!

[slandrum]

Hi, I really need some help. I just replaced the pads, calipers, rotors, bearings, brake hoses and hard lines on both front wheels of my '96 2.2 2WD with new, quality parts. It was time for new pads, etc, and one of the hard lines was rusted and started leaking when I was working around it. Bled lines at all four wheels (trad two-person method). Using new DOT3 fluid. Also had to temp remove both hard lines between master cylinder and BPMV (4WABS).

Got everything together fine, I thought. Quickly noticed that after I first apply the brakes they stay locked (both front, not rear drums afaik).

Calipers and pins are properly lubed and move normally when removed. I removed calipers and bottomed the cylinder, cracking open the bleeder while doing so. Reinstalled, looks fine until I apply the brakes again.

When the pads/calipers are locked up, I can open the bleeder valve, and some fluid runs out (doesn't seem under pressure). This allows the caliper to relax and the rotors to spin normally. Hoses aren't kinked.

No matter what I've tried, as soon as I apply the brakes, they stay locked pretty darn tight. I can turn the rotors, but not really with one hand, they are tight! Before I apply the brakes they spin with only the normal, minimal drag. Brake pedal is fully returning.

I tried driving it about a mile round trip, I could hear and feel them dragging the whole way, no improvement.

Using Bendix TitaniuMetallic II pads, MKD154, I verified fitment.

Is there something I don't know about enabling the pressure to release? Did I do something wrong that damaged the BPMV? Brake light goes out after starting, no SES light.

Sure would appreciate some good advice!
Stuart

[greencactus3]

does it happen when the engine is off too? (once vacuum is gone from booster)?

[slandrum]

Yes, no difference whether engine is running or not...

[slandrum]

Can I bleed the Brake Pressure Modulation Valve? Looks like you're supposed to use a full featured scan tool to do that, which I don't have (just have a basic one). I didn't bleed the master cylinder, but it was never empty. At this point I may be getting it towed to a shop, so if anybody has ANY suggestions I'd welcome them!

[slandrum]

After googling and finding the following info, I decided I couldn't do it myself and took it into a nearby dealer. I drove it slowly, about 20 mph, and stopped twice to check the temp of the rotors, they got hot but not critically. The tech bled the BPMV using his hand held and walla! Under $60 and was back home within two hours. edit: I'm sure what actually caused it is that I disconnected the in and out hard lines between the master cylinder and the BPMV.

For anyone else, here's some background info. I hope it's ok to post the links. The ABS system is specifically a Kelsey-Hayes 4WAL, as described in detail here: http://www.aa1car.com/library/abs_kelseyhayes.htm

I found specific instructions for bleeding here: http://www.aa1car.com/library/abs_bleeding.htm (look towards the bottom for the section titled "Dodge Truck With Kelsey-Hayes 4WAL")

So it seems the main thing you need is an advanced two way diagnostic reader that can cycle the solenoids in the BPMV so get all the air pockets out. Also or alternatively, a little jig that can depress the valves manually such as an OTC Tools 7853, the part number at SummitRacing.com is SUN-7853.

I'd still be interested if anybody has any corrections or additions or experience to share.

thanks!