The ABS comes on for no apparent reason.New calipers,rotors,drums,shoes,springs etc.were replaced.What do you think could be wrong?

try adjusting the rear brakes up correctly
the spring that holds the shoes together pushes all the brake fluid back into the reservoir and each application has to move the shoes back into contact with the drum
that is enough to get the pedal close to the floor

Hey Stan the man,need your vehicles info.,year,make,model and engine size and Tommy on the spot here will send you a picture diagram of your rear brake assembly.There's a special spring tool you can get at auto parts store to remove and install springs,me got one.

Lift the front of your Ford F-250 off of the ground using a jack and jack stands. Remove the wheels from the Ford with a lug nut wrench to prepare the truck for servicing. 2 Open the hood on the engine compartment and take the lid off of the master cylinder that bolts to the brake assister on the driver's side firewall.3 Remove the hex-head bolts on the back of the brake caliper with a socket. With the bolts removed, pull the caliper off of the Ford's brake rotor.4 Pull the old brake pads out of the caliper and discard them. Squeeze the brake piston back into the backside brake caliper with pliers, and then insert the new pads into the brake caliper.5 Pull the rotor cap cover off the middle of the rotor with a screwdriver and use a socket to remove the nut located behind the cover.6 Pull the rotor off of the wheel spindle.7 Remove the old wheel bearings from the brake rotor and insert them into the new rotor. If the old wheel bearings are worn, replace them with new bearings.8 Slide the new rotor onto the wheel spindle and secure it using a bolt and socket. After you tighten the bolt, press the cover back onto the rotor.9 Place the caliper on the rotor and secure it with a socket and hex-head bolts. 10 Duplicate the process on the passenger side of the F-250. 11 Close the master cylinder after putting the wheels back on the Ford and lowering it to the ground. Press on the brake pedal to seat the pads against the rotor
Replace the F-250's Rear Brakes 1 lift the rear of the Ford F-250 off the ground with a jack and jack stands. Remove the wheels from the Ford with a lug nut wrench.2 Place a strip of paint on the back of the brake drum and rear brake drum cover so you can position the brake drum orrectly when you put it back on. If you plan to install new brake drums on your Ford F-250, skip this step. 3 Place the brake drum puller on the brake drum and pull the drum from the wheel hub. The method for attaching the brake drum puller depends on the brake drum puller that you use. 4 Remove the springs that attach the brake shoes to the wheel hub by pulling them off with pliers.5 Lift the old brake shoes off of the wheel hub and place the new brake shoes on the wheel hub. Secure the new shoes with the springs.6 Pound the brake drum onto the axle hub with a rubber mallet.7 Duplicate the process on the passenger side of the Ford.8 Put the wheels back on the F-250, lower it to the ground and, then press on the brake pedal to seat the shoes against the brake drum.

Your Buick has front disc brakes...and rear drum brakes...the usual concern is the front pads as they are used more...these are the easiest pads to replace...as you only need to remove the caliper from the rotor with 2 bolts to lift off...Be sure to push the piston all the way back into the caliper to install new pads...rotors are pop offs too...The rear drum is different...the brake shoes are held on with clips and springs...try keeping one of the shoe assemblies intact while you switch out the other shoes...be sure to inspect the rear wheel brake cylinders for possible leaking...usually an oil build up inside the brake drum...these are inexpensive and should be switched out on a 93 Buick...:) Hope this helps.

if the front are rotors there are two bolts that need to be taken off first.
remove the caliper, then remove the two caliper bracket bolts and remove the rotor
replace the rotor and reinstall the caliper bracket.
pull the caliper sliders and lube them with brake grease.
reinstall caliper sliders and install new pads and caliper
refasten caliper to bracket and your done

if your doing rear disc brakes same as front
if brakes are drum type you will need rear drum brake tools to release the springs and to refasten
the new brake shoes

How to replace the rear brake pads on a 1995 through 2001 Ford Explorer The system utilizes a drum-in-hat type rear brake rotor. The integral drum allows the use of a drum-and-shoe type parking brake system. All other components are similar to their front disc brake components Remove the two bolts on either side of the brake hose with the rubber boots. Do not remove the four bolts where the axle ties in. The two bolts to be removed require a 10mm socket/wrench. Loosen the pads from the caliper Rotor Removal In order to take the rotors off (replace with new or have them machined), it is best to loosen the emergency brake shoes. To do this, behind the rotors, in the back there is a rubber plug, remove that and you can use a screw driver to engage the teeth of the adjusting screw, turn it clockwise to loosen, usually 10-20 teeth. Usually this means turn it downward. After this, it may still be difficult to get the rotors off without tapping them. Use a rubber mallet and hit them from behind. Before really whacking the rotor, make sure you have loosened the adjusting screw enough. It may take heavy swings of the rubber hammer to do this. It will eventually break loose. Parking Brake You might want to check the parking brake while you are here. To remove:

• Remove the rear disc brake rotor.

• Remove the outboard return spring.

• Remove the adjusting screw spring.

• Remove the rear brake shoe hold-down spring and pin.

• Remove the brake shoe adjusting screw and nut.

• Remove the front brake shoe hold-down spring and pin.

• Remove both parking brake shoes and the inboard return spring.

• Check the parking brake lever for excessive wear and replace as necessary.

To install:

• Position the front parking brake shoe to the backing plate and install the hold-down pin and spring.

• Install the rear parking brake shoe with the inboard return spring.

• Position the brake shoe adjuster screw and nut on the shoes and install the rear shoe hold-down pin and spring.

• Install the brake shoe adjuster spring.

• Install the outboard return spring.

• Adjust the parking brake shoes and install the rotor, caliper and wheel.

• Lower the vehicle and tighten the wheel lug nuts to 100 ft. lbs. (135 Nm).

ADJUSTMENT

• Measure the inside of the drum portion of the rear brake rotor

• Remove the rear disc brake rotor.

• Using Brake Adjustment Gauge D81L-1103-A or equivalent, measure the inside diameter of the drum portion of the rear disc brake rotor.

• Subtract 0.020 in. (0.508mm) from the first measurement, adjust the brake shoes to that size

• Adjust the parking brake adjuster screw until the outside diameter of the parking brake shoes measures 0.020 in. (0.508mm) less than the drum measurement.

• Install the rear disc brake rotor.

Reassembly Reassembly is easy. Put new or machined rotors back on by sliding them over the lugs (they should slide on easily.) Loosen bleeder valve (having a catch bottle handy is good). Push calipers in slowly (using a c-clamp or large channel lock pliers), close bleeder valve. Put on pads. Lubricate metal clips with small amount of anti-seize. Re-adjust the emergency brake by turning the opposite direction from loosening. Refill the brake master cylinder

1. Machine or replace rotors and/or Drums
2. New Disc Pads and /or Brake Shoes & springs for brake shoes
3. New or recond Brake Booster
4. New or recond Master Cylinder
5. New or recond Disc brake calipers and/or wheel Cylinders
6. Brake fluid
7. Check all the brake fluid lines for any damage
thats about all I can think of, hope it helps

the shoes not being adjusted properly or if one shoe has more pad than the other like a primary and secondary them wrong will also create this issue, also brake fluid on drums and shoes.

You probably need to surface the rotors and the drums. I have gotten brand new rotors that were so warped that they were below min. thickness (not kidding) after surfacing them. Needless to say, they went back to the parts store. So now I surface every new rotor that I install. Happens to rotors way more than drums, but have hade a couple of drums that were warped when new so I check them before installing them. Good luck. Hope this helps.