Brake overhaul and brake pad wear sensors for ’97 STS
Add brake pad wear sensors to ’97 STS
Over the weekend I spent more than 8 hours replacing both front wheel hub/bearing assemblies dust shields, and full brake (front/rear) overhaul.
Here are the parts:
2 x pcs Front rotors AcDeclo P# 1770980
2 x pcs Rear rotors AcDelco P# 18A488
1x set Front brake pads AcDelco P# 1710980 (will explain later)
1x set Rear brake pads AcDeclo P# 171642
2x pcs Front dust shields GM P# 18023589 and 18023590
2x Brake wear sensor chassis harness P#?.
First front wheel hub/bearing assembly replacement:
As discussed on another thread the Timken equivalent part is very similar at first glance (for half the price). Not sure what is the real difference other than the stamping on the back of the lugs and the life warranty (for AcDelco). The AcDelco part comes with everything pictured above.
Loosen the drive shaft nut (you need a 34mm socket).
Jack the car (proper wheel chocks, proper stands – do not rely on jack).
Remove wheel (you need a 19mm socket).
Remove the brake caliper. Do NOT hang the caliper on the hose, use a wire to hang it on the spring (you need a 15mm socket).
Remove the brake caliper bracket (you need a 18mm socket).
Remove the rotor (may need a hammer if rusted shot).
Disconnect the wheel speed (or ABS) sensor connector.
Press the end of the drive shaft (you may need a press if stuck, normally should not be required).
Remove the 3 bolts holding the wheel hub/bearing assembly (you need a shallow 13mm socket and an extension, most likely need a large hammer to dislodge it from the knuckle).
Push the drive shaft in and on a side to allow enough space to pass trough the wheel speed sensor connector. Do not worry about overextending the drive shaft, it is impossible as it can’t pass trough the hole in the knuckle.
The dust shield may need to be replaced if corroded. Keep in mind the ’97 Seville, ‘97-’99 Deville and ‘97’02 Eldorado parts (18026708 and 18026709) were discontinued, you can use the Gen. V equivalent parts 100% compatible (1 extra ¼” hole).
At this point use a wire brush to clean very well the knuckle deck and the inside of the opening.
Please note the 3 bolts are placed temporarily to hold the shield in place (normally are mounted from the back of the knuckle)
Pass the Wheel speed sensor trough the knuckle hole (pushing the drive shaft in and on a side). Note the wire base is oriented towards the back. Ensure the dust shields are sandwiched between hub assembly and knuckle.
Install the 3 mounting bolts and torque to 70 lb·ft.
Install the wheel shaft nut loosely (final torque with the wheel on ground).
Install brake caliper bracket bolts.
Install the brake pads upper and lower anchor brackets (clean very well the area where the brackets insert).
Lubricate the back plate of the pads and install in position (if only one of the pads has the screech tab install that pad in the inboard position. Use high heat grease (usually supplied with the pads).
Using a “C” clamp compress the caliper position all the way until flush (careful with the rubber sleeve).
Clean the old grease from the inside of the holes of the slider pins and install new high heat grease (caution! cheap grease may harden in time and seize the slider pins). Ensure the slider pins rubber boots are undamaged. If need replacement a caliper service kit is available from AcDelco P#18K960X (front 1 kit services both calipers).
Grease and install the slider pins (ensure the caliper has the slider pins sleeves inside).
Install the wheel (torque nuts to 100 lb·ft) and lower the vehicle on the ground.
Torque the drive shaft nut to 110 lb·ft.
Before lowering the wheel on the ground you can pump the brake few times until the pedal feel is right (the piston needs to get from its retracted position to the normal position). Then rotate the wheel and ensure there is no grabbing (you should hear a uniform “whoosh” as the rotor drags loosely over the pads).
The same procedure applies to the rear brakes with the exception of some minor details and tools:
Release the parking brake
Separate the parking brake cable from the caliper (you need one 13mm socket)
Is recommended (but not mandatory) to remove the parking break cable from the arm (you need to compress ~1” the cable spring, lock it compressed with a locking clamp by pinching – not too tight - the cable and then slide the cable out). You can leave the clamp on the cable until intall.
The rear calipers has only one removable slider pin on the bottom (required 11mm socket). If you need a 10mm socket you have the wrong slider pin. The top slider pin fixed on the caliper bracket uses the exact same bolt but with the head for a 10mm socket).
Turn the caliper upwards to clear the rotor then slide it out (push inward) of the top pivot/slider pin.
Again do not hang the caliper on the cable, use a wire to hang it on the suspension components.
Remove the pads
Remove the brake caliper bracket (you need a 18mm socket)
Remove the rotor (also a hammer may be needed if rusted shut on the hub).
Install procedure in reverse.
Also pay attention to the slider pin booths (especially the bottom slider pin). Ensure good lubrication is provided.
Note the slider pin sleeve (bottom) should have 2 groves (one on each end) while the slider/pivot pin (top) sleeve should have only one groove (at the end away from the caliper bracket). These groves are use for the rubber booths to lock secure. Normally you are not required to remove the slider/pivot pin off the caliper bracket but if you do you know what to look for when installing everything back.
Push the caliper piston in until is flush (also pay attention to the rubber booth not to damage). If damaged a Caliper service kit is also available (includes all the rubber parts for the rear caliper including the piston ring gasket). To “push” the piston in you actually screw it in using a brake cube.
The cube inserts into the recess portion of the piston face and using an extension an a ratchet you will screw the piston in. Stop when is flush and the recessed parts are vertical on the caliper:
Don’t forget to install the parking brake and parking brake cable bracket (in this order).
Now I mentioned something about break bad wear sensors (IN A ’97!)
Unfortunately the proper retrofit procedure other than the brake pads with the sensors and the ‘98+ dust shields require replacing the EBTCM (controller part only), CVRSS module, IPC, add some 2 extra wires on the harness between EBTCM and CVRSS (possibly replace the struts with ‘98+?!?) and the IPC.
Having all these replaced you get the message “SERVICE BRAKES”.
However I can’t replace the IPC so what I will do is use the brake light signal to get a ground connection to the brake sensors (front wheels only). The brake sensors will be connected serial and then the other end of the circuit is connected to one of the unused pins on the IPC connectors. This signal will be used to control the base of a transistor to turn the brake light on.
I can’t use the brake fluid sensor input because that will turn the brake light on but will also trigger the “CHECK BRAKE FLUID” message (not correct). I am not going to use the parking brake switch signal either because that turns on the parking brake light (P) (not the brake light). Basically a simple diode, one resistor and a bipolar transistor inside the IPC should do the trick.
For now I did not do the changes to the IPC, I just ran the harness to inside the engine bay. I used the harness from a donor ’98 STS (connectors and everything are OEM).
The brake pads, calipers and rotors (basically everything for the front brakes) are the same in the ’97 up to ’03 cars (Sveville gen IV/V, Deville, Eldorado), the only difference are the pads, in the cars with brake pad sensors (‘98+ Seville STS) have the little grove where the sensors clip into.
Also the brake dust shields in the ‘98+ vehicles have one extra ¼” inch hole where the brake sensor cable retaining clip mounts (you can drill it if you don’t need to change the shields).
More details when I have the circuit completed.
Best part, I have AWSOME brakes, they grab really nice, is a bit difficult to make a smooth slow speed stop until the rotors and pads break in but boy I have brakes!