BTC

Has anyone here ever followed the brake system pressure bleeding procedure as laid out in the factory service manual for those without a Tech 1?

If it would help, I can post the entire the procedure, but I have questions about the following steps, specifically step 17.

14. Remove pressure to the pressure bleeding
equipment.
15. Attach a clear plastic bleeder hose to the right
front wheel bleeder valve and submerge opposite
hose end in a clean container partially filled with
clean brake fluid.
16. Turn the ignition "ON."
17. Open the bleeder valve and apply the brake until
the red "BRAKE" warning lamp turns "ON." This
shuttles the brake pressure differential warning
valve.
18. Close bleeder valve.
19. Reapply pressure to pressure bleeding equipment.
20. Turn the ignition "OFF."

Over Christmas, I installed some springs, shocks, rotors, pads and stainless steel brake lines on my car. When I got around to bleeding the brakes, I could never get the Brake warning lamp to come on in Step 17.

I tried pushing the pedal down and holding it, which is what they seem to be telling you to do. I also tried pumping the brake pedal, which also did not get the warning lamp to come on. What I did not do was pump the brakes until the master cylinder ran dry of fluid, but if that is what's necessary, it's not spelled out very clearly.

Anyway, just curious if anyone might be able to provide some insight on exactly what's necessary for step 17. I eventually gave up and just completed the remainder of the process as spelled out in the FSM. After completing these steps, you essentially repeat almost everything you have done up to this point, so maybe you are supposed to pump the pedal until the master cylinder is low on fluid, or dry.

The brakes seem to be working, but I haven't really driven the car, at least not to the point of reaching any significant speeds. I just drove it around the driveway after I was finished.

Spartan7

iTrader: (7)

You don't want to run the MC dry, you'll just introduce air into the system again. I'm not sure what the procedure means by that, but I have successfully bled my LT1 ABS system using only a Motive pressure bleeder and no Tech 1 or 2. I just followed the standard procedure of furthest wheel to closest, ABS block, repeat until firm pedal.

BTC

That was pretty much my take, with the exception that you repeat a lot of the bleeding procedure again after that pressure differential valve toggles. After reading some more about what this system actually does, which is monitor hydraulic pressure between the front and rear brake systems, I'm sure that running the master cylinder low, or dry, has nothing to do with toggling the valve.

I posted this on another forum and someone speculated that the valve could be stuck due to the amount of time my car has been sitting.

Are you a Spartan as in Michigan State Spartans? Just curious as I live in Lansing.

Spartan7

iTrader: (7)

No, pretty sure I was watching the movie 300 when I made this profile.

The manual says about the BRAKE indicator:
'The red "BRAKE" warning lamp will be illuminated when a low brake fluid level in the master cylinder is sensed, the parking brake switch is closed, or under control of the EBCM when certain ABS DTCs are set. This lamp indicates to the driver a base brake problem may exist.'

Since our setup doesn't have a fluid level switch in the reservoir like 98-02 cars, I have no idea how it does the first one, possibly in the brake modulator itself. But again, I've always read and been told that running the MC dry while bleeding it bad. When I rebuilt my brake system completely, I had to bench bleed the MC to work all the air out of it before bleeding the rest.

StealthFormula

iTrader: (35)

x2, bled my LT1 this exact way a couple months back and the pedal feels great.

threfoldcord

1993 -97 Camaro Firebird V6 or LT1 brakes 2.0

Brake Light on dash gauges on constant.

• Brake light switch on the Emergency brake. (hard to get to it is inside the console).
• Combination Valve Pressure switch (easy to get to).

Best way to start is remove the electrical plug on the ABS Combination Valve. (easy to find and remove).

• There are three small electrical plugs on the (top) of ABS unit.
• Two electrical plugs are for the ABS Solenoid Valves the plugs sit (side ways)
• One electrical plug sticks (straight up) out of the Combination Valve on the side of the (ABS) unit that faces towards the cars engine.

Removing the electrical plug on the ABS Combination Valve helps to eliminate the Combination Valve Pressure Switch as being the issue.
After removing the Combination Valve Pressure Switch electrical plug turn on your key and see if the brake light went out.

Emergency Brake Switch.

• If it is lit still you need to replace or repair the Brake light switch on the Emergency Brake. (hard to get to it is inside the console at the base of the Emergency Brake Handle).

Combination Valve Pressure Switch.

• If the light goes out it is the (ABS) Combination Valve Pressure Switch. (OEM switch is not available any more).
• (If the brakes work well and your bleeding your brakes regularly as well as keeping up the brake system who needs an idiot light).
• Remove the bulb in the dash, disable the electrical plug on the ABS Combination Valve or you might even be able to find a Good used Combination Valve Pressure switch. (Good Luck).
• I bought an AC Delco 88983914 Pressure Switch the hex/nut part is a larger size but the threaded part is the same size and will work.

Back Brake issues and/or not Bleeding.

• (Don't worry if your (ABS) system has error codes or an (ABS) dash gauge light lit this is all quite easy).
• All this information will still work for your other brake issues, but if you have an (ABS) dash gauge light lit you may want to repair the (ABS) issues or clear those codes.
• Correcting the (ABS) light is not necessary because having functioning (ABS) brakes are not necessary to having good functioning brakes on your car.

ABS dash light lit Issues.

(You can skip this (ABS) dash light lit issues section if you have no (ABS) light issue or don't wish to correct the (ABS) issue) and wish to bleed your brakes however I would read the part of this section on the loose (ABS) Modulator Gears first.

• You may just need to clear some (ABS) (OBD) codes.
• You may have a bad (ABS) Modulator Motor or (ABS) Modulator Valve both are replaceable, but would only be used available parts or get the whole (ABS) unit used. (Have seen some places that claim to rebuild them) same thing most likely they find used parts.
• Your could have a bad Wheel Speed Sensor at the Brakes.
• Your could have a bad Modulation Motor in the in the (ABS) unit.
• Your could have (ABS) Control unit.
• To Check these you will need any (OBD) codes and refer to a Factory Manual (ABS) trouble shooting section.

Read This before Bleeding your Brakes.

• The gears at the bottom of the (ABS) unit may be loose.
• When gear nuts are loose this is (very rare) usually they are never loose it is just slack in the shafts they are attached to.
• During the following brake bleeding procedure use something to separately hold each Gear from moving as you tighten each nut so you don't damage the (ABS) unit Modulator Pistons or Bores.
• (It is also recommended to (turn the Modulator Gears slow and lightly) clockwise from the (home position) found during the following brake bleeding procedure until you feel each gear stop.
• (Then turn each Modulator Gear slow and lightly) back going counterclockwise to find a center point centering the piston in the bore to keep from toping or bottoming out the piston during gear nut tightening).
• Do not over tighten the nuts secure them so they are not loose. (ABS) Modulator Drive Gear Nuts Torque Spec is 8.5 Nano Meters, 75 inch lbs. or 6.25 foot lbs.

Bleeding your brakes.

• Remove the Cold Air Intake Box. (Do not remove the MAF unit as you may want to run the engine when testing your brakes).
• Remove the Large (ABS) Connector at the bottom of the (ABS) unit.
• Remove the 13mm Bolt in front of the ABS unit pull the unit forward to remove it from the frames bracket it has a rectangular bushing holding it in this bracket.
• Don't remove any brake lines slowly turn the unit upward slowly bending the attached brake lines with out putting a kink in them.
• (Don't worry I have done this multiple times to mine with no brake line damage). Just go slow and wide forward and up until the (ABS) bottom cover is exposed and facing to the front of the car.
• Now remove the Torx screws holding the (ABS) bottom cover; be careful the cover comes off easy when (all screws) are removed don't force it.
• (There are some Torx screws hiding on the bottom cover at either end at the bolt and bracket ends of the (ABS) unit).
• Now use a 10mm wrench or socket to turn (2) each large Modulator Gears (counterclockwise) just until you feel the return spring pressure on the gear assemblies.
• (This puts the (ABS) unit in the (Home Position) ready for brake bleeding).
• WARNING: (Never ever run the Master cylinder dry keep checking and filling often during bleeding as your Master Cylinder reservoir is very small).
• Now bleed your brakes starting with the furthest Bake Caliper from the Master Cylinder to the closest Bake Caliper to the Master Cylinder.
• 1st - Passenger/Right Rear, 2nd - Driver/Left Rear, 3rd - Passenger/Right Front, Last - bleed Driver/Left Front.
• I use a vacuum bleeder kit (don't worry about the bubbles) it is just the (bleeder kit hose) leaking/sucking in air.
• (The vacuum bleeder kit pulls fluid out from the Master Cylinder; just continue to pull fluid until the color of the fluid looks clear as in no longer dark and you can see through it and close the bleeder).
• When finished bleeding all your brake calipers test the brakes with the engine off and then running to make sure you have a full peddle.
• Fill the Master Cylinder reservoir a final time never over fill; to work properly you need some air at the top of the reservoir.
• (Know where the fill mark is; stop at the bottom of the slots that can be seen where the filler cap goes onto the Master Cylinder reservoir).
• Now (leave the gears in the home position) and reinstall the (ABS) bottom cover then slowly bend the unit backward and down into place and secure with the removed 13mm bolt.

Not so bad Right now your brakes feel awesome? (Yes your back brakes are now working).

This took me some time to write this but I love My f-body's (have 3 of them) and I am tired of seeing people struggle because of a lack of good information.
I am a Technical Writer by trade I think I have explained all 1993 to 97 f-body brake problems in a way you can easily understand that is what I do best making manuals easily understandable.
(I know the factory manual is hard to navigate and poorly written; you can find all this information in the factory manuals in about 20 different places in 2 different manuals as there are usually 3 manuals for each year model).