Hey everyone,

I'm hoping I can get my van on the road again soon. First I have to fix these brake problems I am having.

I have a new master cylinder wanting to replace my old one in my 1998 Grand Caravan AWD 3.8 litre. I have a haynes car book and it says if I have ABS (which I do) then I have to take the vehicle into a repair shop with a DRB 2 scan tool

Is this scan tool a must for this job of replacing a master cylinder? Can I possibly get the job done still without taking it to a shop?

Thanks

 

67 views and no reply, must be asking wrong questions... Let me try again.

So I I rip off the old Master cylinder and replace it will my new one and fill up the reserve, this probably wont work? Is there a special way I can replace my master cylinder without creating air in the ABS system? (if there isnt air already in there)

 

You sure can replace it yourself, you can even bleed without the drb3....

 

Keep your diaper on, some of us have jobs

BLEEDING MASTER CYLINDER


CAUTION: When clamping master cylinder in vise, only clamp master cylinder by its mounting flange, do not clamp on primary piston, seal or body of master cylinder.

1. Clamp the master cylinder in a vise using only the mounting flange NOTE: Two different size bleeding tubes are used depending on which type of master cylinder the vehicle is equipped with. Vehicles equipped with traction control use a center port master cylinder with a larger diameter brake tube. Vehicles not equipped with traction control use a compensating port master cylinder using a standard 3/16 inch diameter brake tube. Be sure the correct size bleeding tubes are used when bleeding the master cylinder.
2. Install the Bleeding Tubes, Special Tool 6920 for a non traction control master cylinder or Special Tool 8129 for a traction control master cylinder on the master cylinder. Position bleeding tubes so the outlets of bleeding tubes will be below surface of brake fluid when reservoir is filled to its proper level.
3. Fill brake fluid reservoir with brake fluid conforming to DOT 3 specifications such as Mopar or an Equivalent.
4. Using a wooden dowel, depress push rod slowly, and then allow pistons to return to released position. Repeat several times until all air bubbles are expelled from master cylinder.
5. Remove bleeding tubes from master cylinder outlet ports, and then plug outlet ports and install fill cap on reservoir.
6. Remove master cylinder from vise NOTE: Note: It is not necessary to bleed the ABS hydraulic control unit (HCU) after replacing the master cylinder. But, the base brake hydraulic system must be bled to ensure no air is entered the hydraulic system when the master cylinder was removed.

INSTALL


CAUTION: When replacing the master cylinder on a vehicle, a NEW vacuum seal MUST be installed on the master cylinder. Use only procedure detailed below for installing the vacuum seal onto the master cylinder.

1. Install a NEW vacuum seal on master cylinder making sure seal sits squarely in groove of master cylinder casting
2. Position master cylinder on studs of power brake unit, aligning push rod on power brake vacuum booster with master cylinder push rod.
3. Install the 2 master cylinder to power brake unit mounting nuts. Then tighten both mounting nuts to a torque of 25 N·m (225 in. lbs.) CAUTION: When installing the primary and secondary brake tubes on master cylinder, be sure brake tubes do not contact any other components within the vehicle and that there is slack in the flexible sections of the tubes. This is required due to the movement between the ABS hydraulic control module (HCU) and the master cylinder, when the vehicle is in motion.
4. Connect the primary and secondary brake tubes to master cylinder primary and secondary ports. Brake tubes must be held securely when tightened to control orientation of flex section. Then fully tighten the tube nuts to a torque of 17 N·m (145 in. lbs.)
5. Install the vehicle wiring harness connector, on the brake fluid level sensor in the master cylinder brake fluid reservoir
6. Install filler tube into the master cylinder fluid reservoir

BLEEDING WITHOUT A PRESSURE BLEEDER

NOTE: Correct manual bleeding of the brakes hydraulic system will require the aid of a helper.
NOTE: To adequately bleed the brakes using the manual bleeding procedure the rear brakes must be correctly adjusted. Prior to the manual bleeding of the brake hydraulic system, correctly adjust the rear brakes.

NOTE: The following wheel sequence should be used when bleeding the brake hydraulic system. The use of this wheel sequence will ensure adequate removal of all trapped air from the brake hydraulic system.

• Left Rear Wheel
• Right Front Wheel
• Right Rear Wheel
• Left Front Wheel

1. Pump the brake pedal three or four times and hold it down before the bleeder screw is opened.
2. Push the brake pedal toward the floor and hold it down. Then open the left rear bleeder screw at least 1 full turn. When the bleeder screw opens the brake pedal will drop all the way to the floor.
3. Release the brake pedal only after the bleeder screw is closed.
4. Repeat steps 1 through 3, four or five times, at each bleeder screw in the required sequence. This should pass a sufficient amount of fluid to expel all the trapped air from the brake system. Be sure to monitor the fluid level in the master cylinder, so it stays at a proper level so air will not enter the brake system through the master cylinder.
5. Perform a final adjustment of the rear brake shoes and then test drive vehicle to be sure brakes are operating correctly and that pedal is solid.

 

lol, thanks Tizzy.

I am in no rush, I got a workign vehicle while I fix the brakes on my van

Thanks for all that good info. I'll put it to good use soon and report back on my success.

Thanks again.