Transmission, Manual

Clutch Master Cylinder Replacement #2

Clutch Master Cylinder Replacement #2

After I bought my '90 GT my son decided he wanted my '88 S4 5 spd. The clutch master cylinder had started to leak and needed replacing. I talked to him on the phone tonight and he was already nearly done with the project. Here is how he did the replacement. He doesn't have shop manuals so was not impeded by trying to follow directions. He just started in. When I talked to him he was just bolting up the new cylinder and had been into it about 1.5 hours. He estimated another hour to finish plus whatever time to bleed/flush the brakes. He thought it was not a difficult job.

Here is what he told me he did.

1. Cut or pull off the ratty blue hose that goes down to the clutch master cylinder and catch the brake fluid that will drain out from the reservoir.

2. Remove the brake lines from the brake master cylinder.

3. Reach around under the brake master cylinder and take off the mounting nut on the fender side. He used a 13 mm open end/box end wrench. You can't see the nut and have to get it off just by feel. Take off the other master cyl mounting nut and remove the master cylinder with the reservoir still attached. You don't need to remove the brake booster or do anything with the brake pedal position inside to car.

4. Now, you can look down with a light and see the clutch master cylinder. Use a flare wrench to unscrew the connector to the pressure line that goes down to the clutch slave cylinder. There is a good chance of rounding off the connector nut if you try to use a common open end wrench for this so get a proper size flare wrench if you don't have one. (A flare wrench is almost like a box end wrench with a slit in the side to go over the line and it provides more contact area than an open end wrench.)

5. Go inside the car and unscrew the 2 bolts that hold the clutch master cylinder to the firewall.

6. Back in the engine bay, pull out the master cylinder using the old ratty blue hose that is still connected at the master cylinder end.

7. Replace the old blue hose with new blue hose.

8. Reverse procedure to install new cylinder.

9. Refill brake reservoir and bleed brakes. Use enough brake fluid to insure new fluid throughout the brake system.

Hope this will help someone.....

Louis Ott
'90 GT

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