How To: Rebuild Clutch Master Cylinder

Some say rebuilding the clutch master cylinder is not worthwhile, that a rebuilt unit will still leak. However, I believe these problems ocurred because the actual cylinder wall was pitted and in bad shape no matter how good the new o-rings were. So, if you want, dismantle and inspect inside the cylinder before purchasing the rebuild kit. However, the rebuild kit from Toyota is only about $25-$30. Included in the kit is a new piston/spring assembly, crush washers for the reservoir, clip for the clevis pin, snap ring, and washer for the push rod:

(new piston not pictured)

1) Make sure the clutch hydraulics are emptied.

2) Disconnect the clip & clevis pin from the master cylinder push rod, holding it to the clutch pedal.

3) Here’s the location of the clutch master cylinder under the hood. Remove the black plastic cover if you have that in place.

4) Loosen the 2 bolts holding the cylinder to the firewall. Then loosen the banjo bolt. Pull the master cylinder out from the car. It’s quite tight fit in there, so use the appropriate curse words when trying to loosen these bolts 🙂

5) Remove the bolt holding the reservoir to the cylinder

6) Pull back the rubber boot. There’s no need to unscrew the clevis from the push rod. This saves you from having to adjust the clutch pedal after you reassemble it to the car.

7) Using a set of snap ring pliers (or a screwdriver) remove the snap ring holding the push rod/washer in place.

8) Here’s what you should have now:

9) Pull out the piston/spring assembly. You may have to use compressed air to where the banjo bolt attaches to push out the piston. However mine was quite loose, that it just took a small screwdriver & fingers to get it out.

10) Clean up the inside and outside of the cylinder with denatured alcohol or fresh brake fluid. If you notice any pits or scrapes in the cylinder, you will need to replace it with a new one. Here’s mine after a cleaning and a fresh coat of paint:

11) Lube up the new piston o-rings, with lithium soap base grease (the stuff that comes with the caliper rebuild kits):

12) Slide it into the cylinder

13) Pack the end of the piston, where the push rod will rest & pivot, with grease. Here’s how the push rod, washer, and snap ring are inserted. (Your push rod will probably have the clevis and boot still attached. That’s okay)

Using the snap ring pliers attach the snap ring in place:

14) Replace the boot:

15) Replace the reservoir with the new copper crush washers that came in the kit:

16) Reinstall the master cylinder in the car, opposite its removal. Use new crush washers for the banjo bolt. Unfortunately, my rebuld kit didn’t come with new ones.

17) Fill and bleed clutch system according to repair manual.

This documentation in no way replaces the Toyota MR2 Repair Manuals. The purpose of this content is only to provide supplementary information to fellow MR2 enthusiasts. Midship Runabout and its contributing authors will not be held responsible for any injury or damages that may occur as the result of practicing any of the methods or procedures described within this website. Article and photo submissions are property of the contributing author.

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