Friday, 14 April 2017

Toyota 86 - MTEC Clutch spring

Time to address one of the most complained points regarding 86 / BRZ ownership.... The clutch spring. Similar to most new manual transmission cars, Toyobaru included a clutch spring to significantly reduce the effort needed to operate the clutch. This is all well and good for suburban use but it robs the driver of any feel.

Is it necessary to remove? Nope, you can easily adapt to the clutch with the spring. It just means that you need to pay extra attention as the lack of feel will catch you out at times.

So what are the options? Either remove the spring completely or replace it with one that has a "softer" spring rate to reduce the assistance provided. 

Whats needed
  • 12mm Socket and extensions - The 3 primary mounting bolts for the clutch pedal need this.
  • Optional: Torque Wrench to correctly torque all bolts.
  • Flat head screwdriver - To assist with prying out roll pins and c clips where required.
  • Needle nose pliers - To remove retaining clips.
  • Paper masking tape - To avoid losing nuts into the engine bay.

Plan of attack

As this is RHD, it is close to impossible to remove the clutch spring with the pedal in place. This doesn't meant that it cant be done, but be prepared for hours of pain if you are prepared to go that route. The following method is much simpler and allows you to work on the whole assembly on a bench. LHD owners in the states and other countries have a much easier time as the clutch pedal works on a cam system which provides plenty of working space in the footwell.

Step 1: Inside the footwell

Start by removing the following.

1. Undo both sensor plugs as shown in the following diagram. These are a bit tight and don't seem obvious at first on how they should be undone, don't rush and examine it carefully. You will see the prongs to press in to release them.

Both Sensor plug locations are shown in the above pic.

2. Undo the 12mm bolt that supports the clutch pedal, if you are lying on the back this is facing directly upwards.
Supporting 12mm bolt shown (Look directly up and you will see it)
3. Remove the clip from the clutch master cylinder push rod (use needle nose pliers to gently pull it). Once out, look to the other side of the pedal and pry out of the center pin using a flat head screwdriver.

Step 2: Inside the engine bay

1. Remove both the 12mm bolts which secure the Master cylinder and clutch pedal assembly. Becareful not to drop these nuts into the engine bay, otherwise you will have a fun time digging for them or removing the undertrays. Line the 12mm socket with some tape so that the nut stays captive once removed.

Step 3: On the workbench.

1. With the pedal removed, it should look something like this.

Clutch pedal assembly in all its glory.

You can see the stock clutch spring held in place, notice the 2 metal plates on either side. It is close to impossible to swap the springs whilst working in the footwell.

2. Remove the stock clutch spring by first removing the c-clips on both ends of the spring holder. Then proceed to push out the retaining pins, You should be then able to remove the entire spring assembly as shown below. Note you may need to play with the clutch pedal position to push the retaining pins out.

All disassembled, ready for the new spring.

MTEC spring vs Stock spring.
3. With everything disassembled, either replace the spring or leave the whole assembly out (True clutch spring delete). Reassembly is basically the reverse of the above. When re-installing, make sure the push rod is lined up with the pedal. If it is off to either side or seated incorrectly you will not be able to re-install the retaining clips.

Make sure push rod is aligned with pedal.

And thats it, re-torque all 3 nuts to 18nm or 13.3ftlb and check all the sensor plugs are connected.