The OEM rubber clutch line can expand and loosen over time and after hard driving due to rising fluid temperatures. This can result in sloppier pedal feel. A stainless steel braided clutch line eliminates the squishy clutch pedal feel. This upgrade is typically done in conjunction with a stainless steel braided brake line upgrade for the vehicle. It is also recommended to change out the bleeder valve for the clutch at the same time since the OEM one may be old and leaky at this point (will save you another bleeding session to do this sooner rather than later).
Overall Install Time:
20 minutes for clutch line install. Much longer time for clutch line bleeding afterward (if you don't have a power bleeder).
Install Difficulty (out of 5 stars, 5 being the most difficult):
2 stars (and a lot of patience bleeding)
Recommended Tools for Install:
- Standard socket set (10mm and 12mm sockets in particular) and ratchet
- Rubber mallet and PB Blaster/penetrating oil
- 10mm flare nut wrench
- Pressurized/power bleeder for bleeding the clutch line (highly recommended)
- Needle nosed pliers or something to pry/hammer the hard brake line retainer bracket off
- Small metric wrench (7mm or 8mm for bleeder valve)
- 1/8" inner diameter clear tubing for the clutch bleeding procedure
Preparation and Install:
A 6-point flare nut wrench is the recommended tool for the job. A 12-point flare nut wrench may strip your brake line nut. Some people recommend using an offset flare nut wrench, however that is not needed. Just note that the actual "nut" part of the brake line nut is a little higher than brake line retainer bracket, so make sure you are putting the flare nut wrench at the correct height and angle when loosening the nut. It helps to have two people (one looking from the top of the car to help line up the wrench).
Begin by raising the front of the 350z by putting it on jack stands.
You will need to remove the plastic under tray cover behind the engine cross member to access the clutch line. Optionally, you can also remove the metal bracket connecting the left and right header/exhaust pipes for more room to work. The clutch line is located on the driver side running between the wheel well area to the transmission.
Remove the 12mm banjo bolt holding the line to the slave cylinder/transmission area. Allow the fluid to drain into an oil catch pan. After that, loosen the 10mm hard brake line nut with the flare nut wrench. Once that is removed, you can remove the hard brake line retainer bracket. I was able to gently tap it loose with a rubber mallet. You can also use needle nosed pliers to pull the bracket out.
The DiF stainless steel braided clutch line already comes with new fire sleeving, so you don't have to reuse the OEM one (sweet). Notice that the banjo bolt connection does not have the hook to keep the line facing the OEM specified location (currently, aftermarket lines don't have this). So, when installing, you will just need to hold the line in the same direction as the OEM line. Once it is tightened, it won't move anywhere.
Clutch Bleeding Procedure
The bleeder valve is located next to the banjo bolt side of the clutch line. This process takes two people (unless you have a power bleeder).
The factory service manual specifies that the clutch pedal should be pumped 5 times (manually moved back up if needed), then depressed and held while the bleeder valve is opened and closed to allow air/old fluid out. This procedure takes a long time. I recommend to release the clutch pedal slowly so the air in the line doesn't get as disrupted and pump the pedal many more times (up to 30) before opening and closing the valve. We found that there was very little pressure build up when just pumping 5 times during the first several cycles. You repeat this while refilling the clutch fluid reservoir until there is no more air in the system & the pressure builds up quickly.
Alternatively, you can use a vacuum bleeding kit to suck air/fluid out of the bleeder. We did not have our pressurized bleeder handy, so we had to make due with a vacuum brake bleeding kit for a bicycle (avid kit, for reference). First, we build up pressure by pumping the clutch pedal until it returned on its own. After that, we left the pedal in the up position. We then put some fluid into the syringe and filled the bleeding line with fluid so that there was no air in the line. Next, we opened the bleeder valve and sucked out the air/old fluid & closed the bleeder valve as the syringe was getting full. We repeated this step several times until air was no longer getting sucked out.
Some 350z owners found that adjusting the clutch pedal adjustmet rod (under the clutch pedal in the driver's compartment) helped with bleeding by allowing the master cylinder to be pressed in further. You should set this back to your preferred engagement point after bleeding is done.