RX8 Concentric Release Fitting Guide
RX8 Concentric release fitting guide for 5 and 6 speed boxes.
Please note that this setup is to suit a 90mm clutch height from block to fingers. This is the standard setup height with a single plate clutch for a Pinto, Zetec and Crossflow. These do not require spacers or additional work. A stop may be required on your clutch pedal to stop over extension of the slave cylinder. When tested with a 0.75 master cylinder, 18mm of master cylinder stroke was enough to release the clutch. Spacers can be supplied to suit different clutch heights. Please ensure you measure the distance from the block face to clutch fingers and get in touch to clarify spacers at the time of ordering.
6 Speed RX8 Gearbox Fitting
- Remove the original clutch fork from the box. Remove the input shaft cover by undoing the 7off 12mm headed bolts and then tapping the cover with a mallet to remove it. Cut off the nose sleeve where the original release bearing sat and grind or machine down flush so that the cover is 23mm thick from the mounting face where it joins the bellhousing to where you have just cut/machined the nose off. Cut off the original pivot point and dress it flush with the mounting faces of the bolts that hold the input shaft cover on. With the input shaft cover laid on the bench, put the new alloy slave cylinder mounting plate on top of the input shaft cover to check you have taken enough material from the nose.
2. Clean up the back face of the input shaft cover, removing all old sealant and wash out any swarf and dirt from the cover. Refit the input cover ensuring to use new sealer. Flange sealant works best.
3. If you are using a Zetec, Pinto or crossflow, bolt on the new release bearing mounting plate using the 5 off M8 cap head bolts supplied. Tighten these up and refit the original 2 bolts in the bottom two holes. If you are running a different engine you need to measure the distance between the clutch fingers and engine block face without adaptor plate as accurately as possible to calculate spacer thickness.
3a. To calculate the thickness of spacers, put a straight edge across the clutch fingers and measure using a steel rule to the block face.
Spacer Thickness = 90mm - Distance from block face to clutch fingers
If you are running a 15mm machined down bellhousing for K20/24 and Vauxhall/Saab then this calculation becomes:
Spacer Thickness = 75mm - Distance from block face to clutch fingers
If you need to use spacers, ensure that the spacers are sitting between the input shaft cover and the concentric cylinder and that they are flat. See first picture with spacers behind the bracket and second picture with no spacers bolted into the gearbox.
The first picture is with no spacers and second with 2 off 8mm spacers.
4. Pre bleed the slave cylinder by fitting the pipe to the cylinder that runs from the master cylinder. Submerge the master cylinder end in some brake fluid. Slowly squeeze and release the slave cylinder until no bubbles come out and all air is expelled.
5. Bolt the cylinder to the bracket using the 3off M6 cap head bolts supplied in the kit.
Feed and Bleed pipe installation
To aid with bleeding, install a T piece in the line between the master cylinder and concentric slave with a bleed nipple fitted as close to the gearbox as possible.
RX8 5 Speed Concentric Fitting
- Remove the original clutch fork. Remove the input shaft cover by undoing the 4 bolts and discard this piece. Cut back the original clutch pivot point.
- Fit the laser cut seal keep ring by tapping in place.
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If you are using a Zetec, Pinto or crossflow, bolt on the new release bearing mounting plate using the 4 off M8 countersunk head bolts supplied. If you are running a different engine you need to measure the distance between the clutch fingers and engine block face without adaptor plate as accurately as possible to calculate spacer thickness.
3a. To calculate the thickness of spacers, put a straight edge across the clutch fingers and measure using a steel rule to the block face.
Spacer Thickness = 90mm - Distance from block face to clutch fingers
If you are running a 15mm machined down bellhousing for K20/24 and Vauxhall/Saab then this calculation becomes:
Spacer Thickness = 75mm - Distance from block face to clutch fingers
- Pre bleed the slave cylinder by fitting the pipe to the cylinder that runs from the master cylinder. Submerge the master cylinder end in some brake fluid. Slowly squeeze and release the slave cylinder until no bubbles come out and all air is expelled.
- Fit the slave cylinder using the 3 off M6 bolts supplied. Pipe fitting towards the top.
Feed and Bleed pipe installation
To aid with bleeding, install a T piece in the line between the master cylinder and concentric slave with a bleed nipple fitted as close to the gearbox as possible.