Plus 8 is 1992 with 3.9 engine. With car on level surface and in gear with handbrake on, lifting clutch pedal brings rev drop after about 2.5cms (1 inch) travel. What does this mean?
Assuming your clutch pedal was to the floor, that is not good. It means your clutch system is not full engaging for some reason. Those reasons in order of likelihood (and hope) are;
1. The system is badly need of bleeding. (10 minute fix & no cost)
2. The system is very badly in need of new clutch fluid and flushing and bleeding. (30 minutes & 2 bottles of DOT 3 or 4 brake fluid)
3. The slave cylinder is going (very common with pre-1995s) (20-60 minutes depending on the access hassles, minor risks, new slave cylinder for 15 GBP and one bottle of brake fluid).
4. The master cylinder is going, (60-90 minutes, new master cylinder for 60 GBP and one bottle of brake fluid)
5. Your clutch itself is going, (12 hours, engine out job, new clutch for 200 GBP)
I am partial to numbers 1 & 2 & 3.
For 1 & 2 I am guessing the system has not been flushed or bled for a long time. (should be done every 2 years regardless of mileage)
N.B. If DOT 5 was mistakenly used at one point, that could destroy the all the clutch hydraulic seals depending on the circumstances.
For number 3, this is the curse of the Plus 8s from 1976 to 1994)
Maurice Owen had trouble fitting the clutch and Sd1 bellhousing into the Plus 8 bulkhead and adjacent crossmember. So to do so, he cut off the offending bellhousing section that held the standard SD1 clutch slave, welded the resultant hole closed and opened up the top of the bellhousing and fit a totally different clutch slave. He also had to create a box at the top of the gearbox cover as the slave arm moves back into the passenger compartment.
This resulted in a number of problems.
a. The clutch slave is above the master cylinder, making it difficult to bleed and easy to develop bubbles.
b. The clutch slave and its bleeding nipple became a pig to access with the array of EFI gear.
c. The slave's arm enters the slave at a non0ideal angle, making quick wear a certainty. I have never seen one last beyond 20,000 miles and most much less. (The solution is to sleeve your slave in stainless.)
All in all it is a very poor design.
[BTW, The later fix was to change the crossmember to a half-moon shape to accommodate the bellhousing and simply slice off the bellhousing section that covers and closes off the housing at the bottom clutch slave. So later +8 clutch slaves don't fail and are easy to replace, but the bottom of the bellhousing is open to road debris.]
Examine your clutch slave cylinder carefully for any sign of leakage. Then flush and bleed your system and try the clutch again.
Lorne
