Clutch problems

No one has mentioned adjusting the length of the gear cables. This does sound as if it may be your solution.

It took me ages to get the gear change usable & a couple of months, on & off with micro adjustments, to get to where I am now.
I still think the stick is too far forward & prompted by comments on this post I’ll be in the pit later to have another look.
The first thing is to change the scroll pin, it has resolutely refused to move by the “judicial application of standard force” & now I’ll make a tool that will make life uncomfortable as it is pressed inexorably out.
M

Surely just “extending” the cable just places the gear stick in a different neutral position. And if all gears can be selected with engine off it does suggest a clutch problem. However,  why immediately after not being able to select the forward movement of the gearstick is a puzzle unless the loss of the U clip occurred at that moment which seems likely.

As I said earlier I went under the car & disconnected the bottom cable to verify the operation of the extractor tool I made, (which was fine). On reassembly it was notchy, inspection showed I hadn’t got the fixing clip fully home, a further shove & it nestled into place & I’m back to normal.
I think this illustrates how finicky these systems can be or maybe mine is just a bastard & enjoys the inconvenience it inflicts on me.
M

Not being able to select 1st, 3rd and 5th gears after losing the clip is very easy to understand. If you remove the clip and watch the gearbox end of the cable while someone else selects the gears you will notice that when those gears are being selected the end of the cable comes out of the bracket. Essentially you are mostly just moving the outer sheath to and fro to the extent that the bell crank doesn’t move sufficiently into the gearbox to engage the gears. However when you try to select 2nd,4th or rev the cable end relocates into the bracket and gear selection occurs. 

I have had time today to have another go, I bled the master cylinder as per the instructions from the MGF Register and all is back to normal, we have greater clutch disengagement and you can feel the resistance on the clutch pedal for more of its travel. I have also had a ruler up against the slave cylinder and measured the travel of the pushrod, due to cables and hoses being in the way it is not easy to get an accurate measurement but after several tries the pushrod extends by about 25mm, however the bracket moves in the wrong direction by 5mm!. 20% of the travel is lost and it's the most important 20% that would give greater clutch plate separation and raise the bite point further off the floor. I will have a look at the potential for a support bracket when I have time. 
 

It’s good to hear all has been returned to normal, however it illustrates how small increments can create big problems.
Remaining in the clutch / gearbox vicinity, I mentioned the problems I had after changing the to gear cable & it was down to insufficient fine adjustment. The cables terminate in an M6 thread which has a 1mm pitch & as the popper type connector, to the bell crank, had to go right around to relocate. If it is either too short or too long problems arise, I found that that 1mm made the difference between a sweet change & a notch up/down change.
M

Surely one revolution of the rose joint would only reposition the gear lever by an amount equivalent to the relevant mechanical advantage that the gear lever assembly offers . I’m expecting the “gate” to be defined by the movement of selector rods and their relevant movement. The gear lever might tilt more forward/back or left/right respectively. As I see it the only issue might be if the lever mechanism struck the tunnel somewhere etc.
So I’m a bit puzzled why that one revolution can make such a difference. Any one explain that please?

I agree & it’s counter intuitive but there is a sweet spot with my system. There could be a fault elsewhere but I’ve looked, but haven’t noticed anything, either obvious or not.
When I removed the old cable & placed it along side the new, making allowances for the failure point on the original, I found the replacement to be slightly longer.
This in all probability is the root (or route if your are an embarrassed antipodean) cause.
M

Amused......not embarrassed!
You must remember we are shameless brutes, downunder!

Good on ya mate!
M

An update, every thing was working perfectly until last Wednesday when we drove down to Barnstable then on to Heddons Mouth (near Lyndon and Lynmouth) and the clutch was no longer fully disengaging. My wife was driving with me as passenger and became like it was before. I had a look at it today after finding two rosé joints yesterday, I fitted them in a similar fashion to Airportable. The only difference in the method was due to me having 8mm joints I just used one of  the slave cylinder mounting bolts to mount one end. Also because I only had right hand threaded one it was a bit of a fiddle to get it right. There isn’t a lot of room in there!
Due to Ruth going up to Harpenden to look after the grandkids I haven’t been able to bleed the master cylinder yet. A quick test drive confirmed it was working well. 
The question is what is going on? I am thinking that the master cylinder is drawing in air and causing the problem. Next week my helper will be back and I will bleed the system again.