Scimitar - Can't select reverse properly

[geeman237]

1973 Reliant Scimitar with the Ford type 5(?) 4 speed gearbox with OD and its the 3 rod linkage side mounted gearchange.
I just got my Scimitar back on the road after a 3 year lay up. Separated the engine and gearbox and did the following:-
1) New gearbox oil
2) New friction plate
3) New clutch slave cylinder
4) New release bearing
5) New gear selector bush kit
6) Same clutch cover as it was in good condition

The clutch pedal has full travel and I can select all forward gears
The clutch 'bites' at about 2" up from releasing the clutch pedal. Nice and smooth.
When traveling forwards you can push the clutch pedal down and hear the engine revs rise as it the clutch disengages.

However, it will not engage reverse without a gnashing of gears. I can turn the engine off, put it in reverse and then start the engine and its fine.

I have tried pumping the clutch and the rod is properly adjusted from the slave cylinder to the release lever on the input shaft.

Clearly the gears are still rotating hence the grinding of the gears. But as the clutch appears to be disengaging why are the gears still turning and grinding?

[Little Pete]

You are correct in saying the gears are still turning and two things will cause this. Firstly if the drive straps on the clutch cover are worn the cover won't fully release the drive plate. You can't determine this wear by looking at the cover.
Secondly the input shaft support bearing in the end of the crankshaft could be failing and this will continue to drive the input shaft even if the clutch is fully disengaged.
The problem isn't present in the forward gears because of the sychromesh on the gears -the gearbox is always turning when going forward- although I would have thought you might have difficulty selecting first gear.
If you had hydraulic or adjustment issues the bite point would be right at the bottom so I'm assuming these are ok.
Hope this helps.

[geeman237]

Little Pete said:

You are correct in saying the gears are still turning and two things will cause this. Firstly if the drive straps on the clutch cover are worn the cover won't fully release the drive plate. You can't determine this wear by looking at the cover.
Secondly the input shaft support bearing in the end of the crankshaft could be failing and this will continue to drive the input shaft even if the clutch is fully disengaged.
The problem isn't present in the forward gears because of the sychromesh on the gears -the gearbox is always turning when going forward- although I would have thought you might have difficulty selecting first gear.
If you had hydraulic or adjustment issues the bite point would be right at the bottom so I'm assuming these are ok.
Hope this helps.

Thanks for these suggestions. I'm not following you on number 2 though. If I recall this bearing in the end of the crankshaft is probably a bronze/oil-lite type bearing. I can't see how that failing would cause the input shaft to rotate. The rotation of the input shaft is surely via the splines on the input shaft engaging with the splines in the centre of the friction plate?
And when you refer to the drive straps on the clutch cover, I am thinking you are referring to the thin wedge shaped spring steel fingers. I know when I tightened up the clutch cover these fingers pressed out as they pressed against the friction plate.
I am sure the adjustment is correct on the hydraulics.
Maybe you are correct the tension in the clutch cover has worn out.....Oh no engine out again..... :-(

[paintman]

Due to the amount of work involved replacing the complete clutch assembly is always the preferred option.
Damage to the bearing/bush in which the nose of the input shaft sits or damage to the input shaft itself can cause the shaft to bind with the bearing.
Have you tried selecting a forward gear with the clutch depressed & then, with the pedal still down, engaging reverse?

[Little Pete]

Sorry for the confusion, I was forgetting your car would have an oil lite type bearing and not a ball race type. It's an age thing! The theory still applies though. If the bearing is not properly lubricated it will seize (weld itself !) onto the shaft which will then be driven by the crankshaft, whether the clutch fully releases or not.
The drive straps connect the outer cover to the drive face, they look like thin metal strips around the outside. Any uneven wear in these or the diaphragm springs will cause the problem.
Either way, if you are confident all is adjusted correctly, you are taking it out again. Look for uneven contact marks on the cover drive face. Also before you take the cover off the flywheel, check the ends of the clutch fingers. Make sure they are all sitting at the same height where they meet the release bearing. This is a symptom of uneven wear. Good luck.

[geeman237]

Thanks gents
Pumping the clutch pedal and selecting first first makes no difference. I am looking at an engine out again. The 'box is too damn heavy to drop out from below and I don't have access to a lift.
To make matters a little more challenging I am in the US so Scimitar parts are errr a little thin on the ground.
I'll get it sorted soon enough.

Thanks again.