Clutch Woes

[Ictoan]

Hi,

Well, completed my first Classic Rally with the Sprint and managed to get to the finish despite a clutch that would not disengage making gear changing very difficult/impossible. Had to use the key to start and stop.

The pedal started to feel 'odd', then changing gear became nigh on impossible. Checked reservoir and there was still plenty fluid in it. After speaking to a fellow Sprint owner he suggested that the problem is probably to do with the lever arm(?) as this can be a week spot. It feels like the clutch is trying to disengage by a fraction but nowhere near enough to allow a gear change without careful matching of engine revs and I can only get moving by starting in gear.

Can anyone expand on my problem to help me understand what has happened and what it will take to fix? I understand it is a 'box out' job!

Thanks,
Tim

[Pippin]

I had this problem on my Sprint. The clutch slave cylinder operates the clutch by means of a lever arm on the outside of the bellhousing. This lever is prone to cracking, so the lever flexes when you depress the clutch pedal, which decreases the clutch travel. You could possibly get it welded in situ, but you'd need a lift to do it. However, you can check this simply by getting the car on ramps or axle stands and looking underneath.

Jer

[Ictoan]

I had this problem on my Sprint. The clutch slave cylinder operates the clutch by means of a lever arm on the outside of the bellhousing. This lever is prone to cracking, so the lever flexes when you depress the clutch pedal, which decreases the clutch travel. You could possibly get it welded in situ, but you'd need a lift to do it. However, you can check this simply by getting the car on ramps or axle stands and looking underneath.

Jer

Thanks Jer, weather permitting I will have a look tomorrow.

Tim

[Ictoan]

Had a look this morning and, to my inexperienced eye, it looks like the slave cylinder pushrod is only moving a minimal amount, difficult to say exactly how much but the lever looks like it moves about 1cm. I have tried to take a photo but struggled to get the right angle however here they are.



First pic shows pushrod and lever with clutch pedal up.



Second pic shows pushrod and lever with pedal depressed.

Does this look like the correct amount of movement?

Thanks,
Tim

[Mad Mart]

Ther should be about 3/4" travel.

[Ictoan]

Apologies for the constant updates, but I have had a reasonably measure of the amount of movement of the slave cylinder pushrod and it is about 5mm. (edited from cm to mm!)

Tim

[Ictoan]

Thanks Mart for that info. I posted the amount of movement I have before reading your post.

Looks like I am not getting sufficient movement of the pushrod. I will try bleeding the system but should I change both master and slave cylinder?

[Ictoan]

...but of course bleeding the system is easier said than done lying on your back on the drive. Bleed nipple is above feed pipe

I have read about bleeding off the car but cannot get to the top securing nut for the slave cylinder.

[Ictoan]

If a m/c or slave were at fault would they always leak? Mine do not appear to be leaking, though there is a little dampness around the rubber gaiters which I cannot make my mind up if it is just grease or brake fluid. It doesn't feel or smell of brake fluid.

Thanks,
Tim

[Jon Tilson]

This job is all so much easier if you take out the tunnel. If you have air in the system the pedal will feel floppy.
A little air goes a long way in making it all ineffective.

The clutch cross shaft fails in 2 ways....the lever breaks where its welded to the shaft - the weld cracks. Or the wedgelock tapered pin shears allowing the bearing carrier fork to move relative to the shaft. Both can cause the lever connected to the slave to go far enough to touch the bell housing.
These are your worst case expensive fails....

The cheap stuff is re-conning your master and slave cylinders.
If you have a broken wedgelock or cross shaft consider the bellows replacement featured eslewhere e.g. shaune roche's resto project. Not cheap but solves the problem...

If you dont want to take out the tunnel you can maybe get the entire bracket off by undoing the bolts that secure it to the gearbox remote. I think it can just be reached from under the bonnet. You can fish it out and then reseal and rebleed. Clamp the slave piston and bleed it solid - then you know there is no air.

Bleeding in situ is difficult on a Sprint as you get a trapped air bubble. Sometimes jacking the rear wheels up high helps it come out.

Jonners

[Ictoan]

This job is all so much easier if you take out the tunnel. If you have air in the system the pedal will feel floppy.
A little air goes a long way in making it all ineffective.

The clutch cross shaft fails in 2 ways....the lever breaks where its welded to the shaft - the weld cracks. Or the wedgelock tapered pin shears allowing the bearing carrier fork to move relative to the shaft. Both can cause the lever connected to the slave to go far enough to touch the bell housing.
These are your worst case expensive fails....

The cheap stuff is re-conning your master and slave cylinders.
If you have a broken wedgelock or cross shaft consider the bellows replacement featured eslewhere e.g. shaune roche's resto project. Not cheap but solves the problem...

If you dont want to take out the tunnel you can maybe get the entire bracket off by undoing the bolts that secure it to the gearbox remote. I think it can just be reached from under the bonnet. You can fish it out and then reseal and rebleed. Clamp the slave piston and bleed it solid - then you know there is no air.

Bleeding in situ is difficult on a Sprint as you get a trapped air bubble. Sometimes jacking the rear wheels up high helps it come out.

Jonners

Hi Jon, thanks for the explanation.

Re the release internals. If I move the external arm (attached to the slave) manually back and forward on it's 'free' travel I can hear a 'ting' as, I think, the release bearing hits the cover plate fingers-does this sound right? If so, that would suggest to me that the release mechanism within is moving along the splines, it is just not moving far enough.

As far as I can tell there is a healthy lump of weld where the lever attaches to the cross shaft and I could not detect any movement at this point, but I will need to double check when it stops raining (which won't be today due to the rain). Also, the lever does not move very far, only about 5mm from normal resting position to fully forward, and does not go anywhere near hitting the bell housing. Would the internals seize in such a way to stop full movement of the lever and pushrod?

When I depress the pedal it goes virtually to the floor and then the last bit of pedal movement (.5 to 1.0 inch?) seems to give the the 5mm of movement referred to above. I have searched this forum and seen reference to the flexible hose being a potential week point, could this give the symptoms I am trying to describe?

I can see that ultimately I will probably have to remove the tunnel but before doing that I want to get a better grasp of the problem.

Thanks again Jon.

Tim

[Jon Tilson]

The lever is moving the bearing carrier and its fork until the bearing touches the fingers on the clutch cover,
so what you are feeling sounds correct.
It takes quite a bit of effort to then release the clutch. More I suspect than you can manage by hand. If there is
no evidence that the lever has ever fouled the bell housing I suspect that you just have air in the hydraulics.

Yes the hose can fail so check it for bulges if you have the old black type. The red plastic ones just let go with a bang. Not that common on Sprints.

I would just get new seal kits for master and slave and then try again. The unions can be a pain to get out and often shear on the old black pipes. I tend to try them gently and if they dont come I leave them. Its more fiddly
but rubbers can be changed with the hose still in place.

Looks like you have the cheaper failure....good luck with it.

Jonners

[Ictoan]

Thanks very much Jon. I will try the seal kits first, though I will need to id the slave first as I see there appear to be two options (Lockheed and Girling).

Tim

[Ictoan]

Well, having removed the tunnel (you were right Jon, makes it so much easier) I have removed the slave cylinder. The hose appears to be OK with no bulges but having looked at the slave I think it is possibly beyond redemption as the cylinder looks corroded and scored so I will just get a new one.

Can anyone advise of the benefit, or otherwise, between the oem, Land Rover and the 7/8 inch bore examples available from Rimmers?

Thanks,
Tim

[Jon Tilson]

You must stick to the same bore. A larger bore one will move less for the same pedal movement.
Also be careful that the newer ones have the same thread for your hose.
Have you tried cleaning the bore with 1200 grit wet and dry?

I may have a decent second hand one...

Jonners