Lotus Elan and Lotus Elan Plus 2 Forums

Hello all, hoping someone can help me please. I took my 71 Sprint out this morning and, after about two miles and going up through the gears, the clutch pedal went ‘light’. I could feel negligible pressure and, of course, changing gear was then an issue, although I did manage to get back home with clutchless gear changes. The clutch worked just enough so that I could drive it into my garage, but only when I depressed the pedal fully to the floor. On investigation, the clutch fluid reservoir / master cylinder has fluid in it up to the level I would expect. Also, when My wife sat in the car and depressed the clutch pedal, the fluid didn’t react at all, even when pumped. I’d really appreciate any advice on what to do next. Many thanks in advance.

Could be overheated fluid, the slave cylinder is very near the exhaust and gets hot. Or possibly failed master cylinder.

When was the fluid last changed? After a visual check I'd start with new, ideally high temp, fluid change.

My bet would be the master cylinder. Normally when goosed the slave cylinder leaks, which you don't mention, and the m/c reservoir is full. I had one go on my current Elan S/E when I owned it nearly 20 years ago, exactly the same.

Do you have any crystals in your master cylinder?

In the 1980s my +2 clutch suddenly went free and I found lots of small crystal spheres in the reservoir. One had slipped into the works and jammed open the the return valve blade. I had recently changed the fluid and have no explanation. Edit: IT WAS ACTUALLY THE BRAKES THAT FAILED TOTALLY!

I don't think it's your problem as you still have some action.

Get rebuild kits for both the master and slave. Also a new circlip for the slave, just in case. One of your cylinders is failing, and the other might be right behind.

Is there any resistance to the pedal? (other than the pedal return and thrust lever return springs)

I'm not sure that the master cylinder fluid surface would change a noticeable amount whilst pumping the pedal so that might not be a good indicator anyway.

You need to look underneath the car and see if the slave cylinder pushrod is moving when the pedal is depressed. If it is then its possible that the pressed steel lever that operates the thrust race has fractured. I seem to recall that its not such a rare occurrence.

Ian

Has the clip come off the slave cylinder at the gearbox end?

Thanks for all your suggestions. No crystals, so that’s ok. I’ve been under the car and everything moves as it should when the clutch pedal is depressed, and no noticeable fracture. I did notice some fluid escaping from the screw-in bolt on the master cylinder (see pic) when the pedal was depressed. I’ve tightened this and stopped the leak - I’ve also topped up the clutch/brake fluid to the mark. The pedal is still ‘light’ until near the bottom of its travel when there is then some resistance - which does seem to release the clutch enough to select a gear. I’ve decided to strip both master and slave cylinders and renew the seals - just have to order the required rebuild kits now…

if the slave cylinder is moving the lever as it should when the pedal is pushed then the problem is inside the bell housing with a broken lever or thrust bearing or pressure plate

cheers
Rohan

mbell wrote:Could be overheated fluid, the slave cylinder is very near the exhaust and gets hot. Or possibly failed master cylinder.

When was the fluid last changed? After a visual check I'd start with new, ideally high temp, fluid change.

I think you are describing a LH drive car, but the OP was probably driving a RH drive car.

ElanAl wrote:Thanks for all your suggestions. No crystals, so that’s ok. I’ve been under the car and everything moves as it should when the clutch pedal is depressed, and no noticeable fracture. I did notice some fluid escaping from the screw-in bolt on the master cylinder (see pic) when the pedal was depressed. I’ve tightened this and stopped the leak - I’ve also topped up the clutch/brake fluid to the mark. The pedal is still ‘light’ until near the bottom of its travel when there is then some resistance - which does seem to release the clutch enough to select a gear. I’ve decided to strip both master and slave cylinders and renew the seals - just have to order the required rebuild kits now…

You need to bleed the clutch system as well as having tightened the connections. You have the symptoms now of a bubble of air in the fluid.

ElanAl wrote:Thanks for all your suggestions. No crystals, so that’s ok. I’ve been under the car and everything moves as it should when the clutch pedal is depressed, and no noticeable fracture. I did notice some fluid escaping from the screw-in bolt on the master cylinder (see pic) when the pedal was depressed. I’ve tightened this and stopped the leak - I’ve also topped up the clutch/brake fluid to the mark. The pedal is still ‘light’ until near the bottom of its travel when there is then some resistance - which does seem to release the clutch enough to select a gear. I’ve decided to strip both master and slave cylinders and renew the seals - just have to order the required rebuild kits now…

Sounds like you dont have a problem, if as you say 'everything' moves as it should!

We still have no idea of how much resistance there to your foot/hand when you press the pedal. if the hydraulic system is working then the slave piston will be moving its pushrod and then the clutch lever. If the lever does have a fracture the external visible bit will move but any break will be near the pivot inside the bell housing so is quite well hidden.

TBH the fault is most likely to be hydraulic but the symptoms you describe could also relate to a mechanical fault.

Ian

The fact that the issue occurred suddenly whilst driving and there is no significant external fluid leakage suggests to me that you have a mechanical problem with the clutch and not a hydraulic one.

billwill wrote:I think you are describing a LH drive car, but the OP was probably driving a RH drive car.

LHD or RHD doesn't matter. Slave position and exhaust don't move locations between LHD and RHD, just the master cylinder that moves.

Having a leak introduced air in the system so a bleed function is in order but if you're rebuilding
the cylinders, a moot point now.