Elan S4 clutch

[lotusposition]

Hoping someone can advise me. Just fitted my 2nd new clutch master cylinder. 1st one would not allow fluid return to reservoir. This new one will not transfer fluid from the reservoir to the master cylinder. Anyone else had this experience and possibly know what is wrong here?

[oldelanman]

The pushrod needs to be changed on replacement master cylinders to suit the Elan. Have you done this?

[lotusposition]

Yes, Pushrod changed to correct length.

[rgh0]

The symptoms are consistent with the seal at the end of the master cylinder to the reservoir sticking closed. It should close when the pedal is depressed and open when the pedal is released. If not assembled correctly it may not work as intended. It is normally caused by a pushrod that is to long but if this is not the case then it is due to an internal assembly issue

cheers
Rohan

[lotusposition]

Interesting you say that Rohan.
I've had extreme problems since changing the pushrod according to Brian Buckland's book measurement. This is the 3rd master cylinder that's 'failed' me due to what appears to be a problem with the 'valve' within the master cylinder.
Last master cylinder was having a problem returning the fluid to the master cylinder after pedal was released. The new master fitted this morning will not tranfer the fluid from the reservoir.
I'm thinking about reverting to the original push rod that I was using before all this trouble started. Do you know what the pushrod length should be ?

Donald

[rgh0]

If your orignal pushrod length is shorter then I would try that. Sorry I am travelling currently and dont have access to measure the correct length. I have never measured it and just swapped the old rod to new cylinders over the years. I never used or checked the legnth in the Buckland book. However there are a number of things that could affect the required length needed such as extra fibre glass reinforcing added to the firewall which is a fairly common modification or some change to the pedal assembly not allowing the clutch pedal to comeback as far as it should

cheers
Rohan

[oldelanman]

My original pushrod measures 82mm overall from centre of clevis pin hole.

Another thought.. is the pedal moving freely on the shaft and do you have a pedal return spring fitted ?

[snowyelan]

Old posting, but highlights the variability.

viewtopic.php?f=37&t=15030&start=

BB book shows 3.125" 80mm (actually 79.4mm).
Oldelanman 82mm
I'd re-install the original as Rohan suggests.

[lotusposition]

Thanks for all your replies.
Rohan, no, the firewall and pedal box have not, to my knowledge, been changed in any way. I have owned the car since it was 5 years old.
I shall try back bleeding via the slave before I revert to original pushrod...as a last resort!

[gjz30075]

I just checked my S3 and Sprint and there is a very slight free motion between the pushrod and the pedal. That
ensures the master cylinder piston is fully 'up'. There is no slop in the parts. Unfortunately, I
don't know the length of the rods.

[lotusposition]

Thanks Greg.
Do you mean that the clutch pedal should 'hang' slightly lower than the adjacent brake pedal. 2-3 mm perhaps ?

Donald

[lotusposition]

Thanks Oldelanman

Yes, pedal is moving freely on the shaft and no I don't have a pedal return spring fitted. It's never seemed to need one.

[oldelanman]

Thanks Oldelanman

Yes, pedal is moving freely on the shaft and no I don't have a pedal return spring fitted. It's never seemed to need one.

That could be your issue, without a spring supporting the weight of the pedal the pushrod will be resting on the master cylinder piston.

[2cams70]

Sometimes master cylinders can behave strangely when first fitted due to air locks. Have you tried bleeding just the cylinder itself before fitting - i.e operating the pushrod by hand whilst the cylinder is out of the car and pumping fluid through it and fitting it with the cylinder full of fluid? Alternatively crack open the brake line at the cylinder and pump until you see fluid.

[gjz30075]

Thanks Greg.
Do you mean that the clutch pedal should 'hang' slightly lower than the adjacent brake pedal. 2-3 mm perhaps ?

Donald

No, I mean the motion when the pedal begins its travel. So, with the pedal at rest, I can feel the
pushrod is very slightly loose, ie, no tension on it, so I know it's not impeding the piston in the
cylinder from fully retracting.