clutch pedal soft when engine is started

PostPost by: h20hamelan » Tue Sep 03, 2024 4:44 pm

The master controls the slave
100mm total
When you measure the slave, it is at zero-mm when not depressed, and 20-mm when depressed?
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PostPost by: tonyabacus » Tue Sep 03, 2024 8:52 pm

The thing we are all trying to establish is how far the clutch slave rod moves when the pedal is depressed.
So find someone to help by sitting in the car and pushing the pedal whilst you measure the travel on the rod. If you have a mobile phone try and video the operation whilst holding a ruler or measure of some sort to show the travel.

An easy measure can be made out of cardboard, so resting the card against the operating lever and then making a mark at the slave end at rest and another at fully depressed. Post the video here so we can see what is happening.
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PostPost by: rgh0 » Tue Sep 03, 2024 9:21 pm

If the slave cylinder is moving the lever arm by 20mm and the clutch us not releasing then most likely there is an issue internally in the clutch assembly. Personally I would investigate further with a borescope before pulling the engine.

There are multiple issues that could cause the problem and sometimes the evidence gets lost when you pull the engine so any investigation to know what to fix before pulling it apart is worthwhile

i.e.
siezed pilot bearing in the crank
clutch plate in backwards or plate siezed on splines, wrong clutch plate
incorrect assembly of the clutch throw out mechanism of release bearing and carrier and D spacer and spring clips and arm on to the pivot

cheers
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PostPost by: mark030358 » Tue Sep 03, 2024 9:28 pm

Hi all,
From my experience on an Elan the pushrod in the slave will move around 13mm.

Cheers
Mark
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PostPost by: checkrail » Wed Sep 04, 2024 9:44 am

The clutch plate is a Borg & Beck from SJ, definetly fitted the correct way wound. If I keep pumping the pedal it firms up as if there could still be some air in there, but no sign of tiny bubbles in the master cylinder.
I don't want to keep repeating myself but as it's only the plate that's been changed, how could anything be wrong with the operating mechanism. I've noticed that the slave cylinder does not move in the bell housing

John
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PostPost by: Craven » Wed Sep 04, 2024 10:52 am

You wrote,
Hi all, I've fitted a new clutch plate and slave cylinder.
Bleeding the clutch system on an Elan can be very problematic.
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PostPost by: NTG999 » Wed Sep 04, 2024 2:46 pm

I had no gears after my full rebuild despite bleeding the slave cylinder repeatedly in situ. I removed the push rod and fitted a spacer then adjusted it out as far as I could so it was pushing the clutch lever. Started the car and could select gears so I knew it was the pushrod not moving far enough. Removed manifold and bled the slave cylinder with bleed orientated to the highest point - reassembled all fine
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PostPost by: shynsy » Wed Sep 04, 2024 7:54 pm

Probably already said but I take it the blead nipple is at the top of the slave. Otherwise you will never bleed it.
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PostPost by: tonyabacus » Wed Sep 04, 2024 8:15 pm

Had a similar problem on a Mini Cooper S years ago, someone had fitted the brake calipers on the wrong sides, so no matter what they did it would not bleed till the calipers were put on the correct sides with nipples at the top.

So make sure your slave has the bleed nipple at the top, as mentioned earlier
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PostPost by: rgh0 » Wed Sep 04, 2024 8:31 pm

checkrail wrote:The clutch plate is a Borg & Beck from SJ, definetly fitted the correct way wound. If I keep pumping the pedal it firms up as if there could still be some air in there, but no sign of tiny bubbles in the master cylinder.
I don't want to keep repeating myself but as it's only the plate that's been changed, how could anything be wrong with the operating mechanism. I've noticed that the slave cylinder does not move in the bell housing

John


Hi John
You previously stated that the clutch slave cylinder push rod lever moves 20 mm when the clutch predal is depressed i.e. from 80mm to 100mm from the slave cylinder. If this is truely the case then the clutch should release unless there is some internal assembly problem. I gave you a list internal things that can cause the problem. Without futher photos of the clutch slave and lever arm as the clutch pedal its operated and photos from a borescope examination, we are all speculating as to possible cause and you only option is to pull the engine yet again

cheers
Rohan
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PostPost by: 512BB » Thu Sep 05, 2024 7:35 am

'So make sure your slave has the bleed nipple at the top'

That is the bleedin problem! :lol: The bleedin bleed nipple is never at the top of the slave. It is side by side with the inlet pipe which is horizontal. You cannot change the orientation of the slave cylinder as the sandwich plate prevents that. At least it does on ALL my cars, including a +2. What am I missing here?

I have no idea if there is an actual problem with John's set up, but I think the issue could possibly be that he is trying to bleed the system on his own, with no helper, using what ever contraption he has to do the job single handed, and it is not man enough, or efficient enough, to do the job properly. I have to bleed the clutch system sometimes 3 times to obtain a good pedal.

I find the task of bleeding the clutch difficult enough with a helper, pictured, and cannot imagine trying to do it without. Is there not someone in the Lincoln area who can go an give John a hand, or foot?

Leslie
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PostPost by: rgh0 » Thu Sep 05, 2024 8:06 am

I can bleed the clutch on my own. Sometimes I have to wedge down the pedal overnight to get the last bit of air out. And yes i cant rotate the slave cylinder due to the lip on the sandwich plate.

However it does not appear to be a bleeding problem as John states the slave cylinder push rod and clutch lever arm moves 20mm. if that is the case then then bleeding more will not help.
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PostPost by: draenog » Thu Sep 05, 2024 3:38 pm

Although this does not look to be a bleeding issue, FTR I bled the clutch on my own using a "one man" bleeding tool:

https://www.ebay.co.uk/itm/224851359226

I did wedge the pedal down to get the last bit of air out, but the pedal was perfectly usable before.
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PostPost by: tonyabacus » Fri Sep 06, 2024 5:05 pm

John
Have you tried talking to your local garage about using their power bleeder, most garages will have such kit, normally these are not a viable purchase unless you use it on a regular basis, but worth a word or two with the owner, makes bleeding very easy
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PostPost by: checkrail » Sat Sep 14, 2024 2:11 pm

Hi all, I've been without internet connection for over a week now but back online with a new BT Hub.

I would really appreciate some help if there is anybody in the Lincoln area willing to come round and help

Please call 01522 692283 thanks very much John
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