Clutch pedal stuck

[BristolE30]

Hey zone

About a month ago I had a weird situation where the clutch pedal stuck to the floor. Few seconds later it was fine.

Then today my clutch pedal kept getting stuck to the floor in first. When I shifted up to second and third it seemed to work better, but pulling away from first it would bite so quickly and close to the floor.

Managed to get home and then whilst clutch was depressed and to the floor, the engine stalled because it was trying to engage. I’m lucky I made it home!! Pumping the pedal seems to reinvigorate it for a short period of time then it sticks again.

Anyway what do you think this could be? Brand new slave and master 3 months ago when I got the manual swap done. Brand was ridex...

Can’t see any external leaks anywhere but the fluid level Has gone down a bit

[Bally325]

I would start by bleeding the clutch to make sure there is no air in the system prob best to bleed it through to take out all old fluid

[BristolE30]

I would start by bleeding the clutch to make sure there is no air in the system prob best to bleed it through to take out all old fluid

How would air get in the system?

It has been working correctly for months

[rix313]

When was the last time you checked the fluid and looked in the reservoir? The amount I see that get forgotten about. The crud and dirt that’s sitting in the bottom of the reservoir then making its way into the system.

[paultv]

I would firstly do a careful check for fluid loss...inside the car at the master cylinder, inside the engine bay where the hard line exits the MC. Also the feed line from the resevoir and loss around the plastic T piece that connects the flex hose to the MS body. If all is totaly dry get under the car and check the hard line onto the slave, anything getting out of the bleed nipple? Then peel back the dust seal on the slave to check for fluid inside...it can hold quite a lot.

Check the fork retainer spring is correctly located in the holes in the bell housing.

Get someone to operate the clutch pedal whilst you put a thick feeler gauge into the slot where the SC push rod enters the clutch housing, as they depress and release the pedal you should be able to determine the "throw" cant remember off hand the correct distance for this, would have to check Bently.

As this occurred some time ago, I wonder if the push rod and fork are not sitting correctly, but the main concern would be fluid loss.

As the system is so simple there are few places to loose fluid and the clutch self bleeds to a great extent as it's all uphill from the slave cylinder.

Good luck!

Paul

[ocde30]

I had an erratic clutch pedal movement and so investigated underneath and found that the fork retaining spring, as mentioned by Paul above, was dislodged.
It is a simple thing to check off your possible "cause of fault" list.
From underneath it looked like this.

Screen Shot 2019-08-28 at 14.40.22.png

Inside bell-housing it would look like this.

IMG_2755.JPG

New one correctly fitted.

IMG_2763.JPG

Simple modification to avoid same thing happening again.

IMG_2761.JPG

Good luck

[BristolE30]

When was the last time you checked the fluid and looked in the reservoir? The amount I see that get forgotten about. The crud and dirt that’s sitting in the bottom of the reservoir then making its way into the system.

Fluid was completely replaced during the manual transmission swap. Fluid level currently on max, but it was a little higher than that before this happened.

Brand new slave and master cyl and brand new copper lines during the transmission swap.

I’m thinking it must be an internal leak in master cyl, as I am able to repressurise the system with a few pedal pumps. Someone on another forum mentioned this was a symptom of internal leaking.

[BristolE30]

I had an erratic clutch pedal movement and so investigated underneath and found that the fork retaining spring, as mentioned by Paul above, was dislodged.
It is a simple thing to check off your possible "cause of fault" list.
From underneath it looked like this.
Screen Shot 2019-08-28 at 14.40.22.png
Inside bell-housing it would look like this.
IMG_2755.JPG
New one correctly fitted.
IMG_2763.JPG
Simple modification to avoid same thing happening again.
IMG_2761.JPG
Good luck

Thank you mate, and thank you Paul I will check this retaining spring as I guess that could also be the issue! Might explain why it only does it in first gear really. If it has slipped out is it possible to replace/reinstate without removing trans?

[ocde30]

Unfortunately I don't think it is possible to reinstate without removing box. If it has jumped out of position it is likely to be a worn part. It should have been replaced when you had the clutch done - costs a few pence. At least it is a quick visual check to see if it is Ok though. You will see that if it is shiny then it was replaced.

[BristolE30]

After a bit of fiddling with the clutch pedal today I heard the lovely sound of a steady stream of clutch fluid hitting the garage floor. Bell housing was filled with DOT4, so safe to say the slave is gonners.

It was a brand new Ridex slave cyl from autodoc. Avoid this brand!!! Cheap rubbish.

[paultv]

If the push rod was misaligned or incorrectly seated it will pop out of the slave cylinder allowing fluid out...so it may be a slave fault or an install error or a fork failure.
Good you have evidence of a leak, pity it looks like a gearbox out job - bummer

Paul

[Speedtouch]

The slave cylinder can be replaced without having to remove the gearbox! With that wire retaining spring, as long as one side has remained in place, you could probably 'fish' the other side back into position with some careful use of wire poked through the hole...

[Brianmoooore]

The slave cylinder can be replaced without having to remove the gearbox! With that wire retaining spring, as long as one side has remained in place, you could probably 'fish' the other side back into position with some careful use of wire poked through the hole...

This is true, but I suspect there's more going on than a defective new cylinder. It seems likely that the new cylinder has simply popped its piston out of the bore because it had nothing to push against to keep it in.
No reason why you can't unbolt the cylinder to check though, before removing the gearbox if needed.

[BristolE30]

I replaced the slave cylinder today, was fairly easy job. System all bled and it’s working fine again!

Not sure what happened but yes the the rod had popped out of the old slave and was rather difficult to remove. Like it was stuck, had to give it a big tug.

New one went in easy enough!

[BristolE30]

The slave cylinder can be replaced without having to remove the gearbox! With that wire retaining spring, as long as one side has remained in place, you could probably 'fish' the other side back into position with some careful use of wire poked through the hole...

This is true, but I suspect there's more going on than a defective new cylinder. It seems likely that the new cylinder has simply popped its piston out of the bore because it had nothing to push against to keep it in.
No reason why you can't unbolt the cylinder to check though, before removing the gearbox if needed.

All of the fluid had drained out of the slave and into the bell housing, which wouldn’t happen if the rod had just simply slipped out of the bore right?

[BristolE30]

If the push rod was misaligned or incorrectly seated it will pop out of the slave cylinder allowing fluid out...so it may be a slave fault or an install error or a fork failure.
Good you have evidence of a leak, pity it looks like a gearbox out job - bummer

Paul

What would have made it pop out? It doesn’t pop out when it’s sat in the box on the shelf... The guy that installed it is an E30 specialist so I think it was just a bad slave :/ I’ve heard sometimes these cheap factory replicated parts don’t use correct grade rubbers and fluids such as DOT4 can corrode them

[paultv]

If the push rod is not correctly seated in the fork or the fork is damaged then when you push the clutch pedal the entire piston and pushrod could be ejected from the bore along with all the system fluid.

If you've lost all fluid - and the push rod is correctly mounted on the fork, then the slave has popped its seal. If the push rod was not correctly fitted to the fork then it could create binding, or allow the entire piston to pop.

All the manuals such as Bentley and Haynes make an important point about installing the push rod and seating it correctly -

Other information here:

Incorrect installation of either the master cylinder pushrod or
the slave cylinder push rod may cause the clutch release mechanism
to bind. This will prevent the clutch pedal .from returning
or cause the release action to feel jerky

lt may even prevent the
clutch pedal from being depressed.

3. I nspect the plastic tip of the push rod and the release
lever for wear. The pushrod should be worn only on the
tip.

NOTE
The release l ever should show wear o n ly in the
push rod recess. Wear o n the side of the pushrod
tip, or wear on the release l ever other than
i n the pushrod recess indicates that the pushrod
was misaligned.

4. Check the slave cylinder seal for leaks. If the push rod
seal is leaking, the slave cylinder should be replaced .

5. Lightly coat the plastic pushrod tip with molybdenum
disulfide grease (Molykote Longterm 2 or equivalent)
and make sure the tip engages the recess in the clutch
release lever.

NOTE -
When install i n g the slave cylinder, the bleeder
valve faces down.

Not sure if this helps at all -

Paul

[BristolE30]

If the push rod is not correctly seated in the fork or the fork is damaged then when you push the clutch pedal the entire piston and pushrod could be ejected from the bore along with all the system fluid.

If you've lost all fluid - and the push rod is correctly mounted on the fork, then the slave has popped its seal. If the push rod was not correctly fitted to the fork then it could create binding, or allow the entire piston to pop.

All the manuals such as Bentley and Haynes make an important point about installing the push rod and seating it correctly -

Other information here:

Incorrect installation of either the master cylinder pushrod or
the slave cylinder push rod may cause the clutch release mechanism
to bind. This will prevent the clutch pedal .from returning
or cause the release action to feel jerky

lt may even prevent the
clutch pedal from being depressed.

3. I nspect the plastic tip of the push rod and the release
lever for wear. The pushrod should be worn only on the
tip.

NOTE
The release l ever should show wear o n ly in the
push rod recess. Wear o n the side of the pushrod
tip, or wear on the release l ever other than
i n the pushrod recess indicates that the pushrod
was misaligned.

4. Check the slave cylinder seal for leaks. If the push rod
seal is leaking, the slave cylinder should be replaced .

5. Lightly coat the plastic pushrod tip with molybdenum
disulfide grease (Molykote Longterm 2 or equivalent)
and make sure the tip engages the recess in the clutch
release lever.

NOTE -
When install i n g the slave cylinder, the bleeder
valve faces down.

Not sure if this helps at all -

Paul

Interesting... I mean all I can say/make of it is the clutch has been working perfectly for the past 3 months, so doubt it was installed incorrectly. The clutch is now also working correctly, and the pedal has a smooth push all the way down and up.

So I think probably was just a bad part? Seal popped causing loss of all fluid

I’ll double check for any unusual wear on the old one though!

[Brianmoooore]

So I think probably was just a bad part? Seal popped causing loss of all fluid

I’ll double check for any unusual wear on the old one though!

So was the piston popped out of the bore?

[BristolE30]

So I think probably was just a bad part? Seal popped causing loss of all fluid

I’ll double check for any unusual wear on the old one though!

So was the piston popped out of the bore?

I’m not sure, I think so? This video was when I pulled it out. And to note it was quite stuck when trying to get it out.