Sticky Clutch Pedal - 85 V8 110

[the_preacher1973]

Over the last week or so the clutch pedal on my 1985 V8 110 has been getting increasingly sticky. It's a little stick on push and returns in a noisy and jerky fashion on release. It's got so bad that taking of smoothly from the lights is almost impossible.

I removed the top cover from the back of the master cyclinder in the engine bay and hit the mechanism with copious amounts of WD40. This has definitely freed up the release and I'd say it's 90% cured. I therefore believe the problem is the clutch pedal pivot shaft.

How are these meant to operate? Are they internally lubricated/greased? Or is it most likely just clogged with 27 years of crud?

I'm taking the car across to Stradbroke on Saturday so am loathe to pull the whole thing down before then. Any ideas for a good temporary fix?

I'm considering pressure washing the top of the mechanism then spraying some form of silicon lube into the area? Or would spraying it create more issues by removing any remaining grease?

Any ideas would be most welcome.

[Red County]

My 85 110 V8 has a grease nipple on the engine side of the peddle box, look down under the hose from air cleaner to carbs. May have been added in the last 27 years but looks as if it may be original?
Good luck with it,
Phil

[the_preacher1973]

My 85 110 V8 has a grease nipple on the engine side of the peddle box, look down under the hose from air cleaner to carbs. May have been added in the last 27 years but looks as if it may be original?
Good luck with it,
Phil

Thanks for that. I've had a quick look this morning and I can;t see a grease nipple unfortunately. I can see the bolt end for the shaft but nothing else. I guess I'll hit it with some spray on lube this afternoon and hope it will get me through the week OK before I pull it apart.

[JDNSW]

There is a good possibility that the "bolt end" is a plug that can be replaced by a grease nipple. (Mine (86) has a grease nipple).

John

[the_preacher1973]

There is a good possibility that the "bolt end" is a plug that can be replaced by a grease nipple. (Mine (86) has a grease nipple).

John

Ahh. I might have a closer look. Give me somewhere else to spray in the short term anyway.

[the_preacher1973]

Well in the end we took the D3 as I didn't want any niggling issues in the back of my head during the holiday.

Turns out the bolt end is indeed just a cover and the bolt was shiny and new so looks like the previous owner has replaced the grease nipple with a normal bolt.

I removed it and sprayed grease into the mechanism while my son pumped the clutch. Stickyness is now completely gone. Guess the car just didn't want to spend the week in the salt and the spray!

Thanks again.

[the_preacher1973]

And the saga continues.

After the clutch performing smoothly for a few days the stickyness was back with avengeance today.

I figured that maybe it's just due to me not getting at the shaft properly and with the high temps and high humidity that it was seizing up again. Wrong.

Took it for a run through some local bush tracks and when changing gear from 2nd to 3rd (low range) the clutch failed to return leaving me with no drive. The pedal itself came back but the clutch itself stayed stuck disengaged. I pressed the clutch several times but it refused to budge leaving me with a box full of neutrals (the pedal itself was silky smooth though so I've eliminated that problem).

Popped the bonnet to make it look like I was trying to do something, fluid was a bit low but still covering the bottom of the reservoir.

Slammed the bonnet, prepared the kids for the walk out and then gave it one more go. When I pressed the clutch I could feel that it had already returned on its own accord while I was outside faffing about.

Drove it home gingerly, clutch still sticking quite badly. About halfway home the system came good. No stickyness, smooth as silk.

I have since added some fluid at home and taken it for a drive and it's absolutely perfect.

Any ideas?

As the pedal had returned without the clutch and the master cylinder is attached to the pedal, I can't see how the master cylinder could be the problem. Likewise with the slave cylinder as surely unless the line was filled with air the slave cylinder would have to return as well. And while the fluid was low if it was that low I would think it would have been giving me issues under compression as well.

Which makes me think it's something internal with the clutch itself. Problem with the pressure plate?

Any suggestions most welcome.:)

[JDNSW]

I think that the most likely problem is still the hydraulics, probably the master cylinder. To confirm this, next time the clutch sticks in the disengaged position, open the bleed screw on the slave cylinder. If this shows pressure is present, it will confirm this diagnosis.

Even if you cannot get it to stick again, I would be inclined to remove and strip the clutch pedal assembly, and replace the master cylinder, checking everything. A slight possibility is that insufficient free play on the pedal pushrod is preventing the relief port from reliably being uncovered, but most likely is swollen seals.

Another possibility is that debris in the hydraulic line is acting as a one way valve, either at the slave cylinder or at the other end of the flexible line. In any case, replacing both the flexible line and the slave cylinder and thoroughly bleeding the system is probably the way to go. This will ensure that there is no problem in the external mechanism - for relatively minor cost and labour compared to checking for anything internal, which requires the removal of either engine or gearbox.

John

[the_preacher1973]

I think that the most likely problem is still the hydraulics, probably the master cylinder. To confirm this, next time the clutch sticks in the disengaged position, open the bleed screw on the slave cylinder. If this shows pressure is present, it will confirm this diagnosis.

Even if you cannot get it to stick again, I would be inclined to remove and strip the clutch pedal assembly, and replace the master cylinder, checking everything. A slight possibility is that insufficient free play on the pedal pushrod is preventing the relief port from reliably being uncovered, but most likely is swollen seals.

Another possibility is that debris in the hydraulic line is acting as a one way valve, either at the slave cylinder or at the other end of the flexible line. In any case, replacing both the flexible line and the slave cylinder and thoroughly bleeding the system is probably the way to go. This will ensure that there is no problem in the external mechanism - for relatively minor cost and labour compared to checking for anything internal, which requires the removal of either engine or gearbox.

John

Thanks John. I'll start looking at the hydraulics.

[the_preacher1973]

Thought I'd close out this "little" issue.

Replaced clutch master cylinder (leaking), hydraulic hose (deteriorated), slave cyclinder ('cos it was there), thrust bearing (knackered), pressure plate, friction plate (worn), machined fly wheel (scored) and replaced rear main seal (leaking).

Works fine now!

[angus1]

I had a similar problem with my series 3 project but thanks to to this thread I looked at the slave cylinder. Tried leaking off some fluid but no joy. Took off the cylinder and the piston was rusted in the bore. First push down on the pedal simply jammed it tighter and when the pedal came up the clutch stayed disengaged. Thanks to all.

[camel_landy]

FWIW - I usually replace the master & slave as a pair on the basis that if one has failed, the other is just about to!!

I've had a sticky clutch peddle for the past 6yrs. I replaced the master & slave a couple of weeks ago and it's now all working fine. :D

M