Technical Catastrophic Clutch Failure

[Sfrontato]

Hi All,

For your entertainment.... Just replaced this 84000 mile, 13 yr old clutch after what appears to be release bearing/finger failure (see photos - as it came apart). Really quite explosive with little warning (about 3miles). Flywheel survived - driven plate was intact. Fitted new original 3 piece clutch, and a non-original release fork (I know).

Lovely smooth clutch now, with light pedal. 'Only' significant issue is it really crunches in reverse, and 1st really tight... gearbox selects all gears smoothly when engine off. Have bled slave a couple of times, and also fabricated an extension to the slave plunger, but only slight improvement. I've ordered a new slave (not arrived yet), based on info gleaned from this forum, and an unwillingness to open everyone up again and fit a 'proper' release fork. There is some rotational slop at release arm, mostly in shaft (a little on splined shaft), but that is due to new thicker clutch disc and flatter diaphragm spring as I understand? Its about 5mm at the 'cup' of the release arm. I did the selector shaft seal, but checked for proper function of all gears before putting 'box back on car. Gave the input shaft seal a miss as no play in shaft and no leaks (as the photo shows).

After a week of outside November gearbox work and chasing parts, bit deflated! Any suggestions appreciated.

 

[varesecrazy]

Hi

@koalar is probably the best qualified here..

What age and engine are we discussing?

 

[Sfrontato]

Hi

@koalar is probably the best qualified here..

What age and engine are we discussing?

Hi, FIRE 1.1, Sept 2009.

 

[Pugglt Auld Jock]

Had quite a similar situation with my boy's Punto 1.4 8 valve - so clutch almost identical - The pedal was nice and light (as you'd expect when a new clutch cover assembly and pressure plate have been fitted due to the diaphragm being now almost "flat") however gear selection, first and reverse in particular, was poor but gearchanges on the move were good. Conclusion? clutch not freeing properly. Luckily I also have a 1.2 Panda 169 with a very similar clutch setup so I measured the release arm throwout on the Panda and Punto and found the Punto was only moving it's arm about half as far as the Panda. Replaced the master and slave cylinder (being a "newer" Punto - 2012 - the master was a pure sod to do and I actually handed it over to our local Fiat indy whilst I still had any fingers left) My boy ran her for a week after getting her back, but the pedal was still just not quite "right" so I bled it out again and it's been absolutely spot on for the last couple of years and is still fine.

So I believe it's often the hydraulics which are at fault - and other posts on here seem to support that assumption - but also, if it doesn't immediately feel "just right" it may well be because the new friction plate needs to bed down and/or it needs a wee bleed after being allowed to settle down for a while.

 

[koalar]

Drive forward
Wait until the wheels stop
Push the clutch down
Wait 5 or more seconds
Slowly move the gear leaver into reverse

Can you still hear a crunch or feel the gears turning ?

Or is it only crunching when you change gear at a more normal speed

 

[Sfrontato]

Drive forward
Wait until the wheels stop
Push the clutch down
Wait 5 or more seconds
Slowly move the gear leaver into reverse

Can you still hear a crunch or feel the gears turning ?

Or is it only crunching when you change gear at a more normal speed

Thanks for reply, Koalar. Definite crunch with that test. On the move it's much better (but really not good). Rev matching on move helps a lot.

 

[Sfrontato]

Had quite a similar situation with my boy's Punto 1.4 8 valve - so clutch almost identical - The pedal was nice and light (as you'd expect when a new clutch cover assembly and pressure plate have been fitted due to the diaphragm being now almost "flat") however gear selection, first and reverse in particular, was poor but gearchanges on the move were good. Conclusion? clutch not freeing properly. Luckily I also have a 1.2 Panda 169 with a very similar clutch setup so I measured the release arm throwout on the Panda and Punto and found the Punto was only moving it's arm about half as far as the Panda. Replaced the master and slave cylinder (being a "newer" Punto - 2012 - the master was a pure sod to do and I actually handed it over to our local Fiat indy whilst I still had any fingers left) My boy ran her for a week after getting her back, but the pedal was still just not quite "right" so I bled it out again and it's been absolutely spot on for the last couple of years and is still fine.

So I believe it's often the hydraulics which are at fault - and other posts on here seem to support that assumption - but also, if it doesn't immediately feel "just right" it may well be because the new friction plate needs to bed down and/or it needs a wee bleed after being allowed to settle down for a while.

Thanks Puggit - I am hoping hydraulics are the issue. Your historical comments on these issues were invaluable last night. No appetite for removing gearbox again just at the moment. I was super careful with clutch fitting as first one I've done - bolts tight to flywheel then torqued, very light smear of thick grease on input shaft. The rest went together very smoothly. Drove it this morning and it is pretty awful, compared to the really nice gear change pre-catastrophe. Slave first, then master if no joy (which looks ok on Panda) as a plan. Can't imagine the carnage inside the bell housing did the slave any good (as will have been exposed to shock). Slave not turning up for a week so I will report back.

 

[Pugglt Auld Jock]

Thanks Puggit - I am hoping hydraulics are the issue. Your historical comments on these issues were invaluable last night. No appetite for removing gearbox again just at the moment. I was super careful with clutch fitting as first one I've done - bolts tight to flywheel then torqued, very light smear of thick grease on input shaft. The rest went together very smoothly. Drove it this morning and it is pretty awful, compared to the really nice gear change pre-catastrophe. Slave first, then master if no joy (which looks ok on Panda) as a plan. Can't imagine the carnage inside the bell housing did the slave any good (as will have been exposed to shock). Slave not turning up for a week so I will report back.

Aye the slave on the Panda is much easier and comes out into the engine bay. The Haynes manual describes the Punto cylinder as quite a simple operation - although you are extracting it inside the driver's footwell - and I just couldn't understand why I was having so much trouble trying to get it past the pedal. Eventually, after struggling for ages, I put all the fixings back in and drove it round to Kenny's Fiat garage where his foreman told me they changed things around a bit on the newer Puntos and you have to largely remove the pedal cluster to get it out now which is not detailed in the Haynes manual. When I went back to collect the car he showed me the "battle scars" on his hands so I consider it was money well spent to have let them do it for me!

Both the Punto and Panda had their clutches replaced a couple of years ago - at 76 years of age I chickened out of doing them myself and let Kenny's merry men do them - but I did drop in to examine all the reusable parts and examine the boxes for oil leaks etc before reassembly - One of the things that I wanted to check closely was the release forks and pivots and both were absolutely fine. Neither box showed any serious problems with their input shafts - play or leaks - although the Punto had a very small amount of movement in it's input shaft which I considered acceptable. When the Panda was done it had absolutely no play at all - neither box showed any oil leaks or bearing noises when the shaft was spun by hand - which surprised me as the Punto was in the early 40,000 miles whereas the Panda was in the mid 60,000 miles. The Panda has never shown any leaks from the gear selector shaft but the Punto I did soon after we bought it about 4 years ago and I've noticed it has started leaking again when I serviced it a few weeks ago. As it's oil level has not dropped I think I'll keep a watching brief on it for now and maybe do a seal when the warmer weather returns next spring.

Edit. I meant to say I put a slave in the Panda just as "insurance" - slaves are pretty cheap - however I left the original master as it seemed Ok, and it's never given a moment's concern since. The Punto definitely needed both cylinders.

 

[koalar]

Thanks for reply, Koalar. Definite crunch with that test. On the move it's much better (but really not good). Rev matching on move helps a lot.

Right what you describing is clutch drag

It could be slave cylinder. Unlikely in my opinion if it wasn’t a problem before the the failure.

There will always be exceptions

But a high percentage are due to the friction disc not sliding freely on the gearbox shaft

It only takes a bit too much grease on it to stop it from sliding freely.

I take it the new release fork was nice and loose ?

 

[Pugglt Auld Jock]

Right what you describing is clutch drag

It could be slave cylinder. Unlikely in my opinion if it wasn’t a problem before the the failure.

There will always be exceptions

But a high percentage are due to the friction disc not sliding freely on the gearbox shaft

It only takes a bit too much grease on it to stop it from sliding freely.

I take it the new release fork was nice and loose ?

On the subject of spline lubrication I can strongly recommend a specialist grease such as that supplied by Sachs: https://aftermarket.zf.com/us/en/sa...-tips/clutch-systems/greasing-the-hub-spline/ These specialist greases are "extra" sticky and don't get centrifuged off as easily as more common greases. By the way, don't use copper based greases such as those used in the "good old days" for brakes and I find common HMP grease tends to be a bit too easily thrown off. Many factors stock the correct stuff but you often have to ask for it specifically. It's easy to buy on line, Autodoc for instance, have it for a good price. Apply a small amount to the splines and then work the driven plate back and forward a few times to spread it out and get good coverage into the splines. Then take a clean cloth and wipe most of it off again, especially on the driven plate. That's it, ready to go. There should never be loose grease such as builds up when you're working the plate on the splines.

 

[Sfrontato]

Right what you describing is clutch drag

It could be slave cylinder. Unlikely in my opinion if it wasn’t a problem before the the failure.

There will always be exceptions

But a high percentage are due to the friction disc not sliding freely on the gearbox shaft

It only takes a bit too much grease on it to stop it from sliding freely.

I take it the new release fork was nice and loose ?

 

[Sfrontato]

OK - yes there was no issue with slave before. Release fork was loose - as a result of the thrust bearing collapse there was some minor scoring of the gearbox nose, and I cleaned this up with emery paper. Checked carefully for smooth function, and kept release fork and bearing in position when reinstalling gearbox with a zip tie on the release lever.

Whilst not keen on opening things up again, I should be able to do it in my sleep. Will just wait for the right day. Thanks for advice - makes sense. I did look at whether or not to grease splines of input shaft - opinion is divided...

I will report back on results.

Many thanks for advice from you and Puggit - makes sense.

 

[portland_bill]

I'm surprised that Sachs are recommending lubricating the clutch splines, as centrifugal force will try to throw it off, and it will contaminate the friction material. Absolutely must not use copper grease, as it has no ability to cling on, and even a tiny amount will cause judder. (I had 5 years looking at warranty claims on returned clutches) Any grease that does not fly off, will gather dust, making things worse than no grease.
A great alternative to any grease, is graphite. Get the softest pencil, and rub it onto the splines, wipe off any excess. It is a good lubricant, and won't attract dust.

The diaphragm finger failure is usually a result of many years of sitting stationary with the foot on the pedal.

 

[jrkitching]

A great alternative to any grease, is graphite.

You can buy it in powdered form - it's often used for lubricating locks and hinges. Excellent for many applications when you don't want a greasy residue.

RS PRO Lubricant Multi Purpose 50 g Graphite | RS

uk.rs-online.com

 

[koalar]

Clutches are quite an easy job except for the mauling

But it’s also just as easy to get wrong

Drive plate wrong way round

Using longer bolts to pull the gearbox up

Hanging the weight of the gearbox off the input shaft

Excessive spine grease


Release bearing not located to the release fork properly

Just some examples I can think of from the top of my head.

I know of 2 panda gearboxes damaged by careless clutch change at a garage

As to grease or not the splines I do. Then wipe it mostly off. As I see it it’s not there to lubricate. More to stop surface rust if left unused. They are greased from factory


Going back to the original posters problem I suspect a small ding in the splines and the slightly out of balance of the plate is causing it to jam ever so slightly

A broken dremel cut off disc should get between the splines

But when my car is back here I will measure the location and throw of the release lever just to eliminate any possibility of the hydraulics before you drop the gearbox

 

[Sfrontato]

Clutches are quite an easy job except for the mauling

But it’s also just as easy to get wrong

Drive plate wrong way round

Using longer bolts to pull the gearbox up

Hanging the weight of the gearbox off the input shaft

Excessive spine grease


Release bearing not located to the release fork properly

Just some examples I can think of from the top of my head.

I know of 2 panda gearboxes damaged by careless clutch change at a garage

As to grease or not the splines I do. Then wipe it mostly off. As I see it it’s not there to lubricate. More to stop surface rust if left unused. They are greased from factory


Going back to the original posters problem I suspect a small ding in the splines and the slightly out of balance of the plate is causing it to jam ever so slightly

A broken dremel cut off disc should get between the splines

But when my car is back here I will measure the location and throw of the release lever just to eliminate any possibility of the hydraulics before you drop the gearbox

Thanks Koalar - I'll wait for the measurements before committing to a day on my drive.

 

[koalar]

46mm to 62mm pressed roughly

That to the little pip on the slave to the release folk

I guess around 15mm of throw is the important bit as no doubt the position will alter as it wears

 

[Sfrontato]

Finally got time to look at this again - Koalar, thank you so much for the release arm movement measurements. Mine were slightly greater. Dropped the 'box yesterday, and the driven plate did seem a little inhibited on the input shaft. Took my time and scraped out a lot of crud from the splines (bits of Dremel disc worked great), and disc was then 'floating' on the input shaft - with the 'box at a slight angle, the disc would slide down the shaft under gravity.

Put everything back together, and no improvement in drag symptoms (very 'notchy' 1st, crashy reverse).

With the slave out, there is free play (about 8mm or so) in the release arm. This is movement of the release fork rather than play in the splines between fork and lever. I took this as being ok as figured the clutch fingers will be flatter with a new clutch? However this is my first clutch so not enough experience to be sure. The release fork was a rather rushed eBay purchase, but seemed reasonable enough.

I'm obviously trying to avoid more than one additional 'box drop in December (possible release fork and clutch), so having a proper think about this.

The clutch action Is buttery smooth, no judder at all.

 

[DaveMcT]

People automatically change the slave cylinder when clutch fails to release. The master cylinder is usually the cause. Worn seals pull in air so the clutch never gets full travel. You can get masters for under £60. Borg & Beck do a cast metal one. The fancy pre-filled stuff from Fiat is silly money and more hassle to fit.

 

[koalar]

It was working fine before the release bearing failed

You changed the damaged parts

And you have the right amount of movement at the clutch slave

The drive plate slides easy on the splines

I don’t understand why it’s not working

Have to have a think