Technical 100HP clutch slipping

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Technical 100HP clutch slipping

Thanks folks I found the big nut (M12?) Why does it need an inch of free thread poking out? I assumed the starter motor bolt (just above) would also have to come out. Its odd because the clutch was only done quite recently yet there were no witness marks on either of these. Even the bare threads looked untouched.

Anyhow, the box is now off the car. I dragged it onto tool boxes and timber packing. Then with a helper to extract the boxes, lowered it to the floor with a tie-down strap.
 
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The gearbox input shaft is very well lubricated to the extend that the fixed spigot, which supports the release bearing, is covered in a grey sludge as the bearing rubs against it. Getting the clutch off the flywheel is to be done later.

I'm now cleaning up the gearbox to avoid road crap getting inside when I open it up.
 
Thanks folks I found the big nut (M12?) Why does it need an inch of free thread poking out? I assumed the starter motor bolt (just above) would also have to come out. Its odd because the clutch was only done quite recently yet there were no witness marks on either of these. Even the bare threads looked untouched.

Anyhow, the box is now off the car. I dragged it onto tool boxes and timber packing. Then with a helper to extract the boxes, lowered it to the floor with a tie-down strap.

the extra thread comes in handy when putting the gearbox back
 
Gear box is out and opened up. Don't even consider doing this without the amazing thread from Mr Wild.
https://www.fiatforum.com/punto-ii/158346-input-shaft-bearing-renewal.html

You will need some Loctite 518 anaerobic gasket sealant, moly grease for the new seal, PTFE tape to protect the splines and two small zip ties to retain the reverse selector bracket bolts. Magnetic prod to extract any bolts that drop into the gearbox.

The reverse gear selector mechanism prevents the bell-housing/front coming off the gearbox. I imagine the factory fits this end first. Mr Wild explains it well... After unbolting the casing, open it about 20mm and remove the two M8 bolts holding the selector bracket to the end cover. You can now extract the cover from gearbox.

The six speed box input shaft has a no cage roller bearing fully packed with rollers. I have not replaced mine. The oil seal is fitted from inside the cover. Get the correct part from Shop-4-Parts. Mine was age-hardened and not doing anything close to what a seal should do.

I knocked the old seal out using an old flat screwdriver bent at the end like a mini pry bar. The seal popped out easily no need for self tapping screws. New seal was fitted with a suitable socket as a drift. I greased it internally with moly grease. To protect the seal, I wrapped the clutch splines with PTFE tape working out from the bearing end. It's better than PVC tape as you can wrap all the way down and not worry about some of it getting left around the shaft.

You will need a helper to refit the bell-housing end cover to the main gearbox.

(1) Put the two bolts through the reverse gear selector bracket and put a small zip tie around the bolt threads. This stops them failing into the gearbox.
(2) Smear the joint face with Loctite 518 anaerobic sealant.
(3) Slide the cover onto the box. You have to align both bearings so help is needed. When the bolt line up, get them started and align the reverse gear ball joint as you go.
(4) You now need a helper to make sure the selector stays in place while you tighten the two bolts.
(5) Slide the cover fully into place. I used two bolts from the selector cover to pull it on. They are a little longer so the threads don't get stressed. Check the reverse gear selector works then fit the correct bolts and fully tighten them all.
(6) Test fit the shifter cover to make sure the gear selectors are lined up properly. If the top arm flaps about you need to try again.
(7) When you are happy, smear the joint face with 518 and fit the shifter cover. It has four longer M8 bolts plus one that has a stud attached.
(8) Remove the PTFE tape from the input shaft splines. It's self lubricating so no worries if a little tape gets left under the release bearing sleeve.

Job done, Now time to put the box back into the car.

It's clear the input shaft seal can hardly outlast the clutch. Fiat improved the bearing over older models (its a close set roller bearing) but they should have made it possible to replace the seal from the outside. The fix was a poor effort from Fiat. My bell-housing is surprisingly clean inside but the clutch is *ked with oil.
 
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In case anyone wonders what I'm on about with PTFE tape -

The clutch bellhousing is made with a sleeve (spigot?) around the input shaft which supports the release bearing, the bearing body cannot turn with the input shaft. The input shaft splines go part way into the sleeve so any tape used to protect the seal will get trapped. PTFE does the job and is easy to unwind but anything left behind is harmless.
 
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It's clear the input shaft seal can hardly outlast the clutch.
I'd be inclined to agree. If I was to do a clutch on one of these again, I would replace the input shaft bearing and all transmission seals as a matter of course. Otherwise they'll only start leaking at some point when the 'box is back on the car.
 
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I'd be inclined to agree. If I was to do a clutch on one of these again, I would replace the input shaft bearing and all transmission seals as a matter of course. Otherwise they'll only start leaking at some point when the 'box is back on the car.

with a new bearing the input shaft has no wiggle and the seal has an easy life.'

Once there is movement the seal will start to leak

which leads to oil loss

it then became a vicious circle. The bearing overheats, more movement, more leaking.


I can't remember how many miles the 500 gearbox I fitted was either 50k or 70k but there was already a leak

But I have had a Panda go 200K with no problems with the gearbox. That car was regularly serviced early in its life.
 
The bearing on my car looks and feels as good as new. It's a roller so far netter spec. The seal lip looks just like the replacement but the seal material has gone hard so it's not sealing any more.

The problem is caused by bean counters refusing to allow engineering to fit a removable seal housing.
 
Back in the 1970s I took a Vauxhaul Victor gearbox apart. The input shaft had it's own cover plate that could be unbolted from the box. This pulled out the shaft complete with the 4th gear synchromesh. Changing bearing and seal was an easy job. The Austin MGB and other Leyland RWD cars had the gearbox front oil seal in the bell housing so again it was easy to replace. Neither of them bothered with a support sleeve for the clutch release bearing.
I'm generally the first to support the Fiat way of doing things but the work done to fix the weak input bearing was stopped short. The seal should be a clutch service item not a gearbox strip down item.
 
It was oil leaking from the gearbox front oil seal. The seal was hardened and with hindsight I suspect t was leaking before the clutch was replaced last time.

The sleeve (built into the bell housing) which supports the release bearing makes sure any oil gets fed right onto the clutch plate. The clutch was barely worn.
Anyone with a 100HP ending a clutch should factor in the labour costs of replacing the front oil seal. Ideally do all four seals. The front seal is not beyond any mechanic's ability, though many will say it needs the gearbox reconditioning.
 
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It was oil leaking from the gearbox front oil seal. The seal was hardened and with hindsight I suspect t was leaking before the clutch was replaced last time.

The sleeve (built into the bell housing) which supports the release bearing makes sure any oil gets fed right onto the clutch plate. The clutch was barely worn.
Anyone with a 100HP ending a clutch should factor in the labour costs of replacing the front oil seal. Ideally do all four seals. The front seal is not beyond any mechanic's ability, though many will say it needs the gearbox reconditioning.

are you sure

oil from the input shaft normally get flung outwards before it hit the clutch plate


what make was the old clutch ? what condition is it in ?
 
Release bearing spigot and the bearing itself was greasy and driven plate smelled of gear oil. But there was almost no sign of oil on the clutch casing internal surface. However, it needs very little oil to make a clutch slip.

Old clutch was hardly worn and only the driven plate needed to be replaced but I replaced the whole lot anyway. New clutch is Valeo from S4P. The old one looked identical so probably also Valeo.

The car feels nicer to drive so I think the clutch has been slipping (just a bit) for some time. Eventually getting to the point where power at motorways speeds was enough to have it let go.

I dont have pictures because my hands got too dirty to use the phone while doing the job and afterwards I forgot.

My tip is to replace the gearbox input seal at any clutch change. The seal is silly cheap but fitting it will cost in labour time and many garages will prefer to fit a reconditioned gearbox. Overkill for a new oil seal but easier for them.
 
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However, it needs very little oil to make a clutch slip.

really

this had at least 2 litres of oil fall out of the gearbox and still doesn't slip

not the best photo. But does show the sludge on the chisel tip
 

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Driving carefully around town my clutch worked ok. It could judder sometimes but nothing much unless really provoked. Hit the loud pedal at 70 and the revs went literally to the rev limit. It's also the six speed box which might have a different arrangement to support the thrust bearing. The bell-housing has a sleeve/spigot around the input shaft. It's about 50mm long and supports the thrust bearing in very good ways. However, oil escaping along the shaft will not fling off the shaft until it's hitting the pressure plate fingers.

Flywheel was fine by the way - no wear lip.

Picture of the input bearing (the one furthest away). Absolutely not an SKF 6204 ball bearing. ;)
 

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still not sure how oil could contaminant a friction plate from the gearbox side

this gearbox has no input shaft bearing left. The bearing have escaped into the diff housing

No input seal left

oil is free to run out

however spraying oil on a shaft turning at 750 RPM plus just get flung outwards as soon as it can covering the inside of the bell housing

certain as I can be oil contamination of the fiction plate will not be from the input shaft seal failure

too much grease added to the input splines can get flung out.
 

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it only takes a small amount of oil to cause a clutch to slip. Mine was actually OK about town and only slipped when worked hard. It was not splattered like your pictures but it was oily and the clutch driven plate smelled of gear oil.
 
Can confirm my '06 169 1.2 4x4 has the roller bearing, and the seal was still in good condition at ~90k miles (changing the clutch). I put the new seal in anyway, but left the bearing as I had only a 6204 ready to replace it.
 
The input bearing is huge thing and won't be cheap to replace. But, mine was 100% fine so expect others to be much the same. The seal however was hard as nails and the clutch smelled of gear oil. It's not hard to replace the seal but you do need to take care doing the job.
 
Indeed, it'd be easy to gouge the casting with an over-exuberant use of a screwdriver trying to get the seal out! A shame, it'd be quite easy to have redesigned the 'box to allow replacing the seal without splitting the case (as you've said)
 
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