My new Cat N popular arrived today. Really stiff heavy clutch pedal. A real effort to depress. Any ideas on what might be the cause and how I can rectify it?
Technical Stiff heavy clutch
- Thread starter typecastboy
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Technical Stiff heavy clutch
Not sure if it's THIS issue but heavy, notchy clutch pedals that get heavier as you drive the car are VERY common on older Alfa's.
I owned a 147 JTDm that ate clutch master and slave cylinders because of a heavy clutch. It's very common in that generation of Alfa and I assume Fiat's as well. The heavy clutch actually has nothing to do with the clutch plate wear.
What happens is the clutch fork bushes bind and the fork seizes on the bushes. This makes the clutch very heavy. A lot of people have a trick of dribbling oil down the fork shaft to free it. Really though the only way to fix it is a new fork and bushes. My Alfa's clutch was transformed from awful to perfectly light and acceptable after the bushes where changed.
Google Alfa JTD heavy clutch. You'll literally find hundreds of treads.
Interestingly my GF's 1.2 Pop also developed a heavy, notchy and vague clutch pedal. It's not bad enough to warrant doing yet though.
I'm really hoping my new to me 500S 1.4 doesn't develop the same issue but sadly it seems common on FCA cars.
I owned a 147 JTDm that ate clutch master and slave cylinders because of a heavy clutch. It's very common in that generation of Alfa and I assume Fiat's as well. The heavy clutch actually has nothing to do with the clutch plate wear.
What happens is the clutch fork bushes bind and the fork seizes on the bushes. This makes the clutch very heavy. A lot of people have a trick of dribbling oil down the fork shaft to free it. Really though the only way to fix it is a new fork and bushes. My Alfa's clutch was transformed from awful to perfectly light and acceptable after the bushes where changed.
Google Alfa JTD heavy clutch. You'll literally find hundreds of treads.
Interestingly my GF's 1.2 Pop also developed a heavy, notchy and vague clutch pedal. It's not bad enough to warrant doing yet though.
I'm really hoping my new to me 500S 1.4 doesn't develop the same issue but sadly it seems common on FCA cars.
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It works fine and is not notchy at all just really stiff.
So if it is the fork bushes, may as well replace the whole clutch?
Depending on the damage, could it be a bent pedal or pivot? Had one in a Panda a while back and was about to change the clutch when the "thought" light bulb went on (car had only hit a grass verge, no real body damage except bumper, but I reckon the driver must have mashed the pedal somehow in the impact)
Well I greased the pivot point and the rod that goes through the bulkhead (no idea what that is) and it made no difference.
Is it consistently stiff or is it better first thing in the morning and gets stiffer with use? Does your driving pattern affect it at all?
It doesn’t feel so stiff now. Now I’ve been driving it for a week I’ve got used to it. It’s the same all the time though. There’s a bit of a squeak too now.
A squeak suggest to me that it will need a new master cylinder soon. The plastic cylinder gets tight as it wears. Search for clutch squeak on Panda threads.
As things like that are beyond my mechanical capability, I’m assuming that a master cylinder is far cheaper to have replaced than a clutch?
Don't underestimate yourself. Considering the bodywork you do, a clutch master cylinder is no problem. Might need an assistant with the bleeding afterwards.
Cylinder is held in with two nuts. The rod at the pedal is just a ball socket that pops off and on again.
Pipe is help in with a clip. Careful not to lose it. May need to remove battery tray to gain easy access to bleed nipple at slave cylinder.
Here's one. More searching may find one cheaper. https://www.ebay.co.uk/itm/NEW-GENU...270542&hash=item3f8df0b35c:g:BskAAOSwsBtaIdWM
Beware the slave cylinders wrongly described as masters, and avoid any used ones. You have some used ones already!
Cylinder is held in with two nuts. The rod at the pedal is just a ball socket that pops off and on again.
Pipe is help in with a clip. Careful not to lose it. May need to remove battery tray to gain easy access to bleed nipple at slave cylinder.
Here's one. More searching may find one cheaper. https://www.ebay.co.uk/itm/NEW-GENU...270542&hash=item3f8df0b35c:g:BskAAOSwsBtaIdWM
Beware the slave cylinders wrongly described as masters, and avoid any used ones. You have some used ones already!
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After looking at pictures I’m getting confused although it doesn’t actually look as difficult as I first thought.
So the slave cylinder is the one with the ball that connects to the pedal?
I’ve seen a few on eBay (I wouldn’t buy a second hand one) but some look different. I’ve put the pictures here. I’ll have to consult my Haynes.
So the slave cylinder is the one with the ball that connects to the pedal?
I’ve seen a few on eBay (I wouldn’t buy a second hand one) but some look different. I’ve put the pictures here. I’ll have to consult my Haynes.
So it’s actually the master cylinder you said may need changing. What I’ve posted is the slave?
You've posted pictures of both.
The master cylinder is the one that bolts to the bulkhead and connects to the clutch pedal.
The slave cylinder is the one that bolts to the flywheel bellhousing and connects to the clutch release mechanism inside the bellhousing.
If one is knackered, chances are the other one is as well. If the fluid isn't changed regularly, then the absorbed water will corrode the steel parts inside and ultimately cause the seals to fail.
If any part of the clutch release mechanism is corroded or sticking, you may still have a stiff pedal even if you replace all the clutch hydraulics. Inspecting, cleaning and lubricating the clutch release mechanism requires the gearbox to be removed.
Only RHD cars have hydraulic clutch operation. The fitment appears to be an afterthought and IMO the whole thing is a bit naff. OEM parts quality is typical Fiat and some have reported issues on cars fresh from the factory.
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Argh I see. So to someone who has never tackled anything clutch related the master looks like the easier one of the two to replace? I guess I need to buy myself a bleeding kit too?
Before I bought anything, I'd unbolt the slave cylinder and see how the hydraulic system works with no load on it. If everything moves freely and smoothly, then the problem lies inside the bellhousing and no amount of bleeding or cylinder replacement will fix the stiff pedal.
I posted some while ago about bleeding the clutch hydraulics, I'll have a quick search in a minute & see if I can find it.
Update: Check out this thread, and this one also.
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A few bits to add.
Corrosion inside is less of a problem with these, as they are mostly plastic. However, as the plastic bore wears, they get sticky, giving a jerky operation, and the master cylinder squeaks.
If ignored for long enough, the master may stick down, so the clutch won't release. Not a nice place to be with a truck approaching. Lifting the pedal with your foot can drag the piston back, but that 'moment' is best avoided.
I replaced both of mine, for the reasons given by jr kitching, but if it is pedal squeak the master is the main culprit.
Both are easy to replace.
The slave, on the gearbox, has a spring-loaded piston. It comes tied in, but when released it fully extends, so trying to test it off the gearbox will be almost impossible. If allowed to fully extend it won't drop out, but does need a bit of a push to get back in or attach to its lever on the gearbox.
When bleeding, it is best if the slave is pushed as far in as poss, as this will keep the internal volume small and discourage air from becoming trapped. Extended gives a large volume away from the bleed nipple for air to sit.
(Same principles apply when bleeding brakes, especially drums. With 1960's Girling twin-leading shoe front drums, impossible to bleed unless fully compressed, but that's another story.)
Corrosion inside is less of a problem with these, as they are mostly plastic. However, as the plastic bore wears, they get sticky, giving a jerky operation, and the master cylinder squeaks.
If ignored for long enough, the master may stick down, so the clutch won't release. Not a nice place to be with a truck approaching. Lifting the pedal with your foot can drag the piston back, but that 'moment' is best avoided.
I replaced both of mine, for the reasons given by jr kitching, but if it is pedal squeak the master is the main culprit.
Both are easy to replace.
The slave, on the gearbox, has a spring-loaded piston. It comes tied in, but when released it fully extends, so trying to test it off the gearbox will be almost impossible. If allowed to fully extend it won't drop out, but does need a bit of a push to get back in or attach to its lever on the gearbox.
When bleeding, it is best if the slave is pushed as far in as poss, as this will keep the internal volume small and discourage air from becoming trapped. Extended gives a large volume away from the bleed nipple for air to sit.
(Same principles apply when bleeding brakes, especially drums. With 1960's Girling twin-leading shoe front drums, impossible to bleed unless fully compressed, but that's another story.)
