944 judder issue

[silvergrey]

I’d appreciate some experienced advice on an issue I’ve had with my ’83 944 please.
When braking and changing down from third to second gear (specifically), I experience a pronounced judder through the car as I release the clutch. It isn’t prevalent during upshifts at all, nor is it an issue on downshifts involving other gears.
It actually has become better (which leads me to believe it’s not the clutch) than it was a couple of years back.

Things I’ve done:
-new transmission mounts
-new engine mounts
-clutch fluid change
-via the clutch inspection hole, I’ve sprayed a liberal amount of brake cleaner

As I mentioned, it’s improved, but still not remedied.
My instinct is that a new clutch might not be the answer.
Thoughts please?

 

[dlknight]

Check the usual drivetrain culprits:

Clutch
CV joints
Torque tube

Any history of the clutch being replaced? it would have had the rubber center clutch in your car which are notorious for failing. The shock absorbing rubber breaks up, many times the friction surface will be fine, but the rubber center will be completely destroyed. I had similar symptoms on my first 944 and it was the rubber center clutch.

 

[IanK]

I had similar and it was the rubber clutch centre falling apart.

 

[silvergrey]

I appreciate the replies, thank you.

I had read that a deteriorated rubber bung in the torque tube could be a possible cause – so it’s helpful that you mentioned it. What sort of process is involved in inspecting both it and the CV joints? I think I’d prefer to eliminate them before pulling the clutch out.

Regarding the clutch: are modern centres free from this troublesome rubber?

Cheers.

 

[scam75]

You can check the CV's for play by turning them by hand with the rear lifted. They often clunk as well when on their way out. ECP have good prices on them just now, I think I got 4 for £160 recently but that was for a late car, not sure if early are the same.

A new clutch will not have a rubber centre. I'm 99.99% certain your rubber centre is your issue and then possibly other worn drive train parts exacerbating any issues you have. There is an inspection hole for the clutch, not sure if you can check the rubber centre though it though, never checked before.

Stuart

 

[dlknight]

I appreciate the replies, thank you.

I had read that a deteriorated rubber bung in the torque tube could be a possible cause – so it’s helpful that you mentioned it. What sort of process is involved in inspecting both it and the CV joints? I think I’d prefer to eliminate them before pulling the clutch out.

Regarding the clutch: are modern centres free from this troublesome rubber?

Cheers.

You can remove the inspection cover on the clutch and shine a torch in there, you may find that bits of the rubber will fall out when you do!

I think we are all 99.99% sure that your clutch is toast I'm afraid.

Rubber bung in the torque tube? nope, the torque tube has a steel shaft running down the middle supported by bearings. Sometimes the bearings wear out and need to be replaced. But I think we all agree this probably isn't your issue, you'd be hearing the sounds of bad bearing with the car in neutral and engine running if they were worn out. But the only real way to check them properly is to disconnect the shaft at both ends and spin it by hand.

 

[silvergrey]

Great replies, thank you; reading them, I have to concur with the deteriorated rubber clutch prognosis.
dlknight, ref. the clutch reference code, Sachs' website and partsinmotion.co.uk state that 3000950057 is the right clutch for my '83 2.5 944, apparently it's the latest in a string of updates.

 

[dlknight]

Great replies, thank you; reading them, I have to concur with the deteriorated rubber clutch prognosis.
dlknight, ref. the clutch reference code, Sachs' website and partsinmotion.co.uk state that 3000950057 is the right clutch for my '83 2.5 944, apparently it's the latest in a string of updates.

Yes - I'd wrongly believed the kit was the same! Sorry! - however it has been upgraded to the same design with the four large springs in the centre instead of the rubber. Disc is smaller diameter than the turbo and I believe the pressure plate, clutch fork, and bell housing are all different

 

[silvergrey]

No problem, your intent was one of helpfulness. I'd previously priced up clutch kits, and remembered that there were model-specific variants.

 

[IanK]

As an FYI, this was my list including a few "whilst you are in there" items from when I did my clutch a few years back - prices will no doubt all be higher now !!!
£450 Clutch kit (Sachs) Design 911
£54 Fork shaft OPC
£17 Fork bearings OPC
£50 Guide tube OPC
£22 Spiggot Bearing (the one in the centre of the flywheel) OPC
£12 Torque tube Clamp bolts OPC
£110 Crank sensor Design 911
£96 O2 sensor Design 911
£19 Exhaust gaskets OPC

Best part of £800 all in.

This was an S2 btw.

 

[944Turbo]

The fork shaft usually wears on one side - the rollers dig in- you can flip them over and expose fresh new surface if you grind the end of the shaft (from memory its a half moon so you need to make a new flat on the moon side).
Not sure if its in one of the kits but I think there is an oil seal on the crank that is worth changing - don't want it to leak oil all over the new clutch once its all back together.
Tony

 

[GregBarton78]

I have a similar symptom on my S2, having checked the inspection hole the clutch itself is only 50% worn & can't see any debris in there. It recently had to go for a short holiday at Revolution Porsche in Birstall (expensive day out involving a breakdown truck and a sudden loss of oil pressure). Mentioned this to them in case they needed to start doing main bearings and their comment was that this judder can materialise if the flywheel face isn't perfect. Given what I just had to spend, the clutch can survive a bit longer and the rev matching downshift will continue...

 

[dlknight]

I have a similar symptom on my S2, having checked the inspection hole the clutch itself is only 50% worn & can't see any debris in there. It recently had to go for a short holiday at Revolution Porsche in Birstall (expensive day out involving a breakdown truck and a sudden loss of oil pressure). Mentioned this to them in case they needed to start doing main bearings and their comment was that this judder can materialise if the flywheel face isn't perfect. Given what I just had to spend, the clutch can survive a bit longer and the rev matching downshift will continue...

I guess a leaking rear main seal would make the clutch judder as well if the oil was getting between the flywheel and clutch disc