Fiat 125s in South Africa

[Rishal]

Hi Guy,

Thanks for the good advice. Will look for a stock flywheel and lighten as per your recomendations.

My car shudders on acceleration when on an incline. This happins only after a long drive.
When the car shudders and if i depress the clutch pedal, loud noises can be heard from the propshaft and gearbox.
To avoid this shudder the clutch pedal has to be released fast, but then the tires spin. Current flywheel on car is stock.
Pressure plate is old, but friction face of flywheel and pressure plate has been reground. Clutch plate is new.

Any ideas to help me overcome this problem?

Regards,
Rishal.

[Guy Croft]

Not sure.

Is the propshaft out of balance? If you remove it it has to go back on in the same orientation so it is a good idea to mark it first or better get the whole thing rebalanced off-car.

Maybe the clutch is beyond its useable life? The springs in the cover or plate may be worn out?


Any other ideas, readers?

G

[Rishal]

Hi,

Propshaft has been balanced and marked, with gearbox flex rubber and flange.

Its possible that springs on pressure plate collapse with heat, just need to confirm with someone before removing gearbox.

Thanks.

[nabihelosta]

Hello Rishal

As far as I can affirm, you have to remove your gearbox for sure. The shudder is from an overheated clutch disc, and overheating is generally the result of continuous minor slipping. The noise you hear when you depress the clutch, is a worn throw out bearing, and in some cases some broken clutch plate splines too.
Fiat 8v doesn't "like" their plate rebuilt. I learned it the hard way on my car.

My advice is:
-Get a proper clutch kit of a well know manufacturer (Valeo, Sachs..). Just organic disc. No need for materials. It can fully withstand a road spec tuned 2L with no problems.
-Get the complete kit and NEW (Plate, disc, bearing).
-Grind the flywheel's contact face to a true clean grind. If it is already on the engine, balanced and running, mark it before you remove it. It can be bolted to the crank both ways, and the wrong way will upset the balance. Respect the clearances.
-On your way, remove the clutch fork and give a generous lubing to the pivot in the bellhousing, and replace the clutch cable. You will profit from a soft pedal feeling.
-Replace the transmission mount if it shows signs of cracks or age.
-Check the crank rear seal for oil leaks.

And that's it.

P.S: I once experienced a strange shuddering on a BMW, only when decelerating with gear engaged. It turned out to be a slightly longer propshaft (by 3mm than stock).

Thank you

Nabih

[Rishal]

Hi Nabih

Thanks for the excellent advice.

Will have to remove gearbox and inspect. The flywheel and pressure plate has been resurfaced. The clutch plate, throw out bearing and clutch cable are brand new. The clutch fork and pivot ball are in good condition and has been lubricated. Rear crank seal has no leaks. Gearbox rubber mount was bulit up last year. Engine mountings look fine, but will have to remove them and inspect. Propshaft was shortened and balanced to accomadate 131 2L gearbox. Current freeplay between back of propshaft and diff flange is 25mm. Propshaft centre bearing has been changed. Propshaft universal joints has no play and was lubricated.
I noticed that rear leaf springs are collapsed, so will have to change it. I also noticed when in fourth gear at a low speed and I start to accelarate, the car has a vibration at the centre and rear end. Not reali sure were the problem lies.

Can worn out bearings in gearbox or diff cause this shudder?

Problem in South Africa is that a clutch kit is not available. I do have a spare reconditioned pressure plate and a brand new Valeo clutch disc, was thinking to just put it on. Not sure what your views are on that.

Thanks,
Rishal

[nabihelosta]

Rishal

Except reconditioned by Tilton, Helix, or Sachs Racing, I don't trust reconditioned clutch plates, especially those made by local workshops. And my theory is good for Fiat plates only.

Your vibration and shuddering problem on 4th gear lies in: 1- engine mounts, 2- rear propshaft.

Nabih

[Rishal]

Thanks, will have a look at it.

[S&B125]

Hi Rishal
I have much the same problem with my 125T. Since I've gone back to the original gearbox with donut etc my car has terrible shudder upon clutch release, this sets up some sort of vertical oscillation in the driveshaft and thumps under the car. I am running a 4 puck button clutch at present and absolutely everything is balanced. I must stress this exists only on initial takeoff and does not make it's presence felt at all once the car is moving. I am very keen to find the fix as my car was OK on takeoff with a 132 5 speed with a slip/yoke coupling previously.

[Rishal]

Thats exactly the same problem that I have, but mine shudders only when hot and up an incline. I removed gearbox and clutch for inspection. Clutch and pressure plate looks fine. I noticed that my throw out bearing has a bit of play around the gearbox input shaft sleeve, not sure if that is normal.

In your situation you went back to original 4 speed box. That means you changed gearbox, mounting and propshaft. Check
propshaft couplings and balance. Check gearbox mounting and engine mountings. I'm sure your throw out bearing is fine.
Maybe your gearbox bearings are bad. I read an article once that says worn out gearbox bearings can cause shudder, but not
sure how true that is.

In my situation, not reali sure what to do. I can change the gearbox but that will mean going back to original 125 5 speed as I do not have a spare 131 2 L box.

If you have any advice, please share with me because it becomes difficult to drive my car in traffic. I reali need to sort this
problem out.

Thanks,
Rishal.

[Brit01]

A relative of mine here had an Alfa romeo 155.

His clutch shuddered also but only when hot. I imagine that needed replacing. But he sold it 'as is'. Was an expensive job with a 155.

Good luck with that Rishal.

[badlyworntoy]

Rishal

I have a theory...Something Similar I came accross years ago with a Humber Super Snipe. This may be difficult to explain in words but here I go :- Check the splines on the sliding joints at the Donought end of the propshaft for wear or damage. If you've changed the gearbox from 4 to 5 speed and possibly the mounts as well, they is a strong chance that the Spider flange will be sat higher than before,therefore in all likelyhood the angle of the forward section of the propshaft is on a much tighter angle down to the centre bearing,putting the drive on to parts of the splines which are worn or damaged. If you think about live Axles when they work the propshaft must expand and contract with load at the rear of the vehicle and also with suspension movement. You could check this by (and yes this sounds silly but it works) chocking the rear springs with wood and setting off up a steep hill, this will eliminate the propraft from changing its own length.

If this is the case you may solve the problem by

Finding a better propshaft
altering the gearbox crossmember mount (height)
Maybe even your rear springs are worn out (too soft) causing the car to squat thus causing balance problems.
Raising rear suspension ride height

Anyway should give you something else to think about/investigate :)

Ian

[Guy Croft]

I know from exp that the Fiat type rubber donut (as we all call it) certainly does not like any kind of angular misalignment.

I did that on my 1800 TC Gp3 Fiat Abarth Spider when I converted to a Fiat 131 5spd box (yes with shaft shortened and balanced off-car) and encountered the same alarming phenomenon Steve Boyle mentioned and it completely shredded the donut. When I got the alignment of the forward section of the shaft right it stopped.
(For those who don't know that unit has a 2 piece propshaft with a pillow-block bearing part-way along the shaft section)

GC

[Rishal]

Hi Guys,

My rear springs are worn out. I noticed that they are soft.

I changed from 125 5 speed to 131 5 speed. How should the front half of the propshaft sit?
Does it need to sit perfectly horizonal or can it have a slight angle. At the moment the
front half starts to drop as it reaches the centre bearing.

Thanks,
Rishal.

[Guy Croft]

The front section of the propshaft needs to be parallel to the crankshaft in both planes. Otherwise it imposes an eccentric load on the donut.

The section downstream of the pillow bearing can be tilted and indeed needs to accept that load because the axle moves up and down.

G

[Urbancamo]

Kuva151 (Custom).jpg (26.99 KiB) Viewed 9132 times

This is what happens if engine/gearbox vs. propshaft aren't lining properly. Donut will simply heat like mad when there is torsional stress and sooner or later it will explode. This happened me twice until I lined the parts. With naked eye you could tell that parts weren't straight. My own mistake.

Not the nicest things to happen. They both exploded in 4th gear in 4000-4500 rpm region and they made a loud BANG wich scares the heck out of you. Second explosion bent even the 8 mm steel fuel line into V-shape...!