Intermittent judder - have I missed something?

[gammakeith]

This car is currently trying my patience    The clutch cable snapped so I replaced it and also attended to the leaking driveshaft seals last week.  Both rear hub nuts were slightly loose which was odd so were re-tightened.  All seemed fine and I thought I was on a roll until the wife reported today violent load dependent judder on pulling away.  I drove it and sure enough there is a horrific judder in first if trying to pull away even slightly uphill.  It was fine when I last drove it a week or so ago!  Its still fine on the flat or going downhill.  It doesn't feel like its the clutch slipping but is rather more mechanical if that makes sense. Its certainly worse that the judder that you can get with an oil contaminated clutch lining. Once going it seems fine but the noticeable bang when coming off the power in second going down our hill is worse suggesting there is some extra slack somewhere.  I didn't drive it anymore than that for reasons of mechanical sympathy.

I've just checked hubs/wheel bearings/driveshafts for anything obviously nasty and there is none.  The engine and gearbox appears to be hanging fine from the mounts. I think its something clutch/flywheel related.  I adjusted the clutch pedal much higher when I replaced the cable so could that have caused the pressure plate to partly fail?  Or maybe just pure coincidence? I'm pretty much resigned to pulling the engine/box out but thought I'd leave it for tonight to see if anyone could suggest something that I might have missed.

Thanks,

Keith

[gammakeith]

Not sure how I managed to start this thread in "Tuning and Customising".  Sorry about that!  I wondered if one of the flexible drive blocks was starting to fail so whipped both sides off.  The rubber in both looks fine and the splines on the hub, driveshaft  and in the blocks are all OK.  Not that then.......

Keith

[Gadge]

Hi Keith you say it's "mechanical" but just to eliminate a few things have you checked the ignition system. A dodgy condenser or duff coil will make it misfire and judder.

If that's all fine then I fear it may well be a clutch/drivetrain problem. I had (many years ago) a violent judder in first after I changed a clutch. In the end it turned out to be the spigot bearing. The input shaft wasn't seating in it properly and as the drive was being taken up it would judder very badly.

Hope you sort it soon

[gammakeith]

Thanks!  Its actually running lovely at the moment.  Once I got it rolling last night I was able to drive normally so it seems ign/fuel are fine.

I've pretty much resigned myself to pulling engine/box tonight.  I have a spare engine and gearbox so I should be able to cope with whatever it throws at me.  I'm just worried that I'll get it apart and not find anything obvious. I suspect its not the spigot bearing as the symptoms suddenly appeared.  My money is on a broken pressure plate or delaminating clutch plate.

I'm not doing so well at the moment as the dual mass flywheel failed on my diesel Alfa a few weeks back and that was a nightmare to do.  At least the Fiat is nice and simple to strip down.....

Keith

[1973/126]

 Have you put both the springs back inside the driveshafts? If they are broken or not in place they can cause judder when pulling away.

[gammakeith]

Yep, they were both present and correct and the splines etc in good condition.  I'm certainly getting to know the car better......

Thanks,

Keith 

[gammakeith]

Well that's the engine and gearbox out!  I'm guessing two hours is not too bad for a first time.  Would have been even quicker if it had not been for the towbar....

I didn't really have enough energy left for a detailed inspection but the engine/gearbox mounts are all in good condition.  The clutch looks fine and is clearly fairly recent as there is little wear.  No oil contamination and no obvious wear or uneven marks on the plate/flywheel/pressure plate. Thus, I'm comfortable to re-use that.  However, there is a huge amount of slop in the clutch arm so something has clearly gone wrong with the upper bushing in the bell housing.  That is certainly a possible culprit as it could well cause jerky engagement.  The other worry is several mm of slop at the end of the gearbox input shaft which seems excessive to me. I whipped the cover plate off the box and all looks well visually but then there was no swarf in the oil when I changed it earlier in the year.  Anything obvious I can check? I'll dig out the spare gearbox tomorrow night out of the depths of the basement and compare. 

Keith

[gammakeith]

The other thing I have noticed is that I do not have a gearbox support bracket (the pressed steel jobbie that bridges the gearbox cross member to the floorpan).  Is that because the BIS did not have one or has it been lost at some point?

Thanks,

Keith

[1973/126]

 Sounds like it might be a combination of more than one thing.
 You should have the support bracket and it makes a difference.
 Have you got both the clips in place that hold the clutch release bearing in place? That was another thing I thought might cause some problems.

[Gadge]

No the BIS doesn't have the support bracket. If there's excessive movement in the input shaft then it may well be the input shaft bush. It comes as a bronze bush and oil seal all in one little housing that fits on the inside of the bell housing (held on by one single 10mm bolt) I'm currently waiting for one myself as mine was leaking oil. If the input shaft isn't rotating true then as you engage the clutch it could cause the the engine to vibrate as it turns off centre. Can't really think of anything else it could be?

[gammakeith]

OK, thanks for the input guys.  It seems from what I have seen that the 126 is prone to clutch judder and various things can cause it.  My BIS was fine and then suddenly was not so something has worn enough to tip it into "judder" mode.  I was hoping it would be something obvious like a clutch problem but its not that (yes, both clips are in place and release bearing is fine).

I have bushes for the clutch release arm on order.  I will remove and check input shaft bearing seal/bush tonight but it sounds like it would be sensible to change regardless.  Perhaps also worth changing crank spigot bearing as a precaution?  Where have you ordered your input shaft seal/bush from, Gadge?

Thanks,

Keith

[Gadge]

I bought it from axel gersil

http://webshop.fiat500126.com/katalog/artikelinfo/1534/guide_bushing_for_transmission_shaft_radial_shaft_seal

It's worth doing anyway as there not expensive - this one cost me £12. There a bit fidley to remove but dead easy to fit.

[gammakeith]

Super!  I have just ordered one of those along with the crank spigot bearing.  Hopefully if I change those along with the clutch arm bushes then that will cure the judder.

Keith

[Gadge]

cant imagine being anything else? let us know how you get on though it would be interesting to know if it works 

[gammakeith]

I certainly will though having changed three things it will be impossible to know what was the main culprit (assuming of course the problem goes away).  I think its the clutch arm upper bearing causing the problem but the only way to tell for sure would be to change that, reassemble and test.  However, now I'm getting on a bit I don't like taking engines out more than I have too so will change anything that looks worn...

Keith