Knock and shudder turning right (Mi16)

[Doc 205 6 1 Cars]

Hi folks. 

 

Ever since I got my 205 Gti (with Mi16 conversion) it has had a nasty knock and shudder when turning right. Even just when the wheel is turned slightly right of centre when driving straight. 

 

I thought it was perhaps a worn joint so replaced the passenger side driveshaft today, however the noise and shudder is still there. 

 

I think it is maybe being caused by sideways movement from the engine and gearbox, perhaps as a result of the engine being misaligned when dropped in. I wondered if the next thing to try would be messing around with the positioning of the engine and gearbox mountings. 

 

Has anyone else experienced this, and if so, how did you correct it?

 

Cheers. 

[welshpug 1,621]

try the other shaft?

[Doc 205 6 1 Cars]

I don’t think the shafts are the issue. I think it’s play in the engine and gearbox, so maybe the mountings. Suppose it might not harm to do the other shaft. I could live with it, just don’t want to be causing any damage, and it’s pretty annoying. 

[Tom Fenton 1,524]

Is it a single knock or a repeating knock-knock-knock-knock etc?

[Doc 205 6 1 Cars]

It’s more of a continuous rumble and shudder whenever the steering wheel is right of centre.  Particularly at speed. It’s constant. Not intermittent. Pretty violent, not like a wheel bearing. 

[Tom Fenton 1,524]

Sounds like a driveshaft joint bottoming out. Undo the big hub nut with the wheel on and the car on the floor, you should be able to shove the joint in and out by at least 10mm. If you can't, the shaft is too long and its the joint bottoming.

[Doc 205 6 1 Cars]

Ok, thanks for that. If that’s the case, is there a fix? E.g. having a few mm machined off the length of the drive shaft?

Edited April 24, 2019 by Doc 205

[Ozymandis 96]

10 hours ago, Tom Fenton said:

Sounds like a driveshaft joint bottoming out. Undo the big hub nut with the wheel on and the car on the floor, you should be able to shove the joint in and out by at least 10mm. If you can't, the shaft is too long and its the joint bottoming.

This.

 

[Doc 205 6 1 Cars]

1 hour ago, Ozymandis said:

This.

 

Ok, so would the fix be to try to move the engine and gearbox a little in the opposite direction, or to machine off a few mm from the offending driveshaft? Or something else?

[welshpug 1,621]

fit a shorter shaft, there are clip grooves and splines, so its not just a case of grinding a bit off.

 

alternatively find a set of 309 wishbones, as they are 10mm longer, free extra camber, so to speak.

[Doc 205 6 1 Cars]

35 minutes ago, welshpug said:

fit a shorter shaft, there are clip grooves and splines, so its not just a case of grinding a bit off.

 

alternatively find a set of 309 wishbones, as they are 10mm longer, free extra camber, so to speak.

Thanks Welshpug. Really appreciate that. From what I can tell the 205 shafts are the shortest standard shafts available that will fit the 1.9 hub and gearbox (vs. the 309 and 405 shafts, which are longer). So, presumably I’d need to buy specially shortened ones? Sounds expensive! Can you recommend any?

 

If I went down the route of fitting the 309 wishbones, I’d need to replace both the offside and near side for balance, correct?

 

Would this then mean that the driver’s side standard driveshaft would be too short, and I’d need to replace it with a longer one?

 

What would you do if it was you?

 

Apologies for my ignorance - this is all fairly new to me!

[jackherer 543]

1 hour ago, Doc 205 said:

From what I can tell the 205 shafts are the shortest standard shafts available that will fit the 1.9 hub and gearbox (vs. the 309 and 405 shafts, which are longer). So, presumably I’d need to buy specially shortened ones? Sounds expensive! Can you recommend any?

It's possible that you have a 205 shaft  currently that has been made too long. There are some re-manufactured shafts on the market that are effectively too long, possibly 309 ones that have been exchanged for 205 ones or possibly just manufacturing mistakes.

 

There is a little bit of adjustment on the gearbox mount, if you remove the battery and loosen the two nuts holding the mount to the battery tray you can the move the mount left and right a small amount because the stud holes are slotted. This is worth trying but it's only a small amount of movement.

[Doc 205 6 1 Cars]

3 minutes ago, jackherer said:

It's possible that you have a 205 shaft  currently that has been made too long. There are some re-manufactured shafts on the market that are effectively too long, possibly 309 ones that have been exchanged for 205 ones or possibly just manufacturing mistakes.

 

There is a little bit of adjustment on the gearbox mount, if you remove the battery and loosen the two nuts holding the mount to the battery tray you can the move the mount left and right a small amount because the stud holes are slotted. This is worth trying but it's only a small amount of movement.

Nice one. Thanks jackherer. I’ll give that a bash in the first instance. 

 

Ironically, I swapped out the old driveshaft (which in hindsight was probably fine) for a new one, which may well be longer, as the rumbling/shuddering is now worse!

[Doc 205 6 1 Cars]

No luck moving the mount, unfortunately. 

 

I’m thinking a shorter shaft is the way forward. Does anyone know if these are manufactured, or will it be a case of getting my existing one chopped and welded?

 

Any idea of what length I’d be looking for? My ‘back of a fag packet’ calculation is around 580 mm.

[welshpug 1,621]

840mm for a 1.9 205, 850 for a 309

[Doc 205 6 1 Cars]

Ok, thanks folks. 

 

After a bit more reading I’m thinking the 309 wishbones with the existing 205 shafts might be the way forward, to allow a bit of extra play for the driveshafts. Might also add a bit of stiffness to the engine mounts to try to reduce lateral movement of the engine and box. 

 

Hope this combo works, as the car is so close to being ready. 

[mmt 14]

I Would Go for 309 arms first to see if that works. Solid/stiffer engine mounts Will cause noise and vibrations in the cockpit. Unless it is a track car I Would Go for standard mounts. 

 

I have 309 shafts as long as 880. AUTODOC list them at 861mm. 

205 ones are listed at 840 and 841. 

[Doc 205 6 1 Cars]

By way of an update, the 309 arms seem to have done the job. No knocking/shuddering at all! Absolutely delighted! Thanks all for your advice. Really appreciate it. 

[Tom Fenton 1,524]

You probably know this, but make sure you reset the tracking now the 309 arms are fitted.

[Doc 205 6 1 Cars]

Thanks Tom. The guy at the garage was clued-up on this. The tracking was well out after the arms were fitted but he managed to get it pretty much sorted. Apparently one of the track rod ends was pretty tough to budge and didn’t move as far as he’d like it to. So next thing will be to replace the whole rod and get it perfect. Drivable for now though, which is the main thing!