My Citroen SM 1972 EFI

[Eddie nuff]

Nard reckons a decent one from France will need a minimum of £20k spent on it

Gulp! Puts the £600 it cost me to sort my XM out into proportion.

[Eddie nuff]

There are still a few bargains to be had in France (also some dogs). this one should be dirt cheap because without a CG (french V5) it will be impossible to register in France, it must be exported or scrapped.

Still very nice and oh so tempting.

[Charles M]

Well, what fun. Picked up my newly sorted SM from Holland on Monday - adding modern injection, ECU and sensors with a bespoke map have made the engine just sing - fully in tune, much better torque curve, a lot more oomph, and while I have yet to brim it, seemingly more economical. Took it for a joyous drive today, was going home and boom, clunk, something drops off followed by no forward motion. I'll leave the diagnosis to the experts, but these were the bits (from around the front disc brakes - loads of grease there too). It does look like the clutch and gearbox are fine.

I could cry, but I will order a nice curry instead and have a large scotch afterwards.

[russ92xmsed]

Oooerrr! That does not look good Charles. What a shame after the fine results your were enjoying.
Enjoy the curry and Scotch, I think that's the perfect thing to do after that.

[captainhaddock]

Not, no not funny....drive shaft problems? I really really hope you'll get that sorted...

[Charles M]

Looks like a brake disc something

[captainhaddock]

I think looking at this thing, you will need a new drive shaft. I am not familiar with the unique SM. Did you look behind the wheel Charles? Were you driving fast when it happened? I sincerly hope it didn't do too much damage when this shaft came loose. If not, it shouldn't be too bad. But I cannot for the world understand how this thing perished unless something wasn't fastned properly? Or maybe too much torque for the poor old thing, I do not know. I really hope you'll get it sorted soon.

[marc61]

Charles

The tripod housing has broken up alarmingly because it came loose. It's flange is held onto the gearbox with six studs of a fine thread and nuts hold it and the brake disc onto the differential flange. On the SM the tripod housing doesn't need to be undone to get the engine out, but if it is taken off almost always 4, 5 or all 6 of the studs unscrew as you undo the nuts. Now the problem then is its very difficult to separate the nuts from the studs once it's off the car; so the lazy mechanic will on reassembly just screw the nut/stud assembly back in! That leads to disaster as they undo through vibration, everything shakes and the tripod housing breaks up.

The correct procedure is to screw in the studs by hand with a bit of loctite on the stud then put the discs and tripod housings on, then the nuts and do them up damn tight - I forget the right torque setting but it's in the manual. I've always done mine up this way, despite the hassle of separating nuts from studs, and double checked theyre really done up tight because about 20 years ago I heard about a nearside driveshaft exiting leftwards from a DS on a roundabout due to them not being assembled correctly!

So I think you've got an excellent case for a claim against the mechanic who put the driveshafts back in! I suspect the driveshaft will be fine, hopefully the three balls that fit onto the tripod and sit in the housing will still be there somewhere and you'll just need a tripod housing.

Marc

[Charles M]

Marc - thank you, your diagnosis is confirmed by Nard at Renard who said exactly the same thing having seen the photos, with the alarming addition of a bit of gearbox. This is seriously bad news.

This has not been a good week.

[marc61]

That's good that they've acknowledged the reason for it happening. Given the sophistication of what they've done, its such a shame for something so elementary as doing flange nuts up correctly to let things down. But you hear of it happening every now and then, so they're not alone in failing to follow correct procedure. 2 steps forward 1 step back!

Hope you manage to get it sorted. I've got a couple of spare SM driveshafts stored somewhere, might have a housing not sure. The studs and nuts are very rare, Citroen didnt use this size and fine thread anywhere else on the car for some reason known to them!

Good luck.

Marc