removing drivers side axle on the V6 to get alternator out

[cc]

Its just too difficult to remove the rear exhaust in situ....... so I m now looking at making space by taking out the axle...
Elearn states that  the 6 bolts joning the axle to the intermediate are  coated with eslock?? and should be replaced with new..
Anyone know about this??? Its prob the same for a 4 cylinder....
Also The 6  bolts as they now are have rotational free play of about 1/36 of a turn!!!! the other 1/2 axle shaft bolts are tight & have no play..
Anyone taken out a 1/2 shaft??
advice gratefully received!
Have discussed the loose bolts with a local alpha specialist, who said its not uncommon to find them loose! The grease in the CV joint is quite black.

[cc]

Should there be a gasket between the drive shaft and where it bolts onto the output shaft from the transmission? See pic. Have also detailed pics the detail on the 6 nuts and bolts. Its an 8mm hex drive and nylock bolts. Elearn says to replace bolts. A brisbane alfa garage says go with the old. The bolts are in 3 pairs, 2 bolts linked by flat plates. As the  nuts werent tight!!! theres been movement and polishing on the bolts and the flat plates. Elearn quotes 50-61Nm for tightening.
below is a quote from elearn re the 6 bolts attching the drive shaft to the intermediate shaft.

"The bolts securing the front half shafts, intermediate half shaft/differential inner half shaft side, have been treated with Eslok type locking compound; therefore every time they are removed they must be replaced"

[johnl]

Are there any traces of an old gasket? I've not done this job on these cars, so I don't know, but I would expect not. I doubt the grease would be thin enough to get flung out through any minute gap if no gasket is present, but if in doubt it wouldn't hurt to use a smear of silicon (IMO).

Ettore Bugatti once said (words to the effect) that any engineer who needs to use gaskets doesn't know how to machine a flat surface. From personal experience I know that old Bugattis leak oil from every orifice and seam... Having cast that doubt, we're talking a thick grease here, not oil.

If the cap screws (i.e. this kind of 'bolt') come loose then they (or any bolt) weren't tight enough to start with, regardless of the specified torque (i.e. the spec torque may not be enough to adequately stretch the cap screws elastically, which is what prevents any significantly tightened bolt from loosening). Come to think of it, if a gasket were used, then it's more likely that gasket compression / hardening over time could possibly lead to the cap screws losing tension and becoming loose.

My gut instinct is that you would most probably get away with re-using the cap screws (personally I would be happy to take what would be IMO the very tiny risk). However, if there are any parts of the shanks that have been narrowed by wear, or bent, I would definitely replace. For peace of mind, cap screws like that are not expensive from a specialist purveyor of bolts (etc).

Keep in mind that it's not the cap screws' (or most bolts) strength in shear loading that hold the parts together (i.e prevents 'slippage'), it's the clamping force created by the fasteners torqued tightness. If it were the fasteners' shear strength (and not the clamping force), then the fastener would need to have a zero clearance in the holes through which it passes (unlikely in this application), or else fretting would occur, and this would lead to loosening.

Nyloc nuts - I usually re-use if I can't turn the nut on the bolt thread by hand (and never had one come loose). Keep in mind that the nylon insert does not prevent the nut from loosening, just stops it unwinding all the way if it does (it's the elastic stretching of the bolt that stops it coming loose). Much the same goes for thread locking compounds.

If a bolt loosens, then it's not impossible that it's the nut that has failed, i.e. the nut threads may have started to 'creep' as the torque approaches spec tightness. It's my understanding (backed up by my experience with using them) that Nyloc style nuts are generally not made form a 'high tensile' steel, so the threads are more prone to stripping than the cap screw or bolt threads (cap screws are generally quite a high tensile steel, and the threads are fairly tough).

If it's common for these cap screws to loosen, then I have to wonder why that is. Maybe the spec torque is fine for the cap screws, but a bit too much for the nuts? Maybe the person who specified the tightness was having an off day and forgot to think about how much torque the nuts could handle...? Replacing the nuts would probably be a good idea. At the specialist nut and bolt shop, I'd try to find nuts with the deepest thread length I could find (of course the limiting factor here is how much of the cap screw thread you can engage in the nut), and wouldn't be too concerned if that meant not having nylon inserts. Personally I'd also lubricate the threads, under the cap screw head, and under the nut.

Regards,
John.

[bazzbazz]

1/ If the bolts were loose it was because they weren't tightened properly when the last person re-fitted them. IT IS NOT NORMAL FOR THEM TO EVER BE LOOSE!

2/ You can re-use the bolts and nuts as long as there is no damaging wear from them being loose. DO NOT re-use them if there is any wear in the head of the Bolt, they are easily stripped out by people trying to remove them without having the hex drive fully home in the bolt. If the heads are worn in any way replace them, otherwise when you next go to remove them you may have to use an angle grinder! They are available at any good bolt shop.

3/Use red Loctite compound (mild) on the bolt threads.

4/ There is no gasket

5/ The grease used in the joints is Moly disulphide, natural colour is black & very thick.

Baz

[cc]

thanks guys

[johnl]

1/ If the bolts were loose it was because they weren't tightened properly when the last person re-fitted them. IT IS NOT NORMAL FOR THEM TO EVER BE LOOSE!

I would agree, but CC said: "Have discussed the loose bolts with a local alpha specialist, who said its not uncommon to find them loose!".

If so, then that begs the question, why is this apparently happening 'commonly'? Are there a lot of mechanics out there not tightening these bolts tightly enough? Is there something wrong with the torque spec? Is there something wrong with the hardware?  Assuming the anecdotal report to be correct, then it may well be "not uncommon", but as Baz says it shouldn't be considered 'normal'. Apart from potential damage to components, a drive shaft flange with loose bolts is relying entirely upon the shear strength of the bolts, which may cause the bolts to shear off...

Not saying that this is what anyone else should do, but personally, in this application I wouldn't bother using a torque wrench (and on other cars' driveshafts never have, with no loosening issues ever). I'd just tighten them until they felt tight enough. With experience you can feel the bolt elastically stretch, which is when you stop tightening. If you do overdo it the thread (probably on the nut in this application) will start to give way (i.e. plastically deform, because the elastic limit of the steel has been exceeded). You can feel this happen because the bolt starts becoming just a little bit easier to turn. If this happens then I'd replace the nut. This is not a good idea (reasonable risk) where a bolt tightens into an expensive or hard to replace threaded casting, or if the nut is hard to replace, etc. I rarely strip fasteners when tightening, and the ones I have stripped have usually been dodgy in some way (i.e. worn threads, or perhaps previously overtightened, i.e. I can blame someone else...).

Something else that crosses my mind, any washers or plates should be made from hardened steel, not mild steel. Soft washers can crush and affect clamping force seen at X tightness (my understanding).

2/ You can re-use the bolts and nuts as long as there is no damaging wear from them being loose. DO NOT re-use them if there is any wear in the head of the Bolt, they are easily stripped out by people trying to remove them without having the hex drive fully home in the bolt. If the heads are worn in any way replace them, otherwise when you next go to remove them you may have to use an angle grinder! They are available at any good bolt shop.

Yes.

3/Use red Loctite compound (mild) on the bolt threads.

Baz

Won't hurt, and will probably act as a thread lube when tightening, increasing clamping force for X tightness (and it's clamping force that is important here, you want as much as the bolts / cap screws can create short of failing).

On a side note, the faces of the drive shaft flanges work (i.e. don't rotationally move relative to each other, at all, keeping in mind the bolt to hole clearance) because of the clamping force and friction between the component faces. So ideally to increase friction, the faces should be ever so slightly rough (not 'polished') and clean and dry. Grease or oil, maybe silicon sealant, or even rust, could act as a lubricant, probably not enough to cause any slippage if the bolts are tight enough, but something to consider.

Regards,
John.

[bazzbazz]

I would agree, but CC said: "Have discussed the loose bolts with a local alpha specialist, who said its not uncommon to find them loose!".

I am VERY surprised any Alfa "SPECIALIST" would say that.

Saying such is the same as saying "Oh, it's not uncommon for Alfas to have a drive shaft come adrift and spearing off into on coming traffic." It's basically the same thing. I am not saying it's unheard of, but "not uncommon", nope.
(Yes Sheldon, that IS Sarcasm!)

The biggest problem with these bolts is getting them undone, from people wearing the heads out.

And I'll say no more on the matter.

Baz

[cc]

The pic shows the gasket being re fitted.. its about 2mm thick, hard black plastic and it turns out seems to fit in a recess in the flattish surface of the drive shaft.. altho as i didnt fit/see the gasket and d/shaft back to the engine before fitting the sub frame, im not sure its in the exact correct position..

So might be better to do it before offering up the sub frame.

As the grease in the cv joint is sticky and the joint sits proud from the housing, its a battle to fit the gasket over it. theres about 10mm  east west movement Its another impossible jobs done from underneath  the vehicle while trying to hold 3 things in alignment, the shaft, the gasket and the thru bolts.Turns out, doing that with one hand! and turning the axle with the other. It can be done. The sticky grease hopefully not too contaminated by the grit under the vehicle, and not too much missing by being spread on the hands.
Have also put a larger pic of the 156 as found at a local wreckers for sale with a misfire,a glove box of service history and lots of Italian engineering history everywhere you look : )

[bazzbazz]

My apologies as to the gasket, I thought you meant was there one to be fitted on the inner shaft face shown in the photo. I should have been clearer.

[cc]

Hi guys
Anyone know the torque Nm required for the 6 bolts with nyloc nuts attaching the 1/2 shaft to the intermediate axle?? cant find it in elearn. done to 25Nm so far
thanks