Upper strut nut

[lanciamad]

I've replaced the rear shock absorber on my HPE due to the originals not being upto much until i can fit some spax, but have come stuck on the last bit. I used the nyloc nut supplied with the shock, but have now got the situation that i cant fully tighten the nut as the piston rod just spins around and the same when trying to undo it.  I've loaded the suspension up by jacking the strut and also loading the suspension by lowering the car, both with no luck.
Any other idea's 
Or i'll have to remove the unit and try my best to clamp the rod without damaging it 

[HFStuart]

IIRC mine had a 6mm or 7mm flat section on the top which was sufficient to hold it by  - by the time the nylok bit is on the thread it pokes out so you can get onto it.

Is there nothing like this (or a hex socket) on the top of yours ?

[rossocorsa]

yes usually rectangular bit at the top and of course special lancia tool to hold it! but a suitable sized open ended spanner will probably do. best to do out of the car if you struggle try using an air ratchet in similar circumstances the sheer speed often does the job  but I've never done it on a damper original fittings were special sort of out of round nuts on Betas designed to lock into place as opposed to those modern nylok jobs...edit now that I've thought more about it that might only be konis actually, I think the originals use normal nuts  as there is the washer with the tab that is bent up to stop the nut slackening

[hutch6610]

Have seen two different lock-nut arrangements - out of round ended nut as rossocorsa has just mentioned and a plain nut with a lock-tab plate.
Most aftermarket replacement shocks have the Nylock thats so common today.
Seeing as you have it fitted now you want to tighten it up with an impact wrench - the "blows" are guaranteed to tighten it up or remove it with little effort. 
If you cant get hold of one one (impact wrench) you could try a local garage.

[lanciamad]

The inserts i am fitting are koni's, which came with the nyloc nut. I'll use the original nut for the other side! I will be fitting some coupe spax units when i get them from Mark, but for now, with a few events and track days coming up i thought i'd fit the koni's, an improvement on the leaking monroe's 
Here are some pics. of what i've got at the moment:
http://www.flickr.com/photos/lanciamad/3776976143/in/set-72157618547367271/
http://www.flickr.com/photos/lanciamad/3776976301/in/set-72157618547367271/
http://www.flickr.com/photos/lanciamad/3777779852/in/set-72157618547367271/
I do have a battery operated impact wrench which is "suppose" to claim 320Nm of torque, it may in fact tighten or undo it, but due to not being able to get it at an angle where you can push straight down onto the nut, it purely manages to turn the nut and rod, not being able to create it's "blows", "Impacting" effect.
Also due to the strut top design, you cant get a spanner in at good enough an angle to undo it, nor a spanner on the top part of the piston rod as only one side is flat 
Only thing that is concerning me is that the piston rod goes through the top mount which i thought the hole had a flat in it stopping the piston rod from turning, which gives me the impression that flat in the hole has now worn away to a hole so the rod can spin.
I'll have to take it all out and see what's happened/going on. If this rain stops i'll update tonight.
PS. I've been taking pics as i've gone along for the "How-to" section, so far its a what not to do 

[HFStuart]

Also due to the strut top design, you cant get a spanner in at good enough an angle to undo it, nor a spanner on the top part of the piston rod as only one side is flat 

Angle grinder time I'd suggest. The spanner on the flat is by far the easiest and you'd only need to give it a tickle to get enough of a flat to hold it.

[rossocorsa]

The inserts i am fitting are koni's, which came with the nyloc nut. I'll use the original nut for the other side! I will be fitting some coupe spax units when i get them from Mark, but for now, with a few events and track days coming up i thought i'd fit the koni's, an improvement on the leaking monroe's  
Here are some pics. of what i've got at the moment:
http://www.flickr.com/photos/lanciamad/3776976143/in/set-72157618547367271/
http://www.flickr.com/photos/lanciamad/3776976301/in/set-72157618547367271/
http://www.flickr.com/photos/lanciamad/3777779852/in/set-72157618547367271/
I do have a battery operated impact wrench which is "suppose" to claim 320Nm of torque, it may in fact tighten or undo it, but due to not being able to get it at an angle where you can push straight down onto the nut, it purely manages to turn the nut and rod, not being able to create it's "blows", "Impacting" effect.
Also due to the strut top design, you cant get a spanner in at good enough an angle to undo it, nor a spanner on the top part of the piston rod as only one side is flat  
Only thing that is concerning me is that the piston rod goes through the top mount which i thought the hole had a flat in it stopping the piston rod from turning, which gives me the impression that flat in the hole has now worn away to a hole so the rod can spin.
I'll have to take it all out and see what's happened/going on. If this rain stops i'll update tonight.
PS. I've been taking pics as i've gone along for the "How-to" section, so far its a what not to do  

in those pics the strut rod is the type that uses an allen key to hold the centre rod (as opposed to the flat sided rod top) as regards the mount having a feature to stop the rod turning I think you are right but I'm not 100% if it applies to front or rear (it's raining so can't be bothered to go and look!) I don't think you are really meant to assemble struts on the car the idea is to assemble them and fit as a complete unit

[lanciamad]

in those pics the strut rod is the type that uses an allen key to hold the centre rod (as opposed to the flat sided rod top) as regards the mount having a feature to stop the rod turning I think you are right but I'm not 100% if it applies to front or rear (it's raining so can't be bothered to go and look!) I don't think you are really meant to assemble struts on the car the idea is to assemble them and fit as a complete unit

I was right in thinking that the strut tops had a feature which prevented the piston rod from spinning, this is what had happened.... http://www.flickr.com/photos/lanciamad/3778548531/ this is what it should look like... http://www.flickr.com/photos/lanciamad/3778547193/
I ended up clamping the piston rod with mole grips and the use of kitchen roll and tape... http://www.flickr.com/photos/lanciamad/3778547607/ the damage this caused... http://www.flickr.com/photos/lanciamad/3779354050/ was none  This meant i could remove the nyloc nut and fit the original. I had assembled the struts before fitting to the car, it was just the final torqueing up of the four strut top nuts and strut insert nut due to the car being lowered, therefore loading the suspension i was after to finish the job.
All is well now, deffinately a lot stiffer to the ageing monroe's, but i think the spax units will go even stiffer Just the movement in the strut tops to sort out now.

[rossocorsa]

All is well now, definitely a lot stiffer to the ageing monroe's, but i think the spax units will go even stiffer Just the movement in the strut tops to sort out now.

did you adjust the Konis as stiff as they'll go? I thought they were rock hard when adjusted up I can't imagine spax being any stiffer?