BUT these aren’t just any nuts they are Toyota nuts!

[Joesson]

Toyota's recommendation is that the locking nuts (nylon insert type) at the top of the shock absorbers is replaced if removed, for instance, when changing shocks or lowering springs.
The consensus in MR2ROC seems to be that the old nut is reused without problem.
I suggest that this is because those in MR2ROC checked Mr T's prices!
Having removed the front shocks and springs to clean off the corrosion that was an advisory on the last MOT I found that one of the nuts was loose!
The first RH side I could loosen the nut without compressing the spring.
The LH side just turned the piston and on inspection I could see that the flats on the piston were just below the slot in the top plate.
Compressing the spring and engaging the top plate allowed the removal of the nut.
So I considered that the nuts should be replaced.
I telephoned and inquired of my local Mr T (who I have a monthly paid service plan with) what the price and availability was.
£5.38 and available next day! For the 2?  I asked. No each! No thank you or words to that effect.
I didn't ask whether this included VAT.
This is for two M14 x 1.5 pitch nylon insert nuts.
BUT these aren't just any nuts they are Toyota nuts!  
They are deeper than the various DIN specifications but the across flat/ corners dimensions are the same as for an M12 nut (which requires a 19 mm socket).
I found that the DIN 934 M14 with a 1.5 pitch would fit the shock thread and that the necessary 22 mm socket fitted inside the cup of the top shock fixing.
From eBay I got 2 M14 1.5 pitch stainless steel nuts delivered for £3.00 and that was including the postage which was £0.76p or just £1.12p for each nut.
Prices of sundry items such as this must attract a mark-up but these nuts are available retail for around £0.58p each (for 10 off) and so are marked up by a factor of 10 by Mr T if they bought them retail!

[widermuller]

Engineering practice normally dictates, all crush/compression fixings like Nyloc nuts, crinlke washers, star washers, wavy washers, spring washers and gaskets should only be used once crushed ONCE.

If re-used effectiveness in retaining is lost, sounds a racket, I know, but its true.

After all would you re-build an engine or gearbox using old gaskets?

We all have some time re-used plain nuts, washers but even these should really be replaced.

And NEVER using stainless steel ones in stress applications like suspension. Only HIGH TENSILE.

I think you will find even with nyloc nuts some have blue nylon others milky white I think you will find this denotes diffrent specs.

Sure they give a massive mark up, it is possible to buy the same from else where but just be sure in what your buying to do the job safely.

[thekickinside]

same goes for stretch bolts - how do i  know this, but lets say torquing up the last full depth of block stretch bolt - all properly cross torqued in stages - that I thought would be ok to reuse and having it snap *just* below the top of the lower crank case was a very very salutary lesson, not on a '2 but the point remains the same)