gamut200

Hi all...attempting to swop out my leaking dampers on a 91 GT (boge sport). Busy with the rears and got everything off reasonably easily so far using advice from the forum.... But for the life off me we cannot get the nut loose that is at the top of the shock absorber (19mm nut on the piston rod)

Tried it with the springs compressed ....no luck as the rubber and top plate spins around...

Also tried to put the assembly back on the car to hold the top part on place but now the piston rod spins around.

Any advice will be much appreciated!!

GlenL

You have to hold the rod. Some have a hex key. Some just have flats for a vice-grips.

Just need to say, as well, that once that nut comes off the spring is release and the parts will come off violently. Have the compressors on before removing the nut.

gamut200

Thanks ...a bit limited on the equipment side...Tried to hold the piston with a size 8 or 10 spanner but too small to get leverage....any alternative to a vice grip as i don't have one available

Bilal928S4

What year 928 is it? Pictures would help in helping us to help you undo the shocks.
As Glen said you have to be careful. Usually you need an air gun to get that nut off, but you need to make sure the tension release of the spring does not kill you.
If you are trying with just a ratchet it is not going to work.
Best bet would be to take each strut assembly to a shop and have them replace the shock and you can install the assembly back into the car.
Your location might help if there is help available nearby.

GlenL

This may be your best option.

The top is tiny and a wrench (8mm?) that fits it won't work, as you noted.

SeanR

gamut200

Based in London, United Kingdom and car is a 1991 GT with boge sport dampers. Don't have a picture but it is the centre nut (size 19) on the piston of the shock. At the top of the piston the edges are filed away so a small spanner or vice can hold it in love to prevent it from turning during dasassembly ....but easier said than done !

dr bob

Best option for me has been a small pneumatic or electric impact wrench, similar to what is too often used to remove and install wheel lug nuts. Pins the end nuts off and on in a few seconds, with no risk of damage to the polished piston rod.

Speedtoys

With spring extended (not compressed) air gun to remove it.

If it fights, its junk, right? Vise grips or a pipe wrench on the piston. Then it'll come off.

To go on..spring extended, air gun..one quick brrrrap and it should go on. Make sure its on all the way by counter holding on the flats at the top of the piston.

StratfordShark

These are a challenge, as unlike some shocks the piston doesnt have a simple hex to hold it. I've used different approaches, all successful:

- cordless impact wrench on nut (best and easiest, but I didnt have one first time I changed shocks)
- vise grip on piston with wrench on nut
- adjustable spanner on piston, and a through socket on nut so can grip end of piston while putting torque on nut to undo

Speedtoys

And, there's always Plan-C

StratfordShark

I've always had to do this with spring compressed, as you can't extend the spring without removing the top nut to disassemble the shock including spring perches!

Weds

I've used an impact driver to break the nut away from the shaft.. No need to spin it off completely just to loosen it. I think I had the spring compressed when I've done this..

Bilal928S4

You need the spring uncompressed to loosen the nut. Then compress the spring to take it all off, otherwise the spring will become a projectile as the last thread of the shaft is unscrewed and everything just flies everywhere.

MFranke

I put the assembly uncompressed behind a shrub with a heavy blanket over it. Then stand clear on the other side and spin the nut off with an IR 231 torque wrench and socket extension. The spring is at normal compression, so the assembly pops apart, but it is not that dramatic. Nothing goes flying with the blanket.

The other way is to compress the spring first. I did this once but it made me nervous. The potential energy is much higher that way if something lets go while you are hammering on the nut. My spring compressors are not the best quality, so I go easy on them and only use them for putting the new shock in.