Koni Rebuildable Front Shocks.

We previously wrote about our experiences with the rebuilding of the Koni rear strut inserts, the results and outcome of that exercise was excellent. (See link at Bottom Of Page)
So, being armed with that info, why not also tackle the rebuildable front Koni shocks.

There are two reasons for the pull down of the front shocks.

1. The recent purchase of a pair of new Cellasto bump stops. (Micro-Cellular Polyurethane Elastomer foam shaft bump stop which create a progressive bump stop spring effect).
2. The front Koni shocks have not been serviced since new, and have covered about 65,000 miles over thirty years.

Firstly – Some special tools are required, and you may have to make some of these, you will require some marking out tools, a lathe, welder, and of course a collection of the usual workshop tools, spanners etc, in order to remove the shocks from the suspension of the elan, always follow the workshop manual if you are not familiar with the process.

Warning: If you do not understand, or feel comfortable with the mechanical processes of dismantling and re-assembly of shock absorbers, then you might want to rethink if you really want to get involved with this. But there will be people who will want to to do this, and we will go through the process, but please, in no way should you consider this to be professional advice or guidance. But having said that, it can be said here, that the results in the writers workshop have been just as affective as what would have been achieved in an agency workshop, and at a fraction of the afore mentioned costs.

When dismantling Koni shocks or struts, you will encounter seals or “O” rings under the gland nut, the seals are compressed under considerable pressure when the gland nut is tightened, so to get the seals out without damaging them, a mechanics seal picking tool is required, and will make the job much easier than using some kind of “make do” sharp object.

There is every chance the gland seal pack will be OK to use again, if not, new Koni seals will need to be acquired before the rebuild begins.
Koni shocks have a long history of being rebuildable, and if the shocks you have are quite worn, IE,  signs of the hard chrome on the rod showing severe wear, and other really bad wear, then perhaps it is off to the Koni rebuild shop to have the job done, this is a decision you will have to make, it is your call.

If you are the ultimate DIY engineer type, then you’ll love making the gland nut wrench tool. I don’t think this kind of tool would be found in the local tool shop, Koni would have them, but will they sell you one?…. Not likely, but who knows.

If you have lathe and a welder, this tool can be made in about one hour. Basically, the pins are machined from HT 8mm Hex Cap Head screws (Un-brako), the small pin is 3.5 to 4mm Dia and about the same depth, the centre plate of the tool is 50 X 10mm mild steel, the writer used a bit of scrap found in a box under the bench, likewise for the square tube handles that are welded to it.

Use engineers marking out blue to mark out where the holes need to be drilled to match exactly the pin locating holes drilled in the gland nut of the Koni. Use a vernier caliper to measure, and a sharp scriber to mark out, and an engineers set square, you have to be exact, and spot on with all measurements, use engineers marking out blue for accurate work.

Drill and slot the plate as shown because it makes the tool quicker to use… just slide it over the gland instead of having to place the hole over the rod to slide the tool down to the gland nut.

The tool (chuck) shown above may confuse some people. The shock piston is threaded and screwed tightly onto the bottom of the piston rod, to unscrew requires the piston to be securely clamped, a new three jaw lathe chuck may appear to be able to clamp the piston, but no, it will simply turn in the chuck (risking damage to the surface of the piston) when force is applied to undo.

The aluminium chuck was turned to obtain a sliding, or hand push on fit, notice that one side of the aluminium chuck has a slot cut (Hacksaw).

To operate, push the piston into the chuck, then firmly clamp the Aluminium chuck assembly into the three jaw lathe chuck, and tighten, place a spanner or shifter onto the square spigot on the end of the rod and lock the lath chuck, and the piston can be easily undone with doing any damage to it. Remember that all hydraulic parts need to be treated with care and attention, cleanliness is godliness when it comes to shocker parts.

The photo above illustrates – from the top – The Koni shock body, with adjustable spring perches, the inner tube, and the piston rod assembly complete with gland nut, Celasto bump stop, and alloy spring retainer ring.

Because of the width of (Upper part) the Celasto bump stop, it did not fit correctly under the alloy spring retainer ring, so it was modified as shown to make sure that the entire bump stop width across the top was under contact load when being compressed. The Celasto material is far superior to a similar shape rubber bump stop, and they also have the added effect of being an additional progressive spring, and work extremely well with the 120lb Eibach coils assembled to the shocks.

When the spring retainer parts are assembled, the photo above shows what they look like. The red steel flange that acts as the spring retainer stop, was converted to a screw on arrangement, which also meant that the Koni piston rod required a longer amount of thread, the thread was cut on the engine lathe, ensuring accuracy.

As usual, when dismantling shockers that have been in service for a very long time, the oil is as black as the ace of spades, and when decanting the old oil, pour it into a container and measure it, otherwise you wont know the correct amount of new oil when doing the refill.

Spring compressors are essential when compressing the spring so that it can be reinstalled back onto the Koni shock body. Work very carefully and watch closely as the springs are being compressed to keep things even on each side.

The distance between the bottom of the bump stop and the top of the shock body measured 55mm, the Celasto material, being of a progressive design will compress at least another 40mm, and then simply do its work as designed.

You may want to refer to the rear Koni strut rebuild article for other details pertaining to shock fluid used for refill, and other dismantle/ rebuild details, because in reality the working principle and mechanicals of the front and rear shocks is much the same, it is just that one pair  are strut inserts, and the other pair external front mounted coil over shock absorbers.

If you just read this article and do nothing, that’s OK, we hope you have learned something, but if you want to delve further, then do so with caution and care, we know this kind of work is not for everyone, but it is possible to carry out a high quality repair or rebuild job in the home workshop.

Driving Observations Since Front And Rear Suspension/Koni Rebuild.
The S2 elan has now become a different beast to drive… for the better. No longer is there a fear when encountering rough and rutted road surfaces, the elan now handles bad road conditions with far better manners than previously, amazing really, but what a difference rebuilt shocks make, along with the installation of high quality and correct bump stops on both front and rear suspension – The ride of the car has improved out of sight, the handling has improved, the cornering ability has also been racked up several notches. (Big Grin Here).

Now, all we need is a brand new, BIG horsepower 1760cc engine… which, by the way, is now well on the way, and will report on that in the near future.
Click Here To Read More About Rear Koni Rebuild Project.