Adjustable Koni Shock Installation on a Range Rover 4.0/4.6/p38A



Koni and OEM shocksIntroduction
Choice of Shocks
1. Compression for Fitment
2. Insufficient Thread Length
3. Compression Rubbers
Results
More Information

Photo: Comparison of Koni (left) and OEM (right) shocks.


Introduction


The genuine shocks on the 4.0/4.6 give a fairly harsh ride compared to the Classic. To improve the ride,
Allan Hogan replaced his shocks with adjustable Konis -- and was very happy with the result. On their softest setting, he feels they soak up the bumps very well on broken surfaces (certainly much better than his worn stock shocks), and provide a smooth ride under freeway conditions. Details of Allan's installation appear below.

Choice of Shocks

In 2006, Allan acquired a late 1999 RR4.6 HSE (Bosch system) with about 103k (65,000 miles) km on the clock.  When he took delivery, he wanted to upgrade it to new condition as much as possible. Allan makes the following observations on his decision process in selecting the Koni shocks:

Apart
from replacing the usual consumables - tyres, fluids, plugs, HT leads and hoses, I took some time to decide on the shock absorbers.  A couple of the local Land Rover specialists seemed quite content with the Bilstein option.  Having had Bilsteins in a previous (non-4wd) vehicle, I had found them most satisfactory and was initially inclined that way.
The thought occurred to me however that a damper with some form of rebound/compression adjustment might be a better option given the prospect of heavy loads and badly corrugated roads common to outback Australia. Ultimately I chose the Koni adjustables from the "Heavy Track" range - Part numbers 30-1597 (F); 30-1598 (R)  They cost about A$240 ea +GST...not cheap... however.. 

The supplier
strongly advised that the dampers be left on the factory default (lowest /softest) setting for a comfortable ride over most conditions for the first 25,000 km or so.  The middle setting could be a good option later for long trips on very rough roads and max all up weight.

With these words of advice I set about what I thought would be an hour or two leisurely work before Saturday lunch...not so! Below are listed the main issues and solutions encountered during the installation.


1. Compression for Fitment
There is no mechanism  provided  to retain the damper in a compressed state to ease fitting.  A spare "S" shaped  heavy gauge  wire from a lesser brand  was  quickly distorted by the force of the expanding shock absorber.  While the Konís  need to be in the expanded state to adjust them properly, no explanation is offered as to how they might be safely compressed.  I finally resolved the matter with a hydraulic jack, a metre of 5mm stainless steel wire rope and a pair of u-bolt wire-rope shackles tightened to form  simple nooses top and bottom ...

 
2. Insufficient Thread Length

When the washers, insulators and nut are all assembled on the "pin" end, insufficient thread has been machined onto the stem to allow proper tightening of the nut. When  tightened to the limit of the thread, the nut / washer still sit slightly proud of the rubber insulator (see  photograph below left).  The thickness of the receiving suspension bracket is insufficient to take up the slack and so the nut cannot be tightened to achieve the correct compression of the rubber insulators.    

A comparison of external dimensions of the Koni product with the OEM component being replaced is in the photo below at right. The inclusion of a captive "pin" nut (blue arrow in photo) on the OEM product is a superior design feature: it not only takes up the slack allowing the retaining nylok nut to be tightened against the compression rubbers to the requisite torque, but also provides for secure purchase on the body of the shock absorber while  tightening the retaining Nylok nut. For the first (front RHS) replacement, I utilized a spare washer from the OEM shock absorber and added two circular spacers to get the appropriate thickness. The spacers were fashionedfrom a nylon kitchen cutting board (wife not happy!)with a hole saw prior to adding the supplied washers and rubber mounts but it has done the job.  For the other 3 mountings, I  slipped a larger but
snug fitting Nylok nut over the pin to act as a spacer  prior to fitting the supplied metal washers and rubber mounts.

Koni shock top
Koni shock
Illustration of insufficient thread length after fitting rubber bushings on Koni shock.
Comparison of Koni (left) and OEM (right) shocks. Note captive nut (blue arrow) on OEM design.

 
3. Compression Rubbers
 
The Range Rover manual specifies 33 ft-lb while the packing slip with the Koni product recommends 58 ft-lb. I took the RRnet advice and tightened the nut to achieve sufficient compression without "pancaking" the rubber bushes.


Results

I  recently completed an 8 day 3,000 km ( 1900 miles) round trip on a mix of sealed -freeway/secondary roads and well formed gravel with minor corrugations. The general handling was better  than I had anticipated, not being accustomed to live axles for many years!  The vehicle cornered with relatively little body roll and the ride was most comfortable, though I noticed that the rear axle tends to hop a little out of line on corner corrugations irrespective of load conditions.

 
I sent an email to the Australian Koni importer/distributor and was pleased to receive a prompt reply including the fact that he had forwarded it to the Koni people in the Netherlands regarding the length of the machined thread on the pin.
 
PS: Notwithstanding the loss of a cutting board, wife was impressed with the improvement in the ride of the vehicle!


More Information

Changing the Shocks on a 4.0/4.6: Details the general procedure for replacing the shocks.
4.0/4.6 Parts Sources page: Sources for genuine, OEM and generic shock replacements for the 4.0/4.6  (see the "Suspension" section)
Air Suspension Diagnosis and Repair section: Information on air suspension problems, solutions and upgrades appears in the .
Range Rover Suspension page: Discussion of the pros and cons of different suspension setups.


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