Bilstein ShocksP38 Shock Replacement



Introduction: Discussion of Shock Options
Rear Shock Removal
Rear Shock Replacement
Front Shock Removal
Front Shock Replacement
Results
More Information



Introduction: Discussion of Shock Options for the P38

The genuine shocks on the 4.0/4.6 give a significantly harsher ride than the Classic, and in 1997 Land Rover brought out replacements with slightly softer valving. These versions are now universally used. Personally, I still find these a bit harsh over off road bumps, and have always been on the lookout for "comfort shocks" that would give a ride closer to the unmatched Classic smoothness.  Brent Wilhelmi reports "I have just installed the Monroe Wilderness 4x4 shocks on my 2001 4.6HSE. The ride is very much more comfortable than stock. I just returned from a trip from Moab and they performed as well off road as on. There was not as much bounce after an optical as the factory shocks. The installation was easy and every thing matched up perfectly. I highly recommend them especially with the price difference in comparison to the Bilstein shocks."

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 on the Koni Adjustable Shock Installation page.

Many owners, however, seem to prefer a firmer ride. For example, Kevin Kelly, who kindly contributed his experiences in changing shocks on his 1998 4.6HSE for this article, decided to upgrade to Bilstein shocks while he was at it -- he has had great luck with these over the past 20 years on both cars and trucks. He reports that the Bilstein high pressure gas/oil monotube shocks have a design that is far superior to most typical twin tube oil shocks (like the OEM Land Rover shocks) and is better than most other gas/oil shocks that have much lower gas pressure then Bilsteins. After shopping around on line and posting to a couple BMW and Land Rover lists trying to find the best price, Kevin bought his shocks from www.shox.com . A recent price check (February 2005) showed they sell a set of four for about $315.  (See the
Shocks section of the 4.0/4.6 Parts Sources page for up-to-date prices for these and other aftermarket shocks; the present record holder (February 2005)  is British Pacific which has stock replacements for about $50 each).

Adam Moore from the Land Rover Range Rover Owner (RRO) mailing list http://oryooki.caloccia.net/mailman/listinfo/rro was the only one who responded when Kevin asked for tips on changing the shocks on his 4.6 HSE.  Since Adam just did the rear shocks Kevin started with the rear and used Adams tips as a guide.



Rear Shock Removal:
Adam wrote that is not necessary to remove the wheels and all you have to do is raise the vehicle to off road mode with the EAS to allow easier access underneath. Kevin's experience areed with this, and he only removed one wheel since he wanted to take some photos and inspect the pads on his rear brakes.

Adam opens the tailgate to disable the EAS while under the vehicle. Kevin always opens a door in addition to the tailgate in case the tailgate is closed by someone and to be extra safe he puts a jack stand under the frame.

Adam used a thin crescent wrench to stop the shock from turning while he removed the lower shock nut while Kevin used a rubber strap wrench to stop the shock from turning. The nut on the bottom of the OEM shocks was 17mm while the Bilsteins used a bigger 19mm nut.

rubber strap on wrench

rear shock in place

Tools for the job including Kevin's rubber strap wrench he attached to the old shock as shown to prevent it from turning while undoing its lower mounting nut.

New rear shock in place. In this picture it is easy to see the lower mounting bolt that has to be removed when taking the old shocks out; hence the need for the rubber strap wrench or some other means of precventing shock rotation.


Adam used an 18mm socket at the end of a 18" extension to remove the upper shock mount bolt and said "you can access it between the plastic fender well lining and the frame on the forward side of the rear wheel wells. The bolt fits into a threaded hole in the frame so it is not necessary to get under the truck at all for this portion". Kevin used a combination of 1/2 inch extenders to get over 18" (see photo above right) and had to use a breaker bar to break the nut loose. After reading about Adam's problems with the EAS sensor wires (see below) he was careful not to damage the wires when removing the upper shock bolt (photo above right).

extender

topmount

Using an 18 inch extension to reach the rear top shock bolt while clearing the bodywork and tire.

Care is needed to avoid damaging the EAS wires and tubing while accessing teh rear upper shock bolt.


Once the top bolt is out and the bottom nut is off you can just pull off the bottom rubber bushing and lift the shock out of the bottom mounting hole and remove it from the vehicle.

Rear Shock Replacement:
Adam wrote "Reverse procedure to refit shock, it is easier if working alone to fit bottom shock mount first and extend shock by hand to fit upper bolt. The shocks are fairly easy to extend and compress by hand, and they will stay at the length you put them. This is a very easy procedure, probably easier than changing a tire.There is only one catch...............When putting the upper shock bolts back in place you will be working very closely to the brake lines and EAS height sensor wiring harness that runs on the top of the frame rail. If you are working on your truck, trying to hurry.....maybe trying to beat the impending darkness and distant thunder, it is VERY easy to catch the EAS sensor wires in the bolt threads and sever the connection, you are working with a socket extension and unable to see the
bolt as it threads. If this happens you will spend a night tossing and turning, swearing at your own incompetence, before spending the next morning under the truck with a soldering iron and heat gun, swearing at your own incompetence, and hoping that you are able to reconnect the electrical connection."

Kevin appreciated Adam's tips on installing the shocks and he was careful to avoid damaging the EAS sensor wires but since he installed high pressure Bilstein shocks the installation process was very different than Adam's. Bilstein shocks are under high pressure and come with a band around them that should not be removed until the top bolt is in place and you are ready to guide the shock in to the bottom mounting point.

On the Range Rover Classic and 4.0/4.6 the shock is what limits axle travel and limits articulation. Years ago when Kevin installed Bilstein shocks on his Range Rover Classic he put the Bilsteins side by side with the OEM Land Rover shocks and found that the Bilsteins were slightly longer. When he put the extended new Bilstein next to the extended OEM shock from his 4.6 he found that they were exactly the same length.

old shock

new shock

Old rear shock in place

Similar view showing new rear shock in place


The process for installing the Bilstein shocks is to first mount the top bolt (not the bottom as Adam did) being careful not to damage the EAS wires (as Adam did). The Land Rover manual recommends torquing the top bolt to 92 ft. lbs. Then cut the band around the Bilstein and guide it in to the bottom mounting hole as it extends. Do not cut the band around the shocks like Kevin did ahead of time since the Bilsteins are under so much pressure that they are almost impossible to compress by hand and you will have to make a new band out of a bunch of heavy duty cable ties (aka zip ties). Once the shock is in place force on the lower rubber bushing and put on the washer and nut. The Land Rover manual recommends 33 ft lbs torque on the lower mounting bolt, but Kevin recommends just tightening the bottom until the rubber bushing starts to compress being careful not to overtighten. The Bilsteins come with nylock bottom nuts so torque is not real important.

Front Shock Removal:
Adam didn't do the front shocks so Kevin was on his own, but was happy to find that they were almost as easy as the rears. The only difference was that it is not possible to put a socket on the NAS drivers side top bolt. Before you start make sure you have a ratcheting 18mm box wrench and a "cheater pipe" that will fit over the top of a standard box wrench to break the top bolts loose. Kevin did not have an 18mm ratcheting box wrench (17mm and 19mm, but no 18mm) so it took him a lot longer than necessary to remove and install the drivers side top bolt using an open end wrench.

Front left shock top mounting bolt

new ffront shock in place

Top mounting bolt (marked by arrow) on front left shock.

Picture showing position of front left shock, illustrating access to lower mount.


With the wheels on the ground and the EAS on high with the tailgate to and a door opened Kevin just slid the jackstand forward as a safety precaution in case of some freak EAS failure. With the top bolts out Kevin again used a rubber strap wrench to stop the shock from turning. Like the rear the nut on the bottom of the OEM shocks was 17mm while the Bilsteins used a bigger 19mm nut.

Front Shock Replacement:
The process is very similar to the rears, first put in the top bolt, torque to 92 ft. lbs. then cut the band and guide in to the bottom hole and put the bottom nut on. The only word of caution is to be careful on the drivers side where like the rear top bolts there are a lot of wires that could get caught between the bolt and damaged.

Results
Kevin reports: "I am real happy with my new Bilsteins and I would have put them in a year ago if I knew how easy it was. The improvement to the handling is amazing it is really noticeable when accelerating or stopping since the vehicle stays almost perfectly flat and the front end does not rise when starting or drop when stopping".

More Information
Koni Adjustable Shock Installation page details the installation of adjustable shocks on the Range Rover 4.0/4.6.
4.0/4.6 parts sources page has sources for genuine, OEM and generic shock replacements for the 4.0/4.6.
Air Suspension diagnosis and repair section: Information on air suspension problems, solutions and upgrades.

 

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Page revised February 2, 2012