How to: Upgrade your #Suspension

In this tutorial I will show you how to install lowering springs into a RWD Nissan, and how to install coilovers (adjustable suspension).
While this tutorial covers Nissans, it may be applicable to other auto manufacturers.

Coilovers or Lowering Springs?

Lowering springs are a much cheaper option if you just want your vehicle to look lower, or if you already have a good set of shock absorbers. In my case, I had a decent set of KYB shock absorbers in my car, however I wanted the car to sit lower and the bushings on the shocks were already worn out so my shock absorbers actually got damaged while running lowering springs.
Although they are cheaper, they are slightly harder to install than coilovers and don’t drop the car as low as coilovers.

Coilovers.

Coilovers on the other hand, let you adjust how low you want your vehicle so sit, how soft it rides, and in some cases, how much camber you want. However they are a lot more rigid than OEM shock absorbers so ride comfort is lost.

There are two types of coilovers:

1. Partially Threaded
2. Full Threaded

Partially threaded have one adjustment ring - this changes the spring compression at the same time as shortening or lengthening the shock absorber. This type is cheaper to make, however it compromises comfort and limits the dampening effect of the coilover since lowering the vehicle reduces the dampening area.
Full threaded have two adjustment rings - a height adjustment and a spring compression. In this type you will rotate the bottom mount to adjust the height.

Step 1: Jack the car.

In my previous tutorial about upgrading your brakes I showed how to use your factory Nissan jack. This time around I decided to show how to jack the car using a racing or trolley jack.
Remember the notches under the car? Those are the strongest point and can be used with a vehicle lift or trolley jack (hence why mine are warped). After lifting the car, place a jack-stand under the vehicle and move to the next jack point. You can also use a solid part of the vehicle’s structure such as the crossmember or the beam under the radiator. Do not jack up the car using the engine sump or differential as it may break them and/or damage the mounts.

Step 2: Remove the rear seats.

This may not apply to all vehicles - this tutorial shows how to do it in a Nissan Skyline.
The rear seats are made out of 2 parts - the cushion, and the back rest. The cushion comes out very easy - undo one bolt on either side in the footwell. The back rest is held by one bolt on either side as shown above, and by a bar at the centre middle. After removing the two bolts, lift the backrest straight up towards the ceiling. Pull the seatbelts slowly so that they unwind and slide the backrest out one of the doors.

Step 3: Remove the rear shelf.

The rear shelf will need to be taken out if you intend on using a torque wrench when replacing the shock absorbers. At first it is quite hard to take out.
Begin by prying out the clips at the centre, then while lifting the centre, push the sides down and slide them out. You do not need to worry about removing the seatbelts - just unwind them and let the tray sit in the footwell.

Step 4: Undo the mounting bolts.

On a RWD Nissan Skyline, there are 2 bolts on top of the strut, and one bolt at the bottom. You can place a jack under the bottom mount when you undo the top bolts to prevent the shock absorbers falling out when the top bolts are undone.

The top of the front shock absorbers are bolted into the engine bay. As above, undo the studs and place a jack beneath to prevent the shock absorbers from falling or slipping.
If you are installing lowering springs, you can use spring compressors to prevent the shock absorbers jumping out and getting damaged.

Step 5: Remove the Shock Absorbers.

While pushing down on the wheel hub, try to move the shock absorber off its mounts. If it does not move, you can lightly tap the shock absorber with a soft hammer - don’t hit too hard as you can damage the internal components of the shock absorbers.
If you are installing coilovers, you can skip to the next step.
Once the shock absorbers are out, place a spring compressor on the factory springs (if you haven’t already) and tighten them until there is a bit of play when you try to rotate the springs.
Once the springs are safely compressed, place a spanner over the bolt on top of the shock absorber, and use an adjustable spanner to grip the flat part of the shaft on top. Twist the nut anti-clockwise while holding the crescent spanner in place.
Once the nut has been removed, you can remove the top hat and the rubber bushings, but try not to remove what you don’t need to, or remember the order that they came off.
Place the new spring in place, replace the bushings and tophat and tighten the nut until it cannot move anymore.

Step 6: Adjusting the Adjusties.

Skip this step if you are installing lowering springs.

Coilovers come with a set of spanners that allow you to adjust the height of the coilovers.
First measure the distance from the tophat to the height adjustment ring on all coilovers to ensure they are all the same.
Next, use the spanner to loosen the adjustment ring, then twist the ring until it is at the desired height.
Twist the bottom of the coilover until it firmly meets the ring.
Using the spanner again, tighten the adjustment ring against the bottom of the coilover.

Note that it is not always a 1:1 adjustment - I found that the motor leans to one side of the engine bay, placing more weight on the front left shock absorber. Due to this, it may take a good few hours of trial and errors to get all four coilovers to sit at the same height.
Perfecting the ride height should be done after all four coilovers have been installed.

On the top of the coilover is a dampening adjustment dial. Twisting anti-clockwise softens the coilover, while twisting to the right tightens. To keep all coilovers even, count the number of clicks you twist either direction.
On camber-adjustable coilovers, there are two sets of bolts that allow for adjusting degrees of camber.

Step 6: Put it all back together.

On the tophat of the shock absorber are two studs. These can be very fragile, so the best way is to place the shock absorber onto the lower mount, and jack the wheel hub up while aligning the studs on top with the holes in the chassis.
I found that with lowering springs, you would often have to line up the bottom mount and stud holes with the spring compressors on.
When the studs show through the holes in the chassis, go ahead and screw in the bolts on top.

Step 7: Finishing up.

With the shock absorbers in place, it is a good idea to torque them down with a torque wrench or adapter.
The top nuts use between 15nm and 20nm while the bottom uses 40nm - check with your maintenance manual as having them too tight can break the studs, and not tight enough means they can come loose while driving.
Remember to replace the seats and rear tray in the same way that they were removed when you’re done.

Congratulations! You have just lowered your car.