Wednesday, July 15, 2020

DIY - Changing Front Springs

Changing the front spring requires a little more precision and some special tools compared to the rear spring. In addition to the tools needed for the rear springs, this will require

  • A 13mm thin wall deep socket, and you may still need to grid the outer walls of the socket extra to have it fit through the mount to unbolt the struts. I used 1/4" drive socket which is the thinnest wall I can find and still had to grind the outside a few 10th of a mm using a Dremel.
  • TT50 and T40 Torx sockets
  • Long Hex Wrench (4.5 mm or 5 mm)
  • Strut socket
  • Straight edge & marker
  • Spring compressor (This can be rented from a parts store such as O'Reilly and is usually free after the deposit is refunded upon return
Changing front springs.

Start by removing the front trunk (frunk) as per these instructions.Chuck the rear wheel opposite side of the front wheel for which the spring is being changed.

If using one jack or if you are unable to jack up the entire front of the vehicle, it will be necessary to release the tension from the front sway bar. Unfortunately the side of the vehicle that is lifted cannot have the tension removed without lifting the other side.

So here is a quick hack:
- While the car is level, turn the steering wheel completely out in one direction, and keep the steering wheel taught as you step out of the car.
- Use a socket and multiple extensions to loosed the sway bar bolt that is connected to the strut. 
Loosen the sway bar bolt and remove before jacking up car

- Jack up the opposite side of the car slightly. Ever so slightly. The wheel does not need to be lifted at all. The body just needs to be raised less than an inch. This will remove the tension from the side that has been unbolted enough to reach back into the wheel well and remove the sway bar link easily from the strut. Be sure to place it clear of the strut.
Sway bar link removed from 

- This can be done to both sides, but I did it one at a time after the spring on one side was replaced.

Straighten the steering wheel. Now loosen the lug nuts of the front wheel.

Jack up the front wheel of the side which has had the sway bar disconnected. OR Jack up the rear and place a jack stand on the front wheel.

Remove the front wheel and you should have the sway bar link should already be removed. A T-45 Torx will be needed with the docket to tighten the sway bar link back.

Follow the ABS senor cable from the back of the rotor area and pull out each of the carious plastic tabs holding it in place and tuck it away. The ABS sensor cable does not need to be disconnected, just placed out of the way.

Loosen the bolt that holds the strut to the lower control arm using a socket and wrench. You can remove it later by sliding it out, once the top is unbolted.
Lower strut mount bolt.

Next remove the bolts that hold the upper control arm to the knuckle. There is another bit of a trick here as well. 

Removing upper control arm from knuckle

First off, this is where a TT50 Torx sock will come in mighty handy. Loosening the bolt on the left is easy, but the TT50 will be very much needed to tighten everything up properly. On the day I was removing the strut, I did not have a socket, so I used a locking wrench and picked up a socket later that evening. The very important thing here is to press down on the upper control arm as shown by the arrow to remove the bolt otherwise you risk stripping the bolt. Press down on the control arm when replacing the bolt upon reassembly as well.

Do not let the knuckle and rotor assembly fall to far to one side, it will pull on the brake lines and ABS sensor.

Next using the 13mm ultra-thin wall socket that you made to loosen the 3 nuts on the top of the strut.
Remove the 3 bolts to loosen the strut

The strut should now be loose.
Pull out the bolt that holds the bottom of the strut and guide it slowly to rest on the lower control arm.

To remove the struct, simultaneously push up on the control arm at the top, tuck the knuckle and rotor assemble to the side, and push the strut down then out, clearing all the cables and brake lines.

The brake line assembly that is connected to the knuckle can be removed, but I did not need to remove it.
Pulling out the strut

Strut clearing the car. Be careful not to scratch the body with the strut studs. Also not the ABS cable is out of the way as shown by the yellow arrows below.
Strut clears the body easily.

Use a bungee cord or something similar to knuckle and assembly in place so it does not pull on the ABS cable or the brake line while the spring is being replaced.

Secure the knuckle

Important trick here. Because the studs on the strut can only go in one way at the top and the bottom of the strut must also line up exactly to go back into the bottom control arm, it is vital that the new spring goes on exactly maintaining the same geometry.

Once you take out the strut, take a straight edge and very carefully and precisely pout marks on the top and bottom as shown on the picture below with the white line. If the reassembly is off by even 5 degrees the strut will not go back. You will need to recompress the spring, realign and try again. Take it from someone who did it 3 times to get it right on the first side,
Marking strut angles

Tips to disassemble the strut and spring:
While the spring has all the tension break loose the top nut that holds the strut to the top mount plate, as shown by the yellow arrow in the picture above, The Hex wrench shown will be needed for reassembly.

Now use the spring compressor to compress the spring, evenly on both sides. Fair warning: If you have never used a spring compressor, watch some YouTube videos and learn and be very careful the forces which are applied here are enough to kill a person instantaneously. Also, if the instructions say no power tools, then don't use any. Its tough but important. The compressing must be done symmetrically to keep it balanced,

Once the spring is compressed, and the top plate is free to indicate that the spring is compressed sufficiently, then using the hex and socket as shown above remove the top plate.
Strut and new spring being assembled

The old spring will slide out and must be carefully expanded and spring compressor removed.
Another Tip: DO NOT compress the new spring before putting it on the strut. otherwise it will not go on. You must place the spring into the strut and compress the spring as shown above. The spring should be compressed enough to allow mounting of the top plate, easily.

Now would be a good time to trim 20mm from the bottom of the yellow bump stop as per the Eibach instructions. Also make sure that the rubber mounts line up properly. 

To reassemble the strut, place the top plate in the proper orientation, making sure that the marked lines match up. Tighten the mounting nut. This is easiest done using a hex socket and The final torque value for nut is 45Nm or 33ft-lb. This can be final tightened after the tension from the spring is released however, not that the top plate must not rotate while torqueing the top nut. Release the spring compressor slowly.

To re-assemble the strut and spring back into the car, first position it on the lower control arm, letting it rest, then push it so that the studs go back into the upper mount. Very loosely thread one of the 3 nuts and the other two. May be helpful to have some help for this. Care should be taken not to drop the 13mm nuts into the holes.

Once the strut is held by the top studs, then maneuver the knuckle back into the strut mount and slide the 21mm mounting bolt into the assembly. If the angles have been messed up his is where it will show. Hopefully you do not run into this issue and did it correctly.

Torque the top of the strut 13mm nuts. The Torque value is 23Nm or 16ft-lb these nuts.

Tighten the bottom bolt that mounts the strut to the lower arm, the torque value for this is 115Nm or 84ft-lb

Last push the upper control arm into the knuckle and slide the bolt into place. This is where the TT50 socket will be needed. The toque value for this bolt is 56 Nm or 41ft-lb

Replace the bake line mounts that have been removed. Replace the ABS senor cable mounts along the upper control arm and the knuckle.

The last thing to do is the sway bar. If the entire front is lifted then this is easy to do, if not then move the sway bar mount out of the way and mount the wheel to the car and secure the lug nut snugly.

Lower the vehicle on this side. Turn the wheel out. Slightly jack up the car from the other side, as you did before. Work the sway bar link into the strut mounting hole. Using a wrench and the T40 Torx to hold the ball joint, tighten the nut for the sway bar. Final tightening can be done when the car is flat and there is equal tension on the sway bar. The torque value for this nut is 98 Nm or 72ft-lb.

The final torque value for the wheel lug nuts is 175Nm or 125 ft-lb.

Now would be a good time to take a break before starting on the other side. Repeat the same procedure on the other side. Taking note of what needs to be done with the sway bar first. 

Good luck and read my result review on this post after having the lowered suspension for a few weeks.
The car must be allowed to settle and then a 4-wheel alignment must be performed.