Step 1: Relieving the spring of tension
Firstly make sure that there is little to no preload on the spring. If the spring has load on it, you will need to wind the spring-seat down to relieve it of tension. Be sure to measure the position of the spring seat before winding it down. If there is no thread available to wind the spring seat down, you may have to use spring compressors.
Step 2: Undo bottom 19mm nut
You will need to hold the shaft with a 6mm allen key while you turn the nut counter-clockwise with a 19mm spanner. Be sure not to fully remove the nut unless the McPherson strut is standing up the correct way so that the insert will not fall out unexpectedly.
Step 3: Remove the insert and spring
Hold the strut case in the vice for stability. Now pull the insert out whilst trying to hold it central to the strut case so as to remove as little grease as possible. You may need to tap the top-mount with your hand in the direction of removal to free it up.
Once the insert is removed, you are now free to simply remove the spring.
Step 4: Re-greasing
MCA uses Penrite Moly Grease EP 3%, however any grease is better than nothing.
You will see that there are two bushes inside the strut case. The most important area to grease is the gap between these two bushes. The idea is to fill the gap between the bushes full of grease.
NOTE: if there is dirt stuck to the grease remaining in your strut case, it is best to wipe the old grease out with a rag before applying the new grease. Industrial cleaning products such Brake Cleaner and Kerosene may help this process.
Take something precise and preferably with a square edge such as a 30mm rule. Get a healthy amount of grease on the end of rule and carefully wipe the grease into the gap between the two bushes. Once that bit of grease is in the strut case, get some more on the rule and apply again. Repeat until the gap is full of grease.
NOTE: be careful not to damage the dirt-wiper. The dirt-wiper is the rubber seal that is at the top of the strut case.
After the gap between the bushes is full of grease you may want to apply some extra grease below the bottom bush.
Step 5: Refitting the spring and insert
Sit the spring back onto the spring seat and carefully slide the insert back into the strut case. Make sure to hold it central to the strut case to avoid removing any grease from the strut case walls. To know that the insert is correctly fitted, check to see that it is showing all of the shaft’s available thread out of the bottom of the strut case.
Step 6: Refitting the 19mm nut
Again making sure that the McPherson strut is standing the correct way up, screw the 19mm nut back onto the bottom of the shaft that is showing out from the bottom of the strut case. Once finger tight, hold the shaft once more with a 6mm allen key and tighten the nut clockwise with a 19mm spanner. Tighten to roughly 30lb. DO NOT OVER TIGHTEN!