Last week we got down with the strut in MacPherson and said hello to the spring compressor. This week we'll finish things off and put it all back together.
Consider the Years
Odds are if the shock absorbers or springs of the strut assembly are worn beyond useful service the rest of the suspension components could also be kaput. Since disassembly of the suspension is often required to service the struts this is also a good time to inspect and replace ball joints, tie-rod ends, sway bar end link bushings, and the like. Now onward.
Stuff You'll Need:
· Repair or Service Manual
· Set of Replacement Strut Inserts (Shock Absorbers)
· Jack and Jack Stands
· Spring Compressor
· Air Powered or Electric Impact Wrench (Compressor Required for Air Tools)
· Impact Sockets
· Hand Tools
· Strut Bearings (if worn)
· Replacements for Rotten Rubber Parts (if worn)
· Penetrating Oil
· Automatic Transmission Fluid
· Table Mounted Vice
· Torque Wrench!
· At Least Four Hours
· 20-Year Old Mitsubishi Starion, or Similar
With the strut free of the spring and strut bearing it's time to get at the strut insert or shock absorber. Use a table vice and rag to hold the strut tube. Take it easy with vice as not to deform the strut tube. Set up a catch container, and remove the big gland nut from strut tube. If the gland nut puts up a fight, try tapping it on the face with a hammer to break loose the crud stuck in the threads. Crusty old oil may come forth. Remove the old strut insert.
Next stand the strut upright in the vice and add recommended type and amount of oil while moving the new strut up and down in the tube. An inch plus under the top of the tube is a good bet to allow room for expansion. We used some automatic transmission fluid. The oil is there to help transfer heat away from the strut insert. Corrosion prevention is a bonus.
Install gland nut being careful not to nick or scratch the surface of the piston rod. Tighten gland nut to seat strut insert in strut tube. No we don't know why it's called a gland nut.
Check strut insulators. These are also called strut bearings. The insulator on the left is shot. Kaput. The isolator on the right is fresh from sitting ten years in some warehouse in Japan. Note difference in height. If yours look like mushrooms from Super Mario Brothers then they need replacement.
Reassemble the strut lining up those index marks. Install top nut and seat it by hand to hold assembly together. Slowly release pressure on the spring compressor making sure the spring seats properly in the strut housing. Torque top nut with a torque wrench to specification from the service manual.
Sealant may be required to keep water and road crud out of the ball joint. The locating dowel pins on the knuckle are there to help, not hurt. Put your foot down again on the lower control arm to gain enough clearance for the strut.
Reinstall strut and use a torque wrench to torque fasteners to specification. Torque the top mounting bolts. Tight enough is not good enough. Reinstall anything removed to access the strut.
With the car on the ground give it a few jounces to settle the suspension. Double-check strut bearing top nut torque and mounting bolt torque. Pack isolator bearing with grease and replace the dust cap. Recheck all upper bolt torque after test-driving vehicle. Success!