Worn or damaged shock absorbers are dangerous, have them checked on a regular basis. Worn shock absorbers allow the wheels to bounce and the body to roll and pitch. Tyre wear is accentuated due to the irregular battering encountered and braking efficiency is drastically reduced due to tyre-to-road contact being inadequate. Here are a few important points to look for:
LOOSE OR DAMAGED MOUNTINGS
Check that the fastenings are firm, rubbers are not missing and that all bolts are tight. The shock absorber will not do its job unless it is fastened correctly.
LEAKING SHOCK ABSORBER
Look for tell-tale smears on the unit. Make sure they come from the body of the shock absorber and have just not been thrown up from the road, sump or transmission.
Where a test machine is not available an approximate idea of the condition of the shock absorbers can be obtained by the following method: Bounce each corner of the car several times, releasing at the bottom of the stroke. Each corner should rebound to the top of its stroke and then settle in the normal position. If it bounces more than this, the shock absorber needs to be replaced. If the car is difficult or impossible to bounce then the shock absorber has probably seized or has a bent piston rod perhaps due to a faulty mounting bracket. Always use the correct tools for any job, this can never be overstressed. Shock absorber fitment is no different. The following tools will make the fitment much easier: · Spring Compressor · Brake hose clamp · Strut vise clamp · Torque wrench There are three main types of shock absorbers, namely; the wet strut, the sealed strut and the telescopic. Refer to the owner's manual for the type in your vehicle.
1. REPAIRING A WET STRUT
Here are the steps to the follow for wet strut repair.
Step 1. Loosen the piston rod nut and loosen o9ne turn using the correct size socket spanner. Loosen the wheel nuts. Jack up the car and make a match mark on one of the bolts and the rim before you remove the wheel. Use axle stands for safety.
Step 2. Clamp the coil spring with a spring compressor. Clamp the brake hose and remove the spring clip, disconnect the brake hose fittings, do not spill brake fluid, as it is corrosive.
Step 3. Disconnect the steering arm from the strut by removing the bolts. Remove the top three nuts and mark their position. Now, remove the strut together with the brake assembly, by lifting them out.
Step 4. Move to a workbench and remove the old internal parts. Clamp the strut in a strut clamp, compress the coil spring until it moves freely, and remove the piston rod nut. Note the position of the disassembled components so that they can be replaced in the correct sequence.
Step 5. Using the correct size spanner, remove the gland screw, take care as it may have to be re-used. The function of the gland screw is to centralise and clamp the internals. Remove the old internals and check for compatibility against the new insert.
Step 6. Drain the oil and discard it. Clean out the tube and threads with a solvent. Refill the tube with the necessary amount of oil, either Midas SAE 30 or a suitable equivalent. The new insert can be slid into position.
Step 7. Carefully re-fit the gland screw and torque it to the correct specification. Ensure that the new insert is firmly positioned in the tube and make sure that the piston rod is centred with the correct amount of thread exposed. Prime the unit well to get the oil circulating.
Step 8. Align the spring with the seat hollows. Grease the bearings. Tighten the top nut just enough to secure the assembly. The unit can now be installed into the vehicle.
Step 9. Once securely positioned, the top three securing nuts should be tightened to the correct specification. Refit the steering arm to the strut knuckle and tighten the piston rod nut to correct specification. Replace the dust cap.
Step 10. Reconnect the brake hose fitting and replace the spring clip. Refit the wheel, make sure the match marks are aligned. Lower the vehicle and tighten the wheel nuts.
Step 11. Bleed the brake line. It is recommended that the tyre pressure and wheel alignment be checked and the car test-driven. The wet strut repair is now complete.
2. REPLACING A SEALED STRUT
Here are the steps to follow for front sealed strut replacement:
Step 1. The procedure up to this stage is exactly the same for the sealed strut as it was for the wet so we can go straight onto disconnecting the brake hose. Clamp the hose, remove the spring clip and disconnect the brake hose.
Step 2. Note the position of the adjustment cam by making a notch on the lower bracket. Support the suspension with a jack to prevent it from dropping. Remove the two securing bolts. The sealed strut can now be removed from the steering knuckle and lifted out.
Step 3. On a workbench clamp the strut in a strut clamp and compress the coil spring until it moves freely. Remove the top nut and disassemble the components noting their position. Remove the old strut from the strut clamp and compare it with the new unit. Now place the new unit in the strut clamp.
Step 4. Ensure that the new unit is well primed and carefully replace the components in the correct sequence, checking them for wear or damage. Ensure that the coil spring is aligned with the lower seat hollow. The "out" marked stamped on the upper spring seat must face the outside of the vehicle. Tighten the top nut just enough to secure the assembled strut.
Step 5. Remove the spring compressor, the sealed strut is ready for refitting. Tighten the top three nuts to the correct specification. Refit the steering knuckle to the lower bracket. Apply oil to the bolt threads and insert them from the rear side. Align the adjustment cam on the steering knuckle with the notch previously marked on the lower bracket and tighten the nuts according to specification. Finally, torque the piston rod nut to the manufacturer's specification and replace the dust cap. Reconnect the brake hose fittings and replace the spring clip. Bleed the brake line and it is recommended that the tyre pressure and wheel alignment be checked and the car test-driven.
3. REPLACING A TELESCOPIC SHOCK ABSORBER
Fitting a telescopic shock absorber is a lot easier than fitting wet or sealed struts. However, there's always those small but important points to keep in mind. Don't forget to lubricate the bushings, use a rubber lubricant, not oil. For stud applications, the top mounting should be fully tightened only when the full weight of the car is on wheels. And remember, don't overtighten the bushings. When fitting adjustable shock absorbers please follow adjustment instructions on package ( 4 settings). General notes: To remove nuts, use Loctite penetrating oil. Never burn them off. For stubborn nuts use a "nutcracker" and throughout the job, always use the correct tools. Before installing the new unit, make sure it's the correct one for the vehicle. Prime the unit before fitting it and check all components before replacing them - if they're old and worn, they too should be replaced. Don't grip the piston rod with pliers or place the unit itself in a vise, you'll damage it.
Midas Motor Parts Centres recommend ARMSTRONG SHOCK ABSORBERS.