Suspension Repair, Volvo 240, Don Docksteader Motors
The November Technical session was a smashing success by all accounts. The session was held at the Cambie Street location of Don Docksteader Motors. Shop foreman Jeff Wong and his able assistant Jason Leber led us through the replacement of rear trailing arm bushings, rear shocks, front lower control arm bushings and front struts. As a special note, Jeff will be celebrating his twentieth year with Docksteader in May of 1998. This Cambie Street facility was built in the late 1980s to help solve the problem of not enough space at the old location on Main Street. Some people may remember their extended hours in the mid 1980s.
The subject vehicle was a Volvo 242 belonging to Ron Brown's son. This was an extraordinary specimen of a real soldier of a Volvo. The odometer showed 437000 km. Someone added that it was actually 1437000, though I'm sure that it was only in humour. This car is a 1980 GT, Limited Edition. I overheard that only 200 of these were made and that a good percentage of them ended up on the west coast. They can be identified by the distinctive black paint and a dash plaque. And, of course, this was the only year that the car was identified by the letters "GT" on the trunk lid. Apart from this car, there were two other 1980 GTs there that night, both of which belonged to Club members.
There are ten bushings in the rear suspension of the 240: four torque rod, two panhard rod, two at the front of the trailing arms and two which attach the trailing arms to the rear axle. It is the latter which carry the weight of the car, are normally the first to fail and were the bushings replaced on the subject car. A diagram of the bushing is shown.
These bushings consist of a slightly tapered outer steel cylinder, an inner steel tube and a cast rubber medium between the two steel pieces. The axle has two sets of sheet steel brackets which carry these bushings, one on the left and one on the right end of the axle. The bushings are pressed into the brackets from the direction of the centre of the car. Long bolts attach the bushings to the trailing arms. The outer cylinders, or casings, of these bushings are clearly visible from the under side of the car. It should be noted that the brackets on the axle are not overly strong in a lateral direction and can easily be bent. However, they are quite flexible and can easily be bent straight again.
There is no hard and fast rule to determine how long these bushings last; it depends on engine power, type of gearbox, and type of driving. They can easily be inspected by examining them under the weight of the car. If the bolts through the bushings appear to be significantly off center from the outer casing, they are surely worn out. The same is true if there are large chunks of the rubber medium extruding from the bushing. Driving the car may also reveal their need of replacement. Worn bushings will cause an abundance of noise emanating from the back end of the car, especially under acceleration and changing of gears. New bushings can dramatically reduce the noise, as I can attest to, having replaced mine in October of 1997.
The subject car was already up in the air on one of the two-dozen or so lifts in the shop. The car is supported by its chassis.
The bushing bolts are removed by first removing the nuts. In order loosen the load on the bolts, support the weight of the axle with a jack applied to the brake caliper or some other convenient spot. The axle is then lifted up so that the bushings are clear of the trailing arms. The axle could be lifted up as high as necessary or until it reaches the upper rubber stops. Just remember to watch the brake lines and hand brake cables so that they are not damaged.
Jeff explained that the method he was going to show us is a bit different than that described in the manuals. His method, as he explained, was a method you could use in your back yard. Please note, you need an air chisel and a compressor. (I don't know about you, but my back yard doesn't include these tools. My back yard also does not include a lift to get the car up in the air.) Rather than using the press and special tool adapters, they used the air chisel to partially collapse the outer casing of the bushing and then to force the bushing out of the axle brackets. Once the bushings are out, they are certainly not suitable for reuse.
The new bushings are marked to clearly show the correct orientation. There is a very obvious "DOWN" mark in the rubber medium which, not surprisingly, should face the ground, assuming the car is sitting right side up. The new bushings must be forced in by pressing on the outer casing and not the centre tube as this is quite likely to damage the bushing. Part of the special tool is used to cover the large end of the bushing and protect it from damage. They used a large bolt in the centre of this tool to protect the tool. After a bit of gentle adjustment with a very large hammer, the bushings are installed by driving them in with the same gentle hammer. By the way, this is a two-hand job! It is also useful to have the car up high enough to stand under. This will enable getting a good swing on the hammer. Once the bushings are in, the axle brackets are straightened by tapping them back into place with a hammer. The axle is then lowered into the trailing arms and the bolts reinstalled and tightened.
An alternate method, which I used, involves pressing the bushings out and in using a slow, controlled method. Normally, one would use the special tools available to the Volvo dealerships. However, these tools are expensive and not readily available. They can be substituted with a selection of thick walled steel pipe, a few thick washers, a length of threaded rod and two nuts.
The bottom bolts of the shocks and springs can be removed to allow the trailing arms to drop right down and out of the way of the action. This is not absolutely necessary, but will give you a bit more space to work. This may also give you a bit more flexibility as to the position of the axle which is important for the right side due to the exhaust system.
Pressing the bushings out involves placing a short piece of pipe on the narrow end on the bushing, nearest the outside of the car. This pipe must have an OD slightly smaller than the smallest end of the bushings (about 55.0 mm) so that it may travel through the axle brackets without interference. On the side of the bushing nearest the centre of the car, you will need a longer length of pipe with an inside diameter slightly larger than the large end of the bushing (about 58 mm). The bushing will travel into this pipe as it's being pressed out. This pipe should be nearly as long as the bushing casing.
The important part of this task is to support the two brackets with a spacer in between them, otherwise the brackets will be bent towards each other and will cause the bushing to jam. Jeff showed us an example of this type of spacer which he made out of an old brake disk pad backing plate. It was trimmed to width (you can use the spacer on the bottom of the shock to get the approximate width) and then bent into an arc. Optionally, another piece of pipe, cut to length and into a half-circle will work well. It's probably worth while tying this into place so that it doesn't drop or fly out.
Large washers are placed over the ends of the two pieces of pipe, the threaded rod through the pipes and washers, and then nuts threaded down the rod to the washers. Turning the nuts down with two wrenches will start the bushing on its way. Watch to make sure the spacer is doing its job and keeping the brackets from being bent. As the bushing comes out, it will become progressively easier to move.
As mentioned before, the new bushings are installed with the "DOWN" facing down and with the narrow end of the taper in first. The bushings are pressed in in a manner similar to their removal, but with slightly different tools. The bushing must be pressed in by pushing on the outside casing of the bushing, otherwise it will be damaged. Remember, the centre tube sticks out past the outer casing, so a flat tool will not work here. Again, a thick-walled piece of pipe of suitable diameter can be used to press on the outer casing of the bushing. The pipe should have an outer diameter of not less than 58 mm and an inner diameter of not more than 52 mm and needs to be only about 15 mm long. Another piece of pipe is used on the receiving end, next to the brake assembly. This is the same diameter as the piece used to receive the bushing during pressing out only much shorter, about 40 mm. The piece of pipe used during the press out stage is too long to be used for installation process.
Again, washers cap the pieces of pipe. Install the spacer between the brackets on the axle to prevent them from being bent. The threaded rod and nuts are then put in position and the nuts brought up tight to the washers. The bushings are then pressed into position by tightening the nuts on the rod. The bushing is in position when equal amounts of the casing is visible outside each of the axle brackets.
The trailing arm is brought back up and springs and shocks reattached. The axle is lowered into position and the bolts inserted through the trailing arm and bushing.
There are two lower control arm bushings on each side. The lower control arm pivots about an axis which is axial to these two bushings. The front of the two is housed within the cross member and is rarely in need of replacement. Each rear bushings is held in a housing or carrier which is held to the underside of the car by three bolts. This rear bushing supports a shaft which protrudes from the rear of the control arm. This shaft is threaded on its end to accept a nut used to secure the assembly.
The front end of the car is first jacked up and supported on its chassis. The three bolts holding the bushing carrier to the chassis are removed. The large nut on the end of the control arm is accessible through the back of the carrier and is now removed. The carrier and bushing are slid off the end of the control arm shaft. These bushings are normally pressed out using a special tool, however, a swift strike of a soft hammer should work just fine, as Jeff showed. You will want to support the carrier in a vise before hammering. The new bushings are put in in the same manner. The bushings do not have a specific orientation, however the left and right bushings are not identical. One side is softer than the other.
Assembly is simply a reversal of the process.
Occasionally these cars will develop a knocking noise in the front end due to loose cross member bolts. These can be found low in the engine compartment, immediately beside the engine. It would be wise to check these just to make certain that they have not loosened off over the years.
The front struts can be replaced with a moderate amount of difficulty, a spring compressor and a subsequent wheel alignment.
The procedure is started by jacking the car up off the ground and supporting it securely or, optionally, one could use a lift if available. The sway bar is detached at each end and pushed out of the way. It should pivot easily, especially if its bushings are well worn. The tie rod ends are removed from the strut assembly using another special tool: a hammer. I've never seen this done before and was surprised to see how well it works. With the nuts loosened a few turns, the outside of the lever which holds the taper is struck swiftly with the trusty hammer (Whack, whack, whack) and the tapered shaft of the ball joint pops free. This has the added advantage of not ruining the rubber boots if the joint is to be reused. The nut is then unscrewed completely and the tie rod pushed out of the way.
There is a bracket on the inner fender well which secures the two brake lines. Loosen this to allow some additional play in the lines. It is quite important to do this so that the structural integrity of the lines is not compromised in any way. Inside the engine compartment you will see a camber adjustment plate on each of the two towers. These are held down by two of the three nuts securing the top of each strut assembly. Mark the position of the camber plate so that you can get it close to the same adjustment when the suspension is reassembled. This does not preclude the necessity of a wheel alignment once the job is complete. Remove the three nuts holding the assembly in place. The car normally pushes up on this assembly when its wheels are on the ground. However, since the car is in the air and the assembly is hanging, the whole assembly will lower as the nuts are loosened off. It is important that this be done in a controlled manner so that the assembly does not fall and damage either the brake lines or the inside of the fender as the last nut is removed.
The assembly is then withdrawn out of the fender opening and secured from falling and damaging the brake lines by using another special tool. You should be able to do the same with some very stiff wire or some light rope. Use the sway bar or some other object to secure it to. The top bearing and spring are now clearly visible. The top bearings support the weight of the car and surprisingly enough, rarely need replacing. If they do require replacing, it is done as a complete unit. Apparently, they are rather costly.
Now that the assembly is outside of the car, the real fun begins. A spring compressor is used to compress the spring. A pair of spring compressors could be hired from your local rental shop or, if you are lucky, borrowed from a friend. It is rather important that you have your wits about you for this section as it could be rather dangerous. After all, you will be compressing fairly light weight spring with about 100 times its weight. Needless to say, it could be launched like a missile if it comes loose. You should make sure that the two spring compressors are able to grab at least five coils. Compress the spring, tightening each compressor evenly until the spring becomes loose. Now the top nut at the end of the strut, inside the plastic cap can be loosened. An impact wrench is really the trick here. The top shaft of the strut can be held from spinning by reaching in with one finger and applying a slight pressure to it. If you are uncomfortable with this, some rubber tubing, a bicycle tube or some sticky twine can be wrapped around the upper shaft of the strut. Once the nut has been removed, the bearing and spring can be removed. Place the spring in a safe place. The bearing can be examined for wear at this point.
Examine the strut cup (this carries the spring) for rust. These are stamped from sheet steel and rust throughout the years. Jason was asked by one of the observers if he would rust-proof the strut spring cups. His answer was "yes". Check to make certain that the water drain holes are clear of debris. If the spring cups are badly rusted, it is possible that they may fail, leaving the whole weight of the car resting on the rotating tire. This would be bad. If the cups are severely rusted, there is a procedure whereby the top part of the cup is cut away and a new spring cup placed in position. This assembly is held in place by the weight of the car. This also saves having to undo the brake hydraulic lines in replacing the whole unit.
Now that the spring is out of the way, the large nut securing the strut cartridge can be removed. This was done using a pipe wrench on the strut housing and a large pair of Channelocks on the nut. It is quite likely that you may need four hands to do this job. Now that the nut is off, the top of the strut cartridge is visible. Check to see if the top of the strut is level with the tube. Check the threads on the tube to see if they are rusty.
There have been different assemblies depending on year and model. In some cases, a concave spacer may be in the bottom of the tube. The replacement cartridge may come with a new securing nut for the top of the tube. This may have a slightly different offset than the old nut. It is important that when the new cartridge is inserted and the nut tightened down, the nut catches enough turns of the threaded section of the tube, and the nut does secure the cartridge correctly.
Make certain that the thread on the big top nut are clean. If you have some anti-seize compound, apply a bit to the strut.
Replace the spring. Note: it goes only one way. Replace the upper spring cup, bearing, and nut. Tighten the nut in a manner similar to that used during disassembly. The shaft on the strut also has a flat which can be used to keep the shaft from rotating. Release the spring compressors. Replace the plastic cap on the top of the strut assembly. Push the assembly back inside the fender and up inside the tower. Replace the nuts and plate, locate the chamber adjustment to the marks and tighten the three securing nuts.
It is interesting to note that the camber adjustment on the driver's side of the car is usually set as negative as it will go, since the stop is usually encountered before the factory setting. The right side is then matched to this.
Reattach the remaining suspension parts. As they say in the manuals, reassembly is a straight forward reversal of the disassembly process.
Your next stop should be at the local alignment shop.