At this point you can remove the shock absorber if needed. If all you were after was to replace the shock absorber, you can skip most of the steps above, just jack up the A-arm and remove the shock. If you are disassembling everything, then it is easier to do the steps above while the shock arm is still connected.

Sometimes the frame flange may be bent up or cracked in this location due to some prior heavy impact of the tire on a curb or large pot hole. If so, then this is the time for straightening and/or welding repair if necessary.

To disassemble swivel pin assembly, first remove steel bearing tubes from the swivel links, and then unscrew swivel links from the swivel pin. If the steel tube is not removed the links will not come off, or it my bind severely and damage edge of threads from interference of steel tube. Do not disassemble the MGA steering arm and swivel pin from the knuckle unless one of these parts must be replaced. A swivel pin may sometimes be bent from a heavy impact on a tire. If so, then replace it or straighten it before going on.

Rubber bushings for A-arm inner Pivot are "supposed to be" trapped by the end washers and compressed some. In theory they should remain stationary on the shaft, stuck in the A-arm, and twist elastically with suspension motion. For this reason you should set the weight of the car on the suspension to get normal ride height and centralize motion of the arms before tightening the big retaining nuts. In the real world something is going to slip somewhere. Since the steel tube om the A-arm is wide and close to the end washer, there will be motion between the arm and washer that will cause some abrasion in the vicinity of the rubber shoulder. As the rubber gets older and deteriorates there will be more slippage, and very likely the bushing will rotate on the shaft. Original factory issue rubber parts may have had an acceptable life, but a LOT of recent issue replacement rubber parts are notorious for early failure (sometimes less than a year). If the Pivot shaft is rusted and badly pitted it should be replaced (as a pitted shaft can tear up rubber bushings).

Polyurethane bushings work the same way as the original rubber parts, except that they don't flex enough for full suspension motion without slipping somewhere. Due to difference in diameters (and friction) the OD will (most likely) remain fixed in the housing (arm) while the ID rotates on the shaft. The urethane bushings are tough and may last a LONG time even if the Pivot shaft is rough. I once had a set on my car that went 3 years and 40,000 miles and were still like the day they were installed.

A possible alternative to replacing a pitted Pivot could be to install MGB GT V8 type A-arm bushings (click for larger photo). These bushings have a steel tube inner liner similar to silentblok bushings in a leaf spring. When installed the rubber OD is to be pressed into the suspension arm while the steel tube is a slip fit on the inner pivot bracket. Squeezing the sightly oversize rubber part into the A-arm makes it expand toward the ends. When the heavy retaining washer and nut are tightened the steel tube is pinched at the ends so it does not rotate on the shaft. At the same time the rubber is squeezed from the ends causing causing it to expand near the ends similar to having a shoulder on the rubber bushing, also making a tighter fit in the A-arm. Then the rubber part will not slip on either the ID or OD, and it will be distorted (flexing) as the suspension moves. In this case you also need to set the weight of the car on the suspension to centralize motion of the suspension before tightening the big nuts.

The MGB GT V8 bushings have a very long life, but there are a few remaining issue of concern. The bushing OD is press fit in the suspension arm and needs to be centered (equal amount protruding on each end). There is no other means of axial alignment, so if the part is not centered when installed, or if it might slip after installation, it could leave the lower suspension arm misaligned, possibly with metal to metal contact at the shoulders. The other issue is the way the steel sleeve is secured. Some of the currently available bushings have a thin steel sleeve that may be deformed at the ends when tightened. This does not affect performance or life of the bushing, but the mushroomed tube ends might prevent removal of the part for future maintenance. At the very least you should apply anti-seize compound to the pivot shaft before installing the steel lined bushing. Also the heavy end washers are bored to fit a shoulder on the pivot shaft for precise alignment of the washer. Some current replacement washers have the wrong bore size, so they either go on too far (past the shoulder smashing the thin steel tube) or not far enough (stopping before the shoulder and leaving the bushing loose on the shaft). That said, I have these parts on my car for 13 years and 124,000 miles now with no problem.

A-arm brackets often have outer end holes worn oval from the trunnion bolt rotating in the arm when a trunnion bushing has been seized. These holes can be welded and re-drilled, but the parts may be readily available and cheap enough to replace. Any necking down of the trunnion bolts dictates replacement.

Swivel pin threads should be clean and smooth, and the swivel link should be snug on threads of swivel pin. When new and greased there is no perceptible wiggle in these parts. If the swivel pin threads are rusted and rough it should be replaced. If the swivel link threads are worn to be a sloppy fit it should be replaced. The Workshop Manual states, "An appreciable amount of slack is permissible in these threaded bearings and they do not require renewal unless they are very slack". This is a judgment call, as the pieces will not actually fall apart unless the threads are worn enough to be completely stripped. However, excess slop in these threads may contribute to front end shimmy if a wheel is slightly out of balance or not perfectly straight running.

Bottom end of the swivel pin is more likely to be rusty due to water intrusion. Bottom swivel link is more likely to be worm because it carries the weight of the car. Top swivel link threads may last twice as long in service as the lower ones. My top swivel link threads are in good condition after 370,00 miles, while the lower links were changed once around a quarter million miles. Grease is your friend here.

Running clearance between swivel link bushing and the smooth steel bearing tube is nominally 0.002-inch on diameter, similar to a rocker arm bushing or crankshaft bearings (0.001" radial clearance for grease). Measure parts carefully. Bushing bore should be exactly 3/4-inch (0.0750"). Bearing tube outside diameter should be slightly smaller (0.748") and very smooth. If the steel tube is rusted, worn or pitted it should be replaced. In assembly with grease there should be no wiggle between the bushing and steel tube. A small amount of wiggle may not be particularly detrimental to normal function, but excessive slop can contribute to front end shimmy if a wheel may be slightly out of balance or not running perfectly straight.

Bushing in swivel link can be removed by cutting through one side of the bushing from the inside with a hacksaw, then easily pushing the bushing out of the swivel link. It may also be removed with a press if you have a properly sized driver punch. A new bushing can be installed by pressing into place with a large bench vice (or a press with a piloted punch). Do be careful to get the bushing started straight, and try not to raise much of a burr on the end when pressing it in. Hammering on the end of the new bushing is definitely a no-no, but you could hammer one in of you use a properly sized piloted punch (and be careful to keep it aligned). The hole in the side of the bushing must be aligned facing the swivel pin. The bushing must be entirely flush with the swivel link shell at both ends, not protruding at the ends. New bushings must be reamed to finished size after installation.

When bushings and steel bearing tubes are ready for reassembly, carefully measure the lateral length of the swivel link and the tube. The tube needs to be 0.008" to 0.013" longer than the swivel link shell, so the thrust washers will not bind at the ends in assembly. You can determine this with careful measurement, or place it in assembly and check end clearance with a thickness gauge, or check end float in assembly with a dial indicator. If all parts are correct size, changes of length should not be necessary. If the tube may be too long it could be ground down a bit, but it must be kept perpendicular across the ends. If the tube may be slightly too short the swivel link shell could be ground down a bit, but it also must be kept perpendicular across the ends. Do not reduce length of the swivel link shell too much, as it has to mate with the upper and lower suspension arms.

Reassembly is reverse of disassembly, with a little more fiddling. Start by installing the shock absorber and the rebound buffer and spacer block below the shock arm.

Install rubber bushings at inner ends of the A-arm brackets. Original type rubber bushings or urethane bushings can be pushed into place by hand. Urethane bushings may call for some lubricant for the inner bore to shaft joint (or maybe not). Some people say these parts might squeak in operation, but I have not found that to be so even when running dry. Urethane bushings might last indefinitely without wearing out, where standard rubber bushings might need replacing as often as every two years if you drive a lot. Urethane may give slightly more "feedback" from road bumps, but I happen to like the slightly firmer feel of the suspension. The MGB GT V8 style bushings can be wet with soapy water and pushed into place using the bench vice, after which they should stay secure and never move. They may also last a long time without wearing out, because they twist the rubber a bit in operation rather than turning on either ID or OD.

Assemble the Pivot and A-arm brackets and spring pan on the chassis. Tighten the Pivot to frame bolts, but leave the end nuts and A-arm bracket bolts loose until later. For the MGB GT V8 type bushings it is a good idea to put anti-seize compound on the Pivot to make later removal of the steel lined bushings easier. Insert the coil spring and jack up the spring pan. Loosen the pinch bolt located half way out on the shock absorber lever arm so you may be able to spread the arms slightly when installing the upper trunnion.

Swivel pins and swivel links have left hand threads for left side parts and right hand threads for right side parts. Top swivel links have the bump stops. Steering arms point forward and swivel pins tilt inward at top. Be sure the threads run free for full length of engagement. Grease threads a bit before assembly. Install swivel pin seal on the swivel link and screw it fully onto the swivel pin. Back off the thread a few turns until the bushing bore aligns with necked down area on the swivel pin. Insert the steel bearing tube into the bushing. Rotate the swivel link right and left as much as two turns each direction to determine where the steel tube will (gently) interfere with the thread on the swivel pin. Count the turns between maximum and minimum engagement where it binds. Turn the swivel link to be half way between these points. Then turn the swivel up to one half turn maximum (closest direction) to align it for assembly to the mating suspension arm.

The trunnion seal support has a flanged cup shape. The flat side goes toward the nut or bolt head while the flanged side goes toward the swivel link. Put the trunnion seal on the support, put the hardened steel thrust washer inside the seal and support, and install the lip of the seal over the end of the swivel link. A small orbital motion can help to make the seal lip jump into position on the swivel link. Repeat for two seals on each swivel link.

Install the swivel pin assembly onto the suspension arms. Start with the lower trunnion first in case the A-arm brackets may not be in correct alignment. Position the lower trunnion (with washers and seals) between the A-arm brackets. Run an alignment punch or small rod through the holes to align the thrust washers and seal supports with the rest of the bores, and install the lower trunnion bolt. Pull the swivel link assembly into alignment with the shock absorber arm (if A-arm brackets were not yet aligned). Spread the shock arm sides a bit if necessary, and insert the upper trunnion (with washers and seals) into the shock arm. Raise or lower the shock arm as needed, and/or raise the floor jack if necessary, aligning all of the bores with an alignment punch or small rod before installing the top trunnion bolt.

With all bolts still loose, swing the knuckle through a wide sweep, up to 180 degrees, while watching the swivel pin and swivel links. If the swivel pin is straight the swivel links will remain stationary and the swivel pin will appear to stand still as it rotates. If the swivel pin is bent one or both of the swivel links will do a little rocking motion as the knuckle swings around, which is not acceptable. A bent swivel pin could make the trunnions and mounting bolts wobble in operation causing the bolts to work loose and parts to wear when they should not. Do not settle for less than a perfectly straight swivel pin.

When you are sure the swivel pin is straight and everything is in place you can connect the anti-sway-bar link and tighten all of the bolts. If you use the MGB GT V8 bushings, then leave the nuts on the ends of the A-arm Pivot loose until later. Connect the steering tie rod ends securely. Install brake backing plates or dust shield as fitted. Install hubs with wheel bearings and seals and grease covers. Assemble brake parts, rotors, calipers, drums etc. Connect hydraulic pipes and hoses, and adjust and bleed the brakes. Install road wheels, remove jack stands and lower the car to ground.

Bounce the car a little to settle the suspension to normal ride height before tightening the nuts on the A-arm inner pivots. This step is to centralize the BV8 type bushings on the A-arm pivot so they will encounter equal twist with both up and down travel of suspension, not over stressing the rubber. Check and/or adjust front end alignment as necessary. A test drive is a good idea to be sure it all works right before you drive too far.