|The MGA With An Attitude
REMOVING A Front Shock Absorber - FS-128
On 7/9/2012, William B. Weber wrote:
"I am trying to remove the front shock but can not get the bolt out (Moss part 321-568) that connects the shock to the upper link. Once I had the nut off I tried to back out the bolt with a socket but it is really stuck. Tried a long "cheater bar" on the ratchet for more leverage but it wouldn't budge".
If the bolt will not turn after the nut is loose, hell has frozen over and you have a BIG problem. It may help if you understand how the parts are assembled, to figure out what is frozen where.
Starting with the swivel link (5) and going inward, the bi-metal bushing (6) is press fit and reamed to size after installation. Inside that is a precision ground steel tube (39) that provides the bearing journal surface for the bushing. When it is new, working diametrical clearance is 0.002" (0.001" on the radius for grease film). Inside of the steel tube is the long trunnion bolt (44), originally with a little more diametrical clearance.
At each end of the trunnion there is a thin metal cup washer (42) that holds outboard edge of the rubber seal (41), and a slightly thicker hard steel thrust washer (40). Outboard from these bits are the shock arms, and the bolt head and nut. When the bolt is tightened it pinches the shock arms to hold the cup washer, thrust washer and steel tube all tight to move as one with the shock arms, while the trunnion bushing rotates on the steel tube. So far so good.
Then run the clock forward lots of years and introduce dirt, water, corrosion, lack of lubrication, and perhaps some years of storage without use. If the bushing seizes on on the steel sleeve so it cannot rotate, the suspension will no longer move. If the steel tube seizes on the bolt, the bolt cannot be removed. Now what?
If you jack up the frame the suspension should drop until the shock arm is sitting on the rubber snubber. Then set the frame on a couple of jack stands. Then put a jack under the lower A-arm, directly underneath the outboard edge of the coil spring, and lift. This should raise the suspension enough to lift the shock arm slightly away from the rubber snubber. This unloads all of the suspension parts except the coil spring and inner A-arm pivots.
If dropping the suspension does not result in shock arm sitting on the rubber snubber, the trunnions are frozen (or maybe the shock absorber is frozen internally. If jacking the suspension does not result in any motion of the suspension, then something in the suspension is frozen. When you loosen the nut on the trunnion bolt, and then the bolt itself will not turn, that means the bolt is frozen in the steel tube AND the steel tube is frozen in the bushing. If you can get the bolt to turn some, but it cannot be driven out, that means the bolt is frozen in the steel tube while the tube can rotate inside the bushing.
Penetrating oil might help (if you could soak it for a week). You can remove the grease fitting and apply penetrating oil there. Apply penetrating oil to both ends of the trunnion. You can try a grease ram to attempt to force penetrating oil into the grease fitting with high pressure.
Get a longer breaker bar and apply more torque to the bolt head. If you apply enough torque either the bolt will turn or the bolt will break off the head end. If you get lucky the bolt may break loose from the steel tube and turn while the steel tube stays frozen in the bushing. In that case you can drive the bolt out, and the shock arm would be separated from the trunnion. Ditto for the bottom end trunnion joint. You can then take the swivel pin assembly to the work bench to drive the steel tube out of the bushing, or drive the tube and bushing together out of the swivel link, whichever comes first with enough force.
If the bolt turns and cannot be driven out because the steel tube is frozen to the bolt, then the next move is to remove one arm from the shock. There is a cross bolt holding two arms together, and a pinch bolt on the inboard end of one arm. Remove those bolts and remove the arm from the shock. If that arm is on the side with the trunnion nut, the arm will come off the outboard bolt leaving the bolt and trunnion assembly still attached to the fixed arm. If the arm you are removing is on the side with the bolt head, then the bolt and trunnion assembly comes along with the arm leaving the fixed arm on the shock. End result is the two arms are then separated while the bolt and trunnion is still attached to one of the arms.
Next move is to cut off the bolt head and grind it flush with side of the arm, then punch the bolt out of the arm. This leaves the trunnion assembly with the stuck bolt and steel tube with no bolt head. Take that to the workbench and use a press or heavy hammer to drive the bolt out of the steel tube (not actually required), and/or drive the steel tube out of the bushing. The steel tube must be removed before the swivel link can be unscrewed from the swivel pin. Then you can split the bushing down one side with a hacksaw (from inside the bushing), after which the cut bushing is easily driven out of the swivel link.