Suspension fork replacement

New Ferrari 308 suspension fork

This is one of the four suspension forks used to attach the front lower wishbones to the chassis. They also provide camber and toe adjustment via shims slipped in behind, between the fork and the chassis.

Removing the forks is not without issues however. First of all, one cannot really get a socket on the back of them due to some angled frame rails and pipes. Access is really only practical with an open end wrench. Also, the forks are open to the road spray and debris so the have a tendency to corrode and freeze solid onto the chassis. A frozen fork is annoying since it cannot be adjusted for a proper alignment making the rest of the alignment a compromise.

These are the tools for removal:

  • 22mm wrench
  • BFH (Big ^&#*ing hammer)
  • Liquid Wrench/Sea Foam/PB Blaster*
  • Torch*
  • Pickle fork*

* In case things get really tough

Once the nut is loose, it can be backed-off until it’s just proud of the bolt and given a whack or 10 with the BFH. With luck the fork will drop out the other side along with any shims.

Of course the other possibility is that it won’t move at all because it is well and truly rusted into the chassis… Additionally, the driver’s side rear fork does not have clear access to the back of the bolt. The tube containing the clutch cable runs immediately behind it so this fork is typically the hardest to remove because its difficult to get any force onto it.

Ferrari 308 clutch cable

Good luck driving out that bolt

My driver’s side rear fork was completely rusted to the chassis and all manner of beating on the back of the bolt and pulling from the front had failed to move it.  By the look of the chassis paint all over it, its been stuck there for a while.

Ferrari 308 frozen suspension fork

Stuck solid

The next step was the torch. I heated up the fork several times with no apparent improvement. I dumped a can of CRC freeze penetrant on it; again with no apparent improvement. Next… a liberal dowse of PB Blaster which is supposed to be the best of the penetrating oils. No change. I tried to drill out some of the welds on the front to see if that would help. All it did was blunt my tungsten carbide drill bit. I even switched the drill to hammer mode to see if I could get some vibration in there to crack it loose or atleast aggitate the penetrating oil.

So after no progress hiting it from the back, dowsing in penetranting oil, freezing it, heating it, drilling it and vibrating it, I started banging away at the front with a pickle fork wedged between the fork’s arms and the chassis.

Ferrair 308 suspension fork and pickle fork

The pickle fork is essentially a wedge for forcing things apart

If I could get it to twist in its chassis hole, then it would mean the fork/shim was no longer frozen to the chassis and neither was the bolt through the chassis.

I pounded the pickle fork on one side then the other for a good half an hour when it finally rotated clockwise a small amount. Another 10 minutes and a small second rotation back again. I repeated back and forth until it became loose enough to rotate about 15 degrees with each big hit.

Loose Ferrari 308 suspension fork

Rotating the fork in place by force

With the suspension fork rotating in its hole, then I resumed the attack on the rear of the bolt. 5 big hits square-ish on the back of bolt (again with the pickle fork) was enough to finally get the fork out.

Ferrari 308 suspension shim

A bent and beaten shim rusted to the chassis

Ferrari 308 chassis suspension mount

Some of the corrosion that froze the shim to the chassis

New Ferrari 308 suspension fork

Test fitting the new fork – so shiny 🙂

Old Ferrari 308 suspension fork

The old fork and shim

Corroded Ferrari 308 suspension fork

While there is definitely corrosion between the fork and the shim and the shim and the chassis, I actually think the fork was rusted on around the bottom of the shaft of the bolt, next to the shim.

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