Are the front a arm caps just supposed to be friction fit?

Or can the outer edge of the a arm be peened over to keep them b from coming out or smacked with a cold chisel or put a small tack weld on it?Click to view attachment Click to view attachment

yes

Press fit. I would put a small dab of epoxy if you want to be sure.

They operate like a Welch plug. They have a dome shape. Dome goes to the front with the protrusion facing out.

Then use an appropriate sized socket or punch. Hammer in slightly - this expands the diameter of the plug to a tight fit that wont come loose on its own.

I wouldn’t peen or tack weld.

The plug is designed such that you can drive the torsion bars out the front and pop out the Welch plug / cap when the torsion bar pushes it out.

Then reuse or replace (new plugs are available).

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