On my '86 car, I pulled out the complete unit from the car using the three or four nuts, I think, on the engine side. The headlight fits into a bracket/holder that comes out as a unit. You do not have to reassemble anything or readjust the aim. The chrome top strip just screws onto it.

I then used compressed air applied where the bulb fits in. I used an air nozzle wrapped tightly with a rag and slowly turned up the pressure regulator.

I think I plugged the atmospheric relief vent on the top side with my thumb to make it work quicker. Watch how you take it apart as it acts as a bleed valve. Failure to assemble it back correctly will cause the front lens to deform inwards when you travel up and down in altitudes. That was a nice surprise for me to see them caved in slightly from a casual side view shortly there after.

When you apply the air, the lens will go pop when it breaks loose from the seal and the pressure is over in a blink. It may seem scary but it works slick and not a whole lot of pounds per square inches are used. The lens is about a couple square feet of surface area where the seal is a few linear inches.

The neat thing is the front lens receives force evenly from the inside and releases the weakest side first from the sealing groove.

I stayed away from RTV or silicone sealants, as they are hydroscopic in nature when I put it back together. Volvo caulking dries out and cracks. Therefore, I tried clear sealant adhesive products. So far, they have stayed dry inside.

Phil