Back in 1973, I was in a HAWK Air Defense Battery. We had Self Propelled Launchers. They were on M548 chassis. To protect the track durring launch, a blast shield was added. To get at the engine compartment, you could start the engine, and use the Hydraulic system to open up the blast shield. It had to move several feet, before you could get into the engine compartment. When the engine blew up, no hydraulics. There was a hand pump. After 80-100 pumps, the shield moved about an inch. One of my first "extra training" sessions that I had after being absent from my place of duty, was to open up the blast shield, of a track that had a blown engine. I was there for about 4-5 hours. My arms were about to fall off and I had lost a few pounds, when I had it open. SFC Lonnie Holland had been watching from time to time, to ensure no one helped me. He came over, looked at me, then waved his arm. Another track fired up, and drover over to park next to the dead track. A sgt jumped out with two hoses coiled around his arm. He plugged them into two quick disconnect fittings on his track. Then he plugged them into two fittings on the dead track. Went to the hydraulic controls on the dead track, and closed the blast shield. He disconnected the hoses and drove away. SFC Holland looked at me, and said" Why ain't the blast shield open yet?" So yes, I can feel for anyone having to hand pump up an aircraft, to change a tire. Oh yeah.