Visible crew/equipment: After Al fixes the roof and Peg reminds him to fix the TV antenna, when Al says he can do it, a shadow can be seen moving across the blue bucket on the table. (Probably a crew member or equipment.)
Visible crew/equipment: At the beginning of the Last Will reading we see that there's no-one sitting left to the female notary. But in the close-ups there is a small round silver-shining object at the right edge of the picture - left from her. Must be some equipment. (00:04:20)
Visible crew/equipment: Right after Jefferson walks out after saying what he was in jail for, when they are showing Bud and Al, you see a large head shadow go across Bud's leg from left to right.
Visible crew/equipment: When Bud and Kelly are sitting on couch, after Al goes upstairs, you can see the shadow of crew/equipment go across Bud's shirt from right to left.
Visible crew/equipment: When Peggy enters you can see the shadow of someone's head at the left edge (the kitchen). It can't be anyone of the actors. (00:12:05)
Visible crew/equipment: When Buck is sitting on the couch before Al and Bud come back, the shadow of the camera boom can be seen moving on the stairs.
T-R-A-Something-Something Spells Tramp - S7-E2
Visible crew/equipment: When Jefferson talks about his little impotence problem, you can suddenly see a shadow walking from left to right across the whole set. (00:14:25)
Visible crew/equipment: In the scene where the Bundys are riding around the city in their loaner Lincoln Town Car, you can see an unlit Klieg light on top of one of the buildings revealing that one of their rare outdoor locations is actually on the back lot.
Visible crew/equipment: At the end of the episode you can actually see a crew member at the door waiting for his cue to throw the tumble weed through the door.
Visible crew/equipment: When Al gets up to answer the phone near the start of the episode, a microphone can be seen above his head which then moves out of shot. More easily noticed if the episode is watched on a widescreen TV. (00:03:55)
Visible crew/equipment: When Marcy announces they only have time to grab their most precious personal possessions Kelly notes her own, and in the next shot the boom mic makes a happy appearance at the top of the screen. (00:07:45)
Visible crew/equipment: When Al and Jefferson are knocking down the door with Bud, the shadow of the camera is visible on the wall for a second or two.
Answer: It was one of the hoses connected to the engine, nothing specific, but to indicate that Al tampered with the vehicle.