Other mistake: On scene at the traffic accident, when the woman and the boy with non-serious injuries are seated at the back of the ambulance, neither Roy or Johnny are going along with them to Rampart, yet Johnny puts the drug box inside the back of the ambulance with them, and the ambulance drives off. With their drug box! Captain Stanley even says that he'll advise dispatch that they're available for a run at the scene, while the guys will be looking for the dog.
Visible crew/equipment: When Roy and Johnny leave Rampart and are heading back in the squad, about 16:40 minutes in, as they are discussing whether Roy has told his wife about house hunting, you can see two signs on the ceiling of the squad's cab. The signs say 'Emergency Saturday 8PM Rehearsal Mark VI Prod'. Possibly they are magnetic signs for the squad doors so people don't mistake the squad for a real fire department vehicle? (00:16:20)
Visible crew/equipment: While Roy and Johnny are climbing up to rescue the boy on the bridge, there's a closeup of the boy as he breathes heavily. When this shot pans to the right we see Roy (his stunt double actually) place the rope behind his back, and a mysterious dark gloved hand quickly appears behind Roy (and it's not Johnny's hand).
Visible crew/equipment: When Gage and DeSoto are driving away from Rampart, discussing DeSoto's possible purchase of a new house, dispatch calls about a traffic accident. In this exterior closeup shot of Squad 51, the reflection of the camera's flatbed vehicle is visible on Squad 51's red surface.
Continuity mistake: Squad 51's lightbar has a center chrome piece which has slats at the front and is solid at the back. When the squad's dispatched to the vehicle accident with the two student drivers, on scene the lightbar's chrome center is on backwards, it's solid at the front for some inexplicable reason.
Visible crew/equipment: After Roy and Johnny speak to Chet's friend the realtor, when Station 51 is being dispatched to the accident on Harbor Freeway, in the overhead shot of the apparatus bay, we can see the shadow/reflection of production equipment moving on the engine's windshield.
Visible crew/equipment: When Station 51 is dispatched to the rescue on Johnson Canyon Bridge, just as Engine 51 rolls out of the apparatus bay, the reflection of array lighting and two reflector screens are visible on the engine.
Continuity mistake: When Station 51 is dispatched to a structure fire (with the two girls trapped upstairs) the address given is 1911 Harper Ave, but when they reach the house with the fire, directly across the street that house number is 1637.
Answer: I believe you are speaking of the old man, Mr. Wilson. He's played by J. Pat O'Malley.
Bishop73
Correct, it was J. Pat O'Malley...he also played the grandfather with his grandson when their rocket exploded, and also played "Old Bill" in the episode with Ann Prentiss, where Gage saves the little girl from the burning tree house, and her mother falls in love with him.