Lets start with the information you are giving me.Both Daisy and Crosman made air guns for Sears. All the Daisy models started with 799. the next 4 or 5 digits could be cross referenced to the original model number. The same is true for Crosman except the number 126 indicated the air gun was made by Crosman not Daisy. However you have omitted the following digits that come after the 126. There were several target pistols made for Sears and it is not possible to identify your pistol with the information you have provided,
Yes you can replace the seals or worn parts. OR, Crosman air gun owns Benjamin. Crosman offers a free service to locate shops who repair old rifles. See the link below.
I believe you are asking about a Crosman model 38T target. they were made from 1964 to 85. Crosman offers a free service to locate shops that repair older air guns. See the link below. Further research indicates it was made in the 7 month (July) of 1981. The first 3 or 4 numbers of the serial number indicate the month and year. 781xxxxxxx
First of all DO NOT use regular oil on an airgun, Always use "air gun oil" like RWS or Crosman pellgun oil. Regular oil will eat the seals. You did not state who manufactured this pistol. I'm going to guess 'Crosman." Oil the hinges, Put a drop of oil in the breech and the barrel to coat the inside. Put a few drops on a small rag and wipe the pistol down. That's all that is needed.
NO never use any oil other than Crosman pellgun oil or RWS air gun oil. Other oils will slowly destroy the seals
Needs the seals replaced
See the link below. Parts are still available from Crosman. I've rebuilt 5 of them with new seals.
The Marksman doesn't require much cleaning. I suggest you purchase Crosman pellgun oil and put some on a cloth and wipe down the pistol. Open the breech (Barrel) put a drop of oil on a q-tip and run it through the barrel. Do this until the Q-tip is clean. DO NOT use any firearms cleaning agents on the pistol or it will ruin the seals in the gun.
Crosman still has parts for this model. See the links below for Customer Service Contact and all the Crosman parts and Owners manuals online. BTW it's an Air Rifle not an Air gun.
Pellgun oil by Crosman. Do not use anything else. It will ruin the seals.
A person can make the pump easier to operate on a Crosman 760 air rifle by applying oil to the seals. This will provide lubrication and improve the overall action of the weapon.
At least 2 times but NEVER more that 10 times, or you may damage the seals. Also you can find the owners manual on the crosman home page, see the related link.