Crosman Crosman Model 1389 Backpacker Seal Kit

so, when you have a Crosman product you go to Crosman and look up the model and see what parts that would be used on their parts lookup
but what you find is what other products use the same parts and that helps you find the parts
so here is the parts diagrams
https://support.crosman.com/hc/en-us/article_attachments/201667824/C1389-EVP.pdf

https://support.crosman.com/hc/en-us/article_attachments/201589330/C1377-EVP.pdf

now do all of them come in kit maybe not
i would take the parts number to Crosman and see if they will sell them to you with their new rules they might not
 
sorry to hear about your medical issues
now the reason i make a post like this is to help others also
with Crosman parts they have a 3 number starting number that is the model the part was first used and in this case 2 of the Orings are 130-34 and 130-35 those would be simple to find but the Oring are worth less than $0.20 and people will charge 10 to 20 times that
the stem is 1322-a011 and that was used on the variant 1322 model first and the part 1322-056 the check valve
and there is the piston cup 760-140 first used on the 760 rifle at some point
now you never state the problem
now i am surprise these guns don't have wipers for the cylinder and you just add oil to the piston cup itself
a dry cylinder would make this multi and or SSP gun not function