Ruby wont print variable

I've been trying to work on a fake little pin-cracking script, but somethings wrong and it's making me frustrated. It randomizes 4 numbers and checks them against 4 other numbers, but for some reason, after the numbers are guessed, it won't print them anymore.

#RubyCodeStart

pass1 = 4
pass2 = 9
pass3 = 2
pass4 = 8
guess = 0
flag1 = 0
flag2 = 0
flag3 = 0
flag4 = 0
loop do
    if flag1 == 0
        crack1 = rand(0..9)
    end
    if flag2 == 0
        crack2 = rand(0..9)
    end
    if flag3 == 0
        crack3 = rand(0..9)
    end
    if flag4 == 0
        crack4 = rand(0..9)
    end
    if crack1 == pass1
        crack1 = pass1
        flag1 = 1
    end
    if crack2 == pass2
        crack2 = pass2
        flag2 = 1
    end
    if crack3 == pass3
        crack3 = pass3
        flag3 = 1
    end
    if crack4 == pass4
        crack4 = pass4
        flag4 = 1
    end
    guess += 1
    puts "#{crack1} \| #{crack2} \| #{crack3} \| #{crack4} === Guess \# #{guess}"
#   if crack == pass
#       break
#   end
end
sleep(30)

Nothing I do works, and it refuses to print it pass it being found. I'll add data if needed.

Output:

8 | 0 | 6 | 1 === Guess # 1
4 | 6 | 1 | 8 === Guess # 2
 | 1 | 3 |  === Guess # 3
 | 1 | 5 |  === Guess # 4
 | 3 | 9 |  === Guess # 5
 | 3 | 3 |  === Guess # 6
 | 5 | 4 |  === Guess # 7
 | 3 | 4 |  === Guess # 8
 | 4 | 3 |  === Guess # 9
 | 0 | 6 |  === Guess # 10
 | 3 | 8 |  === Guess # 11
 | 4 | 5 |  === Guess # 12
 | 2 | 4 |  === Guess # 13
 | 8 | 7 |  === Guess # 14
 | 8 | 4 |  === Guess # 15
 | 9 | 5 |  === Guess # 16
 |  | 7 |  === Guess # 17
 |  | 5 |  === Guess # 18
 |  | 7 |  === Guess # 19
 |  | 7 |  === Guess # 20
 |  | 7 |  === Guess # 21
 |  | 1 |  === Guess # 22
 |  | 2 |  === Guess # 23
 |  |  |  === Guess # 24
 |  |  |  === Guess # 25
 |  |  |  === Guess # 26
 |  |  |  === Guess # 27
 |  |  |  === Guess # 28
 |  |  |  === Guess # 29
 |  |  |  === Guess # 30
 |  |  |  === Guess # 31
 |  |  |  === Guess # 32
 |  |  |  === Guess # 33
 |  |  |  === Guess # 34
 |  |  |  === Guess # 35
 |  |  |  === Guess # 36
 |  |  |  === Guess # 37
 |  |  |  === Guess # 38
 |  |  |  === Guess # 39
 |  |  |  === Guess # 40