I put the cap on but not tight, just to keep the fluid from burping out but let air in. I had no problem bleeding mine without a power bleeder and help from an inexperienced friend.

1957 Chevrolet 5700 LCF 283 SM420 2 speed rear, 1955 IH 300U T/A, 1978 Corvette 350 auto, 1978 Yamaha DT175, 1999 Harley Davidson Softail Fat Boy