Our Classic Car adapter kits come with everything you need to convert your POWER BLEEDER to work on most early volvos that do not use a 1.75 ID female threaded cap. Round internally threaded master cylinder openings 1 3/16 inches ID. The 1132 adapter also fits some trailers with a hydraulic master cylinder. If the master cylinder has a male threaded cap 1 3/16 in diameter at the threads and 18 TPI you can use this cap to bleed the brake system on your trailer