MG Car Repair: 78 MGB Brakes, differential switch, brake caliper

Question
I recently replaced a brake caliper and the flexible lines on the front of my 78 MGB. When I was ready to bleed the system i found that the pressure differential switch has been replaced with a bolt. Do I need to replace the switch or can I leave the bolt? And do I need to back the bolt out 3.5 turns in order to bleed the brakes?

Answer
Hi Jonathan.  The short answer to your question is YES, you can undo the bolt to bleed the brakes.  

However, this is only a quick fix.  Please remember that the brake differential switch is a safety feature.  It operates a warning light to tell you that half the braking system has failed.  For your own safety, you really should fit a new switch and wire it in correctly.