Hot Rod Forum : Hotrodders Bulletin Board - View Single Post - Master Cylinder Vacuum Leak???
View Single Post
  #1 (permalink)  
Old 06-26-2012, 04:18 PM
Hawkfan Hawkfan is offline
Registered User
 
Last photo:
Join Date: Jul 2011
Location: Tinley Park, ILL
Posts: 62
Wiki Edits: 0

Thanks: 25
Thanked 0 Times in 0 Posts
Master Cylinder Vacuum Leak???

Background:
72 Chevelle with moreate engine mods to a 454 I just rebuilt. Also, converted rear drums to disks.

Now this one really has me baffled. Due to a lack of vacuum to the booster/brakes I installed an auxillary Summit vac pump. Per the instructions, I ran a vac line from the pump directly to the break booster. When I turned it on there was a vac leak around the master cylinder. Upon further evaluation I was surprised to find at the bottom of the master cylinder just before it bolts to the booster, a through hole which intersects a vertical hole in the master cylinder housing. If I place my fingers over the hole I eliminate the vac leak. The hole looks like it was machined at the factory.

Would anyone know the purpose of this hole and if I can block it up so I have complete vac?
Thank you in advance for any input you may add.

Thanks
Brian
Reply With Quote