What Master Cylinder To Use For 4 Wheel Disk Conversion

[erikcroissant]

Hey all, converting my 68 Coronet from manual drums to manual disks using DoctorDiff kits. Wondering what the wisdom is regarding upgrading my master cylinder- what brands should I be looking at? I'd prefer to continue using the factory brake pedal, thought it's not a problem if I need to switch. Thanks in advance.

 

[davek]

You should ask Dr Diff,give him a call.

 

[MIKESPOLARA]

You can just remove the residual pressure valves from your drum master(if they're in there) and it will be good. No rocket science in masters, only bore diameter changes how a master functions. Your drum master is 1" bore which is perfect for your manual disc

 

[R/T Boy 67]

Just get a proper disc master, with the larger reservoirs, so you don't have to check your fluid levels constantly. As stated, talk to Dr diff.

 

[MIKESPOLARA]

Just get a proper disc master, with the larger reservoirs, so you don't have to check your fluid levels constantly. As stated, talk to Dr diff.

You won't have to check fluid level constantly. Probably 15k miles before you need to take a peek at the level
But the $95 master kit from DrDiff is reasonably priced.

 

[Angleiron2]

I tried the 15/16 Master Cylinder from Doctor Diff and it didn’t work well on my car , so I switched to the 1 1/32 and it worked great. It has 73 Mopar disc front brakes and it has Ford 8.8 in the rear with Disc brakes …. Manual. The 15/16 created spongy soft pedal, we bled the system thoroughly and it didn’t change, put the 1 1/32 on and just gravity bled them and they were great.

 

[MIKESPOLARA]

I tried the 15/16 Master Cylinder from Doctor Diff and it didn’t work well on my car , so I switched to the 1 1/32 and it worked great. It has 73 Mopar disc front brakes and it has Ford 8.8 in the rear with Disc brakes …. Manual. The 15/16 created spongy soft pedal, we bled the system thoroughly and it didn’t change, put the 1 1/32 on and just gravity bled them and they were great.

Smaller bore more pressure but pedal travel increases and it's softer, larger bore has firmer pedal and travel is reduced. 1" would be great, obviously 15/16 was a bit too small