Brakes SN95 Cobra brake swap - Too much pedal effort

Discussion in 'Classic Mustang Specific Tech' started by ForceFed70, Apr 2, 2013.

  1. Hi All,

    Just finished installing SN95 Cobra Brakes Front and Rear on my 1970 Grande using a kit from Street or Track.

    Everything seems to work well except for the pedal effort. I have to stand on the pedal to get the car to quick stop and I don't think I could lock the wheels up if I tried.

    I'm still using the OEM 1970 Power Disc Master Cylinder. From what I've read, I should probably switch to a different MC with a smaller bore.

    What MC would you guys reccomend? Will a manual disk MC for a 1970 mustang be a good choice? I've also read that folks are using MC's from a 93 cobra. And there are also lots of aftermarket MC's available.
  2. Im using a mc from a 2000 v6 mustang, has a 1 inch bore. Works pretty good.
  3. Weird. My stock MC should also be a 1" bore. So I'm confused as to why it takes so much effort to stop the car if it works well for you.
  4. willwood has a new 7/8 bore master cylinder for front and rear disks that works realy well a friend just put one in his car and he realy likes it
  5. Yeah, saw that. It's a pricy unit tho.

    Apparently a master cylinder for a mid 80's mustang is also 7/8th. Only issue with using one of them is that the outlets are on the wrong side requiring you to build custom brake lines.

    I'm starting to wonder if something else is going on tho. I messaged StreetorTrack and they got back to me saying that pedal effort shouldn't be too bad with a 1" bore and power booster. Combined with Falcon79's feedback, I think I should investigate further before swapping MC's. Although I'm not sure what there is to investigate. The brakes arn't showing signs of air in the lines (pumping the brakes doesn't help). Only thing I can think of is some sort of restriction in the hydrolic system. The proportioning valve perhaps?
  6. is the booster providing any assistance? try pressing on the brakes, then start the car, and see if the pedal goes down any. if not, then it might be the booster, or a hose going to it.