Trouble with 11 inch rear drums

[jeffs73v8vega]

This winter I put a 12 bolt rear end in with 11 inch drums. Now I have a soft brake pedal. I bled the brakes twice. If I pump the brake it only helps a little.I have the stock master cylinder. 73 vega manual brakes no proportion valve.Stock front brakes for now. Should I put a proportioning valve on the stock m/c? Dont know if that would help. Maybe m/c is bad. Any one have trouble like this before? Thanks

[spencerforhire]

Just a stab in the dark(or at the pedal if you prefer), but somehow I doubt the 73 Vega master cylinder can move enough fluid to properly apply the larger wheel cylinders that came on the 12-bolt. I don't think a proportioning valve would help. Obviously, you need a different master cylinder from a bigger vehicle.

[Sirshredalot]

You could also try smaller wheel cylinder bores....would be more pressure.

Im sure the 12 bolt came with more than one option.

God bless
-Shred

[jeffs73v8vega]

I thought if I put a bigger master cylinder on with the small vega front brakes it would give me a real hard pedal. I my see if I need a new vega master cylinder though. It's really to cold to do much here at times.I was hoping somebody tried 11 in drums with stock front brakes that could help me out.

[Yenkoboy]

I had a friend that did the same swap and used a Jeep MC it worked fine don't remember the year of the jeep. You do have to change the threaded end as they are different. Changing MC's will fix your problem. Mark

[Astre-mutt]

This is a pic from that Motion Vega every one was talking about. Looks like a stock master cylinder with no proportioning valve. Most be some way to make this combo work. Look at the Motion Vega post in the general forum. There is a member with a old Vega V8 manual. Ask him to look up the parts to use the 12 bolt rear in your car. I'm sure he will have part info you need.