73 Vega P/B conversion

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73 Vega P/B conversion

Postby sgancarz » Wed Mar 19, 2014 11:19 pm

I would like to convert my 73 Vega to power brakes. I found a complete remanufactured unit for a 75. Looks like it comes complete with the master cylinder booster and push rod. Anybody know what I would need to do to install this in my 73, or if it will even work at all?
Steve
1973 Vega GT
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Re: 73 Vega P/B conversion

Postby cosvega76 » Thu Mar 20, 2014 7:54 am

First of all, what brakes do you have on your car? If you're using the stock '73 brakes (solid-rotor fronts), the 3/4" bore master on a '75 master will be okay. You should have no trouble mounting the booster to the firewall, but you'll need to fabricate a pin for the brake pedal. Power brakes uses the lower hole on the pedal, which - I believe - is a larger diameter than the pin installed for manual brakes.

Naturally, you'll have to fab some brake lines to mate from the master to the distribution valve. The front and rear lines may be reversed, though. I don't have access to master cylinder blueprints anymore. The factory also used a brace from the master cylinder mount to the fenderwell. Whether you really need it, I can't say, but some tubing, flattened at each end with a bolt hole, should be easy to fabricate.


Chuck
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Re: 73 Vega P/B conversion

Postby sgancarz » Sat Mar 22, 2014 8:44 am

Currently still has stock calipers and disks. So, no problems there. Thanks for the response.
Steve
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Re: 73 Vega P/B conversion

Postby sgancarz » Sun Mar 23, 2014 2:59 pm

Chuck,

Can I tell front from rear on these by the size of the reservoirs, or are they both the same size?
Steve
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Re: 73 Vega P/B conversion

Postby cosvega76 » Mon Mar 24, 2014 7:52 am

Steve,

If I remember correctly, the reservoirs are the same size. But GM didn't change the line nut size, though. The thread size will be the same for the front brakes, for example, no matter which reservoir it is attached to, so you can tell that way.


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Re: 73 Vega P/B conversion

Postby cjbiagi » Mon Mar 24, 2014 8:32 am

71-75 H bodies used the same master cylinder, including Monza's, Skyhawks & Starfires. When GM went to the larger rear brakes and vented rotors in 1976 they changed the master cylinder and reversed the lines off the master cyl. I know Vega's never switched to the vented rotors, only the larger rear drums I believe. If you have an actual proportioning valve then you have the later style master cylinder. H bodies up to 75 only had a distribution block (kind of looks like a proportioning valve but it is not). If you just want to convert to power brakes and leave everything else stock you should be able to do that fairly easily. If you want to upgrade to the later style with vented rotors and larger rear drums then you need to get everything. You may need to do a little modification on the rear drum center hole if you decide to upgrade to the later rear brakes as the center hole on the larger drum is slightly smaller than the flange on the axle. Not a big deal, just something to be aware of.
Clyde.........75 Monza 2+2
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