I want to convert the power brakes in my '73 A body to manual. It's presently the factory disk front/drum rear. I have my reasons, mostly more space, and I just don't like power brakes. I know I'll need to change the pedal linkage but what parts am I looking for? And otherwise, can I just remove the booster and bolt the master cylinder to the firewall. I see that the four studs at the firewall are wider spaced then the holes on the cylinder. Has anyone done this?
Thanks!
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Fix Ps3

i just did this... i used my old manual MC which was on a drum front and rear. it bolted right up. u just got to make sure you got the pushrod for it, and make sure the MC you are using will accept this pushrod. the manual drum MC does hold less fluid, and has different piston bore, but that only affects pedal feel and travel, but no complaints here

I would use a MC and push rod from a 73-up manual disc brake car. You need the correct MC for disc brakes because as the pad lining wears you need more fluid to the piston to make up the difference. Should be a easy swap.

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Thanks guys. Brian, this is a disc brake master cylinder, and according to the Hollander manual is similar to the manual cylinder. All I want to do is remove the booster. I was assuming I could simply do that, but wasn't sure about the pushrod. Thanks!
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ARX-02a

IIRC, all you have to do is remove your disc/drum master cylinder and booster (obviously, plug the vacuum port on your manifold also), then just bolt on a manual disc/drum master cylinder.

Someone please correct me if I'm wrong, but I seem to remember the difference between manual and power disc/drum MCs is that the plunger where the pushrod contacts is the same distance from the mounting face as the booster's is for a power application, so no pushrod work/swaps are necessary.

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'74 Duster w/ HEI ignition, beat to snot suspension, A904, 8.25" 3.55 SG rear, still being tuned up and gets 17 MPG

Know how they always build a better idiot? That's me

Thanks Jopapa. I found the master cylinder lolcally. As I am told, the power brake cylinder may or may not have the indentation in the back to hold the manual pushrod. So I suppose I'll search out the pushrod. We don't have much in the way of boneyards where I am, so does anyone know if a repo rod is available?
Thanks!
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Yamaha DX7

ya but the power MC will not allow the pushrod to jam in and stick in. you dont want a random condition where the pushrod misses and jams and you got no brakes.

What you can do (and I did recently) is with a QUALITY and WORKING M/C is instead of using a pushrod retainer, you can use black RTV.

AFTER bleeding the brakes---

You squirt a generous amount into the pushrod slot, then put the pushrod in, make sure it seals good. DO NOT touch the brakes for at least overnight, preferably 24 hrs. The RTV will be a pretty good safety seal, a lot of people use it, and some new M/C even say to do it in the instructions if the retainer doesnt work. For added safety make sure the brake light switch is adjusted right, so if you pull-back on the brake by accident it will stop the backwards travel.

i just dont see RTV holding up to everyday braking. im sure my brake pedal goes up and down at leaste a hundred times a trip

Like I said, the M/C needs to be a very good quality one. That way the release won't put pressure on the pushrod.....it should stay retained unless you yank on the pedal...

If you are using a POS M/C that goes nearly to the floor, and requires a lot of pumping, it's a whole new ballgame.

The master cylinder I'm getting is reconditioned by Cardone. I'm told that they are pretty good. They usually come with the little locking grommet.

I think the RTV, or better yet a urethane paste (some of which will cure as hard as motor mount rubber) would work, as it only grips the sides of the pushrod to keep it in place, but is normally not under pressure.

Still, I need to find a pushrod. Anyone know of an aftermarket source?
Thanks!
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SH150i

i would lookup wildcat auto wrecking out here in oregon. your close and the will ship. this is my option when i get this all straight. cept im drivin the 35 mins there

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'72 Valiant DD for over a decade-225-Disc brakes, big T-bars, big Sway bars f/r, carter bbd/super six, GM HEI, 2- 12" subs in trunk, 1000w amp...
'77 cherokee cheif widetrack-360-33x12.5 tires-no lift. keeps driveway dry-project/backup DD/mudder

On my 63 Dart, I used a master for a 74 Road Runner with manual disc/drum and it came with the push rod already installed.


TopHat

wut brand? wagner?

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'72 Valiant DD for over a decade-225-Disc brakes, big T-bars, big Sway bars f/r, carter bbd/super six, GM HEI, 2- 12" subs in trunk, 1000w amp...
'77 cherokee cheif widetrack-360-33x12.5 tires-no lift. keeps driveway dry-project/backup DD/mudder

I don't remember what brand, but I got it at AutoZone for like $17.99 or so, not counting the core charge of $5.00 or so. It bolted right up like it was meant to be there.

TopHat