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70 Nova Power Brakes

9K views 17 replies 9 participants last post by  Donnie L. 
#1 ·
I have a 70 Nova street/strip car with factory power disc front brakes. I'm removing the 377 sb, and installing 355 sb which has cam that will not produce the vacumn required. Any suggestions for master cylinder replacement to avoid buying electric vacumn booster?
 
#6 ·
I had the same issues with a vacuum can after putting a big cam in. The can gave me one good stop, and then no assist. I went back to manual brakes and took the can off. Mine stops great without the booster, and the rod relocated to manual position.
On your Nova you can use the same master you already have, but will need to move the pivot point on the brake rod where it attaches to the pedal. There should be two holes, and it goes in the hole closest to the pivot point for manual brakes.
 
#7 · (Edited)
Yes you can use the cylinder you have now and still have some braking but there is a problem because Stock small cam engine cars power booster master cylinders have a larger diameter bore And some a shorter stroke, and stock big cam no boost master cylinders had a smaller bore and most a longer stroke to replace the lost pressure to your brakes!! So you need to order a standard master for (something like)a solid cam L88 or early Lt1 that came stock with low vacuum and no power assist! Many Novas till about 74 had no power assist you need to order one of those and the actuating rod !!!

Jester
 
#9 ·
In looking through my catalogs, I can only find master cylinders with drum/drum or disc/drum. I see no reference to power or manual, and haven't seen that before. Every GM I've worked on used the different hole position on the brake pedal arm to change leverage point for power or manual.
Can someone please point me to the listings for these power master cylinders for a Nova?
 
#10 ·
Part #: 85-22771
Nova Drum Brake Master Cylinder, Rebuilt, Manual Brakes, 1" Bore, 1967-1974


Part #: 85-22767
Nova Drum Brake Master Cylinder, Rebuilt, Manual Brakes, 1" Bore, 1967-1974


Part #: 85-22773
Nova Disc Brake Master Cylinder, Rebuilt, Power Brakes, 1 1/8" Bore, 1968-1974



BENDIX BRAKE MASTER CYLINDER, IRON, NEW -- 1.125 in. bore size; Dual bowl design; Includes cap and reservoir; This is a high quality OE replacement brake master cylinder.
SKU#: BF11944
Brand: Bendix
Fit Note: Power Brake System


Chevrolet Nova 1962-1974 Non-Power 1" Bore Master Cylinder; Dual Resovoir - McGaughys Part# 63203
RRP:
$140.76
Your Price:
$93.60 (You save $47.16)
SKU:
63203-14
Brand:
Mcgaughys
Shipping:
Calculated at checkout
Quantity:
Product Description
Fits: Chevrolet Nova 1962, 1963, 1964, 1965, 1966, 1967, 1968, 1969, 1970, 1971, 1972, 1973, 1974
- Non-Power 1" Bore Master Cylinder; Dual Resovoir
 
#11 · (Edited)
:mwink:Sorry not to finnish that post ( eating Spaghetti )!!!

In the past I had to rebuild masters and the kits for power and mechanical brakes were different most of the time I did get a few that may have been the same ? Can't remember now ! But I do remember that the power booster does not increase braking ability LOL it was just an addition to ease pressure on old or lazy legs and knees, And the Mechanical smaller bore masters applied the brakes harder the harder you pushed with your strong robust young racing legs LOL!!!

Jester
 
#12 ·
Switched my disc/drum power assist '72 Nova to manual brakes and also used the same existing master cylinder, just needs the correct manual brake rod and rod needs to be hooked to the upper hole on pedal instead of the lower hole, to give the proper pedal ratio. No real difference in pedal pressure needed to stop it, just wasn't as touchy.

In my case, the brake light switch contact tab was bolted into that pedal hole, had to invert the tab and bolt it into the former power brake hole.

I don't totally recall the piston size, but seems like it was 1-1/8".

The only thing you really have to make sure of is that the master has a 1" deep or so pocket for the brake pushrod rod, so it cannot fall away from the cylinder. I have seen some GM power assist masters have just a small dimple in the piston, rod can easily fall out when switched to manual....bad deal if that happens. :pain:

I know the metric A/G-body and the S-10 you have to have the brake rod retainer ring/bracket just for this reason, those masters have just a dimple.
 
#13 ·
I did the same thing on my '71 Camaro when I swapped to power and added a booster behind the manual master. Just moved it forward and added the booster behind.
On a '69 Nova I recently swapped I added an aftermarket booster and found the adjustable rod on the output side of the booster wouldn't adjust far enough out to operate the master. I had to turn a longer replacement out on my lathe to make the master/booster work together.
 
#16 ·
I had to put the Nova aside in early March, finally took drivers seat out today to move the brake rod up. I removed the brake light switch contact tab, removed the funky retainer off the rod/pedal pin, attempted to move brake rod up to top hole in pedal, will not go up high enough, it hits inside the rear of the m.c. where it comes thru the firewall. Put it back at original location, I wanted to try this as mentioned in couple of the above post before spending more money. Anyone have this happen & or have a solution?


Thank You
 
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