coppercutlass

ok so my car has weak brakes due to the cam i am running . i have decided to upgrade my drums to manual drums with adjustable prop valve and a wildwood manual master . my question is when i take off the booster what do i mount the master to and will my stock push rod work or should i find one for manual brakes or buy an adjustable one . also how do i find out proper distance for the rod . any help is greatly appreciated .

Rickman48

I think it'd be much easier/safer to go with a vacuum tank than to remove the booster!
Even an electric pump would be better!
If you've ever driven a hi-po vehicle in city traffic with standard brakes, you'd realize it's downright dangerous!

Tony72Cutlass'S'

On a side note, i think the cutlass had possible manual brakes. So there should be a place on the firewall to mount it.

I'm at work so i dont have the factory assembly manual handy. Perhaps others can chime in.

Or maybe you can just leave the booster on your car and not bother removing it. WHen you push the brake pedal. that actuating rod still goes through it.

OLDSMORAT

How about a hydro boost conversion. I've seen them done with a astro van hydro boooster. It's a cheap to do conversion.

oldcutlass

A hydro boost would be perfect in your situation!! Another thought would be a manual disc brake conversion!! They work pretty well, I was happy with that setup on my 63 Plymouth!

Tony72Cutlass'S'

Side Question,

How much vaccum are you pulling at Idle? Maybe if you check that, your drums just need to be adjusted?

coppercutlass

i adjusted the drums i only get one pump before vac. is gone . i found all the right peices to go to non power drum brakes under 100 bucks not bad. My only issue is where to mount the master cylinder . i drove around all summer with no issues its just i dont have enough vac. to pump it more than once . Since my car see's alot of drag strip action i dont want the hydro boost too much drag lol. I think the manual brakes will work fine getting the right peices was a big issue for me .

Run to Rund

The stock type master cylinders mount onto two studs coming into the engine compartment from the brake/clutch pedal pivot bracket. The clevis goes through the hol closer to the pivot point, and be sure to use a derby hat shaped retainer at the end of the master cylinder so the pushrod can't fall out. All 67-72 A bodies with manual brakes used it, and I believe Inline Tube reproduces it.

coppercutlass

im juming back on this subject because i cant seem to find the right master cylinder. Are all manual brake cars the same even front disk ? im trying to go to the local parts store and buy a reman they have one for a manual application but for front disk brakes . I have heard alot of guys used the vette style manual brake cylinder but im guessing that had disk brakes any help is appreciated. I have tried locating it every where the only place i found it was summit but it does not appear right .

oldcutlass

You can look at Chevelle manual brake setup, "A" body is an A" body.

55miketn

The car doesn't know it has power brakes. The power is for your convenience. If you eliminate the power unit and plug the vac., the m/c will perform like it should. If you are going to race it, I would suggest disc brakes for more stopping power( especially if the stopping strip is short at the strip.) Seems standard m/c is 1" now; which is probably what you have.

coppercutlass

That's what I saw all bores where one inch . I think I'm just going to actually hook up a vacuum canister and go from there . They aren't too bad as is just I run out of vacuum too soon.

covertolds

Here is what I did when I went from power drum/drum to manual Wilwood front discs and rear drums.

Master cylinder is from O'reilly auto and is for a Dodge Caravan. Part number is MC39476. I paid like $33.00 three years ago. Cheap and lightweight.

I had to elongate the mounting holes somewhat with a rat tail file, but it was easy, the mc body is aluminum.

CIMG0660.jpg

The brake lines on the new M/C are standard thread, 3/8"X24 if remember correctly, so that's not really a problem. I did however need to find an adapter for the rear line because the line itself is too large to use a 3/8" fitting. Found an adapter at NAPA.

As for a pushrod (which will go into the top hole on the brake pedal), I came up with this set-up:



The master cylinder has a deep hole so the pushrod won't fall out. The rod has adjustment to it.

Works great and really cleans up the firewall.

CIMG0700.jpg

coppercutlass

Thats what i was looking for. This exact set up. as for the push rod i found a reproduction one for 18 bucks. Did you need a specific length to run that set up or will the stock manual push rod work. Btw love the car i think you where up at byron this past septmber.

covertolds

I don't believe the rod will work with this ,M/C. You will want one that is adjustable.

The "ball" end that seats into the m/c is a 3/8" grade 8 bolt that threads into the hex piece. I used Loctite on it and a jam nut. The jam nut does two things, it obviously locks the ball end in place, but it also seats against the piston in the m/c and pushes against it when you push the brake pedal. The head of the bolt was then cut off and rounded to make the "ball" end.

Thanks for the compliment and I remember talking to you in Byron. Been going there for many years. It's my favorite track.

507OLDS

That's purdy Bill. It looks like you have an adapter on one of those lines.Is that from standard to metric?I just run the regular Delco style MS to keep it simple,but I have been looking at some of those aluminum cylinders out there.I just figure they probably have metric ports,so I probably need to cut & reflare my ends,with the metric fittings.
CopperCutlass,
If you want to try the manual brakes,without spending too much at the moment,you can remove your booster,and bolt the existing master cylinder right to the firewall,using the upper pair of studs.You will still need the factory style manual pushrod for the pedal though,and that needs installed before the master cylinder is bolted to the firewall.If you look at your brake pedal,you will notice two different holes for mounting the rod clevis.The lower holes is for the power booster,which is where yours should be right now.The upper hole is for the manual brake clevis/rod.You will use the upper hole for any/all manual brake set-ups.You might also need to adjust the brake light switch,which slides backward/forward in a barrel clip.

Run to Rund

Again, get the derby hat shaped pushrod retainer, and use a pushrod with a flared out retaining step that engages the retainer. Every year we hear about a racer who thought the pushrod couldn't fall out, but it did and he wrecked the car going over 100 mph.

507OLDS

Yes,the one I am referring to can't go anywhere.It has that metal hat,and the flared ring.Once the master cylinder is bolted in place,it can't get out.

coppercutlass

The pushrod I was refering to is o.e. Style it has the pin and everything and the derby hat I believe. I bought a new master cylinder my old one always leaked. I'm gonna try that and see how it works and eventually upgrade to what bill has. Thanks for the help guys.