Sn95 Master Cylinder

[billison]

Ok, I've read and read and can't find a simple answer. For my 5 lug swap. I got front and rear disc off a 94 v6/gt. No cobra parts. I would assume I'd match the master cylinder from a similar car right? The cobra would be overkill I think.

I was hoping to keep my stock booster

 

[stykthyn]

93 cobra booster and a stock 94/5 master.

 

[billison]

Just making sure I'm understanding things before I just buy parts.

The booster seems like it makes sense because otherwise I'll end up with a stiff pedal . I know the master is needed to move enough fluid. And if I upgrade to larger brakes later I'll already have a good booster..

 

[stykthyn]

Bingo

 

[7991LXnSHO]

@stykthyn
Please tell @billison and me why we need the Cobra booster. How is it different than the stock fox booster? I have the front half of the swap, I think. ('94 spindles, PBR calipers, disks and hoses, and extra '96 up straight arm spindles I should post for sale.)
someone, can you post exactly what else I need or send me to the link for the rear disc swap? And what to do to get the MC, hoses and a poportioning valve together right? There are so many brake posts I am confused.

Also, what wheel fitment works with this swap? I wonder about offset and 5 holes. I like my '91 pony wheels, but they are for 4 lugs.

 

[stykthyn]

If you have rear drums the stock fox booster is adequate. The cobra unit has a larger diameter and makes for less pedal effort. You can try the fox booster but I believe you won't be satisfied with the results.

 

[7991LXnSHO]

I am also researching a drum to disc swap on my GM A body, (THAT will be a big improvement!) and they have a option for a dual diaphragm unit that produces more boost for the size, but looks thicker. I was wondering if it was that kind of a deal.

So what about the rear discs, matching axles (stock length from one side of a Ranger?) and right wheels?

 

[stykthyn]

I went with north race car brackets to keep stock fox length axles from a ranger. You can modify the stock Rear caliper brackets from your donor but I didn't have the tools at the time to make it work. Any sn spec wheel will work. I have 10.5 inch wheels on the back and 315s but it is an EXTREMELY tight fit. If I had to do it over again I wouldn't go over 9 in the rear and just run a 275 series tire.

 

[billison]

So.. I feel like I've come full circle with this. I have all the sn 95 parts, fox length axles and drums. I honestly think I'm just gotta toss that stuff on for now. I figure if I'm gonna do the 4 wheel disc and upgrade the mc/booster I'll wait till I'm putting bigger Brakes on. Seems like a bunch of work for a mild upgrade. I can swap the parts and get the style now and wait for deals on the upgrades.. Thoughts?

 

[stykthyn]

So.. I feel like I've come full circle with this. I have all the sn 95 parts, fox length axles and drums. I honestly think I'm just gotta toss that stuff on for now. I figure if I'm gonna do the 4 wheel disc and upgrade the mc/booster I'll wait till I'm putting bigger Brakes on. Seems like a bunch of work for a mild upgrade. I can swap the parts and get the style now and wait for deals on the upgrades.. Thoughts?

I ran that way for a while. No worries. As long as your booster isn't worn it will work fine.

 

[Noobz347]

Even with drum in the rear, if you get the brake bias correct then it's still a very nice upgrade over stock Fox brakes.

Were it me, I'd tackle the booster when I could, just to get it out of the way.

 

[Mustang5L5]

@stykthyn
Please tell @billison and me why we need the Cobra booster. How is it different than the stock fox booster?

The booster is physically larger in diameter which gives it larger mechanical advantage over the stock booster.

You don't need a Cobra specific booster. The 94-95 boosters are the same. Pick any.


Master cylinder selection all depends on the brakes on the car. You should match the factory setup. The diameter of the bore of the MC is sizes to a specific ratio in relation to the caliper on the car to give certain pedal effort when combined with the booster and pedal arm geometry. Forget the fact that there is a Cobra master cylinder and only pay attention to bore diameters and not assume Cobra = best. Mixing and matching parts can lead to poor performance so you should really use what the factory did as a guide and go from there.

I've been involved in plenty of threads over the year where someone will install cobra brakes and complain they such, only to find out the issue was mismatched parts.

To answer the OP's question. With 1994 V6/GT brakes front and rear, the proper MC and booster setup is a 94-95 GT/V6 MC (1 1/16" bore) and any 94-95 booster. If you were to put a 94-95 cobra MC on (15/16" bore) your pedal would be super hard and you'd have trouble stopping

 

[billison]

What about this. If I put a 93 mc in with the sn brakes. I know it's a bigger bore, so with that make the brakes touchy?

 

[Mustang5L5]

1993 cobra mc is smaller than the 94-95 gt MC.

Smaller bore translates to softer pedal and longer stroke.

1993 cobra mc = 1" bore
94-95 gt mc = 1 1/16" bore.

If you aren't going to swap the booster, go 1993 cobra mc and try it out. But, it's not the proper combo.


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