Master Cylinder for 73mm front/TC rear

Topic: Master Cylinder for 73mm front/TC rear (Read 1460 times) previous topic - next topic

Master Cylinder for 73mm front/TC rear

May 04, 2009, 10:44:51 PM

Would a 94/95 Mustang MC work decent with stock booster and 73mm front pistons with the stock TC brakes in the rear? I figure while redoing the front brakes, suspension, and steering, I might as well put the better calipers on but need to get the right part for the job...I'm not sure if I want to use the SVO master cylinder.

Would the 94/95 MC work decent at all with 73mm calipers or is the SVO one basically a requirement?

I've been up on the fence over 5 lug but honestly, I doubt I'd ever have the desire for any of those rims and I don't need 13" brakes on the street...

Master Cylinder for 73mm front/TC rear

Reply #1 – May 04, 2009, 11:04:48 PM

You'll want the bigger MC with those huge pistoned front calipers and rear discs.

Master Cylinder for 73mm front/TC rear

Reply #2 – May 05, 2009, 01:53:08 AM

I've seen a few people report good braking and pedal feel with properly bled brakes, a sn95 MC, their stock brake booster(s) (with some still opting for the '93 Cobra), and 73mm up front/38(?)mm out back. Both with and without stainless steel brake lines. These reports are what make me question the larger 1.125" bore master cylinders and whether the 1.0625" ones would work more ideally.

Then again, it's also not that much of an improvement over the 60mm ones if the 60's are setup properly and can lockup the tires themselves. Pro's and Con's as with everything else...

Master Cylinder for 73mm front/TC rear

Reply #3 – May 05, 2009, 08:19:39 AM

Well the SN-95 unit should work OK if that's the bore.

Master Cylinder for 73mm front/TC rear

Reply #4 – May 05, 2009, 08:53:13 AM

I am going off of numbers from corral and here: http://mjbobbitt.home.comcast.net/~mjbobbitt/mustang/mc.html

Master Cylinder for 73mm front/TC rear

Reply #5 – May 05, 2009, 09:25:13 AM

those sizes are correct AFAIK, but you didnt specify v6/GT or cobra in your first post.

MC bore size is greatly based on personal preference. i run the 15/16" cobra unit on mine. based on all the guys runnin 1" bores with the same brake setup, id guess alot of them wouldnt like the feel of my pedal, but i do.

the 1 1/16" v6/GT will probly work fine with those calipers, but the pedal feel will be up to you.

Master Cylinder for 73mm front/TC rear

Reply #6 – May 05, 2009, 10:50:08 AM

I doubt the pedal can be any worse than it is now. People hate to drive the car as it already goes halfway to the floor before doing anything - it's always been that way even after brake jobs from shops. The booster works find but I'm assuming something is amiss elsewhere. It does not quite hit the floor before it's able to lock up the tires though.

I did mean the standard sn95 Master Cylinder, not the Cobra. What I can't figure out is what is so different with the Cobra MC versus our 1" bore stock one?

Also, what adjustable proportioning valve would you guys recommend? Plain valve or replacement block altogether?

Master Cylinder for 73mm front/TC rear

Reply #7 – May 06, 2009, 01:44:06 AM

Is there any reason to do the 3-2 MC swap and not keep the 3rd line, that goes straight to the brakes before the shuttle valve, wired up right after the master cylinder and before the meter block? It seems like it's the safer way to install a 2 port MC into the vehicle as long as making the new lines up isn't a problem. I'm not sure how reliable that fault tolerance is but it's better than nothing.

I'm just trying to decide how to plumb up the brakes so I have everything ready before attempting to do the install.

Master Cylinder for 73mm front/TC rear

Reply #8 – May 16, 2009, 07:54:17 PM

So apparently after driving around, I found the opposite to be true for my brakes (I don't drive it too often). I've got a HIGH pedal which gets hard fairly quickly without locking up. It takes a bit of effort to stop the car rapidly, compared to driving a Saturn that has a wider pedal travel and much easier to slow down quickly. Does this sound like a bad brake booster? Putting a lot of pressure on the brake pedal, it will basically get to locking the brakes up about halfway down to the floor. I've got like 2-3" of pedal travel from relaxed position to fully depressed. The pedal is rock hard with the engine off. I have to put about twice the effort in with the engine off to get any decent (as if on a hill) compared to half the effort for good braking with the engine running.

With this high pedal feel, I should be able to stick with my current MC for just the front calipers being 73mm but need to swap once I go rear disc this summer. Either way, I may as well think things out now for a better braking system in the end. Ideas? What about pads? Semi-metallic or ceramic (neither of which the cheapest part numbers the stores have to offer - I don't want to buy )? I've got parts now but just trying to see if I should make some changes here soon before installing it all. The install will likely be in 1-2 weeks.

Master Cylinder for 73mm front/TC rear

Reply #9 – May 17, 2009, 01:38:22 PM

Check for a vacuum leak in the brake system....

Master Cylinder for 73mm front/TC rear

Reply #10 – May 17, 2009, 04:20:58 PM

I already did when I was trying to diagnose other engine issues months ago. There are no vacuum leaks anywhere in the brake booster or vacuum tree. I test with an oilless Thomas 28in vacuum pump and a vacuum gauge.