Master Cylinder PSI upgrade?

[CDW6212R]

How's it going, I've been busy getting my 99 running, it has over 11,000 miles on it since built now.

I've had my big brakes done for a long time now. The Corvette calipers are more than adequate with the 12.75" rotors I used. They fit in every 16" factory wheel I have tested except for the Sport Trac 16's that I have snow tires on.

They work great, they will lock the fronts if not for ABS. The only thing I wish was better is pad life, the 65-82 Corvette's don't have especially large pads. The pad life is similar to what I had, for mail delivery that isn't really ideal.

I haven't been driving my 98 much, less than 2k since February. I'd like to hunt a bigger caliper(bigger pads, not pistons), and attempt a different bracket for them. I have not looked much, the SRT8 cars were possibilities, but not. I spoke with a couple of specialty brakes guys, there are likely calipers to choose, but price will be a factor. That's why these Corvette calipers were a good choice. Regards,

 

[Xan]

WOW, this should be stickied this is an awsome post with lots of good info! Nice brake upgrade Don i'm impressed

 

[r37ribution]

How's it going, I've been busy getting my 99 running, it has over 11,000 miles on it since built now.

I've had my big brakes done for a long time now. The Corvette calipers are more than adequate with the 12.75" rotors I used. They fit in every 16" factory wheel I have tested except for the Sport Trac 16's that I have snow tires on.

They work great, they will lock the fronts if not for ABS. The only thing I wish was better is pad life, the 65-82 Corvette's don't have especially large pads. The pad life is similar to what I had, for mail delivery that isn't really ideal.

I haven't been driving my 98 much, less than 2k since February. I'd like to hunt a bigger caliper(bigger pads, not pistons), and attempt a different bracket for them. I have not looked much, the SRT8 cars were possibilities, but not. I spoke with a couple of specialty brakes guys, there are likely calipers to choose, but price will be a factor. That's why these Corvette calipers were a good choice. Regards,

Thats incredible man!

Yeah bigger front brakes is exactly what I need. I get kinda concerned when I'm traveling a little closer and the guy in front stops quickly. The pad life is similar to what you had before you say? Thats great.

If you do have a bigger caliper in mind price really isn't a problem for me when safety is being compromised. I actually stopped driving the truck due to other problems I'm trying to work out but I don't want to drive it on the street again until I get bigger brakes.

I head down to Fl sometimes maybe I'll take the truck down there when I get it running right. Would be cool to meet the brains behind the operation.

 

[CDW6212R]

I'm usually around. If you had seen either of my two brake threads when I started this, I explained how the Explorer rotor offset is much different than a Cobra rotor, or a Corvette rotor. There have been at least two combinations made with the Cobra rotors. I could have done that also, but my mock up showed that those Cobra rotors(.350 offset) would be right out at the wheels. Very few wheels would work to clear those. The Corvette offsets are .850 inches, and the Explorers are near 1.450 inches.

My brakes are large and will fit inside most 16" wheels. They fit inside of three out four which I tried. The rotors had to be made custom two pieces to get the proper offset. The rotor surfaces cost almost $150 each, and the "hats" ran about $175 each. My first set were machined Subaru hats, about $150 each after machine work. The end cost was just over $1250, so I figured to ask $1400 for the whole kit of front parts. Different calipers might easily add $500 or more compared to the Corvette $270 calipers. Regards,

 

[r37ribution]

Yeah I haven't been doin much lookin around on here so I missed those threads.

I have 17" rims anyways so I'm sure they will fit fine... you think I should check the offset on my rims?

$1400 isn't bad, I'll be getting a hold of you about those just not sure when.

 

[CDW6212R]

I was the first to look at the Cobra brakes(calipers and rotors). I have had a spare set of 96 Cobra parts since 1997, before EE made their prototype. They spent the money to adapt them, and then didn't sell them to anyone. They knew that they were not an improvement. Since then someone has talked them into helping to put together a kit with them, the selling price was over $1700.

I had the Cobra calipers and rotors mocked up with a wooden bracket, soon after I discovered how much smaller the Cobra calipers are compared to stock Explorer calipers. I started my Corvette project with those Cobra rotors(with $45 of machine work), and mocked that up.

The offset of the Mustang rotors places the calipers extremely close to the wheels, they barely cleared my 18" wheels at the spokes. The difference in rotor offset is about an inch(.90 inch), so wheel choice would be a problem.

My use of custom 1.450" offset rotors creates plenty of wheel spoke clearance. Notice the two pictures again in post #13 above. The first shows a Cobra rotor with a .350" offset, those calipers were within .100" of my 18" wheels. The lower picture is a properly offset rotor, with clearance to the tie rod just like OEM rotors. Corvette rotors fall right between those two at .850" offset. Regards,

 

[r37ribution]

Good info. I will check the backspacing on my rims.

So the larger diameter rotor was enough that additional pistons were not required?

 

[CDW6212R]

The key is the total braking power. That is determined by caliper piston area, the rotor swept area and radius, and fluid pressure. We have very good OEM calipers and pressure, the stock pistons are 1.75", very large compared to any smaller vehicle. Our stock 11" rotors are the only real weak link. What Ford should have done in 1995 was upgraded all Explorer wheels to a minimum of 16", and used 12.75" rotors.

So all of the common four piston calipers that you can find from tons of other cars, they are a waste to use. The Cobra/PBR/Corvette(twin piston) calipers are about 1.625" in per piston diameter. A smaller caliper loses brake power, that's why the Cobra brakes are not any real improvement for a 4500 pound truck.

The Corvette 65-82 four piston calipers have 1.875" pistons, much larger than our OEM calipers. They provide much more braking power, and the 12.75" rotors provide much more heat capacity than the original rotors. I have no rotor issues, even with mail delivery. The calipers are large enough that the ABS is required for high braking effort, it will kick in at any high speeds like 80mph.

As I hinted, I'd like to hunt a caliper with larger pads. From what I've learned, I would choose a piston size in the 1.75" and 1.875" range. The rear brakes could use upgrades already, there are a few 8.8 kits, but none of those are a perfect match for our needs. Ideally I'd like to buy the 12" rear kit without the calipers, or with something larger. What comes in that kit is a little too small, the pistons need to be bigger for us. So that is a future project still. Regards,

 

[Stanleyjd]

very good cdw. if i keep my X i am serious about a brake upgrade. i think our X's weight over 5k. i have braking issues with my previous 98 sport with 4.0 sohc. at speeds over 70 or so the brake fade was terrible. it actually caused me an accident when i was drinking (i know i know) but i have done more work to the power of the truck and nothing to the brakes and was getting up to 100 easy and topping out at 110 maybe 112 with out a struggle. so you know the stocks werent ment for that speed. combine the power with weak brakes and drinking and you got disaster. i dont drink and drive at all now. but the brakes didnt help. they are weak and now i got a 302 more power and weight with same weak brakes. very very wise investment. how much improvement did you notice on the slotted drilled rotors? did you just do the front or all 4? thanks

 

[CDW6212R]

I still have been avoiding driving my Mountaineer, I have brand new tires on it and I don't know what the alignment is like. I wanted to rebuild the suspension soon after the tires, I'll do it soon.

If I knew of a caliper with a bigger pad size I would be planning to build new brackets to change calipers. I searched for a couple of hours in Spring, I haven't spent any more time looking. You can buy super calipers for $750-$1500 each, but I would rather find something which could be reasonable, say less than $750 for a pair. The 65-82 calipers are very good, but the pad life is not any better than stock pads. I would like to have gained something in pad life, especially for my mail truck.

I'll do something with the rear brakes eventually, a balance of power saves pad life for the front also. Drilling rotors is more for looks than anything. I chose to avoid the drilled rotors mainly because serious professional rotors cost over $25 each for the holes in one rotor. Regards,

 

[Stanleyjd]

i have have the understanding that the drilled help cooling with the escape of the gases that causes that fade/ what i called snot. and the slotted was suspose to help with the esacpe of the gases that causes the brakes to lack grip. correct me if i am wrong. thanks

 

[CDW6212R]

A great deal of that talk, whether from the sellers or just enthusiasts, it's not very important. For street use you should never notice any difference. The affect on appearance is far greater than real performance gained.

Many professional racers state that the drilling can lead to cracking, and almost an equal amount state that no harm is done. If I had more of a show vehicle it might be worth it for looks. My truck with the slotted 12.75" rotors and Corvette calipers would lock the front tires at 80+mph. I have smaller SSBC Force 10 calipers now that are not as powerful, but still strong enough for my truck and towing.

The size of the rotors and the calipers is five times more important than other factors. Pad and fluid quality is second to those. Regards,

 

[r37ribution]

How's she holding up Don?

I did a quick search and could not find your thread on your brakes. Can you post a link?

 

[CDW6212R]

Well hello, you were away from here for a good while. I just looked and didn't find any links to my old thread. I searched several ways and it doesn't turn up, I wonder if some things have been lost here. On the other forum I go to my thread there had some of it lost with a server change last Spring.

Anyway, I've been a little busy. I finally got my front suspension rebuilt so that I could align it and feel comfortable to drive it more. Now I'm trying to get prepared for a 347 I have coming soon.

I have looked off and on for a caliper to use with bigger pads. My brakes are doing fine as they are, but as I mentioned last year, the pad life is not better than OEM. I gained brake power but the pads wear based on their size and I didn't look hard enough for something bigger.

So far what is unfortunate is that calipers with bigger pads are very expensive, or the pistons are too small. I know that I haven't searched and looked at every caliper from all companies. Hopefully something will come up that is more reasonable.

What I have had, the two Corvette calipers, both are very good for just about all applications. My use for a mail vehicle just brought up the pad life issue much faster for me. I want to see if I can find something feasible for my Mountaineer, as well as my 99 mail vehicle. I could splurge for one vehicle, but not for both, and no one else would buy the high dollar calipers either.

The Wilwood line seems to be the widest and easiest to find, calipers and pads. The reasonably priced Wilwoods have piston sizes too small, or the pads are not big enough. Their three top models would be great, but the cheapest is $1600 each new. There is a used pair for $1600 on eBay right now, from an old ASA race car.

Brakes are a long subject when done right, I spent a long time getting what I have. I need to find the time to finish my best truck. If I can duplicate the brakes for my other truck(feasibly), I can have those and/or my current used parts available. Regards,