Master Cylinder PSI upgrade?

[r37ribution]

I'm going to be getting 35s soon and have been reading a lot about upgrading the brakes on the X...you can't. My truck already stops crappy with my 31s on it and 35s I can bet will be horrible.

Precision Brake quoted me $6500 to custom design a new front brake setup, thats out of the question.

I called speedfreak.cc and left a message today. I have read that he is the only person with a front brake setup for sale, although it wasn't on his web site.



I read another thread thread where someone saw a Truck show in which they upgraded the master cylinder and some lines and they went from 500psi to 1500psi. This sounds like it would be the most inexpensive way to do it.

Has anyone upgraded their master cylinder like this and does it work well? How did you do it? I'd rather not replace all my brake lines tho that looks like a PITA.

 

[00XLS]

I believe they did something like that on trucks, some type of electronic master cylider if I remember correctly. Sorry I couldn't help more.

 

[r37ribution]

Man wish someone knew where I could find this mystic "master cylinder"

 

[mrboyle]

Your stock master cylinder is capable of producing over 2000 psi! More pressure is NOT what is needed to increase the vehicle's braking. You either need to increase the mechanical advantage of the brakes by using a larger diameter rotor, or increase the contact area of the friction material by installing a larger caliper/pad combo. Neither option is readily available and I doubt it will ever be. Your only real option is to learn to drive with the less responsive brakes and adjust your driving style to suit.

 

[inh]

or get powerslot rotors and those other pads that everyone recommends

 

[r37ribution]

that really SUCKS...

I'm gonna try to call Troll again tomorrow. Hopefully I'll get around to it before 6.

 

[CDW6212R]

The real issue is wheel/tire weight, my 18's are 72 pounds each. Weigh your stock wheel/tire, and your bigger wheel/tire.

These are for 4WD/AWD only, the hat type of rotor. They even can fit into some stock 16" wheels.

How patient are you? I had started on bigger brakes last year for my AWD 98 Mountaineer. I could be testing within a couple of weeks. The hard part is that a special offset is needed, stock is over 1.2", while Mustang's are .35", so a two piece rotor is needed(about $250 each). Here are a couple of pictures, 12.90" rotors, and 65-82 Corvette calipers. Regards,

 

[CDW6212R]

I originally tried to use a stock Cobra rotor, when done the offset placed the brakes too far outward. That's the .350" offset that I mentioned, it barely fit inside my 18's, but no other wheel of mine. I even ordered an aftermarket Cobra rotor drilled to fit. Note that stock rotors are 11" and 1" thick. Mustang rotors are 1.1" thick, and old Corvette rotors are 1.25" thick. The high end two piece rotors will be more than adequate, even better than the Saleen 13" XP8 rotors/Alcon calipers. The only question yet is if the calipers are too big, they have four 1.875" pistons each. I have a VC2000 testing device, I should be able to get 0-60-0 braking numbers for before and after. Maybe I can get the brackets finished this week, night.

 

[r37ribution]

I can be patient...

I would definately be interrested in near 13" rotors and 4 piston calipers...

Why would the calipers be too big? You mean to fit in the rim?

I'll be ordering my 35s this morning with rims, I'm assuming I will need at least 17" wheels from the sounds of this project. Please let me know if you think 18s would be better, I don't want to spend $2k on these if I can't upgrade my brakes.

What were you saying about wheel/tire weight? I have heard that 35s weigh close to 125 lbs each + the weight of the rim...

This sounds really good, I'll also call Troll tomorrow anyways just to what he has to offer, if anything.

 

[CDW6212R]

The stock wheel weight is in the 55 pound range, and when you get over 60-65 pounds you definitely will lose performance. Acceleration, braking, and fuel mileage will drop.

The stock calipers have two 1.75" pistons, and any other application with that much piston area is rare. Most trucks likely have that kind of area, but most performance applications are cars, and they have less.

The Mustangs have something in the 1.625" range, about 38-40mm. Many combinations can be made, but having larger rotors with smaller calipers offsets what you are after. I chose the old Corvette rotor, because it is common and easily attainable. I also chose it because there are two calipers made by Stainless Steel brakes(Force 10). The piston sizes come as 44mm or 48mm in those.

 

[CDW6212R]

Note the 3rd picture that I posted, that is a 16" Limited wheel. The Corvette calipers were on 12" rotors, inside of 15" wheels. I knew that this would work in all 17"+ wheels. That they fit inside of the three different stock 16" wheels is a pleasant surprise.

I only regret one thing about the parts combination that I am putting together. Much grinding must be done to clearance all of the parts. I am almost satisfied with the clearance of my brackets, they need a small amount of touch up and final fitting. The calipers need to be clearanced slightly for the larger rotors(12" versus 13"), and I have touched on the brake line fittings slightly also.

This means that I have to aquire all of the parts myself, and fit them together.I had hoped to just make brackets, and give source information to anyone wanting to duplicate this. The parts aren't cheap of course, and I only have one person so far that I believe is serious about doing the same.

I ordered the rotors to be 12.90" this first time. The cost would have been the same for a 12.75-13.0" rotor. The bracket must be made to match that dimension. I knew that some clearancing of the calipers was required, and I chose the 12.90" dimension because I had the first brackets close to fitting that already. If the brakes turn out to be too much at all, a 12.75" rotor could be done, but I'd prefer to get the smaller Force 10 caliper.

 

[CDW6212R]

These calipers were about $270 from discbrakesrus.com, rebuilt, powder coated, with pads. The SSBC calipers are over $750, and aluminum. Clearancing on an aluminum caliper isn't desired of course. Regards,

 

[CDW6212R]

There are or have been other brakes made for these 95-01 4WD Explorers. The type that you saw on Mike's truck likely came from Explorer Express. I have spoken with them, and other's who have worked on different combinations. What EE originally put together they only put on their one prototype truck. They touted them in ads, but decided that there wasn't enough improvement, or market for them.

That was/is essentially a late Corvette rotor, drilled to fit the 4WD hub that we have. That has a better offset than the Cobra rotor, but not much better. Note the two pictures below. One is a Cobra rotor, the other is my two piece 1.25"x12.90" rotor. See that the gap between the tie rod and rotor is larger with the late model rotor. With the rotor outboard that much, there is far less room behind any wheel.

The caliper that was used with those is a Mustang type caliper, it has piston sizes that are smaller than our trucks. Brake power is gained with those rotors, and some is lost with the calipers. I did start to put 96 model Cobra rotors and calipers onto my truck. I decided that as hard as the bracket would be to make, the small improvement wasn't worth it. I believe that I sould help you to find those EE type brakes if you wanted them, but know that $1500 was what I read about them. The actual parts would be less than half of that.

If I do make what I have available, it would be under that, and I likely would make not much more than $100. Everywhere else will be about the profit. The Saleen parts can also be put together, but you will have to source separately the rotors($1000), calipers($800), brake lines, and brackets. An original XP8 owner in Sweden still had the brakes(recalled), so he reproduced the brackets in steel($150). Regards,

 

[CDW6212R]

The clearance above is close to the stock specs, the stock rotors are actually about .100" closer to the suspension parts. I created this offset to make the brackets easier to make. I used 1/2" steel plate, the brackets for the Cobra rotors were fairly simple. Those that I have for these rotors require more work, because of two 1/2" spacing ears that had to be welded on. These brackets mount to the backside of the spindle, instead of the frontside. The brackets have to be bolted on before the rotors are installed, using the stock bolts.

FYI, check out the 2001+ SportTrac or Sport brakes on my 99 Explorer. The extra inch of rotor was my first step last year, before starting on these custom parts. Regards,

 

[Jefe]

What pads are you running? That will make a noticable difference.

I am running chevy single piston calipers w/ 11" rotors up front, and stock sized brembo slotted rotors in back with Hawk HP SuperDuty pads front & rear and can lock up all 4 35's on dry asphalt. Granted you have to be serious about wanting to stop to do so, but I see no reason that the stock explorer setup can't do the same.

Your only real option is to learn to drive with the less responsive brakes and adjust your driving style to suit.

Yup, you're not driving a sports car, don't expect it to perform like one.

 

[r37ribution]

CDW6212R - this sounds really good so far, I am really interrested.

Jefe - I had Raybestos rotors (best you can get without going slotted) and bosch ceremic pads (I know not the best pads) and I couldn't get the ABS to kick in for the lift of me with my 31s on dry pavement. I'm sure 35s are gonna make my truck blow at stopping. I actually have ran in to two vehicles when I really should have had time to stop but the wheels just kept turning without the slightest hint of locking or ABS kicking in.

 

[Jefe]

I tried ceramic pads once and will never use them again. The supposed advantage of low dust and no noise was not true, and braking was crap.
How does the pedal feel? Something is obviously not right if you can slam on the brakes and not have ABS kick in.
Other than pads you may want to flush & bleed the system with some fresh fluid if it hasn't been done recently.

CDW, I'm not trying to distract from you're efforts. A big brake kit would be a great addition for long term braking. Upgraded pads can only do so much as I can still smoke pads on a downhill stretch if I'm not carefull. And if you can do it relatively inexpensive I'm sure many will be interested.

 

[r37ribution]

I have two explorers that brake the same way the '96 4.0L and the '97 5.0L in my sig. The '96 has 200k and the '97 has 127k. I dunno why it's like this, maybe Ford improved the master cylinder/brake booster in the 98+ models?

Can a brake booster wear out? I'll check for a vaccume leak to the booster.

 

[CDW6212R]

The over all condition of the brake fluid, pads, etc. can hurt brake power a lot. I had an 85 Lincoln Mark VII with hydraulic assist braking. The brake fluid and power steering fluid were both contaminated. I flushed both extensively after a brake job, and everything was much better.

My 18's with 72 pounds of weight are very hard to lock up. They will just barely, and I have quality EBC rotors and pads.

A big reason I've been serious about brakes is to lengthen the life of the brakes. Given any brake potential, a driver will only use the amount of pressure needed to stop the way he/she is accustomed to. I would rather only need to use 50% of the brake potential for most driving, never to need full pedal force. The brakes will last longer that way, and be less likely to make noise.

Brake life is very important for myself and my mail vehicle. There are Subaru right hand drive cars which can eat their stock brakes in six months to a year. Those are light cars, and tiny brakes. These 4500 pound trucks need better than 11" rotors. Regards,

 

[r37ribution]

Hey Don, you still workin on those brakes? I'm still very interrested!