|
A brake conversion article by Calvin Sanders Like everyone else, I decided the stock brakes on my 89 Mustang were not adequate for much more than casual street driving. I also did not have enough cash on hand to step out and buy the Ford Motorsports M2300K brake kit (currently running $1500-1800 for the kit). The M2300K kit is very worth the money in that there are quite a few parts that come with this kit. But that is also quite a bit of change. I decided to shop around and see what else I could come up with that would fill the bill. I wanted to have brakes on my car that were probably overkill for a CP autocross car. But I want to run the occasional track event with my car. So I looked into all sorts of options. I really thought the 94-98 Cobra front brakes (especially the front) fit the bill for what I wanted. I gathered up lots of information from the fordnatics e-mail list and archives (http://www.listquest.com/ search 5.0natics or 5.0racing or Fordnatics) and pretty well decided on the late model Cobra brakes. I first checked the junk yards and found no Cobras available locally. When I checked the national level junk yards I discovered the Cobra parts are basically considered gold. So.... What else could I consider. According to my research, all of the front spindles from 94-95 Mustangs were the same, so I could get spindles and hubs from any 94-95. I have a local junk yard that specializes in late model Fords. I am in pretty good with the owner of the junk yard and he let me go out and look, compare, and measure whatever I wanted. It was nice having 3 good rows of 79-current Mustangs to compare against each other. With this I looked and measured and discovered that in 96 the spindles were changed to accommodate the Modular engine. The only modification is the steering arm. For anything near stock location you will probably want 94-95 spindles. If you have heavily modified your K-member you may find the 96-98 spindles to be an advantage. Basically if you determine that you need to space the outer tie rod ends way, way down for bumpsteer correction, you may do better with the 96-98 spindles, othewise stay with the 94-95 spindles. I chose my spindles from a '95 six cylinder that was crunched in the rear and appeared to be very low mileage. I have heard people paying anywhere from $40 to $100 each for the spindles. From Ford the spindles are nearly $300 each, so guage accordingly. I got mine with the hub with bearings in fairly good shape. I did check buying new hubs with bearings (all together as one serviceable part) and they run about $45 each from most auto parts stores. While in the junk yard I realized that I really didn't like the rear brakes from anything but the Cobra in the SN95. The GT and V6 brakes just were not going to work for what I was looking for. So I looked for a Cobra setup, but again the price of these was prohibitive for what I was trying to do. I checked the local trading post and happened to find several listings of SVO Mustang or Lincon MkVII rear ends. These both have the same 5 bolt rear disc brake setup that could be adapted to my Mustang. I bought an entire rearend from an SVO Mustang. The SVO unfortunately has a 7.5" rear, but the axles, brake brackets, rotors, calipers, etc will easily bolt onto the 8.8 in my Mustang. The Lincon MkVII is exactly the same, except that it has ABS sensors, otherwise it is the same setup. The Lincon has an 8.8" rear end with a 3.27 gear typically, so this may provide an upgrade for some people. Most of the Lincons I have seen have an open diff. If you are considering the Lock-rite type locker then this is the case you need to convert, so the Lincon may be a good choice, I would have used one, but I got the SVO rear for almost nothing. I should note that the emergency brake must function and be used regularly with these brakes. The emergency brake cables for the SVO Mustang are fairly expensive from the parts suppliers, so if you get the e-brake cables with the rear end you will save yourself much time and money. At this point I put all of the rear brake parts on my car with the stock front brakes. I did the typical rebuild of the parts. The best thing to do with the rear calipers was to buy re-builts. The calipers can be rebuilt, but there are tricks to these calipers. If you rebuild them I suggest you read the shop manual because there are a few special things that just don't seem intuitive to me that I am not going to go into explaining. You have to adjust the calipers when you install them. This was easy, but not intuitive again. I suggest reading and following the shop manual again. The stock SVO/Lincon setup used 5 rubber brake hoses. While this is OK, I don't really like it. I would of course suggest getting Earls/Aeroquip brake hoses. With 5 flexible lines in the system (2 jump from the axle to the calipers, and one from the axle to the chassis, plus 2 fronts) this becomes a more important upgrade. I have seen some people run a hard line from the axle housing to the caliper. With a complete 360 degree loop in the hard line this will probably be just fine. Many people don't like doing this, but there are many race cars on any race track with this sort of setup. There is a little movement between the caliper and the housing, make sure there is enough "spring" in the hard line if you do this. It will also make brake pad changes much more of a pain. This installation is very straightforward since you have the existing setup as an example. You have to pull the diff cover and use the Lincon/MkVII axles, brake brackets, calipers, and rotors. The hard lines will not go directly from the SVO 7.5 onto the 8.8, but making new or bending the existing is easy. The important thing is to remember to get the mounts for the e-brake cables. Typically we think our "race" cars don't need e-brakes, but they, and their regular use, is part of the normal function of these brakes. Everyone said I would have problems with this setup and my stock front brakes, but they did work OK. Not the best, but still way better than stock for the Mustang. I would not have left them like this in the long run, but it was not unsafe in any way. Back to the front. First thing I did was go to my local Ford dealer. They gladly gave me a print out of the exploded parts diagram of the 95 Cobra front brakes. This is a helpful thing to have. Looking at the list I first priced all of the big parts. I called around for rebuilt calipers and also compared against new part prices. I found the best deal on calipers from PepBoys. I had to wait for a special order and when they arrived I got brand new calipers, not the rebuilts I had ordered. When I picked them up the person at the counter asked for the core and I said what I was doing and he said to just put my old 89 GT calipers in the box and return them for the core charge. On his advice I did exactly that. I spent the next couple of weeks comparing and collecting parts. I got the pads from Autozone. They carry the entire Performance Friction line of pads and warranty them for life. How can I go but so wrong with this deal. The caliper mounting brackets were only available from the Ford dealer for $47 each. I have been told that the Chevrolet dealers have the same bracket from the Corvettes, but I am sorta out of place in a Chevy dealership :-\. The caliper retaining pin is another hard to get part. I do not like the simple E-clip retaining pin for the stock Cobras. I searched for alternatives. Baer has an alternative I didn't like either. I must admit that any production part should be plenty safe, but the looks of the pins just didn't work for me. I made up some pins from some hardened AN close tolerance bolts I found in a surplus store. I forget the dimensions, but they can be made up. If you choose the pins, I found the Ford dealer to be the place to get the pins and clips. I also got the bolts that mount the caliper brackets from the Ford dealer, but they are just high grade metric bolts. Before installing I checked the fitting with my rims. I have simple Diamond steel 16" rims. I had ordered the offset of the rims for maximum brake clearance. They just hit the calipers. I determined I needed about .25" of spacer to make them clear the setup with the stock 13" rotors. I decided to install longer studs and use spacers. I had to pull the hubs and press out the studs and install new ones. The only studs available have a .625" knurl and are 3" long. I chose the Dorman HPX studs because of cost and availability. To install this I had to press out the old studs and drill the holes (in my drill press) with a 39/64" drill bit. This is .609", the specs for the ideal installation of the .625 knurl is .619". It is best to ream the holes the rest of the way with a reamer, but I and many others have just installed the studs in the drilled holes, but YMMV. I do this installation with a press, I don't like installing them by pulling them in with a nut. When I installed the spindles the ball joint taper is the same as the Fox Mustangs, but the taper is thinner on the SN95 spindles. You need a washer that is 5/16" thick. I think the hole diameter is 5/8"? but I don't remember exactly. Measure the threaded area of the ball joint. You can but the spacer from some of the Mustang parts places, or just stack a couple of thinner hardened washers. I recommend using a good washer for this. The mounting flange for the strut is lower on the SN95 spindle. If you have spaced up your camber plates more suspension travel after lowering your car, you will probably want to remove the spacers. Bolting the Cobra brakes on the SN95 hub is very straight forward. Simply bolt it all together. I was told that my brake lines would not bolt onto the Cobra calipers, but the Earle's lines I had made up for my Fox brakes bolted directly to the Cobra rotors. I had bought the banjo bolts and new copper washers from one of the auto parts stores. For the master cylinder I went through all of the options. I started to choose the 95 Cobra master cylinder. It was very available, but I chose the SVO/Lincon MkVII cylinder. I had used it before on another car and liked it. I used the brass line block from the SVO Mustang. I opened the end with the "proportioning valve" to the rear brakes and removed the spring and replaced the seal. It is hard to explain, but it makes the thing ineffective. Some people remove the entire piston, but you have to replace the plug on the end with a solid plug. The rubber in the plug bothers me and I would rather replace the plug with a solid one, but I could not find one at the time. When I opened this valve I found lots of "gunkey" stuff. So I pulled the whole thing apart and cleaned it. I think this will be true with any high mileage part. I also had to replace the hardline from the block to the left front brake. This was different than the line on my '89. On an earlier car I have, I did not have to replace this line. I just got the left front from a '79 or '80 Mustang in a junk yard and it worked fine. You could also make your own line for this, but the stock '89 had a different style flare on the master cylinder end. The 13" rotors are 1.125" thick. Their diameter may cause problems with some (most) 16" rims. Does that mean you can't use this system? No! The rotors are larger in diameter than you need. The machined surface continues in towards the hub quite a bit beyond the pads. This means the rotors can easily be machined down .5" to .75" with no problem. Or if you choose you can get fairly available 1.1" thick by 12.??" diameter racing brake rotors and hats made (Coleman has these available almost off the shelf). The caliper mounting bracket can be slotted easily .25" to .375" to move the caliper inward to match the smaller diameter rotors. This will give the "cool" factor with the real racing hats and rotors. When installed these things look awesome. It made my car the best braking Mustang I had ever driven. It is probably overkill for a CP car, but on the other hand it gives you the freedom of taking your CP car to the occasional track event for added fun. Below is my shopping list. It was from about May of 1999 so the prices may have adjusted themselves somewhat. The national chains were sometimes the best, and other times the local parts places were the best. If the part was not listed for that chain then they could not supply the part. These are just my notes
Brake stuff for SN95 or SVO Mustangs Advance Auto 94 GT Front calipers 45.99 +50 core 95 Cobra rotors 57.99 SVO rear calipers 59.99 +50 core SVO reart rotors 31.99 SVO Master Cylinder 44.95
AutoZone 686-4850 94 GT Front calipers 36.99 +50 core 94 GT rotors 33.99 95 Cobra PF Pads 69.95 SVO rear calipers 86.99 + 80 core SVO rotors 66.99 SVO Master Cylinder 49.95
Twin-B (A local auto parts chain) 94 GT Front calipers don't have 95 Cobra Calipers probably don't have 94 GT rotors don't have 95 Cobra rotors don't have SVO rear calipers 49.99 + 55 core SVO rotors 10.88 I couldn't believe the proce, but I bought them Dorman HPX studs 15.88 / set of 5 SVO Master Cylinder 38.95 Pep Boys 488-1979 94 GT Front calipers 60.84 +35 core with street pads 95 Cobra Calipers 49.86 +50 core 94 GT rotors 29.99 95 Cobra rotors 89.94 SVO rear calipers 47.95 + 18 core lifetime warranty SVO rotors 79.99 Raybestos SVO Master Cylinder 54.95 |