My Cobra Build Site

I’m finding it’s great to do this blog entries, it gives me a chance to look back and get a real sense of what I got done over the weekend. I was thinking I didn’t get a lot, but looking back now, it was a pretty big weekend.

I had hoped to get both the 3-link installed and the fuel tank up, but alas, just the 3-link is in now…but…THE 3 LINK is IN NOW! ;-> That’s pretty exciting.

I’m learning more and more that with each step of this project, there’s always a step 1, step 2, etc, and between each of those, there’s this whole other set of steps a-z required to get it done. In the case of the 3-link, it involved modifying the chassis, fabricating my own spacers from pipe, a couple of trips to the hardware store (10 miles away), and some creative use of an angle grinder, drill, and ratcheting tie downs.

3-Link Install (Retrofit – Frame Mods not FFR Installed)

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The kit can be ordered from FFR directly for $550 plus shipping ($40 for me, the bracket comes in a HUGE box. It’s important to note that they also send you a battery relocation kit, additional limiting straps, and new axle mounts. In my case, none of this was needed since I had them all with my new kit, and at least for me, the brackets were the same (not sure why, the kit was ordered with 4-link.)

There is a great set of instructions from HOZR on the 3 link installation here. There are some missing pieces to it due to some changes, but it’s way better than the FFR instructions, which are also outdated. This document doesn’t reference the steps required for retrofitting a car that was originally setup for 4-link, either on the road, or new from the factory (like mine).

The pictures I used most, which were awesome were found here.

Between those 2, if you’re looking for instructions on installing your 3-link, you should be pretty well covered. The following were missing or different with my configuration, and probably for others whose car is originally setup for a 4-link solid axle:

1) Upper Control Arm Mounts – If you’re thinking about ordering a 4-link with the prospect of maybe going 3 link later…save yourself some trouble and just go 3-link. This was probably the hardest part of the process, and also made me a little sad cutting up very nice welds and powercoating. You have to remove the upper control arm mounting bracket completely. The FFR instructions and other pics I’ve seen for the retro kit show the upper arm bracket for the 3 link as the old style, which just had the 2 bolts for the down-bracket. The new style weld in and retro bracket also attaches to the passenger side frame for additional lateral support. This means all of the 4-link bracket has to come out, and the welds ground down flat.

The main issue I faced was trying to get an angle grinder to the welds with a cut off wheel. My sawzall is an 18v rechargeable, but my metal blades weren’t sharp enough (too lazy to make another trip to the store). I ended up cutting the main parts out, then going back and cutting the smaller stuff out, then following again with the grinding wheel. Took me a couple of hours to get it all done and ready to go. I can’t imagine doing this while laying on the ground, and I was especially thankful for the lift.

I was originally going to take the DS one out too, but after all that, I’ll just use it for mounting position for brake and fuel lines, etc.

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2) Retrofit Bracket Installation – (this bracket is actually very well designed, and bolted up very easily, probably the easiest part of the whole prcess.) The instructions from the websites above are for cars that already have the main 3-link bracket installed, so they didn’t account for the installation of the 3 link bracket. This was actually pretty straight forward, but a couple of gotchas here as well:

a. Leave on the upper bolt locations (trunk area), it’s best to leave the front bolts out while you get the 4″ frame connection marked and drilled. This allows you to rotate the bracket against the 4″ tube, mark, then drill, then rotate back to bolt in. You can then easily put the other bolts in. The instructions say not to tighten these at that time, which I didn’t, but after it was all said and done, I didn’t really see why this was true, so either way could probably work.

b. I found it helpful to run a ratcheting strap around the 4″ tube bracket bolt location so I could force it into position to mark it. This allows you to get it into a position so you have easy access underneath for the nut, etc.

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3) Banana Bracket Brace Pumpkin Hole and Bolt – That sounds like a messed up Thanksgiving dish… ;-> This is a common issue, but the hole in the pumpkin (if provided by Ford) don’t always line up with the brace from the banana bracket. It’s very easy to solve, all you have to do is enlarge the hole. The supplied allen head bolt is also both wimpy, and too sort. I just replaced it with a longer and better bolt.

4) Upper Banana Bracket Brace – Not really an issue for me, but worth noting. This is somewhat of a debated topic, both whether you must weld the banana bracket into the axle tube and/or add an upper brace to keep the bracket from slipping. For relatively low HP cars like mine, the brace and sandwich force should prove sufficient, but you can either fabricate a brace, or buy a nice heim-jointed one from VPM. It connects from the pumpkin ears to the banana bracket where the upper link connects (via a longer bolt.) It’s $115 though. The prototype for this was made from steel stock, however, so it might be possible to do that cheaper. I’m considering this still and talking to my buddy Mike about it since he’s had the 3 link on his car for 5 years now.

5) Shock Spacers – There are spacers used for the panhard bar and upper link that are included. My shocks (coil overs) also needed spacers (all do), but they didn’t come with them. So, I made my own. I went down to the hardware store and picked up a 12″ piece of 1/2″ steel pipe, and measured and cut it to size. I also beveled the ends where they connected to the heim joints to prevent binding. I made 8 of them for $3, so can’t beat that.

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6) Limiting Strap – it seems that depending on your shock choice, these may or may not be needed. In my case, on the driver’s side, when the shocks were at full extension, the axle was actually resting on the 3-link bracket. Not a huge deal when your slowly lowering it on a lift, but a pretty big one if you happen to get airborne and it slams into it at full force. Unlikely, but since I had the strap, an easy solution. I used the upper shock mount bolt, then I used the original 4-link bracket itself as mounting points. I lifted the axle to the position I wanted (about 1/4″ of clearance so I could maximize suspension travel) with the ratcheting strap, and drilled and bolted it in. The space between the bracket and axle tube was too small, so I bent it out a bit, just enough for a nut. Then, I cut a bolt short to fit perfectly, and it all went in great.

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Other than that, between the FFR manual, HOZR’s pdf, and the items above, the 3-link is pretty straight forward.

Final Product:

Again, all of the pics are here:

3 Link Install Pics

Brake Reservoir Mounting Bracket

I decided I simply didn’t like having my brake fluid reservoirs on the firewall. They just didn’t look right there, and I was worried they’d ultimately be in the way. So, after looking around, it seemed the next best location was right in front of the driver’s foot box. So, a very easy mod, measure and bend a piece of strong aluminum, drill a couple of holes in the 3/4″ tube, and there you go (of course, wait for the paint to dry too!)

I made mine so I can unbolt the assembly if I need to, even with the body on, and just used some screws and nuts to hold it in place. It’ll work fine, and I like how the tubes from the master cylinder to the reservoirs are short and easy to route.

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Air Compressor Sound Abatement Enclosure – Final Addition

It occurred to me that in order to easily check and change the oil, and to clean the air filters on the air compressor, it would be way easier to have a trap door on the upper front panel. So, I took the panel off, took the jigsaw to it, added an old frilly draw pull and a couple of hinges, and there you go, instant trap door. So, the enclosure is officially completed now.

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This is Thanksgiving week, and other than t-day itself, I’ll be here at the house by myself with the mutts, so I’m looking forward to continuing the build. Next on the list will be putting the rear brakes on, getting the fuel tank assembled and installed, and then running the rear brake lines and fuel lines. I’d love to have this all done this week. We’ll see how it goes. Mike Forte is supposed to be sending the rest of the engine parts, so before you know it, the engine will also be in!

Another pretty productive weekend with lots of different activities. It’s hard to concentrate on one particular area of the car as there’s always one thing that needs to be done while you work on other stuff.

Most of the waiting time is for paint-related items. Lots of spray paint flying around the shop right now as I paint all of the aluminum panels for the engine bay, the rear end parts we’ve been working on, and the brake booster setup.

More detailed info:

Rear End:

I made the decision that for autocross (which I’ll be doing in this car), the 4-link suspension setup was going to be wholly inadequate. That means I need to upgrade it to a 3-link setup, which uses the original 4-link as the base. Fortunately, FFR sells a retrofit kit that includes the panhard bar, cross members, braces, and all necessary hardware. All in all, the upgrade is reasonable at $550. Considering the 5-link is $1700, this isn’t a bad option. This is going to be my birthday present this year (and probably most of Christmas!

Since the original 4-link was going in, the lower control arms are designed for it, and have brackets and perches we don’t need. We decided to be both anal and brave at the same time, and we broke out the grinder and get rid of the extra stuff. Michelle made quick work of it as a start, and I finished up the first one. We also cut off the quad-shock mounts from the axle housing and drilled holes for dv/dt’s possible bracing mode using the upper ‘ears’ on the axle.

Unfortunately, I also finished up my cheap grinder. A combination of using the wrong wheel, and not cooling it adequately…I let out the magic smoke.

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Driver’s Side Footbox, Brake Booster, Pedal Box, Engine Bay Aluminum:

This is a multiple-personality set of projects. I’m putting the footbox together, putting the master cylinder and brake booster together, and putting the pedal box together as well.

Everything has to be painted before going in. I’m using Hammertone on the panels, and although it looks nice, I’m not that happy with how it all goes on. It does not touch up well as it more or less has engineer “orange peel” so you get high and low spots as you try to touch it up.

Other parts like the brake booster and pedal box are getting just a metallic aluminum paint, and I like it much better.

Brakes:

I decided after driving Mike’s non-powered brake car, I definitely wanted to go with the boosted system. Whitby Motors puts all of the necessary parts together for you, and the kit is top notch. Since you have to cut the frame to make room for the big booster (the car is designed for manual brakes), they even include a well-designed frame brace to make it possible. If you want power brakes, this is the way to go.

You do have to make room in the footbox metal to get the booster’s boot and push rod assembly through. This was a bit of a challenge for me, and I ended up kind of hacking it up a bit, using my sawzall. If I had it to do over again, I would have bolted in a piece of wood or metal as a backing, and simply used a large holesaw instead. You need the backing so you have something to guide the holesaw.

You also need to move the steering shaft bracket to the inside of the firewall. Despite the spacers, the booster will still hit. This is a very easy movement though, so not a big deal.

A bit of bad news, as I assembled the pieces, I discovered the booster is broken. The good news is as I was doing this entry, Jeff got back to me. I’m shipping him the booster and he’s replacing it. He’s a good guy!

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Bench Bleeding – since I hadn’t done this before, I had to look it up. A lot of guys say it’s more trouble than it’s worth, but after doing it, I can see the value. This includes filling the reservoirs, hooking up the tubing, and then actuating the push rod piston manually until you get all of the air out (AIR IN YOUR BRAKES = BAD.) The basic procedure is to clamp the master cylinder in a vise, get it totally level so the bubbles will come out, and then push the piston in and out until it gets the air out (this primes the system). This is easier said than done. I ended up removing the plugs one at a time, and mounting the resevoirs to a board high above the bench. I used 2 3/8″ socket extensions to push the piston in. You’ll start with more than 1″ of travel, and eventually when it’s primed, you’ll get less than 1/8″. It took me maybe 100 strokes to get it there. Much better than doing it with the pedal and pushing air through the whole system.

Engine Bay Aluminum – This was a pain. The guy I bought it from was not going to paint his stuff, so the f-panels and firewall have all already been sealed and riveted into position. I’m doing all hammertone as mentioned already, so in order to paint what’s there, I could either drill out and remove the panels, or tape and mask around them. The 2nd was the lessor of 2 evils, but it took forever, and was a pain. The good news is that the frame (powered coated) cleans up easily with goof off (lots of over spray, despite my efforts).

If you want to see what white engine bay panels look like, see the in progress pics, the primer I’m using is white.

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Pedal Box and Pedals – I put in Russ Thompson’s go-pedal and brake and clutch pedal covers, which required a lot of cutting of the stock mustang pedals, but it came out nice. The throttle pedal is aluminum, so you have 2 options for paint (if you want them to match), either paint that one black, or paint the other 2 aluminum. I chose the latter. I’m not sure if I’ll keep it that way, it might be too much contrast on the back carpet, but I’ll give it a dry. It’s easy to brush on the black latter.

The main issue I’m facing now is my size 11 feet. The pedals are pretty close together like a race car, which isn’t a big deal, but the gas pedal is only about 1″ from the side wall panel. Greg M did a nice bump out to give him more room, and I’m waiting on measurements to do the same thing. Hopefully, that’ll give me the room I need.

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Next Up:

I’ll wait for the new booster to show up, and work on the bump out on the DS box. I’m also going to mount the steering shaft in place so the booster will go in and stay there. I also need to figure out where to mount the reservoirs (probably on the firewall) and get the hole drilled out for the heater (actually need to modify the one that’s I did already for the ffr heater…I switched to a summit one instead.) So…big fun and continuing on…