Wednesday, July 20, 2016

Front Coil Springs - selection, cutting, and installation

Coil springs, finally.

This isn't supposed to be hard, but I found a way to overcomplicate it anyway. My original intention was to remove the old front coil springs and put in new ones. There are many different springs available out there for the Mustang aftermarket, so many that it can get confusing pretty quick.

I'll warn you now, this one is a little long.

The old springs. I suspected all of this was original. 

Coil spring as it sits in the spring perch.

I've already posted on this when I pulled the springs out, and there's a lot of info on this on the interwebs already, so I'll just say be careful, as it's easily the scariest thing I've done yet on the car. 

When you go to order new springs for an old car like this, you need to know not just the year and model, but the engine, body style, and what accessories came on the car, such as A/C, power steering, or other heavy items, and which trim line it came with from the factory, such as the GT handling package. It matters because the springs carry the weight of the car and those things add significant weight, so they need to be accounted for in the springs to get the right height and spring rate. And that's only if you're trying to get exact replacements; if you want 'upgraded' springs, you have more work to do.

My car is supposed to have the competition handling package on it; as a rare option, it's harder to find replacements. I'm almost positive that it's the same package that goes on Shelby GT350's, and there's usually a substantial price premium for anything that says "Shelby" in the parts' application notes. Plus, I was worried that it might be stiffer than I wanted, so I decided a while ago the car was going to get GT springs all around, slightly softer than the competition handling package, but firmer than the standard factory springs. I've already put new GT leaf springs on (Eaton springs). I discussed this with John at Opentracker Racing and mentioned what I wanted, he suggested the GT springs from a big-block car to make it just a little firmer.

New GT (big block) springs on top, old springs on the bottom. The new springs are about 2" longer than the originals. 

The tell-tale yellow and pink paint daubs on the springs indicate the competition handling package.

I compressed the spring to put it in and found it was hard to get it compressed enough to fit easily. The spring pocket is about 11" high, and I struggled to get the spring down to 13"...too high still. I needed a spring that is about 2" shorter to fit in the pocket. I eventually had to disconnect the sway bar and the strut rod to get the upper control arm low enough just to fit the spring in. It has to have room to go in easy - no push/shove/rock-n-roll with a compressed spring. Eventually I got it in...

And it looked like this. Please notice the spring is actually bowing outward. This was uniquely scary,  as well as wrong, so I promptly pulled the spring back out again. I wonder if this is what working on a bomb squad feel like. I called up John at Opentracker again and told him my story, and he replied simply that , yes, you should expect to trim the tops a little for height - that's not surprising at all. So, now I know. Again, this is my first rodeo. 

So, how much should I cut off the spring to fit the car and still behave like it's supposed to? Turns out that's a hard question to answer simply.

Most folks I see cutting springs are talking about 1/3 or 1/2 coil, maybe 1 full coil, and they all say to do it in iterations - install, measure, remove, cut, repeat. No thanks - I want to minimize time with the coil spring compressor. I'm going to try to calculate an answer, cut it once, and get close enough for now. Needless to say, much research ensued. Please see the FAQ at Eaton springs. I used the same equation they list, and checked it several ways before committing to cutting.  

The springs have some fixed values like wire diameter and spring diameter, and some variables like number of springs and the height. I also spent a lot of time trying to figure out what factory spring rates were for original springs as a sanity test for my work. Then I wired up the spring equation in MS Excel and varied the number of coils (and thus the height) to see how much I needed to cut off the springs to get close to by desired spring rate (less than  the competition handling springs, close to GT rates). 

As it happens, cutting a spring raises its spring rate. Cut too much and you'll have a spring that's not only too short but too stiff as well. Both values change as a function of spring length, so I put in a range of values to see what would happen. I used the stock values, the rates I found for original competition handling springs, and some in-betweens.


At a glance, it looks like cutting one coil from my new coils will drop the height by 2 inches (which I want) and increase the rate from 284 lbs/in to 325 lbs/in (which I also want). It also shows that I'd have to cut these new coils down to 12.5" to match the old competition handling spring rates. Finally, I plotted the all these points as height versus rate to make sure no weirdness was afoot.

This also illustrates that when someone says they have "620" springs in their car, they're likely referring to the wire diameter, not the spring rate. I'd have to cut my big-block GT springs in half to get to a 620 lbs/in spring rate.

After all that, we're going to cut exactly one coil. Be patient, spring steel is harder than most. Be sure the cut end is as perpendicular as possible to properly seat against the spring seat tab.

And then one last time with the coil spring compressor. Sure enough, the trimmed springs go in a lot easier, and sit in the spring perch nicely. I won't know for sure until the car is pretty much fully assembled if I got it right or not. Let's pretend it's right.

And I never want to mess with them ever again.

Sunday, July 17, 2016

Rocker Panel undercoating

While spending all those hours (so...many...hours) under the floor of the car cutting and welding, I noticed that were some very distinct spots on the floor that were basically sandblasted from road debris and had quite a bit of surface rust on them. I decided I would do some preventive work on these areas after the floor had been primed.

Here's the rusty wear patterns under the passenger rocker panel. Dirt and rocks kicked up by the wheels would get spit up here and just ablate away the factory paint. The metal is still good, it's just beat up a bit.

Same view on the drivers side. The previous owner, if I heard correctly, lived on a dirt road, thus all the damage.

I chose the DupliColor Bed Liner in a can for this job. I shot a piece of scrap metal with three coats and then the Apprentice and I went out back and threw rocks at it for 'simulated' road rash. It doesn't build up a thick layer, just a few mils thick. The coating holds up well enough - it takes big rocks to hurt it, and it tends to peel a little instead of chipping off, so I think it'll work well in this application. I'll also use this later on the outer firewall an torque boxes for the same protection.

Masked off the rockers. I used the old rusty wear patterns as a guide for how much to mask.

And the finished product. It's hard to get a good shot of matte black on satin black, but here you can see the texture of the undercoating. I didn't shoot the fuel line that runs down the rocker because I like the look of shiny steel next to the rocker. (And I should've done this before installing the fuel line.)

Saturday, July 16, 2016

Brake Bits, pt. 2 - Parking Brake installation

The coil springs are here, but they aren't quite right, and need cutting or returning. I'm spending the weekend with a summer cold, and don't feel like I can do the writeup for the spring install justice. So, in the meantime, I'll finish off the remaining brake bits. Here's an easy one - installing the parking brake assembly.

The parking brake is a fairly simple affair - the parking brake cables are attached, one to each rear drum.  A ratcheting handle on the dash pulls a cable that pulls on the equalizer rod via a floor-mounted pivot point that pulls the brake cables. The equalizer rod is really the only part that provides any adjustability in setting up the system. Naturally, this is where I have all my problems.

New parking brake cables were installed when I rebuilt the rear drums. What I should've done at the same time was measure the length of the cables versus the old ones. I bet the new ones are about a half-inch shorter, based on what happens next.

Old parking brake cable handle assembly and piece-parts. All of these were reused.

Here's everything stripped, cleaned and repainted.

First step is to connect the brake cables to the mounting brackets on the rear frame rails.

Installed the handle assemble in the dash. The cable goes through the firewall inside a little section of rubber hose to keep the cable from abrading on the firewall hole, which would surely cause the cable to fail. So, rubber hose as safety gear. Why not?

My first attempt to get this all wired up was much harder than it should've been. Much pulling and grunting. I fully expected this to all work since all these parts, save the new cables, are original, but it was a struggle. 

 Once I finally got it hooked up, the rear wheels were firmly locked in place even though the dash handle was pushed in all the way. That's not good. The cable is adjusted out to the very end of the equalizer rod, so there was no more slack to be had. That equalizer rod is how you adjust the parking brake for proper operation once it's all installed. My best guess, as stated above, is that the new cables are shorter, and therefore I have no slack to work with. 

I found another equalizer rod in the NPD catalog listed as 'cut to fit', which means it should be longer - and it is by a good inch and a half. Perfect.

Once the new equalizer rod was installed, the cables went together with no problems. and adjusted in easy-peasy.  So now I have a way to keep car from rolling away once it's on the ground again.

Wednesday, July 13, 2016

Brake Bits pt. 1 - the distribution block

I changed my mind. The coil springs are still scary and so they'll have to wait. I have some brake parts to work on still.

The brakes are a pretty involved project, and there seems to always be one more thing to do. While I have all the front and rear brakes rebuilt and installed, there's still a lot left that's brake system related --- a parking brake to connect, brake lines to mount, a distribution block to rebuild, the master cylinder to bleed and and power booster to bolt to the firewall, the the brake pedal assembly goes in. Turns out there's a lot of parts in the brake system.

The distribution valve is a little brass block that serves two purposes - it splits the brake fluid coming from a single line out of the master cylinder into two separate lines for each front wheel, and it houses the Brake Warning Switch (which lights up an angry red BRAKE lamp when the brake system develops a hydraulic fault.) The valve has a tendency to seize up after time from old brake fluid, especially if it hasn't been driven in over 30 years like my car.

Here again, the factory service manual is super handy. There's a fantastic page on how this thing works and a cutaway drawing. I can't really describe how great the FSM is - I love this book. The descriptions of the systems, the old school cutaway illustrations, the exploded parts drawings, the tables full of torque values - I could go on. Even if you're not doing a full blown rebuild like me, this manual is easily worth its weight in Cobalt (look it up). 

67 mustang distribution block
Here's the distribution block as it came out of the car. It's a brass block, but the janky rattle can black paint job makes a mess of things. The brake warning switch is the plastic socket on top. The front brake line comes in at top right and is split out the right and bottom ports. The rear brake line simply passes in through the top left port and exits out the bottom. 

All blown apart. The little shuttle valve is what makes the warning switch work. Normal operation has balanced pressure between front and rear brakes. If a line opens up when the brakes are pressed, the shuttle will be pushed to the low pressure side and depress the plunger switch, lighting up the "you gonna crash" lamp on the dashboard.

The secret for getting it apart is a couple of specific tools. First, line wrenches to get the old brake lines off the block, and then a hemostat (medical locking scissors) to grab and pull the shuttle out. I had to push the shuttle in a bit with a punch to "unstuck it", then use the hemostat to pull it out. 

67 mustang distribution block rebuild kit
A rebuild kit is available for about $10. A replacement part is $70 and has different sizes of ports, so you'll very likely have to re-flare all your brake lines to get it to work. The rebuild kit has a copper crush washer and 3 o-rings. The '67 block only uses two of the o-rings (the square edge ones), whereas very late '67 to '69 I think) will also use the third o-ring.

Everything cleaned up on the bench grinder (brass wheel!) and ready for reassembly. Only use brake fluid for lubricating the o-rings and shuttle. The bore of the valve body is cleaned with a brass bottle brush and some brake cleaner.

 A rebuilt distribution valve. Shiny!

I wanted a quick and easy win, and after the pedal assembly turned out to be neither of those, this was fun and rewarding. It only took a couple hours to do this, and $10 in parts. What's not shown is all the messing around with the replacement valve and finding it won't work with my lines without a lot of work, shipping it back, trying to figure out how to get the shuttle out. and then driving around town looking for a hemostat (Communist Freight, naturally).

OK, seriously, I'm doing the coil spring cutting and install next. Really.

Sunday, July 10, 2016

Pedal Assembly restoration

While procrastinating about cutting my new front coil springs, I figured I could get some other sub-projects done just to keep moving. The brake & clutch pedal assembly needs some love, so I figured I'd get a quick one out of the way for an easy win. Probably should've chosen a different assembly if I was after quick and/or easy.

The pedal assembly contains the brake and, if you have one, clutch pedal mounted around their respective pivot points. Where it gets complicated is that the assembly has a lot of varieties it can come in to accommodate various vehicle options:

  • Pedal hanger bracket - different for manual or power brakes
  • Brake pedal - different depending on Auto or Standard transmission. The Standard transmission is further differentiated based on power or manual brakes.
All of this gets a little confusing, but I found a great site at Mustang Steve's that lays out all the options and pics to show the differences. I won't belabor the details here, let's just say that I found I have a brake pedal for a non-power brake car on a power brake hanger bracket. Others may want to verify what they have before, say, ordering parts (cough, cough).

A mug shot of the pedal assembly as it came out of the car. The hanger bracket was unpainted at the factory, as were the upper half of each pedal, so naturally they're covered in a nasty layer of surface rust after nearly 50 years. Well, we can't have that, can we?

The other mug shot view. Notice the clutch and brake pedals are on the same pivot (manual brake setup).

Here's a nice shot of the clutch return spring that tried to eat my face when we took it out of the car.

Time to take stuff apart! It's similar to a hand grenade - all you have to do is to pull that little pin...

...count to three and throw it across the room! (Not really, but it's quite easy to get apart). Parts laid out in order of installation for those who care.

The first nasty surprise - at the top of the rod, you can see it's got a notch worn away by from use when the stupid little bushings gave up. 

But first, let's indulge in a little OCD exercise - blasting the rusty parts clean at Ted's. These get repainted with Rustoleum Satin Black.

Since the JB-Weld fix worked so well on my power steering center link, I thought I'd give it a go here as well. A new clutch pedal is expensive. It took several layers of application and sanding it with a fine emery tape to get it smooth, but the finished product is smooooth. Eyes closed, you can't feel any hint of a worn spot. My only concern is longevity of the JB-Weld; I'll be using it as a load bearing surface every time the clutch is used. Anyone know the load bearing limit on JB-Weld?

Here's a nice comparison of the new power brake pedal that came in my CSRP brake kit (left) and my old brake pedal (right). The power brake pedal mounts in it's own hole at the top of the hanger bracket instead of sharing the same one as the clutch.

New plastic bushing and some grease. This is likely fine for the abuse the brake pedal gets.

I'm also going to take the liberty of upgrading the pivot for the clutch pedal while I'm here. Unlike the pivot on a power brake car, which sees much less force applied on average, the clutch pedal is working a mechanical, spring-loaded linkage and it needs more force each and every time it's used. 

The factory solution was the same little plastic bushings (shown above in the brake pedal) between the clutch pedal rod and the fixed pot metal "bearings" in the hanger bracket. This, of course, fails over time - the plastic bushings aren't up to the abuse, so they break or wear out, and then the clutch pivot rod starts grinding itself and the hanger bearing surface away into oblivion. It's not unusual to see oblong holes where the clutch mounts if it's been bad for a long time.

There's a couple fixes out there. Mustang Steve will sell or install a full roller bearing kit that requires welding, but is robust enough to make it a permanent fix. The other, cheaper, option is a "half-roller-bearing" kit from Scott Drake (via NPD and other part houses) that mounts a real roller bearing in the hanger bracket and uses the clutch pivot rod for the other half of the bearing. There's some heated debate on the interwebs about this, but in the end I went with the half-roller option - cheaper, less involved installation, and still "Better Than Before" ;)  I mention the Mustang Steve option because I have not heard of anyone that was unhappy with that kit.

"Half-roller" clutch bearing kit - the needle bearings are in the top piece. Install was easy on one side, and a bear on the other. 

Other (must have!) new parts - clutch return spring bushings and a clutch pedal stop pad. 

Blamo! Installation is the reverse of removal. Pedal Assembly is done and ready to go back in the car.

The work itself didn't take long here, total of about 6 hours (teardown, strip, paint, fix, replace, assemble). But it took much longer to figure out all the options, what parts I really had in my hand, and what I needed to replace, etc. These pedal assemblies are a little bit of a rabbit hole, especially if it's a mishmash of parts like mine was.

I have no idea what I'm working on next. Probably the coil springs. Yeah. Springs. That's the logical answer. I really need to figure those out so I can get this car off jack stands someday.

Bummer. I hate messing with coil springs.

Tuesday, July 5, 2016

Safety Wiring the caliper bolts

Just a quick post to show the "really" final step on the front brake installation. The original brakes came with a set of caliper bolts that had holes drilled in the heads to support safety wire. The replacement kit didn't have these, just regular bolts. I decided to keep my old bolts, clean them up and reuse them. I like the look of them and it gives the brakes that final authentic look.

Safety wire is used to secure bolts in place and keep them from backing out. Essentially, the wire puts the bolt head under a little constant tension by pulling the bolt head in the tightening direction. It's sort of like a mechanical version of thread-locker. It's used a lot in aviation on fasteners that are exposed to a lot of shock and vibration - and a failure would be more spectacular - but this is the first time I'd seen it on a regular road car.

Here's the old brakes before they came off. The safety wire is visible holding the two caliper bolts together, but was improperly installed and had a lot of slack, rendering it essentially useless.

The new brake CSRP kit came with regular bolts. The old safety wire-compatible versions fit just fine, so I can reuse the old ones.

I picked up a set of safety wire pliers and some wire from Communist Freight.  The pliers clamp the wire and lock in place, then you pull the handle on the back to spin the pliers in place, twisting the wire as it goes. I had to practice a little bit with them to remember how to do this, as I haven't actually used these since my "government yachting" days. It comes back pretty easy, and there's decent instructions for those who are new to it.

Oh, yeah, use gloves and goggles - that wire will slice flesh at the first opportunity.

Drivers side - the wire is started at the top bolt and wound so puts it under clockwise-tension, then around the bottom of the lower bolt so the wire can pull it in the clockwise direction as well. The extra could get cut off or, like here, wound around the long run. 

Passenger side - same thing. 

Now all that's left for the brakes is the installation of the hard lines.