Alright guys, here we go. Finally another long awaited and promised update.
***Disclaimer*** - This is gonna be a long one, so grab yourself your favourite beverage and get comfortable, lots to cover here.
So for those of you that follow along with this thread may remember, I've been concentrating on finalizing the installation of the ride height sensors for the air springs on the car.
This was supposed to be a quick "week or two" distraction and break from bodywork on the hood, but as with most things car related it morphed into a task all its own. Surprise surprise.
With the rear sensors installed and wired up, I wanted to get onto figuring out where and how to mount the front ones. However, while I was still finishing up at the rear, I decided it was a good time to re-visit another unfinished question mark, the emergency brake cables.
Much previous to my joining the forum, I had bought and installed a Lokar e-brake handle and boot to relocate the e-brake actuation onto the driveshaft tunnel, as I plan on incorporating the handle into the center console like almost every new car. The handle was mounted, and Lokar's matching stainless steel braided cable kit was bought and installed as well.
The path I initially chose for routing the cables looked good, but unfortunately I had too many bends in it and getting enough tension on the rear park brake drums to hold the car from rolling wasn't physically possible. Furthermore, while I had them hooked up to the brakes, I was undecided on how to final route the cables in a manner that wouldn't cause rubbing or interference issues when the suspension cycled.
"Do I go infront of or behind the #4 body mount bushings? Should I secure the cables to the frame, or just to the body? Route the cables along the inside of the frame, or outside? Above, below, or through the frame? Do I need slack in the cables for movement? If so, how much?"
These were some of the questions that I didn't have answers to... until now.
I was able to determine the best possible solution with the least amount of compromises. The cables were routed from the driveshaft tunnel to behind the body mount bushings. This keeps the cables in a straighter line and will reduce the amount of "yanking on the handle" force required to hold the car.
From behind the bushings, they run across the tops of the framerails and exit into view in the rear wheel openings. From there, it's a straight shot to the back of the brakes where they attach. That left only one thing I still wanted to do, secure them so as not to interfere or rub on the inside of the back tires. This meant mounting them to the frame.
This initially sounds like an easy task, just clamp the things to the frame and be done with it right?
However.
Keep in mind as the ride height changes every time I air the car up or down, it changes the relationship between the frame and the wheels. This means the cables have to move with the axel as well.
Air it up, the cables have to point down(ish). Air it down, the cables have to point up. You get the point.
At some point, the cables should have a "pivot point" where they can move freely as the suspension cycles, but after that point, they can safely stay stationary back to the handle.
With some assistance from my lovely female companion, I was able to locate the pivot points by holding the cable against the frame in a couple test spots and having her cycle the axel up and down through its travel with the floor jack.
My anal retentive tendencies wouldn't live with the thought of those purdy stainless cables rubbing through the powdercoat on the frame as the cables pivoted tho, so it was time to come up with an ingenious solution.
The cable clamps that I'm using throughout the rest of the car would be used, however I needed to come up with a way for the clamps themselves to rotate slightly as the axel travels.
I wanted to use the same stainless button head machine screws that I've used elsewhere through the clamps, but they had to have a shoulder on them.
Simple right? Drill and tap a hole in the frame at the pivot point, install and tighten the screw until the shoulder bottoms out on the frame, but before it tightens down on the clamp. Piece of cake. It lets the clamp pivot, but is still tight and secure.
Turns out, NOBODY makes a 10-24 stainless button head machine screw with a damn shoulder the length I needed! Weird right?
So I made my own. I took some scrap 1/4" stainless tubing, cut it to the length I needed, and drilled out the ID slightly to go over the screws. From there, I enlarged the hole in the back half of the clamp to accept the "shoulder".
To allow the clamp to pivot but keep the cables from rubbing the frame, I needed to make a "standoff" or spacer between the clamp and frame. More scrap stainless tubing was used here, in 3/8" diameter to help distribute the load and support the clamp. It simply slides over the screw behind the clamp like this:
Finding just the right length of spacer to use behind the clamps was a bit of a challenge. I started off with a 3/8" spacer, but it put the clamps too far out and the tires hit the clamps before they were even fully seated on the rotors. Many more little bits of tubing were cut and tried before I finally settled on 1/4" as the magic number. This placed the clamp and cables just far off of the frame to where they wouldn't rub, but still stayed a healthy distance away from the insides of the tires.
The next two pics are of the extremes of travel of the axel through its arc, and the relationship of the cable and clamp to it.
Axel at full droop (same as aired all the way up):
And up as far as it'll go. (Same as aired all the way down).
Kinda interesting to see the two pics side by side. As you can see, the clamp doesn't rotate very much, but it definitely does. I may have been able to get away with just fastening it firmly to the frame and not worrying about it pivoting, but I feel much better about this solution. At least this way the cables (and the clamps) will never get stressed this way.
This last shot shows the distance of the cable from the frame as taken from just above the axel looking forward. The e- brake mounting bracket at the drum is in the foreground, the clamp is just visible in the background.
The whole point of knocking this off the "question mark" list was that once I finished the front ride height sensor installs, I'd be able to set the e-brake and not worry about the car rolling around once I got to the self calibration programming portion on the AccuAir controller. Well, THAT didn't go exactly as planned...
I won't go into too much detail on that just yet, but suffice to say the driveshaft comes into contact with the exposed part of the e-brake handle below the driveshaft tunnel when the car is aired all the way down. It's that close!
D'oh!
Oh well. I know what'll need to be done there, but it ruled out being able to set the e-brake for the calibration process. The 'ol trusty 2x4 blocking the back tire will have to continue to suffice for now.
Onto the next. The stock height 3" poly bumpstops on the 12 bolt rearend were keeping the car from going as low as possible when aired out. I figured the best (and easiest) solution was just to "keep it simple, stupid", and cut them down.
Again, through a couple of trial and error tests, I found the optimum height of the stops to keep the axel from contacting the frame. All but a 1/4" of the bumpstops was cut off, this still provides a bit of cushion while not adding too much height loss (gain?) when aired down. A bit of a compromise, but an acceptable one for me.
Quick pic: the upper stop is the final height, the one below it had already had over an inch cut off of it.
The beauty of this is I still get to mount them in the proper location, and in the way they're intended to be. No sense in reinventing the wheel here.
Sorry, no pics of them installed, but I don't think I really need to show one anyways.
Continued >>>
