Subframes – Part Four

 

Subframe leadOver the past several issues of “The Burnout”, we’ve been assembling a basic Camaro (Nova) subframe for drag duty.  In those segments, we started with a stripped subframe, detailed and powder coated it, installed the solid subframe bushings from Classic Industries and installed the TRZ Motorsports suspension and Classic Industries steering parts.  In each of those segments, there was a common thread:  The parts were bolt-ons (no fabrication necessary). If you go back and review the articles, you’ll also find there was one other commonality:  We used very high quality components that anyone can mail order.  That means everything was accessible (no “unobtainium” stuff here).  We’re going to continue with that premise in this final segment — high quality, readily available parts and no fabrication necessary during the install.  In this issue, we’ll look at installing Baer’s Deep Stage Brake kit (covered in detail earlier in “The Burnout”). Check it out:

The first step in the brake install is to mount the base caliper brackets to the OEM spindle. These pieces are marked with regard to the side of the car they’re installed.  Baer supplies a ½-20X3.0-inch and a ½-20X2.75-inch bolt and lock nut set for each side of the car.  The longer bolt is inserted through the spindle into the steering arm closest ot the tie rod.  Next, the fasteners are torqued to 85-foot-pounds.

The second step involves the installation of the brake hubs. These come pre-packed with synthetic grease. There’s no need to add more grease (bonus as far as we’re concerned).  Simply add some grease to the seal surfaces and install.  The spindle nut should be tightened to approximately 5-10 foot-pounds.  Next, spin the hub to seat the bearings.  Loosen the nut and then re-tighten to remove all play.  Tighten it approximately 1/16th of a turn (or slightly more) to align the cotter pin holes.  This provides a small amount of preload on the bearing.  Baer includes a new spindle nut and cotter key in their brake package. Install then dust cap (which is sealed by way of an O-ring and simply taps on by way of hand or a rubber mallet).

Next up, the intermediate caliper bracket is installed with a pair of supplied 9/16X1.5-inch bolts and washers.  They mount to the base caliper bracket.  There’s a part number engraved on the bracket. It faces outward.  Don’t tighten the fasteners yet!

Install the rotor (they’re marked left and right) and secure it with a couple of lug nuts.  Remove the pads from the calipers and install.  What’s up with that?  Simple. You’ll need to shim the calipers.  The reason for this is to ensure the caliper sits square to the rotor.  This compensates for the wide tolerances found in the OEM spindles due to production line machining processes.

Baer supplies a complete set of marked shims with the brake kit.  What you have to do is measure the gap from the rotor to the caliper body at four separate points – top inside, top outside, bottom inside, bottom outside.  When you arrive at the dimensions, then it’s a matter of determining how much shim is required, and where to place it.  For example, if the top inside measurement is 0.865-inch and the top outside measurement is 0.905-inch, then there is a difference of 0.040-inch. You need to divide that by two and place the shim between the caliper mount and the intermediate bracket.  Pretend the measurement numbers are reversed:  0.905-inch inside and 0.865-inch outside.  Then you’ll need to shim the intermediate bracket outward by placing an 0.020-inch shim between the intermediate caliper bracket and the base bracket.  Sounds a bit complicated, but in practice, it’s very simple.

By the way, we arrived at out dimensions using a common dial caliper. If you don’t have one in your toolbox, Baer suggests you install the brake pads and use a feeler gauge between the rotor and the pad.  Take measurements from the top inside and top outside along with bottom inside and bottom outside.  Baer points out there is 0.010-inch minimum clearance between the pad and the rotor, but you should aim for gaps as close to equal on all four measuring points.

With the shimming process complete, torque the 9/16X1.50-inch bolts to 100 foot-pounds of torque.  Torque the caliper to bracket bolts to 75 foot-pounds.  Aside from plumbing (which weren’t not doing here), you’re done!

That put a wrap on our basic “Drag Duty” subframe build.  As you can see, it’s entirely possible to build a high quality front end for your early Camaro or Nova with bolt-on parts.  So what have we accomplished?  First of all, each and every steering component is brand spanking new.  You don’t have to concern yourself with 40+ year old components, plus it’s now very easy to adjust toe.  The subframe is locked in place via solid body mounts.  The control arm package allows for much more positive caster, which means the car will track far better than stock at speed. The suspension doesn’t bind due to the use of Delrin bushings (downstairs) and rod ends (upstairs).  It’s lighter overall and chrome moly tubing construction offers considerable strength benefits in comparison to the stock hardware.  The brakes are designed specifically for cars such as this (relatively heavy).  The brake package is as large as possible and it still fits within the confines of a narrow 15-inch wheel, plus they’re extremely capable of hauling the car down from warp speed.  So far so good. And down the road, we’ll show you the shock absorbers we picked.  They’re actually matched to the rear suspension and we’ll show you the complete package in another issue.  Meanwhile, check out the accompanying photos.  The bottom line here is, it’s really not that difficult to set up a super high quality drag duty subframe in the your own home shop.

Subframes Part I

Subframes Part II

Subframes Part III

The first step in the brake setup is the base bracket install.  Baer provides Grade 8 fasteners for the job.
The first step in the brake setup is the base bracket install. Baer provides Grade 8 fasteners for the job.
Once the fasteners are torqued to spec (see the text), you can install the hub.  As you can see, this setup includes long ½-inch ARP wheel studs.
Once the fasteners are torqued to spec (see the text), you can install the hub. As you can see, this setup includes long ½-inch ARP wheel studs.
Baer pre-packs the wheel bearings, so it's a simple matter to seat the bearing setup and tighten to specs.
Baer pre-packs the wheel bearings, so it’s a simple matter to seat the bearing setup and tighten to specs.
The intermediate bracket goes on next.  It's marked for orientation.  Don't tighten it yet.  You'll need to shim the caliper.
The intermediate bracket goes on next. It’s marked for orientation. Don’t tighten it yet. You’ll need to shim the caliper.
The rotor is installed and the caliper can be shimmed so that's square to the rotor (see the text for full details).  Sounds difficult, but it's actually very easy.
The rotor is installed and the caliper can be shimmed so that’s square to the rotor (see the text for full details). Sounds difficult, but it’s actually very easy.

Subframe27

Here's the finished "Drag Duty" subframe.  As you can see, we've come a long way from the grimy, crusty mess we started with (refer back to the first segment for a refresher!).  Best of all, anyone can copy this in the confines of their own garage.
Here’s the finished “Drag Duty” subframe. As you can see, we’ve come a long way from the grimy, crusty mess we started with (refer back to the first segment for a refresher!). Best of all, anyone can copy this in the confines of their own garage.
  • Pay Attention

    Great series but you should post a link on this page to the other 3 parts of this series. Not make people go back and search for those. Ease of maneuverability on websites these days is everything.

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