- Direct bolt in for GM Metric G-body race car chassis
- IMCA approved for Stock Car classes and other sanctioning bodies that allow multiple hole mounts for trailing arms
- Machined full floating axle housing design with fully welded 3-inch axle tubes
- Pre-fitted upper and lower control arm mounts
- Fully machined 2.5-inch axle tube ends for fitting Grand National hubs
- Axle housing features centered pinion design for maximum driveshaft clearance
- Available in 58 and 60 inch wheel flange to wheel flange measurements
- Housing includes oversized fill and drain plugs for easy fluid changes
- NPT threaded axle vent located on main housing, vent fitting included
Upgrade To a Full Floater Rear End for Increased Strength and Safety
The full floating rear axle has been around for decades. Primarily designed for heavy duty truck use, it was found to be a great solution for circle track racing and has been a race-spec axle housing used in all levels of circle track racing ever since. Today you’ll find high horsepower street cars that see extreme cornering g-forces (auto crossing, road racing, etc.) using full floater rear end setups as well. So why the change to a full floating axle from the more conventional semi-floating axle found under just about every rear drive production car made in the last century? It’s easy really when you compare the differences between full floating vs semi floating axle assemblies.
In a semi-floating axle, such as the popular GM 10 and 12 bolt rears, or Ford’s 7.5- and 8.8-inch rear ends, the axle assembly is retained by a C-clip at the differential end and rides on a single bearing seated in the end of the axle tube. The full weight of the vehicle rides on this single small bearing while the differential end of the axle shaft floats in the differential or spool, hence the “semi” floating term. This rearend design puts a lot of stress on the axle bearings and seals and it is not uncommon to bend axle flanges in hard cornering or chew up a bearing (which ruins the axle). Additionally, if the C-clip should fail from side loading, or the axle break from excessive torque, the broken axle with wheel and tire assembly can exit the axle housing causing extensive damage and loss of control of the vehicle. While a bolt-in axle like the popular Ford 9-inch is an improvement, axle flange stress can still lead to bending or breaking right at the bearing in hard cornering.
Meanwhile, the full floating axle uses a hub that rides on a pair of large bearings on the end of the axle tube itself (similar to your front disc brake rotor and spindle). This allows the full weight of the vehicle, as well as all acceleration, braking, and cornering forces to move through the axle housing itself. Due to the dual bearing hub on the end of the axle housing the axle itself "floats" between the differential or spool and a splined drive plate that mounts between the hub and the wheel (engaged via the wheel studs), thus the “full floater rear end.” If an axle should break in a full floating rear axle there is zero chance of losing a wheel and tire assembly. Furthermore, due to the fixed hub location disc brake pad knock back (a common issue on semi-floating axles where hard cornering pushes the caliper pistons into the caliper) is eliminated. This provides constant and firm brake pedal application no matter the cornering forces. Hit our Toolbox article onfull floater rear axlesfor more details.
Strength and Precision That Can Handle the Track or The Street
Standard production car rear axles are assembled with thin wall press in axle tubes that often use nothing more than a couple of plug welds to secure. This allows the axle tubes to flex at the union with the main housing, causing axle stress, rear alignment changes, and fluid leaks. Sure, these areas can be welded, but you’re still left with those C-clips and the unsure feeling of what will happen if you ever break an axle. Our full floating rearend housing is a precision made fixture welded piece using all new 3-inch axle tubes made from .188-inch thick wall steel. The thick wall steel construction includes the center section, which has a fully welded and machined mounting surface for the third member, virtually eliminating any potential leaks at the housing to third member union. No ancient used center with just new axle tubes welded in here. The larger center section allows additional oil capacity for increased cooling (we recommend filling withfour quarts ofgear oil). Oversized fill and drain plugs allow quick fluid changes or draining for differential/gear swaps.
Speaking of gear swaps, we know that you have at least a few 9-inch3rd membersfor various track conditions or track layouts/lengths and utilizing a full floater axle housing makes these gear changes effortless. Simply unbolt the drive plate cap, screw a 3/8-24 bolt into the end of the axle (or use our niftyaxle pulling tool) and pull the axles out to clear the differential or spool and then swap to your needed gear ratio. No longer do you have to pull wheels, brakes, and more to slide out a traditional axle assembly to clear the differential or spool for pulling your third member for a gear swap. Axle lengths are measured from hub to hub and are available in 58- and 60-inch widths with a centered pinion location. The 58-inch housing uses one 27-1/2-inch axle and one 31-1/2-inch axle, while the 60-inch housing uses one 28-1/2-inch axle and one 32-1/2-inch axle.
Pre-Installed GM Metric Control Arm Mounts
We make installation into your G-body stock car or other GM Metric chassis setup with our welded upper and lower control arm mounting points already in place and ready to go. The upper mounts are reinforced with welded tabs and feature preinstalled bushings. The adjustable lower control arm brackets have holes located 1-3/4, 2-1/2, 3-1/2, 4-1/4, and 5-1/4 inches from bottom of the axle tube to the center of the hole.Simply add your choice ofregularorlight weightspring perches and you’re ready to build your new full floating axlehousing. These axle tubes feature a standard 2.625-inch ID, allowing optionalinner axle housing sealsto be installed for better oil control if desired.These GM Metric floater housings use standard Grand National-style hubs and bearings, allowing quick assembly with our GN hub kits.
We do offer our Stock Car-spec floater housing in a complete rear axle kit that includes axles, hubs, bearings, brake rotors, and welded caliper mounts. However, we know that some racers wish to build their own floater assemblies with a specific set of parts or will use this housing as a service part to swap their existing hardware over to. In these instances, you’ll need to add a set of weld-on or bolt-on brake caliper mounts to use with 11.75-inch brake rotors and 5-1/2-inch mount spacing calipers, such as the popular IMCA-approvedGM Metric caliper.
