UMI Performance 78-88 GM G-Body Non-Adjustable Tubular Rear Control Arm Kit - Black

Non-Adjustable Tubular Rear Four-Link Control Arms for the 1978-1988 GM G-Body, in Black

These are rear axle arms, not front A-arms. UMI's official name for the part is Rear Control Arm Kit, Non-Adjustable, and the four pieces in the box replace the G-Body's factory stamped rear four-link: two long lower arms from the chassis to the axle housing, and two shorter uppers.

The design goal here is quiet. Every mounting point uses a greaseable fluted polyurethane bushing with a Zerk fitting instead of a rod end, so the kit kills the wheel hop and the deflection that come from forty year old rubber without adding the metallic chatter a spherical joint transmits into the floor pan. It bolts in with the factory hardware and needs no drilling.

Key Features

• Full set of four rear control arms, uppers and lowers, in one kit.
• DOM mild steel tube throughout: 1.500 inch lower arms and 1.625 inch upper arms, both 0.120 inch wall.
• Fully TIG and MIG welded with CNC machined ends.
• On-car greaseable fluted polyurethane bushings with Zerk fittings at every mounting point.
• Bushings and sleeves arrive pressed into the arms, so nothing has to be assembled on the bench.
• Reinforced sway bar holes in the lower arms, which UMI states accept OEM and aftermarket rear bars.
• Bolt-in using the factory rear control arm hardware, with no drilling.
• Grease pack supplied so the bushings can be coated at assembly.
• Gloss black powder coat.

Fitment

UMI publishes this kit for the 1978-1988 GM G-Body. UMI publishes year, make and model only for this part number and lists no submodel or trim breakdown, so the fitment tags on this listing stop at model rather than inventing a trim.

One documented inconsistency in UMI's own data: this product page lists the Oldsmobile Cutlass as 1981-1988, while UMI's 3011, 3028, 3034 and 3035 pages list the same platform as 1978-1988 and nothing in the engineering description changes by Cutlass model year. This listing publishes the 1978-1988 G-Body range that four other UMI pages agree on, and the conservative buyer-facing statement remains to confirm the year on a Cutlass build before ordering.

One shared-document caution: the cover of UMI's 3016 upper arm installation sheet also names the 1973-1977 GM A-Body, because the same upper arm is used on that platform. The 301516 kit itself is sold and listed by UMI as G-Body only, so no A-Body vehicles are tagged on this listing.

Specifications

What's Included

• Two non-adjustable tubular rear lower control arms, part 3015, with polyurethane bushings and sleeves already pressed in
• Two non-adjustable tubular rear upper control arms, part 3016, with polyurethane bushings and sleeves already pressed in
• One installation instruction sheet and one grease pack with the lower arms
• One installation instruction sheet with the upper arms, plus the grease packet its procedure calls for
• All four arms finished in black powder coat

Mounting bolts are not included: UMI publishes hardware as not included for this kit and the factory rear control arm bolts are reused. The grease packet is genuinely in the box for this kit, which is a difference from UMI's adjustable 301417 kit, where no grease pack is documented.

About UMI Performance

UMI Performance builds chassis and suspension parts at 509 Hemlock Street in Philipsburg, Pennsylvania, using North American raw material from USA steel suppliers, machine-guided precision DOM tube bending, laser-cut plating and welds laid by skilled and robotic welders. Its G-Body rear four-link is sold in two forms, and this is the street-first one: no rod ends, no threaded adjusters, greaseable polyurethane at every joint, and reinforced sway bar mounting holes in the lower arms.

Related Parts

• UMI 3028-B rear control arm reinforcement braces for 1978-1988 GM G-Body
• UMI 301417-R adjustable rear control arm kit for 1978-1988 GM G-Body
• UMI 3008 Super Lube synthetic grease for the greaseable polyurethane bushings

FAQ

Rear. UMI names the part Rear Control Arm Kit, Non-Adjustable. The four arms are the G-Body's rear four-link between the chassis and the axle housing, and none of them is a front A-arm.

This one has no adjustment. It is built from UMI's 3015 lower arms and 3016 upper arms, uses greaseable polyurethane at every mounting point and comes with a grease pack. The 301417 kit uses the 3014 and 3017 arms, adds QA1 rod ends and a solid chrome moly upper adjuster so pinion angle can be set on the car, and does not include a grease pack. Choose this kit for a quiet street car and the adjustable kit if you need to dial pinion angle.

Yes. UMI puts reinforced sway bar holes in the lower arms and states they work with OEM and aftermarket sway bars. The bar has to be unbolted from the lower arms during the installation and refitted afterwards.

It reuses the factory hardware. UMI publishes mounting hardware as not included for this kit, and the installation sheet works with the original 18 mm control arm fasteners. If those bolts are rusted, bent or previously over-torqued, replace them with correct-grade equivalents before installation.

UMI publishes 72 ft-lb on both the lower and the upper control arm bolts, and specifies that they are torqued with the weight of the vehicle on the rear axle. Torquing at full droop twists the polyurethane bushings into a preloaded position and is the mistake to avoid here.

UMI's sheets call for 1 to 1.5 pumps per fitting on the lower arms and 2 to 3 pumps per fitting on the uppers. Before assembly, coat the outer surfaces of every bushing heavily with the supplied Energy Suspension grease. Point the lower arm zerks toward the ground and the upper arm zerks up toward the floor board so a grease gun can reach them later.

They transmit more road texture than worn rubber does, which is the point, since that deflection is what lets the axle move under power. Squeak is almost always a lubrication problem rather than a material problem: use the supplied grease at assembly, keep the fittings serviced, and the greaseable fluted design is specifically there to stop the noise.

No. There are no adjusters, and the arms are fixed at the factory length, which returns pinion angle to stock geometry. If your car has been lowered heavily, has an aftermarket housing, or you want to tune pinion angle for launch, the adjustable 301417 kit is the correct choice.

No, and UMI's kit page can mislead here. The single 1.625 inch figure on that page is the upper arm tube. The lower arms are 1.500 inch outside diameter. Both are 0.120 inch wall DOM mild steel.

Yes. The B and R suffixes are powder coat colours only. Tube sizes, welding, machining, bushings and included grease pack are identical.

UMI publishes this kit for the factory G-Body rear suspension, so the arm lengths and mount spacing are written to the stock housing. If the car has a swapped housing, measure the control arm mount spacing against stock before ordering, because a non-factory housing can change both arm length and bracket width.

UMI publishes a two year warranty from the original date of purchase against defects in materials and workmanship, to the original purchaser only, and it is not transferable. The same policy excludes misuse, exceeding the design limits of the product, improper installation, altered product, non-UMI components, incidental costs such as towing and labour, and normal wear items including bearings and bushings. UMI also states it cannot guarantee compatibility with other manufacturers' components. Note that the printed sheet in the box still carries an older, narrower disclaimer that predates the current two year term. The policy page is the current document. Neither is a Black Ops Auto Works warranty.

Installation Instructions

1. Raise the rear of the car, support it safely, and disconnect the rear sway bar from the lower control arms.
2. Replace one arm at a time, one side at a time, so the axle housing never loses its location. The factory control arm fasteners are 18 mm.
3. Before fitting each arm, apply a heavy coat of the supplied Energy Suspension grease to the outer surfaces of its polyurethane bushings.
4. Install the lower arms with the grease fittings pointing toward the ground.
5. Install the upper arms with the grease fittings pointing up toward the floor board.
6. Refit the rear sway bar to the reinforced holes in the lower arms.
7. Lower the car so the weight of the vehicle is on the rear axle before final tightening.
8. Torque the lower control arm bolts to UMI's published 72 ft-lb, and the upper control arm bolts to the same 72 ft-lb.
9. Grease each fitting: 1 to 1.5 pumps on the lower arms and 2 to 3 pumps on the uppers.
10. Recheck the fastener torque after the first drive and re-grease on a regular service interval.

The 72 ft-lb figure is UMI's own published value for these arms. Any fastener outside UMI's sheets, including sway bar and shock hardware, should be torqued to the General Motors factory service value for your year and model.