UMI Performance 1978-1996 GM B-Body Adjustable Extended Length Rear Lower Control Arms, Black

Adjustable Extended Length Rear Lower Control Arms for the 1978-1996 GM B-Body

These are the pair of rear lower control arms that replace the stamped factory arms on a 1978-1996 GM B-Body, including the 1994-1996 Chevrolet Impala SS, the 1978-1996 Chevrolet Caprice and the 1991-1996 Buick Roadmaster. They arrive 5/8 inch longer than stock with a further 1/4 inch of adjustment available at the threaded adapters, so rear axle thrust angle can be corrected on the car instead of shimmed around.

Construction is 1.500 inch DOM tubing with a 0.120 inch wall, fully TIG welded, with a 0.120 inch steel sleeve reinforcing the sway bar provision and a billet aluminium sway bar spacer. Greaseable Energy Suspension polyurethane bushings ride on 4140 chrome-moly threaded tube adapters, and the black variant carries UMI's glossy powder coat.

Key Features

• Extended 5/8 inch over the factory arm, with an additional 1/4 inch of user adjustment for thrust angle correction
• 1.500 inch DOM tubing with a 0.120 inch wall, fully TIG welded
• Sway bar provision reinforced with a 0.120 inch steel sleeve, TIG welded and sanded, plus a billet aluminium sway bar spacer
• Greaseable Energy Suspension polyurethane bushings with grease fittings
• 4140 chrome-moly threaded tube adapters and bushing threads at the adjuster
• New 10.9 grade sway bar hardware supplied in the box
• Glossy black powder coat finish and a direct bolt-on fit with no modifications

Fitment

The packaged instruction sheet is headed 1991-1996 GM Impala SS, and older catalogue copy repeats that range. UMI's live application table lists the Impala SS itself as 1994-1996 within a 1978-1996 B-Body platform, so the 1991-1996 wording is B-Body generation shorthand rather than an Impala SS fitment range. The years published here follow the manufacturer application table.

UMI publishes year, make and model for this part number without a submodel, trim, engine or drivetrain breakdown, so the fitment tags on this listing stop at model level rather than inventing a trim. The one exception is the Impala SS, which UMI names directly.

UMI notes that a longer driveshaft may be needed depending on final ride height, and that the arms are compatible with UMI weld-in lower control arm relocation brackets. Rotating the sway bar spacer block on top of the arms allows those brackets to be used while the factory sway bar is reinstalled.

Specifications

What's Included

• Two extended length adjustable rear lower control arms with greaseable polyurethane bushings installed
• New 10.9 grade sway bar hardware
• Energy Suspension grease packet for pre-lubing the bushing surfaces
• One installation instruction sheet

UMI does not publish a bagged, piece-by-piece fastener list for this part number, so no counts beyond the items above are claimed.

About UMI Performance

UMI Performance builds chassis and suspension parts at 509 Hemlock Street in Philipsburg, Pennsylvania, using precision bent DOM tubing, laser cut steel, TIG and robotic welding and durable powder coat finishes. The B-Body rear lower arms are part of UMI's full-size GM chassis programme, built around DOM tubing, greaseable polyurethane and chrome-moly adjusters rather than stamped steel.

Related Parts

• UMI Performance adjustable extended length rear upper control arms, poly ends, for the same 1978-1996 GM B-Body application

FAQ

Yes. UMI lists the 1994-1996 Chevrolet Impala SS inside the 1978-1996 GM B-Body application for this part number, alongside the Caprice, Roadmaster, LeSabre, Bonneville and Catalina.

That range describes the late B-Body generation and appears on the cover of the shared instruction sheet. UMI's application table lists the Impala SS itself as 1994-1996, so the years published on this listing follow the manufacturer table.

They are 5/8 inch longer than stock as delivered, and the threaded adapters give another 1/4 inch of adjustment for setting rear axle thrust angle.

UMI notes that a longer driveshaft may be needed depending on the ride height you end up with. Measure the slip yoke engagement after the car is back on the ground.

No. The arms reuse the factory control arm bolts. New 10.9 grade sway bar hardware is included, and separate mounting hardware can be bought if the original bolts are worn.

UMI's sheet calls for 72 ft-lb on the lower control arms with the weight of the car on the rear axle, and allows going as high as 90 ft-lb only if a clunking noise is present after installation.

Yes. The sway bar provision is sleeved and reinforced, a billet aluminium spacer is supplied, and the instruction sheet covers reinstalling the bar. Grease the arm before the bar goes back on, because the bar covers the rear grease fitting hole.

Loosen the bushing from the axle side, loosen the jam nut, turn the adjuster to move the axle, then retighten the jam nut and the mounting hardware with the suspension loaded.

Marine type grease two to three times a year, one pump per fitting. UMI specifically warns against over greasing.

No. The two year warranty covers defects in materials and workmanship, and it excludes normal wear and tear on bushings and bearings. Treat bushing service as scheduled maintenance.

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, use beyond the design limits of the part, improper installation, acts of God, handling and shipping damage, any product that has been altered, adjusted, tampered with or defaced, components not made by UMI, 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. The sheet packed in the box still carries an older disclaimer that predates the current two year term, and the live policy page is the document that governs. Neither is a Black Ops Auto Works warranty.

Installation Instructions

1. Jack the rear of the vehicle and secure it with two jack stands under the frame. Do not support the car by the rear axle at this stage.
2. Remove the sway bar from the lower arms.
3. Work one side at a time so the axle stays located, and remove the front and rear control arm bolts from that side only.
4. Pre-lube the bushing surfaces with the supplied Energy Suspension grease packet.
5. Install the new arm with the grease fittings angled toward the ground, and leave the fasteners loose.
6. Repeat on the opposite side. A helper, or removing the driveshaft, can make lining up the axle easier.
7. Reinstall the sway bar, greasing the arm first because the bar covers the rear grease fitting hole.
8. Transfer the weight to jack stands under the rear axle so the suspension is loaded.
9. Tighten all four mounting bolts to 72 ft-lb. If a clunking noise is present after installation, UMI allows torquing the control arms to as much as 90 ft-lb to prevent it.
10. Set thrust angle if required by loosening the bushing from the axle side, loosening the jam nut, adjusting, then retightening.

The full manufacturer procedure is published in UMI's installation sheet for part numbers 3612 and 3614 at https://static.speedwaymotors.com/pdf/1853614B.pdf.