O P E L   M O T O R S P O R T    C L U B


GT Suspension

  • Suggested articles, sometimes including step-by-step procedures, are indicated with orange colored text. You can also submit YOUR Opel TechTips, for consideration by the Editor of the OMC Blitz, to: joinomc@opelclub.com
  • A long list of articles from OMC concerns the sometimes tricky front suspension. Critical issues include the safe release of high-tension of the front transverse 3-leaf spring during disassembly, the need for lubrication and rust-protection of the four (vertical) 15mm lower control arm mount bolts, and inspection of the rust-prone upper shock tower areas (a layer of grease here helps). Upgrades include polyurethane control arm bushings, installation of sway bars and performance shock absorbers, and suspension alignment options.

How to Order: Reprints of Individual OMC Blitz issues, can be ordered by mail from the OMC Treasurer (3824 Franklin Ave, La Crescenta CA 91214) for $2.00 each (cost includes postage). This offer is subject to availability.

Dec 2006

Opel GT Front Control Arms
Includes procedures on disassembly and lubrication of upper control arm and lower control arm "A arm" bolts (including procedures on removing rusted or stuck bolts), safe release of tranverse front spring tension, illustrations of polyurethane bushings, casters, shims, toothed metal sleeves, front spring perch and other hardware pieces, and notes on upper and lower ball joint installation.

Dec 2003

Ball Joint Failure (Check Dust Boots), 1 page
Notes the lower ball joint fails from front spring tension, if the dust boot fails and water and dirt enter the joint, and excessive wear results.

Nov 2003

GT/Kadett Spring Lubrication (Motorcycle Chain Lube), 1 page
Suggestions include spraying on motorcycle chain lube on the stock 3-leaf transverse front spring as a quick-fix, and for more extensive disassembly: leaf separation, surface grinding and painting with POR-15, and 1/16" polythene sheets between leaves.

Aug 2002

Momo Steering Wheel & Adapter, 1 page
Nathan A. mentions Momo adapter is about 3 1/2" long, to space aftermarket steering wheel at about same distance as stock wheel.

Aug 2002

GT Steering Wheel Leather Cover, 1 page (illustrated)
Otto B. uses "closed cell" foam insulation and "superskin" black leather to build a custon "fat grip" GT steering wheel cover.

May 2002

GT Steering Wheel Pullers, 1 page (illustrated)
Two methods of devising a GT steering wheel puller: One restates the 5/16" grinded-bolt head method of fashioning 2 puller bits (also in 6/1997 Blitz), and the other illustrates a 1/5" thick plate drilled with 6 holes, using 6 6mm bolts (1.0 pitch, 4 cm long).

Dec 2001

GT Front Suspension Alignment Settings, 1 page
Bob L. recommends 4 or 5 degrees of positive caster, 1 to 1.25 degrees of negative camber, and zero toe-in, on a street-driven GT.

Nov 2001

Front Spring Shackles, 1 page (illustrated)
Wayne T. provides template and procedure, for installing a front GT spring shackle, for improved handling in a GT while retaining the smoother ride of the stock 3-leaf front spring.

Sept 2001

Adjusting GT Negative Caster, 1 page
Bob L. suggests checking front lower control arms for angle (many are bent), considering effect of a raised rear end (also affects front end caster), and swapping shims.

April 2001

Reproduction Steinmetz Racing Watt Linkage for GT, 1 page (illustrated)
Pictorial re-introduces linkage kit for GT rear axle, which limits travel to vertical only for stiffer handling. Kit can be machined as a copy (by using the photos as a reference guide), or special-ordered by Opel retailers from European suppliers.

Dec 2000

Suspension Coatings: POR-15 vs. Powder coating, 1 page
Comparison recommends using POR-15 paint on suspension components vs. pros and cons of powdercoating.

Sept 2000

GT Suspension Modifications: Bushings, Springs, Tires, 2 pages
General discussion touches upon polyurethane bushings, rear coil springs, shocks, tires. More a conversation than a tech tip.

Aug 2000

GT Suspension: Bushings, Springs, Tires, 1 page
Questions and considerations on rear polyurethane bushing replacement and rear spring replacements on a GT.

March 2000

Blitz nostalgia: 1985 Shimmy stoppers tech tip, 1 page (illustrated)
Reprint of now-obsolete method of stabilizing GT front suspension.

March 2000

GT front suspension assembly tips, 2 pages
Starting with observation that the upper ball joint is reversible (to gain camber), it suggests to mark original upper ball joint mount hole orientation and to diagram shim locations on upper arm before disassembly (rather than reliance on memory). Suggests inspecting front shocks, ball joints and tie rods at once. Also suggests obtaining supplies, such as: Extra teflon grease, ball joint and tie rod end dust boot covers, and replacement rack mounts and boots (if needed), and tools such as a "pickle fork" ball joint separator and a propane torch (if original rubber bushings are to be replaced with polyurethane), in advanced of starting the work.

Jan 2000

Aftermarket wheels & tires for your Opel, 3 pages (illustrated)
Detailed article covers rim measurement, rim sizes and limits, and aftermarket wheel sources, and the DOT UTOG tire rating system.

Nov 1999

Aftermarket steering wheels, 1 page
Discussion of Momo, Grant and Formuling France steering wheels and adaptor manufacture and installation.

Jun 1999

Poly bushing squeaks, 1 page
Installation suggestions regarding lubrication of inner washer and correct torque spec on control arms, also suggestion of installing a zerk type grease fitting for periodic re-lubrication.

May 1998

Patching performance radials, 1 page
General article text reprint discourages patching high performance tires.

Dec 1997

Building a dolly for moving your GT while the front axle is out; 1 page
Louis V.S. illustrated a dolly/caster substitution, for bolting onto a GT in place of a front axle, keeping it mobile on a solid floor while repairs are being done.

Jun 1997

KYB shocks, 1/3 page
Lists (1997) source: Performance Suspension Technology of Montville, NJ.

Jun 1997

Fabricating a steering wheel puller, 1/4 page
Joel R. uses 2 hardened (grade 5+) 5/16" bolts of 4" length; heads ground to fit.

March 1997

Refurbishing a cracked steering wheel; 2 pages (illustrated)
Reprinted generic article suggests to grind cracked areas with Dremel tool, fill in with auto body filler, sand to match shape, then paint to match original woodgrain (with walnut or caramel color paint), then clearcoat to finish.

Feb 1996

Rack and Pinion rebuild, 1 page (illustrated)
Paul K. writes, in a reprinted 1991 NWOC (NorthWest Opel Club) article, notes on disassembly, lubrication and reassembly, of an Opel GT steering rack. Note: If a rack has a worn-out sintered metal bushings (typically worn on the passenger side), these must be remachined or replaced, for correctly functioning reassembly.

Oct 1995

GT Front Suspension Notes; 1 page (illustration)
Notes describe various inspection, maintenance and repair procedures now necessary (after 30 years of operation) on the Opel GT, including notes on the upper control arm, upper ball joint, shock absorbers, lower control arm, lower ball joint, front spring, tie rods/steering rack and wheel bearings. A good overview, to supplement service manuals (with many details not found elsewhere).

Oct 1995

Front GT Spring Tech Tips; 2 pages (illustrations)
Tony D. describes a front spring compressor made of long wood 4' x 6's with channels cut into end sections, and Ken N. describes a "J-Hook" made of bent, threaded 5/16" "ready rod" which holds a lower control arm in place, through the upper shock mounting point.

Oct 1995

Wheels That Fit Opel's Lug Pattern Notes; 1 page (illustration)
A list of wheel applications from other vehicles, that match the Opel GT "4J x 100" bolt pattern. (WARNING: You MUST match the Opel GT's offset, or these wheels may rub against the wheel well when car jumps (rear) or when you turn the steering wheel (front)). The best GT wheel matches, generally, are the BMW 320i and 2002. Others that may only appear to match are: Acura Integra 1985-87; BMW 318, 325 1984-1993; Dodge Omni, GLH & Charger K-Car; Honda Civic, CRX, Accord, Prelude, Del Sol; Isuzu I-Mark, Impulse, Gemini, Stylus; Mazda Miata; Nissan Sentra, Stanza, NX; Renault Fuego; Toyota Celica GT, Corolla GTS, MR2, Starlet, Tercal; VW Rabbit, Scirocco, Golf GTI, Jetta, Corrado. This is not a recommendation!

July 1994

Installation Instructions for Rear Anti-Sway Bar Brackets, 1 page (illus)
Reprint from Opel parts supplier, includes procedure with diagrams illustrating dimensions of spacing and angle, for welding aftermarket mount brackets to stock GT differential.

July 1994

GT Front Suspension Camber & Caster Adjustment Tips (Letter); 1 page
Editor's reply suggests that the camber can be adjusted further, by elongating the upper ball joint mount holes in the upper control arms, noting that the arm surface should be reinforced by welding an additional plate, and self-locking or "keps" nuts must also be used.

April 1994

GT Suspension Racing/Remedies "Tech Talk"; 3 pages
Bob L. discusses individual suspension component upgrades, to correct the stock U.S. model GT's original front end understeer and excessive body roll on hard turns. Bob mentions adjusting the vehicle ride height, replacing the suspension bushings with polyurethane (also Delrin A), installing front and rear sway bars, using rear coil springs that are stiffer than the stock ~150lbs. rating, replacing the front suspension transverse leaf spring with an aftermarket sport or fiberglass model (or lowering the ends with shackles), and adjusting the front suspension alignment camber/toe-in specs. A detailed article.

Dec 1991

Tire Pressure & Cornering Tip "The Hard and Fast Rule"; 1 page
John M. mentions immediate handling upgrade, by increasing GT tire pressure to 36 PSI in front tires and 34 PSI in rear tires.

Nov 1991

Opel Front Suspension Lower A-Arm Reconstruction Tips; 4 pages (illus)
Blaine S. lists step-by-step procedure, for Opel GT front suspension lower a-arm (control arm) inspection and rebuilding. Includes replacement of lower control arms, lower ball joints, and lower control arm bushings.

June 1991

Adjustable Shock Tower Strut Brace for GT Tip; 3 pages (illus)
Carl G. describes and illustrates fabricated strut brace, to add 0.7 degrees negative camber, by installing adjustable bar and mounts between upper GT shock towers in the front suspension.

Sept 1988

Fabricating A Steering Wheel Puller Tool for GT; 1 page (illustrated)
Chuck N. suggests a method of fabricating wheel puller bits (to replicate Kent Moore tool J-21686-01) from 2 bolts. Specs: 17/32", 3 1/2" grip length, grade 5 SAE or Grade 8 metric hardness; illustration template shows amount of bolt head to remove.

Aug 1988

Rear Lowering Coil Spring from Mazda RX-7's; 1 page
Carlos G. mentions an older Mazda RX-7 rear coil spring swap, which is 5/8" lower than the sock Opel spring, and can be heat-set by a suspension shop to retain spring rate and lower the car 1 1/2".

April 1988

Reversing Upper Ball Joints (Lowered Front End); 1 page
Roger L. reminds that on an Opel with a front sport (lowered) spring, the upper ball joints (with off-center bolt holes) need to be reversed tocorrect the negative 2 degree camber angle. He also suggests resetting the toe-in to 1/16" and leaving the caster alone.

April 1988

Required Jack Heighth to Remove Front GT Spring, 1 page
Gil W. states that the front suspension crossmember needs to be jacked up a minimum of 24" off the ground, to clear the 10" arc in the front leaf spring (when control arm tension is released).

April 1988

Fabricating Rubber Parts "Fake It 'till You Make It" 2 pages (illus)
Paul K. explains how to custom-produce your own rubber parts, using homemade molds and "Flexane" by Devcon Co. of Danvers, MA. Examples are rear sway bar busings, rack boots and a pinion shaft cap.

Feb 1988

Aftermarket Control Arm Bushing Operation; 2 pages
Gil W. details the differences in the pivot point changes on the GT suspension control arms between the original rubber bushings and replacement polyurethane bushings. He also notes the change in the outside diameter of the inside sleeves of the lower control arms; they measured .705 inch in 1968-1971 GT's and .745 inch in 1972-1973 GT's, and he notes that these should be checked with a dial caliper to assure the correct diameter replacement polyurethane bushings are installed.

Jan 1988

Ball Joints (Installing Grease Fittings); 1 page (drawing)
Mentions adding a grease fitting by drilling at center (of tie rod ends and upper ball joints) and by drilling just off-center (of lower ball joints), with a no. 3 drill bit, 1/4x28NF tap and 1/4x28NF grease fittings, to extend life of functioning ball joints (and to make steering easier).

Nov 1987

GT Front Lowering Leaf Spring Installation Tips; 2 pages
Gil W. lists step by step replacement procedure of original GT front transverse 3-leaf spring, with a shorter sport 2-leaf spring. (Note: Use extreme caution in lowering the end of the original spring, as the design causes a highly pressured tension release, which can seriously injure any person or body part located below it.)

Oct 1986

Wheel Studs Repair Kit, Part # by Heli-Coil; 1 page
"Sav-a-Stud" Heli-Coil #5576-56 (size M12 x 1.5).

June 1986

Over steer & Understeer, List of Adjustments to Opels; 2 pages
Defines Understeer as "when you turn the wheel a lot and the car responds a little," and defines Oversteer as "when you turn the wheel a little and the car responds a lot." List of options & adjustments vs. steering response includes: Change of tire pressure, tire width, camber, spring stiffness, sway bar installation, weight distribution, and aerodynamics.

Dec 1985

Take Care When Fitting Wide Wheels (1975 vs. pre-75's); 1 page

Aug 1985

Shimmy Stopper Installation & Ad; 2 pages (illustrations)
A now-obsolete method of stabilizing GT front ends, involves a ribbed washer kit sold by an OMC member as a temporary quick-fix.

Jan 1985

GT Front Wheel Shimmy Problem Fix (Washer); 1 page (illustration)
Stu W. created a ribbed washer to cure GT front end 55mph "shimmy." These had an outer diameter of 1 1/4", a hole with a diameter of 3/4", and were 1/16" thick steel stock. A set of six was installed on the GT lower control arms (3 per arm), 2 in front and on the rear of each.

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