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Brakes
  • Suggested articles, sometimes including step-by-step procedures, are indicated with orange colored text. You can also submit YOUR Opel Tech Tips, for consideration by the Editor of the OMC Blitz, to: joinomc@opelclub.com
  • Safety First! A complete brake system inspection should be done, before any Opel is returned to street use. This includes the master cylinder, brake vacuum booster, hoses, steel lines and connections, and wheel cylinders. A common problem area, is an incorrect or cracked brake vacuum booster air hose always replace with a new reinforced air hose (not a "heater hose"). Common upgrades to the stock Opel brakes include installing the larger 1975 model-year components, as well as even larger after-market "big brake" kits.

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.

May/June 2007

Rear Brake Shoe Lever identification (1 page, illustrated)

Nov 2005

Brake Upgrades (5-Lug GM, Fiero), 1 page (illustrated)
Suggests that Fiero front brake and hub assemblies will  bolt onto earlier Opels. (NOTE: This would require a greatly  altered wheel rim offset, to safely fit on the GT and other Opels).

June 2004

"GT Master Cylinder rebuild"
Includes step-by-step procedure, with illustrations of individual components, of rebuilding and reinstalling an Opel GT Master Cylinder.

Dec 2002

4 Wheel Disc Brakes Tip, Revisited, 2 pages (illustrated)
Dennis G. critiques specifications of overtorquing axle mounting bolts to correct backing plate interference found in prior Isuzu rear disc brakes installation article.

Nov 2002

4 Wheel Disc Brakes Tip, 3 pages (illustrated)
Charles G's description of Bob Legere's suggestion of installing rear disc brakes from an Isuzu Impulse rear axle, extensively modified, into an Opel Manta. Reprint from March/April 1999 OANA newsletter, with liability disclaimer.

May 2002

Reprint: Guide to Better Brakes, 2 pages (illustrated)
Reprint of text from June 1995 Brake Upgrade article by Bob L. (described below).

April 1999

Brake Bleeding; 1/2 page
Gary M. suggests using the one-man brake bleeder screw produced by "Russell" (part #3957 front and #3952 rear).

Jun 1995

GT Brake System Tips "Give Me A Brake"; 3 pages
Robert D. describes necessary inspection areas on the GT, with parts replacement and upgrade tips.

Jun 1995

GT Brake System, "Discs On All Four"; 1 page (illustration)
Ron I. and Preben J. discuss their experiences driving Opel GT's with aftermarket 4-wheel disc brakes installed. Mentions made that some kits won't fit bolt pattern of 1968-1970 rear axles, and of installing larger 15&16-inch tires and wheels with the correct offset for clearance.

Jun 1995

Brake System Upgrades; 2 pages
Bob L. discusses installation of larger 1975 Opel brake components, his personal modifications to use vented 1977 BMW 320i front rotors, and other mods such as the Isuzu Impulse rear end with Porsche 914 calipers and racing brakes from Wilwood of JFZ Racing.

Jun 1995

The Poor Man's Guide to Big Brakes; 2 pages (illustration)
Step by Step guide to removing front brakes from a 1975 Opel,  and installation onto an Opel GT. The only illustration is of the various styles or original GT wheel rims -- as the early "4-hole" 1968-1970 style will not clear the larger 1975 calipers when installed on a GT (later 1971-1973 style stock rims are OK). (Note: A later correction, specified that only steel brake hoses should be installed with 1975 calipers on a GT, as the extra length of 1975 rubber brake hoses leads to interference with the inside edge of the stock wheels).

Sept 1994

Silicone Brake Fluid: Yes or No (Article Reprint); 1 page
Discussion copied from "British Car" magazine, October 1993. Not necessarily recommended, as all brake hardware must be replaced, to change brake fluid application in an Opel.

Sept 1990

GT Braking System Steel Hoses and Fitting Upgrade Tips; 1 page
Blaine S. provides hardware and vendor information on adapting steel hoses for the GT brakes.For a stock GT, use Earl's brand; qty. 3 of #620608-4 and qty. 6 of #989544. For a Manta, substitute qty. 2 of #620614-4 (14" length). For a GT with larger 1975 brakes, use qty. 3 of #620608-4 and qty. 2 of #592042 and qty. 2 of #966304. Includes mention of need to ream holes in suspension cross member brake hose bracket approx. 1/32" to 1/16" larger, to fit steel hose fittings.

Dec 1989

Parking Brake Cable Repair Tip; 1 page
Blane S's. repair involves buying a thin clamp at hardware store, with best application as a short-term repair.

Feb 1989

Cutting Horizontal Slot in Opel Brake Pads for Cooling; 1 page (illus)
Roger L. suggests cutting this slot with hacksaw or grinder,and the Editor reminds readers to avoid breathing asbestos particles.

Aug 1988

Measurement of 1975 Brake Rotors vs. pre-75's (Dangers); 1 page
Cal H. warns that chain-store auto parts retailers, frequently have incorrect part number systems, and sell smaller 1968-1974 brake parts (when you ask for and pay for larger 1975 parts).

Feb 1987

Brake System Tips (Reply); 2 pages
Roger L. discusses brake upgrades on his racing Opel.

Dec 1986

Opel Parts Upgrades (1975 Alternator, Brakes, Clutch Fans); 1 page
Gil W. explains the value of acquiring parts from a junked 1975 Opel.

Nov 1986

Make It Stop, Opel Brake System Upgrade Tips; 3 pages
Rick G. article discusses topics introduced by a speaker at the September 1986 OMC Meeting. Suggestions include: Converting 1968-1974 1.9 Liter Opels, to the larger 1975 Opel brake components (rotors, calipers, pads, wheel cylinders), considering change from DOT-3 to DOT-5 brake fluid, using Semi-Metallic brake shoes and larger wheel cylinders in the rear, and Cross-Drilling the front brake rotors and rear drums for better ventilation.

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