Synopses of the Technical Documents and Presentations

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Safety - - -

GMCer's Fire Prevention Guide

Throughout a portion of 2011 Rob Mueller collected information regarding fire prevention, causes and issues related to the GMC Motorhome. Many GMCers contributed to the development of this excellent guide on covering fire prevention and what to do in case of fire. Every GMCer should read this informative document. (updated 10/31/2011) View/download the article.

GMC Towing Guide

In response to concerns about towing a GMC Motorhome, Robert Mueller (The Man from down under) has assembled
an excellent step-by-step procedure to use in requesting a tow service via AAA, Sam's Club, Coach Net or whatever road service provider you may have. The document includes three, succinct illustrations giving a visual of what to watch for as well as two pages from the Maintenance Manual on approved towing methods. View/download the article.

Tire Safety for GMCers

Byron Songer has assembled this presentation with the GMCer in mind. It provides several tips with regard to tire issues including safety, issues that effect tire longevity, information relating to correct pressure, guidance on reading the DOT serial number (and date code), and a tip on examining tread depth. The information was gleaned from several trade articles and information from multiple manufacturers. View/download the presentation.

Engine and Transmission - - -

Rebuilding that Motor

Larry Weidner, whose GMC coach features a 500 cu. in. Cadillac engine, weighs in on what he has learned and observed over the years about rebuilding engines. Though careful to stress he’s providing only his opinions, the article is quite powerful and worthy of reading by all owners. View/download the article.

Rebuilding the Olds Engines

Jim Bounds responds to an email detailing the work done at the Cooperative Motor Works with Jasper rebuilt engines. Jim provides an overview of what needs to be considered when taking on such a project. View/download the article.

Rebuilding and Tuning the Olds 455/403

Dr. Oldsmobile, as Joe Mondello is called, presents an overview of the process he and his company have developed in rebuilding the Oldsmobile engines like those used in the GMC Motor Home. This presentation includes several points that were clarified in the presentation. Still, the reader will get the gist of the excellent work done by Mondello in building a durable and finely tuned engine that will get greater fuel economy while yielding increased horsepower and torque. Delivered at the 2010 Spring Rally in Calhoun. View/download the presentation.

Throttle Body Fuel Injection Upgrade

Ray Swartzendruber provides an excellent overview of the throttle body fuel injection system. What is covered is generally applicable to most TBI systems, but while putting particular emphasis on how it applies to the engines of the GMC Motorhome. The file contains the 77 slides and notes from Ray’s original presentation. View/download the article.

Fuel Injection for the GMC

As Richard Waters writes, “This is about how a not very experienced, ‘shade tree mechanic’ figures out how to install Fuel Injection in his GMC Motorhome. This presentation is for those non-engineer/professional mechanic types that want to install TBI.” Don’t be fooled by the disclaimer, Waters provides lots of photos and pointer in this 171-slide presentation while crediting may other members of the GMC community who also provided advice. The fous of Waters’ project is the installation of a kit from Howell Engine Developments, Inc. View/download the article.

Steering, Suspension and Towing - - -

The Basic GMC Motorhome Steering Inspection Guide

In response to concerns about loose steering and “road wander”, Robert Mueller of Australia provides
a step-by-step procedure to check for play in the steering system. The procedure starts at the bottom of the steering column and works its way out to both of the wheels. View/download the article.

The GMC Motorhome Steering Box

If the steerin
g on your 30-year-old GMC is getting a little too loose then this informative document is for you. Don Wirth gives details on the Saginaw power steering box. He tells how to identify the proper style used in the motorhomes, how to disassemble it and the proper way of adjusting it. View/download the article.

Saginaw Steering Boxes

In a reprint from Hemmings Motor News, author Jim O’Clair goes over some of the virtues of the venerable Saginaw equipment used in so may GM vehicles. An important thing to remember when interchanging Saginaw gearboxes is to use your original pitman arm and idler arm, if possible, to maintain the proper steering geometry. Ken Henderson highly recommends this article. View/download the article.

Steering Column Upgrade and Repair

Are you interested in having a more modern steering column with the dimmer, cruise control and wiper switch on the turn signal stalk? If so, this detailed article is for you. Richard Sowers provides images and notes in a step-by-step format for doing a complete job. View/download the article.

NEW - Replacing the Upper Steering Column

Based on Richard Sowers' information (see immediately above), John Sharpe provides an annotated and revised view of replacing the upper steering column. The steering column swap yields a multi-function switch on the stalk including wiper control (if electric wipers replace the vacuum style). View/download the article.

Backup Cameras and Tire Pressure Monitor Systems

Based on real-life experience, Byron Songer provides an overview of the varieties of camera and monitors suitable for use in GMC motorhomes. He also provides a look at TMPS, something he considers essential to avoid a costly blow-out. Though inexpensive units for after-market backup systems are available, Byron cautions against using license plate mounts (designed for cars). Wired and wireless systems are available. View/download the article.

Custom Instrument Panels for the GMC

Well known among most TZE owners, “Mac” McNeal presents his lineup of custom instrument panels and explains the details available for each one. Other panels for use in the motorhome are also shown in this comprehensive overview. Delivered at the 2010 Spring Rally in Calhoun. View/download the presentation.

A GMC-specific Toad Brake System

Fred Veenschoten provides an overview of the different types of brake systems for a towed vehicle (toad) before detailing how to build a VIP System (variable, independent pressure system). Controlled by the driver’s foot, the toad brakes can be applied independently of the coach brakes or in conjunction with the coach brakes. View/download the article.

The Power Level Air Suspension from the Top Down

The Power Level system was the standard system in 1973 through 1976 GMC coaches. Rick Denney's article presents the Power Level system starting with its basic theory of operation and proceeds from there to troubleshooting and leak detection and repair strategies. Many of the principles in this article also apply to later Electro-Level systems, but the article does not attempt to address that more complicated subject. . View/download the article.

Suggestions for Installing the QuadraBag System

Bill Brown offers practical and helpful suggestions for installation of the new QuadraBag system for the rear suspension of our GMC coaches. The system, designed by Jim Bounds and Jim Kanomata, has many advantages of the original single-bag system developed by GMC. The document is based on Bill’s notes and observations from installing a new system on his personal coach. View/download the article.

The Southland Air Bag System

Matt Frady’s presentation contains information related to the development of a single cone system to replace the discontinued air bag from Firestone for use on the GMC’s rear suspension. Southland Motorhome is located in Buford, Georgia which is north, northeast of Atlanta. The presentation a brief overview of the air bag development and advantages and disadvantages of other systems. Delivered at the 2010 Spring Rally in Calhoun. View/download the article.

Wireless Air Leveling System

John Shotwell had a problem: The original leveling system was not functional and rebuilding the system was going to be expensive. He made the decision to replace the system with newer technology which included a wireless controller that could be operated in and out of the coach. In this brief presentation, John outlines the installation of the packages system from a company called Air Lift. Delivered at the 2011 Spring Rally in Dillard. View/download the presentation.

Miscellaneous Vehicle Issues - - -

Guide to Final Drive Ratios and Tire Size Information by Brand

Don Brown provides a handy table for evaluating the difference from original specs for a combination final drive ratios and tire sizes from Michelin, Goodyear and Bridgestone. View/download the article.

NEW - Briggs & Stratton Locks and Keys in Your GMC

Joe Ekl, a professional locksmith, presents detailed and accurate information dealing with the Briggs & Stratton locks and keys used by GM in the GMC MotorHome and TransAm coaches. Joe even give information about what years used what key codes as well as giving information on what not to use to lubricate the lock. View/download the article.

The Forgotten Ammeter

An Ammeter measures the direction and quantity of electricity flowing through it. It has been replaced by the voltmeter. In pointing out how the ammeter has become the forgotten gauge a vehicle, Frank Folkmann tell the proper way to install one as well as the two wrong ways. View/download the article.

GMC Motorhome Electrical System from the Top Down

The electrical system of the GMC is fairly simple when considered as a system, but it’s easy to get lost in the details. We work on those details, and sometimes miss an understanding of the system as a whole. In this document Rick Denney lays out the system as a whole so that GMC owners can see how the details fit into the big picture. View/download the article.

Grounding the GMC Motorhome

Ken presents a thorough overview of the three electrical systems in the GMC motorhome; auto 12 volt, house 12 volt and house 120 volt. He presents how they should be properly grounded, how they are inter-connected and some excellent advice for reliable operation. This presentation is text-intensive and self-explanatory. View/download the article.

LED Tail Lights Connected by Tail Light Bulb Base

Interested in upgrading the tail light/turn signals of your coach with LEDs? Tom Whitton tells how to adapt a trailer light kit from Harbor Freight for use in the GMCs lense. Tom shares with you his secret of repurposing the standard bulbs wiring the LED set into the bulb base. View/download the article.

All Around the House - - -

The Wonderful World of Type II HVAC Systems

It began with one question: “Why is my dash airflow so bad?” In a well-documented and photographed procedure Mark Wall tells how he greatly improved the stock system in his pre-1977 Motorhome. In the process he rerouted ductwork, added vents and installed a second evaporator
. View/download the article.

Water Too Hot? Problem Solved

Armand Minnie never liked the fact that the water heater in the GMC can put out water at 180°F or better. So, he set about to solve the issue. After seeing similar setup on a cruise ship he decided to implement the simple "fix" for his situation. The result, no more fear of being scalded while taking a shower. View/download the presentation.

GMC Motorhome House Electrical System: Troubleshooting, Maintenance and Safety

Don’t be fooled into thinking this document is a repeat of the one listed immediately above. In this document filled with illustrations, Bob Hendrickson takes the reader through the processes involved in troubleshooting and maintaining the house electrical system of the GMC Motorhome with an emphasis on safety. View/download the article.

Water Quality and Sanitizing Issues

Frank Folkmann provides a common-sense guide with regard to water quality, it's safety and sanitizing issues. View/download the article.

Horizontal Installation of the Atwood Furnace

Ray Swartzendruber shares his experience and insight into installing an Atwood furnace in a horizontal rather than angled orientation. He gave this presentation at Elkhart in 2004. Note that the typical installation is made to line up with the angle of the outside panel where it is installed. Ray’s method saves space and yields extra storage capacity as well. View/download the article.

Operating and Troubleshooting the Suburban Dyna-Trail Furnace

Though John Nicholls will be the first to tell you he’s not an LP gas technician he does provide some good advice in this article about the Suburban furnace in many coaches upfitted by Coachmen. The reader should take note that he/she is responsible for making your own determinations as to validity and applicability of the information presented. View/download the article.

Rebuilding the RV Refrigerator

Leon's step-by-step process of rebuilding the Norcold or Dometic RV refrigerator is graphically and clearly presented in this document. Those in attendance were impressed with the high level of knowledge and capability exhibited by Mr. Herschberger. The presentation also covers the theory of design of the RV refrigerator. Delivered at the 2009 Fall Rally in Elkhart. View/download the presentation.

Etc. - - -

Repainting the GMC Motorhome

This presentation contains many photos and illustrations of coaches at various stages of progression in the painting process. Illustrations of a variety of typical paint schemes done at Topeka Graphics are also shown. Topeka Graphic is located in Elkhart. They have painted over GMC 200 coaches. Illustrations are by Byron Songer. Delivered at the 2009 Fall Rally in Elkhart. View/download the presentation.

Principles of GMC Paint Design -

Byron Songer, who has developed the promotional graphics for GMCES and GMCMI gatherings as well as T-shirt designs used by MI recently, gave this presentation (along with audience handout) at the 2011 Fall Convention in Goshen, Indiana. The presentation includes both the slides and notes. The handout was used to accompany the presentation and to give those who attended a "take away". It is available here as a separate file. View/download the presentation. View/download handout.

My TZE Land Yacht

Prigmore, a new owner but not new to wanting a GMC motorhome, was featured by FMCA on their website. Though unable to be present, this presentation shows several photos and lists much of the work done in renovating his beautiful coach. The article is archived and available at this website under About/FMCA Articles. This presentation contains photos and an extensive list of work done that is not contained in the FMCA article. Delivered at the 2010 Spring Rally in Calhoun. View/download the presentation.

Coach Weighing Results

Alex Sirum, who began working on GMC Motorhomes several years ago, brought his portable scales to Calhoun. Owners got their coaches weighed (see Results) prior to Alex’s Q&A session about the effects of ride height, balance and adjustment of the torsion bars. Delivered at the 2010 Spring Rally in Calhoun. View/download the presentation.

GMC Maintenance and Friends Application

Database developer, Byron Songer, has made available his standalone application for tracking maintenance and upgrade information for owners of TZE coaches. The user can provide information on work done as well as line item costs. On the friends side the user can keep a listing of GMC friends, see where they live in a Google map or view a related website all within the application. The log of maintenance work can be printed or previewed. Download file for Macintosh. Download file for Windows.