Think Tubular: Classic Tube brake and fuel lines for the late model GTO

Cruisin Style MagazineCruisin' Style

September 2006

Out of sight, out of mind! An age-old quote, and most likely never intended for automotive restoration topics. But in this case it's more than relevant. Hidden under your Pontiac are several very important fluid transfer items, namely your brake and fuel lines. Since these are never in your face, it's easy to overlook them, even during a resto. These tubes are basically the same for the 1964 through 1972 GM A-body, but the late model cars, with evaporative emissions plumbing, have vapor tubes at the gas tank and a fuel return line, not used on the early cars.

This GTO convertible lived much of its life in damp, wet and icy conditions and the underside was less than pristine. The area of the frame rail, where the lines mount, was caked with dirt and rust was hiding in the shadows. The resto shop that removed the body simply cut the old tubing at the front and rear for instant removal and then promptly lost the original mounting clips. Hey, what's new? Anyway, new replacement clips were secured and the correct pre-bent brake and fuel lines were ordered in original style steel from Classic Tube. Stock replacement brake lines for the rear end and master cylinder, along with the fuel vapor lines, fuel return line, carb to pump fuel line and 2-quarts of DOT 5 silicone brake fluid also came from Classic Tube.

This is a very unusual late model GTO in that it has four-wheel drum, non-power brakes and no power steering. It was obviously ordered to simply go fast with not much concern for stopping! Classic Tube had all the required pieces in stock, and with a few tweaks they fit the car perfectly. Where necessary, the end fittings are color-coded and the tubing sheathed in gravel guard. All the correct double flares are installed on the tubing to provide leak proof seals.

Tools requirements are simple, the most valuable being a set of good line wrenches to avoid rounding out the end fittings. Some rust buster might be required, a normal array of hand tools, a set of heavy-duty jack stands and a floor jack round out the list. The icing on the cement would be a padded lay-down creeper, which we had.

Like most restoration projects, a secure garage with a flat floor, transportable lighting and a comfortable temperature will make the job easier. We started at about 8 AM on a non-football Sunday (no distractions) and had the lines installed by "pop a cold one" time. If you are detailing the frame and each part along the way, allow a couple of weekends to complete the whole job. The original rear end, with new Classic Tube brake lines attached, was installed a week later and the emissions lines and new gas tank installed at the same time. That way the fuel and brake system can be buttoned up and ready for the engine install and hook up. There is a maze of tubing at the gas tank for the emission lines, so it might be a good idea to take a couple of pictures of your original layout before disassembling it. Our gas tank had three additional emissions related connections along with the sending unit and return line connection.

If your original chassis tubing is kinked, rusty or missing, this is the simple and completely stock looking solution to the problem. Classic Tube has all the tubing required for almost any Pontiac restoration in steel or stainless steel as well as brake hoses, tools and fluid. The rest is up to you so think tubular!

Prebent Brake Lines

We ordered all the necessary fuel and brakes lines from Classic Tube. This pre-bent steel tubing makes replacing damaged or rusty original tubes a simple job for the amateur restorer. Classic Tube stocks steel and stainless steel tubing for most Pontiac models.

Pontiac Brake Lines

The new tubing must be snaked between the frame and reinforcing member at the rear of the car. Some calisthenics are required here, but the tubes will fit. Notice the gravel guard wrapping to help protect the tube from road debris, etc.

Brake Line Retaining Clips

After we had the steel lines in the correct location front and rear, and positioned as the factory originals, new retaining clips were installed. These clips are unique and you should remove your originals with care for cleaning and reuse.

Installing Brake Lines Through Frame

At the front of the frame rail is a small oval hole that the fuel and brake lines pass through. A heavy insulator to prevent metal to metal rubbing protects the lines here. The tubes should be inserted at the front and rear before securing with the clamps.

Installing Vapor Lines Through Frame

Here we're installing the vapor lines that are attached to the passenger side frame rails. The process is the same, get the rear in position and then feed the front through the access hole. Again, the correct insulation is supplied on the Classic Tube tubing.

Brake Lines Installed Through Frame Rails

Here's how the lines will look on both sides at the front of the frame rails. They protrude about 6" from the access hole and will receive rubber hoses to finish the connections.

GTO Front Crossover Tube

This front cross-over tube is original and was in excellent shape. It's in a protected area, so we simply wire wheeled the tube and connectors and reinstalled it. The complete frame had been sandblasted and painted with a super hard enamel to prevent chipping.

Reinstalled Crossover Tube

Once the fuel, brake and vapor lines were installed we turned to the rear end. The original line is on the floor and the new Classic Tube replacement is being installed.

OE and Replacement Brake Lines

The brake lines are held in place by factory clips attached to the axle tubes. Close these clips over the tubing carefully so you don't crimp the brake line.

Rear Brake Fluid Distribution Block

The rear brake fluid distribution block is original and here you can see the color-coded end fittings on the brake hard lines.

Rear End with New Brake Lines

This factory 12-bolt is now decked out with new lines and is ready for reinstallation. We still have to install new bushings in the case and control arms, so it will be another week before the rear is installed.

Reinstall original distribution block

The restored original distribution block is now installed and the brake line to the rear end and master cylinder are attached. Use line wrenches on the fittings to prevent rounding out the edges and don't over tighten the fittings. Too much pressure will crack the flares on the tubing resulting in a fluid leak.

Install Brake Lines Carefully

Like the other lines running down the frame rails, these master cylinder lines have specific bends to mate to the master. Don't force or change any bends until the master is installed and you're ready for the final attachment.

Attach crossmember line to distribution block

The long brake line that travels across the front cross member can now be attached to the distribution block. This line feeds the passenger side front brake cylinder. Several clips along the cross member secure it.

Master Cylinder Brake Lines

The finished master cylinder and lines are now permanently connected. We're still shaking our heads over this Judge with non-power, four-wheel drum brakes. But at least now they'll work properly and we don't have to worry about damaged original lines.

Emission Lines at gas tank

Here's a view of the many emission lines all converging at the gas tank. This is why we think it a good idea to take a picture of all the original connections before you disconnect them and remove the tubes.

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