by Terry McGean

Upgrading to stainless hard lines is simple-and worth it


You’ll hear us complain with regularity about the effects of our environment up here in the far reaches of the Northeast. Long winters with ample doses of road salt wreak havoc on ferrous materials, like the ones that our favorite cars are rife with. Naturally, most car enthusiasts in the region don’t drive their classics all year, stashing the vintage stuff after the leaves have fallen and breaking out the late-model ride.

The thing is, most of the cars we lavish our attention upon were at one time the “late model,” and were likely subjected to the elements to some degree. The surviving cars—at least the ones that haven’t been completely restored— often exhibit some effects of exposure, even if they were relatively well cared-for. We like to classify such vehicles- the one’s that remain fully functional, while perhaps showing evidence of their- as “drivable dreams.”

Associate Editor Matt Litwin is quite familiar with the drivable dream concept, having two original-paint Buicks in his fleet, a 1952 Roadmaster and a 1961 lnvicta. He also has a ’72 Skylark convertible that he purchased from the original owner a few years back. Despite a life as a pleasure car, the New England weather still managed to nip at it” steel here and there. Someday the ragtop will get the body-off treatment, but for now, Matt’s wife Sunny enjoys driving it too much to let him take it apart, and since it’s really her car, Matt does like he’s told.

The problem arose on the way to work, when Matt went for the brakes and the pedal just squished towards the floorpan. Thanks to tandem master cylinders, there were still enough brakes left to stop, but something was obviously awry. Closer inspection revealed a common malady around these parts; rotted steel brake lines. Rather than splice in some new parts store mild steel tubing, Matt took the opportunity to upgrade to stainless steel, and to take care of all the lines now, rather than waiting for the others to catch up and spring their own leaks.

To make the job more of a bolt-in and less of an ordeal, we contacted Classic Tube in Lancaster, New York, and ordered a pre-bent brake line kit, made specifically for the ’72 Skylark convertible. When the kit arrived, the new lines looked just like the originals, including spiral armor shielding in the same places that the factory installed it on the original lines. The only real difference here is that the new stuff is stainless steel, so rust should never be an issue again.

While we were at it, we decided to replace the flexible brake hoses, too, and upgraded here as well, using Classic Tube’s Stop Flex stainless braided flex lines. The stainless hard lines cost a little more than mild steel, but the benefit it of corrosion protection is well worth it. The braided flex hoses should provide a more positive pedal feel by eliminating the slight expansion OE-style rubber lines experience under pressure.

This job is a lot easier on a lift and, fortunately, we recently installed a two-post unit from Bend-Pak in our shop. If you have to do it on the ground, use large, high-quality jack-stands to get the vehicle up high enough to provide you with ample workspace. Follow along as we replace the brake lines on an original, unrestored vehicle.


The kit from Classic Tube included every brake line, pre-bent to factory contours and covered in spiral armor shielding where appropriate. All of this stuff could have been replaced with standard steel line, bent to fit during the installation, but the upgrade to stainless is well worth it for vintage cars; in addition, the pre-bent lines fit and look right, and they’re easier to deal with.


The first step, which should probably be done days before the Install begins, is to go around the undercarriage and spray all of the brake line fittings with penetrating oil. Even though this stuff is going to be replaced, the job will go more smoothly if the old lines come off without rounded fittings and other irritations.


Here’s our culprit; a crusty front-to-rear steel brake line that finally rotted through, allowing brake fluid and System pressure to escape. This section could have been repaired with new steel, but all of the lines showed some level of corrosion. However find brake lines repaired with standard compression fittings, replace them immediately. Compression fittings are illegal for brake systems in most states, as they are not intended to contain the level of pressure generated by typical brake Systems.


Since some of the main stem-to-stern hard lines are extra long, they have to be coiled a bit for shipping. Our front-to-rear line was the only one in our kit that had what is referred to as a shipping bend, denoted by a small tag to alleviate confusion. This gentle bend must be straightened before installation. Go slow and don’t concentrate your effort on one spot, or you can kink the line.


We start disassembly by loosening the fitting at the proportioning valve on GM A-bodies of this vintage, the valve is located on the lower section of the driver side frame rail, near the column shift linkage. This makes replacement easier than on many other cars, where the main line must be snaked up to the area around the master cylinder. Notice we’re using a flare-nut wrench; If you don’t have a set, make the investment for a job like this, and get good ones- they’re worth it.


In the rear, we found a brass union fitting joining two sections of steel line. A pair of line wrenches made quick work of it; brass fittings have the benefit of not rusting to steel. We couldn’t tell if this junction was factory, or a repair made later on. If it was a repair, it was nicely done- this is what a proper brake line splice should look like. Our replacement line did not have a union at this point.


With both ends of the main line disconnected, the next step is to unfasten the factory clamps that hold the line in place. Most of the ones on the Buick were made to hold two lines-the other is the fuel line. Removing the bolt in the center allows the loops of the clamp to come free so the line can be removed. Ours were still in good shape after we cleaned them up, but new ones can be had from Original Parts Group.


We were thrown a curve with this hard-line bracket, which was completely enclosed and bolted together on the top of the frame rail. Some fastening brackets like this were likely installed at the factory prior to the body-drop, so dealing with them now can be tricky. We were able to remove the mounting bolt with a box-end wrench without dropping the bolt into the frame.


We recommend removing the old hard lines intact, rather than mangling them in the process. The old lines should be compared to the new ones to verify that all the bends are in the right place. This can save a lot of frustration during installation of the new stuff, as there are occasionally variations that will need to be dealt with. Using the original lines as a template makes this much easier if a correction is needed.


We opted to remove the entire rear brake circuit before installing any of the new parts. Here, the rear flex hose is fastened to one of the crossmembers over the rear axle with a typical clip. We find the easiest way to remove these without damaging or gouging any surrounding pieces is to simply pry the tab on the clip away from the hose with a medium-size screwdriver, using the fitting as a fulcrum. This works better than pulling on the tab with pliers, since even rusty clips usually slide right out; they can even be reused if necessary (though our kit Includes new ones).


Rather than fighting with more rusty fittings than absolutely necessary, we opted to disconnect the brake lines at the rear wheel cylinders, then unbolt the center junction from the differential housing and pull the whole thing down as a unit. All of this will be replaced, but even if you’re keeping the junction, it will be easier to work with on the bench.


While we were at it, we opted to replace the wheel cylinders on the Buick. If your car has been sitting for a long time, or if the cylinders are just very old, this is cheap Insurance, as it’s common for old wheel-cylinder seals to fail. We were also going to install new shoes, and a leaky wheel cylinder can ruin shoes in no time, soaking them with fluid. For this car, replacement drum-brake parts are easy to find and cheap to purchase.


Installing the new axle-tube hard lines can be frustrating. Start with the wheel-cylinder end and carefully attempt to thread the fittings in; cross threading is easy to do and can damage the fittings or the threads in the wheel cylinders. If you’re having trouble, try loosening the wheel cylinders from the backing plates to provide a little extra movement. After the threads start, re-tighten the wheel cylinders


To upgrade from the stock rubber flex hoses, we ordered a set of Classic Tube’s Stop Flex braided lines. The stainless braided sheathing is actually covered in clear tubing to prevent chafing of surrounding components and to help keep them looking good. All fittings are included to make the swap a bolt-in.


Before fastening the new junction to the differential housing, we loosely threaded the fittings for each of the axle-tube hard lines. Again, this will make it easier to get the lines started without cross-threading. Once the lines were started, we bolted the junction in place and fully tightened the lines.


Installing the main front-to-rear line requires some finesse, to keep from introducing any kinks or other unwanted bends. We carefully fed the new line into place without fastening any of its fittings or retaining clamps. Then we put the old line in place next to it to verify the placement. We had to make a few minor tweaks, using the old line for guidance, and then threaded the fittings into place.


The front hard lines are more of the same. The tricky one is the passenger side, which has to follow the front crossmember under the engine. Two people make this task easier, with one guiding on the passenger side.


Our front flex lines install right in place of the stock rubber hoses. Make sure the braided line and the new end fittings are tight-they ship loose. On GM cars, the front calipers use banjo fittings, but the factory fitting bolts are too long for the new flex-line fittings. Make sure to order the proper banjo bolts when ordering your kit-they’re sold separately.


All that remains is to bleed the brakes. We like to use a Mityvac vacuum pump tool to pull the fluid through the lines; traditional pedal-pumping techniques can take awhile when all new brake plumbing has been installed. If you can’t get the air bubbles to stop after a few cycles, go back and check your fittings-new fittings sometimes don’t seat right away, or need additional tightening. It is possible to have a minor leak that will suck air but not leak fluid; try wetting the fittings you suspect and putting pressure to the system while watching for bubbles.