Is there a trick to installing pushrod tubes in my 79 RS? I don't want to force them for fear of damaging them.

The trick to installing the tubes is in the preparation. The actual installation will take seconds, if you've got everything ready. If you're not ready, destroying the tubes, and possibly the cylinders, takes only fractionally longer.

First, you need a stepped mandrel to drive the tubes in. Once you have the right mandrel, you can begin the process.

(but where do i get a mandrel?),

/2 and early /5 owners can use their front axle; the rest of us will have to make one: imagine a broomstick poked in a pencil sharpener.

First, measure the amount that the new tubes project from the cylinder flange to the stop ring for the rubbers. This is the critical distance, and there is no 'stop' to assure you of proper installation depth. I also make a mark inside the cylinder hole where the tube ends.

Chamfer the edges of the tubes where they enter the cylinder using a little stone or sandpaper. Now you prepare the new tubes by cleaning them thoroughly and stuffing all but one tube with strips of rag soaked in water.

Put the axle in the last one. Set all the tubes, and the axle, into the freezer overnight. Wrap in paper and mark "Fish Bait" or "Fresh Liver" to be sure nobody eats them. Don't remove from the freezer until you're totally ready to install them.

Remove the old tubes from the cylinder. The easiest way I've found is to grip them right above the seal stop ring with a pair of vise-grips, heat the cylinder around the tube, and hammer smartly (never hammer dumbly) on the vise-grips to knock the tubes out. Try to go nice and straight, and don't
crush the tube. They ought to come out pretty easily.

Now chamfer the lower edges of the tube bores in the cylinder so that the new tubes will start in easily. Clean the inside of the bores with a brass bristle brush. Wash the cylinders completely with solvent and rinse with hot, soapy water, followed by hot clear water.

Heat the cylinders to 200 degrees F in the oven to dry and expand them. Remove from the oven, and keep heating the area of the tube bores with a commercial heat gun or BernzoMatic MAPP gas torch held at a short distance away. They're hot enough when a little goober* of spit, applied with your fingertip, sizzles away fast and loudly.

Pull the axle and tube from the freezer, line it up in the bore, and push it in, assisted with a steel hammer on the axle, until it is seated to the correct depth. This has to happen very fast, or the tube will stick, and you'll be tempted to hit it again, which will crush the tube and gouge out the bore. (If you've planned ahead and gotten an extra tube, you can knock out the tube and try again with a new one.)

When the tubes are installed, set the cylinder aside to cool, return the axle to the freezer for a bit, and then go on to the next cylinder. Use the axle to push the frozen bits of rag out of the tube as you're ready to install.

When everything is cooled off, drip a couple drops of Green "Wicking" Loctite around the tubes where they enter the cylinder, to prevent oil seepage and air leaks.

See, easy, huh?

-Tom Cutter


*This is a technical term, meaning "more than a drop, but not quite a
dollop."

(Originally posted to the AIrheads list)