Leaking oil cooler
Hey jon*jon**, I have a '90 73. My oil cooler sprung a leak also. To remove it, I followed this procedure:
1. drain oil, 2. Drain antifreeze, 3. disconnect telescopic portion of steering column (one bolt at top, in the universal knuckle and one bolt w/ 10mm wrench head at split collar which attaches to steering box splined input.) 4.Adjust the power steering pump so to slacken the belt. 5. Remove the P.S. Pump and its bracket as a unified unit. 6. use a small needle nose vise grip or a hose clamp plier to pinch off the power steering hose which is attached to the nipple on the power steering pump reservoir's bottom rear side and the pull that hose off the reservoir. (my reservoir is plastic and the hose slips on and is secured with a pinch type hose clamp) 7. I was able to set the pump aside and rest it atop the air filter housing. Beware of fluid leaking from the reservoir. You may need to cap it. I used a flexible vinyl cap of the sort that is used to protect the end of a tube, cap a vacuum line or cover the rough end of a cut end of a typical closet shelf wire end. 8. Remove the radiator hose from left (driver's) side of Rad. Take the hose out of the truck. 9. If you want more space, you can remove the weather neck, by which the rad hose was connected to the block. I did not remove that part but managed to work with it in place. 10. remove the bolts from the cooler and wrangle it out of place. Watch out for oil and coolant which will spill from the cooler. I got the cooler to exit downward and had a helper support it while I manipulated it. It actually came out quite easily.
Cooler remediation: Mine was rusty, crusty and greasy. I degreased, scraped and wire wheeled it. I then used a screw driver and then an "O" ring pick to clean the circumference where the steel tube met each aluminum header. I then soaked the mating positions with Aerokroil from Kano Labs. Any good penetrating oil ought to help. I carefully knocked off one header with an oak block against the edge of the header mouth, setting the oak against the aluminum and hitting the block with a steel hammer. I applied blows alternatively to one side of the mouth and then the other so I did not **** the assembly. The second side did not want to budge, so I juiced it up again with Aerokroil and held it vertically, the casting down, above a pile of shop rags (to protect against it being damaged when it flew off and hit the bench or the floor). I then repeatedly struck all around the edge of the casting mouth directly with a steel hammer (about 12 ounces). I hit it pretty hard but stayed mindful to not break the casting edge. After about three minuted of persuasive beating, the casting broke loose but did not separate. One of the seals ("O" ring) was brittle and held the tube in the casting. I was able to break up and remove the brittle "o" ring in pieces and then the assembly came apart. I cleaned up all parts, removing oxidation from mating surfaces, and carefully scraped off the old gaskets. Got new seals and gaskets from Ford dealer (about $70.00). I had some pin holes which I brazed closed and I slathered more braze over some of the thinner sections of the pipe which had been compromised by rust pitting and flaking. Before you braze, I recommend rinsing the finned core of the cooler tube thoroughly with solvents and then blowing it dry with compressed air, to evaporate the solvents, unless you like fire and smoke. I chipped off most of the hardened braze flux and thoroughly degreased the tube exterior with old fashioned Brake Clean. Then I painted the exposed part of the tube with Rustoleum Rust Reformer spray paint. I will apply a coat of spray enamel and then reassemble everything, with plenty of Vaseline on the "O" rings. I've read that the headers ought to be pressed onto the tube. I suspect that is best to do for good control of the assembling procedure. I do not think the press is needed for its force capability but is desirable to use for ability to control the process. Be sure to align the cooler tube entry and exit ports with the corresponding ports in the header castings.
I suppose larger holes in the tube can be restored with some bits of heavier sheet metal and careful brazing. It is a bit of a rig job, but then, do you plan on driving this rig til your dying day?
Remember to clean your bolts and use anti-sieze compound.
I also pulled apart the telescopic steering column section, cleaned and greased it.
That e-bay oil cooler looked pretty good and I would have tried to snag it if I had known earlier.
I expected a tougher job than it turned out to be. Good luck!