I am rebuilding a front axle. The one I have came from a 26 coupe that was hot rodded and is quite rusty. What are my chances of success in removing the spring perches by soaking with penetrating oil and using a 20 ton Harbor Freight press? Can I get them out without using a hot wrench?
Sometimes you get lucky and they come out easily, but usually not. Many times trying to just press the perch out will squash the end into a mushroom. Before applying the press, fill the cotter pin hole with a piece of nail or welding rod so the hole won't squash. Then put a nut on the end to keep it from spreading. Here's the info on penetrants:
Penetrating oil comparison
Machinist’s Workshop magazine actually tested penetrants for break out torque on rusted nuts. Significant results! They are below, as forwarded by an ex-student and professional machinist, Bud Baker. Don’t forget the April 2007 “Machinist’s Workshop” magazine comparison test.
They arranged a subjective test of all the popular penetrants with the control being the torque required to remove the nut from a “scientifically rusted” environment.
Penetrating oil ….. Average load...Cost per ounce
None ................. 516 pounds
WD-40 .............. 238 pounds ... 25¢
PB Blaster ......... 214 pounds ... 35¢
Liquid Wrench ... 127 pounds ... 21¢
Kano Kroil ........ 106 pounds ... 75¢
ATF-Acetone mix.. 53 pounds ... 10¢
The ATF-Acetone mix was a “home brew” mix of 50 – 50 automatic transmission fluid and acetone. Note the “home brew” was better than any commercial product in this one particular test. Note also that “Liquid Wrench” is about as good as “Kroil” for about 20% of the price. Your experience may vary, etc., etc.
Here's what worked for me.
Remove the perch nuts and then put the nut back on the stud (loosely). Jack the car up by placing a bottle jack under the perch stud nut. I then struck the top of the axle next to the perch with a 5 lb hand sledge.
Three or four raps and the perch popped right out. Won't work every time, but the combination of the constant upward pressure and the shock from the sledge seems to work well.
Incredible. . . almost unbelieveable, Bud. Was your front axle inundated in cosmoline for the last 85 years? And you use no penetrating oil or the oxyacetylene wrench? Ted, you'll not like my 'best practices' because they entail a 30 ton press and torch. No, not propane. I'll put a nut back on the perch threads - level with the bottom of the perch - and put slight hydraulic pressure on it. Then oxyacetylene both sides of the front axle where the perch goes through until you hear the '30-06' shot. The heat won't hurt the axle or the perch. Somebody smarter than me declared that on this Forum. This item has been discussed on a number of occasions here
You've already got good answers, Ted, but here's another thread: http://www.mtfca.com/cgi-bin/discus/show.cgi?tpc=331880&post=527901 where I described my recent perch removal experience. The good old hot wrench was indeed necessary due to lack of a nearby press. From may 30th: "I removed a perch from a rusty axle a couple of weeks ago. Took lots of heat from the acy/oxy torch on the axle until I could turn the axle with the perch fastened in a vice. Took even more heat until I could put press on the axle with a spud bar while turning it, then slowly I could get the axle off the stationary perch in the vice.
Took some time - should probably have driven the 15 miles to a friend instead - he has a large press. There's a big risk to damage the threads when using a press, though, maybe a special push tool can be made in the lathe that threads on the perch a few threads but still has a small enough diameter to go through the hole in the axle?"
Roger, theres absolutely no risk of thread damage if you reinstall a nut on the perch. I prefer not to use the original special perch nut because of the bevel on one end and the castellations on the other. I can understand thread damage to a particularly aggravating and stuck perch if you simply put a nail through the cotter key hole and hydraulically press on the threads tho'. When you press the perch out to where the nut reaches the bottom of the axle, remove the nut and use a 1/2" deep well socket or something similar. Watch out ! the axle is very hot!!
Have you tried a long bar inside the perch and trying to rotate it. Sometimes if you can get it to rotate, it will then press right out. If the perch is reusable, it might be best to leave it in place. If you want to replace it, the press would be best method. If you want to save the axle, do not hit it with a sledge hammer. You might even leave it in the press under pressure overnight and see if it breaks loose.
One of our club members has removed many perches quick and fast with a heavy duty air chisel. He has a pointed chisel that fits the little dimple on the perch. The hammering and vibration just pushes them right out of the axle with no damage. I had to see it to believe it.
I've never seen a perch removed with an air chisel, but I have seen them move rusted in pieces that I thought would take explosives to separate.
Your suggestion is a good one. I just hope i can remember it for my next "rusted in place" job.