So what else could go wrong...everything is starting to leak....on my 71 F-100, the rearend is leaking. It appears that it is coming out of the third member, where it bolts to the housing. Has anyone ever had this happen and how hard is it to fix?

 

pull tha axles out about a foot by unbolting the axle backing plates by the rear brakes. Next unbolt the U joint then unbolt the pumpkin and remove from housing, whip out all the old fluid scrap the gasket off any surface install new gasket then reverse the job to assemble. If you don't know about your rear axle bearing this would be the time to replace them and don't forget the new axle face plate gaskets and seals.

 

The seal is very small (paper thin) back there, have you tried snugging up the nuts on the housing? I would try that first, and then reseal it if that doesn't work.

John

 

> foot by unbolting the axle backing plates by the rear brakes

If leaving the axles in the housing, make sure you support the axles on the end so you do not damage your axle seals. You might damage the lower part of the rubber seal, where you need it the most. Been there, done that.

In my experience tightening a leaking rear end does little. The damage is already done to the gasket and the space has filled up with road junk and axle junk and probably the 3rd member was not torqued correctly.

What has worked for me is to completely clean both the 3rd member mating surface and the housing down to bare metal (light sanding if required), clean with brake clean on a towel (dont overspray into the housing or unto the gears unless you intend to clean out the whole housing). Let it dry for ten minutes. Then apply BLACK RTV and smear a thin layer over the housing and goop around the base of the studs (!) near the bottom while avoiding the threads. Apply the paper gasket to the 3rd member (gasket glue is okay) and install. Torque to spec. The lower bolts you have to guess at since a socket will not fit, though if you alternate going around the housing (left to right, top to bottom) it will snug down fine.

Take a gallon of gear oil and put it in front of your brake pedal. Because you are going to let the gasket cure for at least a couple of hours and this way you will not drive on a dry rear axle. If possible I let mine cure overnight, though on a customer's vehicle, since everyone is in a rush, I just fill it.

I have used this basic procedure on everything from Explorers with plastic diff covers to my 1971 F-100 with no leaks.

When you have your 3rd member out, check the housing for cracks, but, especially check the 3rd member for cracks around where the studs go. If you have cracks you can fill them with JB Weld (not quick) and it should be a repair that will hold. Though the best thing is a new/used 3rd member.

 

Thanks yall....I was in tennessee visitin the girlfriend so I havent been on the internet....i tightened the bolts and it worked....now the u joint is going out and vibrating me to death....thanks for the help yall