1975 620 Leaking Differential

[B-rads PL620]

Hello all,

Just finished pulling my rear leaf springs for a bushing replacement, rear eyelet bushings had worn through the rubber for a metal on metal fit, “WOW”,  but in the process I have a rear differential gasket leak, a small one but it has over the years coated the diff with an oil crust. Long story short, if I split the differential will I be opening a Pandora’s box? Things dropping out on the floor? Or can I split it, replace the gasket and slide the half’s back together, any help out there would be greatly appreciated, Thank all. Have a peaceful day and make someone smile, you will not believe how that would make you feel like, let alone that someone. Food for thought.

[datzenmike]

Nothing will fall out but un-drained oil.

 

You'll need to unbolt the backing plates from the axle tubes and yank them with the axles out about 4" to disconnect the spline from the differential. There may be enough brake line slack to do this. If not the lines on each side will need to be unscrewed and the system bled when done. This might be the better way as the axle can be removed and not left in unsupported and crushing the soft wheel bearing seals.

 

Now you are free to disconnect the 3rd member after draining the oil and removing the drive shaft.  Mark it so it goes on the same position it came off. Be prepared, it's fucking awkward and HEAVY. Scrap ALL gasket or sealer off the housing and the 3rd member. Degrease with brake or carburetor spray. I don't think the gaskets are available anymore. I used Permatex Blue  Gasket Maker. Follow the directions. Don't overdo it! Almost all will pinch out anyway and what pinches out also pinches IN. Let sit for 10 minutes I think, to set, then assemble.   

 

 

 

[B-rads PL620]

Thank you so much, was worried, not much knowledge on differentials, picked up a gasket on eBay, hope it works, says direct fit, we will see, but good to have a plan B, diff is basically out of truck as I am in the process of replacing leaf spring bushing. Worried about the old brake lines and taking them apart right now, think that’s another project down the road so to speak, hope that’s not literally! Thanks again.

[datzenmike]

You can buy pre-made brake lines of various lengths. Just remove the old ones and get something at least that length. If you have a flaring tool you can even shorten them.

[Goemon]

If you are going to mess with brake lines, invest in a good line wrench.
One that is thick and won't flex.