TomP

So someone took the tires off the junkyard car, I had to scrounge for a decent GM spare tire jack (instead of those flimsy import ones), lift the car up, break the rusty bolts free on the diff cover, crawl among bugs and odd looking plants...

And the pinion lock bolt snapped. The guy at the yard said I could try taking a cold chisel to it and splitting the center in half... that would free up the pinion shaft. But there's not much room to move on that junkyard floor. It'd be hard to swing a BFH to drive out the pinion shaft. So I was thinking; what if I can get a drill in there, and drill out the shaft itself. Sound like an idea? Don't really care what happens to this center; it's an open diff anyway.

Then my only problem would be getting a power wire long enough from their office "shack" to the car. Maybe it's time to get a 1000 foot extension cord from Home Depot!

b91z28

I had the same thing happen to me on an '82 Z28. You will be suprized just how easy it is to bust out that center section. Just grab about a 2 or 3 pound sledge with a short handle (so you can get in there) and a beefy punch. Just act as if the small bolt is already taken out, turn the center section so the rear (opposite end of where the small bolt is) is facing out and knock the crap out of it. I resorted to this after trying a number of ideas. Good luck.

Brandon

TomP

Really? Does the bolt itself shear off, or does the pinion shaft crack? Hell, I could buy a 2/3 pound short-handle sledge and a large punch.. I'm sure they'd come in handy for the future. The sledges I have now have 3 foot handles on 'em

b91z28

The bolt did break a little, but mostly it just knocked a big hole in the center that enabled me to remove everything.

Brandon

TomP

Oh, right, okay! Sort of like, screw the bolt, as long as we knock the center pin out, we're good? Makes sense. The bolt can stay in there. You were banging on that shiny pinion shaft, right? Any idea of a diameter of punch that I should buy? I don't have any punches that big... maybe I could use a thick 10.9 bolt?

Or when you said "knocked a big hole in the center", did you mean the center carrier split open?

b91z28

I had an extra complete rear from an '84 Z28, so yes my attitude was screw the bolt as long as we get the center pin out. I have no idea what size punch you need. Just grab one that is just a little smaller than the center pin. Just to make sure we are on the same wave length, you are refering to the big pin that goes right through the center of the carrier, right? The one that is held in place by just one small bolt. The small bolt that from the head there are a few threads then its just basicly a pin with no threads to the end. The little pain in the rear bolt that when it breaks off in there, with no way to get it out it causes the large center pin to be basicly stuck in there. With the big pin stuck in there you can't push in the axels in to remove the C-clips, and without the C-clips removed you can't remove the axels. Without the axels removed (or just slid out a little) you can't remove the center section. Without the center section removed you can't really do anything to the rear. Now imagine having a set of broken spider gears in there that you can't remove in order to replace them. That really drove my decision to just drive the center pin out with a small sledge. By "knocked a big hole in the center", I meant that I drove the center pin , with part of the small retaining bolt still installed, through the other side of the carrier. Without the retaining bolt installed the center pin can slide out of either end of the carrier, so you just need to drive the pin on the opposite side of where the retaining bolt is installed. Either the bolt will shear off or you will knock out a section of the carrier or, like mine, both. A 10.9 bolt might work. I would recommend something flat on both ends. Just make sure the car is supported well, and wear safety glasses . I can tell you all about metal chips in your eye too (twice), and that is no walk in the park. Good luck

Brandon

Jay 727

Yes wear safety glasses and gloves, when you bang on hardened steel little chips can fly of, I had one stick into my arm once.
The part you are trying to bang out is sometimes called the cross pin, it holds the spider gears in, you should bang on it until the bolt just breaks free then turn the differential 180 degrees and pull it out the rest of the way. If it's driven in until it hits the case and stops you will no longer be able to turn the differential, the cross pin won't be clear of the axles and the c clips won't come out. Then you'll need a torch.