Drivetrain Rear axle difficult to slide in

So, wrapping up a rear disk conversion on my 89LX, and had an issue that’s concerning me on the rear axle:

When the caliper mounting plate is installed on the axle housing, the axle is very difficult to slide in. I’ll define very difficult as: to install, both palms on the hub with fingers on the backing plate and I have to firmly squeeze. To remove, I have to put a foot on the LCA for leverage to pull out. When the axle is seated/installed, it spins just fine with not binding (can spin the axle with one hand.

Here’s the rub: if I remove the caliper mounting plate, the axle slides in easy-peasy with finger tips. The caliper mounting bracket is a brand new Ford piece, and the axle shout was cleaned (first a screw driver to remove flakes, then a wire brush/scotch pad and brake cleaner).

Could the mounting plate really be deforming the axle housing that much? Has anyone ever had this issue?

That’s the plan. It went up flat, bolts drew down real easy. But am going to pop it off and check those points.

Even Ford Tech said “we’ve never heard of that. Check the mating surfaces and hardware”

giddyup306 said:

My vote goes for hardware. The only time I have seen any axle housing distort by any amount worth noting is on the 9.75" that you have to spread the pumpkin to get the gears in and out. And the cases are made from aluminum. Are the mounting plates on the wrong side by chance? Had that happen once when I was putting the brackets that hold the pads in were on the wrong side preventing the wheel from going on correct. Never saw that before or after. My boss was a Master ASE tech and he said he never saw it either.

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Correct side/face thankfully. I seem to find new and improved way to break these cars... My buddy initially forced the plate on when we first installed, so it had to be a hardware issue. We finally fixed it though

The ears on the axle shaft were bent a bit - enough the bolts were difficult to get out. A few taps the BFH and a check with a square to get straight to the eye. Then took a wire brush/metal file to really clean the mounting surface take down any bumps/clear any rust or gunks build up. Finally we checked the caliper plate for true (look perfect to the eye, these Ford pieces are beefy...) and cleaned up the holes so the bolts easily go in/out.

After all of that, the axle was significantly easier to slide in, but still a little more resistance than I liked - so we took a brass drift and carefully tapped on the bolts (from the outside, not the bolt head side and witht he caliper plates properly torqued down) and the axles slid super easy/smooth in an out. New bearings/seals to be safe and everything is like stock