Axle U-bolt groove

[Litdave]

I was just wondering. I am in the process of installing 5-lug disk on front of my 69 and swapping in a 5-lug rear on back.

My question is; so far I have pulled two different axles and both of them have (what looks to me pretty deep) grooves worn in the axle housing where the u-bolts hold it to the control arms.

Is this common? Is it a concern as for as weakening the axle? How thick is the axle housing?

I could fill in the groove with weld and grind it smooth but I am afraid that the welding would pull the axle tube out-of-line and give me bearing problems.

Any response would be appreciated.

Thanks, Litdave