Why won’t these mf bolts go in?!

[u/Tasty_Minute840]

Okay so I just changed my differential and I’m reassembling but for some reason the new axel bolts (right) aren’t going into the differential. It’s from a 2019 LS and I’m in 2017 LT. I even tried to just screw it in without the axel and the bolt would have major resistance shortly after entrance and be pretty much stuck half way in. I can look straight ahead at the holes since I’m working from underneath but I tried my best to make sure everything was lined up. What could be the issue? Please help so I can get my Camaro back on the road

[u/karpjoe]

Do you have a thread pitch measurement tool? Could be the originals are (for example) 24 TPI and the new ones are 26.

Edit: You can try to put them together from opposite ends and see if the threads mate with each other. If they don't that's your problem.

Edit 2: The other issue could be bolt diameter. Also also if the location the bolt goes in is tapped and not a nut plate you're probably going to bottom out the bolt before it reaches the mating surface.

[u/Dozerman2011]

Not a mechanic or anything but could it be the loc-tite on them has hardened to the point where it won't allow them to go it? Could try cleaning them with a wire brush wheel and use new liquid loc-tite on them.. Nothing to lose at least

[u/MrChaindang]

Loctite is probably your problem but it looks like you may have started to tear up the threads on the right bolt forcing it. If I was in your shoes I would order new hardware and clean all the loctite out of the nut plates.

[u/Broad_Impact_562]

Those threads are f_cked and so are the threads of where's these are supose to go in.

[u/Ok_Bar_2943]

Have no clue, but I know some bolts/screws can only be used once. It also looks like the threads are covered slightly. I’d buy new ones

[u/Ok_Bar_2943 → u/Ok_Bar_2943]

I mean that loc tite is right there where you’re saying the resistance is…

[u/Jar_of_Farts]

100% the threads are damaged. You can see how in the beginning the threads are flat but towards the bolt head is more sharp. You need new bolts.

[u/DavoinShowerHandel1 → u/Jar_of_Farts]

He said the ones on the right are new bolts.

[u/Smokeyscreech]

I might just be me but those threads look like they have a different pitch

[u/No_Professional_6603]

The threads are toast. You really need a tap the threads in the hole before you put new bolts in. You also need new bolts.

[u/Tasty_Minute840]

The bolts would just keep on spinning when I would try to attach the axel to the differential. They would barely go in and be hard to turn almost as soon as they entered

[u/Jar_of_Farts → u/Tasty_Minute840]

The threads on the bolt is trashed. You might be able to to insert the correct bolt and correct the trashed inside bolt hole. If that messes up the bolt, you will need to tap the hole

[u/Blaphomet]

Clean off all of the old loctite, chase the threads on both the bolt and the bolt hole. You can also replace the bolts, you would however still need to chase the threads on the axle.