Ford Fiesta mk6 issue with rear axle bracket bolts. They wont screw in all the way when trying to tighten them to the chassis.

[SparkEli]

Hello, I have replaced my axle bushes as advised from the mechanic who carried out the MOT. I got some powerflex bushes and installed them. I bolted on the bracket with no issues. When I was trying to attach the brackets to the chassis the bolts won't screw in all the way. They stand about a cm away from the bracket and there is a lot of resistance. So much so I have to put a lot of effort into it. I'm not sure what to do next. I don't want to damage the internal threads and the bolts I have are all brand new genuine replacements. Any advice on what to do next? TIA 

[unofix]

Are you using new bolts ?

What length are the bolts you are using ?

 

[isetta]

Have you compared the new bolts to the old to check the comparative length. And using the same washers?  Although the gap you mention is more than washer thickness