New Series IIa - 4x4 engage problems...

Hello all! I'm new to the Land Rover scene, at 20y/o and having previous experience on classis cars I thought I'd embark on finishing a restoration project of a Series IIa with my dad. All is going still need to rehang the doors, sort out seals and other minor things! Having a problem with engagin te 4x4 in high range, the yellow lever just won't lock into place, any advice (am on on teh wrong thread). Hope to hear from you all soon!

there are 3 shafts that poke through the housing 1 has the red knob lever the other 2 covered by the tin cover you will probably find those 2 are sticking in the housing

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