Two piece lower unit

[papajax]

Help, I am trying to separate the two halfs of the lower unit to a 40hp Force. In changing the impeller, I removed the shift pivot pin ( OOPs Genious!). It has a short stud in the rear of the gear housing and then a longer stud on the other end. I've removed the nuts, used Liquid Wrench, used heat, still won't budge. Any suggestions would be greatly appreciated.

thanks

 

[Frank Acampora]

Re: Two piece lower unit

Poor design! The long stud in the front goes through an equally long hole and it is only sealed by the gearcase gasket. When running, the gasket has all the water pressure against it and some weeps into the hole, so, of course, it corrodes tight.

Unfortunately, the pinion bearing rides in between the two halves so you can't even try spinning the lower half off.

You can TRY double nutting the stud and really lay into them, then try to back off the stud---but realistically, it's a last ditch effort and probably isn't going to work.

So: you are left with heating and beating on the end of the stud. You will probably need to beat it so hard that the stud will be bent. At a minimum, the threads will be dicked-up.

If you do get it apart, when you reassemble, remember the magical powers of gobs of anti-seize. And try some RTV silicone under the washer and nut to attempt to seal it.

Sorry, but good luck.

 

[nathanglasgow]

Re: Two piece lower unit

Had a similar problem on a 1975 30hp chrysler that needed pinion gear replacement.In the end i had to cut the long stud by using a hack saw on the upper part of the two part housing and sawing through the part where the stud passed through.This was after using using heat and i mean heat almost to the point of melting the ali housing with oxy actyl torch and smacking with sledge hammer.All that did was wreck the stud so cutting into the housing was a final solution.After the two were apart i could drive the remains of the stud out using heat and and a two day soak in diesel oil.The part of the stud that remained in the lower gear casing had to be drilled out (what a B***H that was) and retaped and a new stainless stud used.I have the ability to weld ali so the damage caused by cutting was repaired.In retrospect a replacement lower unit would have been easier but these are hard to find in Scotland.I would imagine if you are in the States these are plentiful so save yourselfe all the grief and get a second hand unit.