Heard something today from a reliable source. My buddy had his 87 softail bottom end rebuilt well actually he had the entire motor rebuilt from the same harley mechanic that did my bottom end. Last summer both of us found that the bottom end case bolt had some seepage, he loosened off his bolts one at a time and put some CAT thread dressing (like silicone ) on the threads and under the heads, this sealed up the seepage for about 1000 miles and it started again. He went back to the mechanic and expressed his concern, the mechanic told him to swap out the casing bolts with the S&S stud kit, the mechanic said this happens with every EVO motor hes done unless there swapped out.
Anyone else ever come across this?

 

Never heard of that, but I couldn't tell you it's not true.
The cases are sealed with sealer & no gasket so the mating surfaces must be very clean & close in tolerance.
This thread will be interesting to follow!
Hatch.

 

I'm hoping it gets some replies, unless no one has ever done the bottom ends.

 

My case would leak where it splits,in the winter but never on the bolt ends. I tightened all of them this past summer when I rebuilt the top end and now it doesn't leak in the center.

 

I'm never retorqued the bolts on the bottom end since it was reconditioned , good idea.

 

Well... first off let me make perfectly clear I am in no way trashing or questioning the skill of the mechanic mentioned in post #1. I wasn't "there" when they were assembled and I don't knock anyone's work without first-hand knowledge of the person, situation, conditions and parts used...

So, sorry if I cut a potentially mega-response thread short, but I've split and reassembled a good number of cases over the past 8 years or so (some more than once for this very problem) and if it leaks out the bolt heads (there are only 4) or from any of the stud nuts, and assuming the parts that were used were in serviceable condition, either the case was improperly assembled, and/or improperly sealed - period!

There are a couple very narrow seam areas to seal on the cases. Too much sealant makes a mess and too little... well you already know that answer. There is one "cheat" that works 80% of the time if it's simply weeping from a hex nut or bolt head. Using the copper washers supplied in a top-end or engine gasket kit, and using a uni-bit graduated in 1/32" carefully drill out the 1/4" copper washers to 5/16" and install them on the leaking stud (or bolt) with no lock washer and torque it to the "high end" of specs which is 15-17 ft/lb. Don't go over 20. Those particular washers will be virtually "hidden" under the nuts or bolt heads because of the smaller OD and are a perfect thickness/softness to do the job... if anything will. And yes, I have tried injecting various sealers into the bores as a helper, but seriously from my experience, if the copper washer trick doesn't stop it, time to split the cases again.

 

The sealer that goes between the case halves hold the halves about a thou apart. If the sealer is either applied wrong or isn't applied all the way around the boss for the case bolts that thou of clearance will allow oil to migrate out of the case bolt holes. This as previously stated is usually the reason for leaks in this area.