Primary Oil Leak ? Maybe not

[TimH]

Think Ive seen this mentioned before. Last year my compensator gave up the ghost so I replaced with a new SE unit. Around the same time my front pulley came loose and chewed its spline so a new one of them too. Had a nasty oil leak which seemed to be the rear Primary Seal and the main transmission seal so all new in there. Finally got it all repaired towards end of summer and everything was good. But then a month or two back I noticed a fair bit of oil around the Primary drain plug, not dripping but quite wet, I cleaned it all off and monitored. Couple of weeks later wet again, bugger I think what's leaking now. But then I notice the front of the engine below the Stator grommet very wet so I clean up that area, pull the grommet forward and RTV it. And that seems to be it, happy days, the oil was obviously being blown back from there. Happy Bunny.

 

[SJC69]

What tends to happen is when on the stand on most H-Ds with alloy primaries the drain plug is the lowest point and near the back, so any oil tends to migrate down to there and drip.

An old tip for finding oil leaks and small weeps is to dust the area with 'french chalk' (these day in reality just use talcum powder) and any weep will show up quite quickly, you don't need much, it will not blow off on a short run.

Don't cover the whole area in thick powder, just lightly and apply it with a brush. (Steal one of the misses fluffy make-up brushes is ideal for the job)
I've found a couple of very small hairline cracks on engine cases with this method and eliminated the possibility of a cracked case by the oil pressure switch on another, it turned out to be the oil filter housing above weeping!