Leak at RPM/TDC sensor

[savagehenry]

Have done plenty of searches, haven't found this one yet.

 

It looks like I have a leak at my RPM/TDC sensor. It appears to be an O ring, and a proper thickness shim (there are 7 sizes listed to maintain the .028-.036 gap) will do the trick from looking at the drawings. Can I just use my old shim? Or is there some reason this will this require pulling the timing cover to verify that gap? Any advice from the previously initiated would be appreciated, thanks in advance.

 

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[Admin Jaap]

I used the original shim with a bit of liquid gasket on both sides of the shim. No more leaks.

[Guest ratchethack]

SH, this has come up several times. Yes, use the factory issue shims, and be careful! They're very soft aluminum, and bend very easily! Mine are .025" and .030". There's just about no circumstance that would alter the clearance, unless you've futzed with the shims. One guy awhile back evidently arbitrarily took out the shims and the teeth of the phase sensor wheel chewed into the sensor. Not good.

 

I've no "silver bullet" for you. Like Jaap, I've tried progressively more "aggressive" sealants on this, each time believing the problem to be solved after a few days with no seep, only to have it show up later. . . The problem seems to be unusually tenacious due to the location of the sensor, which (contrary to wot might be expected from external appearances) evidently picks up unusually high direct oil pressure on the inside from oil slung off the timing chain. I find that longish rides on warmish days will invariably overwhelm the o-ring (tried replacing mine, and using sealant very sparingly on it -- no joy). It seems to be a challenging application for sealants, since the joint has such a tiny surface area, and it uses a critical shim in place of a gasket, which would at least provide something for the sealant to "bite into".

 

Best I've come up with is, "Grin & bear it until you can't any longer, then wipe/clean it off."

[Guest frankdugo]

there is a drawing in the factory shop manual for clearance mesurement.as jap &rachet said a little silicone.took mine off,just for previent maintence.luckilly no leak.