traction rear crankshaft seal

C

CARPETSNAKE

Member
Tadpole
Joined
Feb 13, 2012
Messages
33
Location
vermont sth, melbourne
Hi All,
Hopefully someone has had experience with this problem: I have tried three times to fix the leak from the rear crankshaft seal on my 1954 L15 but without success. The first time I used a rope type seal. The last time was with the newer rubber split seal but still it leaked badly. I am about to try again with a new split seal. Is there anything I have to be careful about when fitting the seal? I have previously used plenty of sealant as an extra precaution. I am very frustrated with taking the engine out all the time and would appreciate any tips to solve this problem.
Thanks in advance,
Rod (carpetsnake)
 
I have not done one of these engines, but done plenty with the rope type seals & a few where the more modern neoprene seal halves have been used to replace the older rope one.

The important things to note are that the crankshaft is perfectly true not grooved or rust pitted....'fitted properly' the rope seal can be a little bit more forgiving, but the neoprene type will leak with pitting or grooved journals.

The rope seals of old used to be an asbestos fibre compound & impregnated with graphite & pre-lubed.
Not sure about now, but the journal & seal lip no matter what type need to be lubed when fitting.

From what I can glean the seal is held to the rear of the engine block with 2 aluminium halves. These do two things ~ hold the seals tightly in place & compress the seal ends together [if one correct length or halves together] to seal the ends & stop oil wicking.

It is important theses aluminium halves are perfectly flat then tightened progressively to torque just like an engine head.
Over-tightening will distort these & the seal & this can contribute to leaking issues. If warped they need to be planed to flat.

Depending on what the technical manual says sealant is only used in specific places & definitely not in others, like the ends of the seals.
Mis-using & too much sealant [especially of the wrong type] will also contribute to leaking.

Neoprene seals must always be installed with the lip toward the oil to be retained.
If either type of seal is in 2 halves the seal ends must be indexed @ least 10* off the the 2 aluminium half ends.

All in all the new seal must be tightly held in place to form a perfect concentric circle with the crank journal with adequate force plus hold the seal ends together tightly enough to become one. Without pistons etc fitted there will be a noticeable drag when a new seal has been fitted.

Mechanics know what this feel should be. It is harder to gauge on an assembled engine but possible with turning the crank before the seal is installed & after & gauging the difference.

Take the time to watch this video [not the same engine obviously] but it will explain the intricacies of fitting a rope seal & get an understanding for what is involved.


https://osl282.info/page.php?18
 
Checking the manual shows you need to press in the packing as the manual shows
Rear Main seal page 15A, quite fascinating pictures actually
 
Page 15A is not dissimilar to that shown in any manual [or the Hoden video] of the era & how mechanics were taught to fit these 2 part 'rope' seals.
Other good methods are leaning on & using the old lady's rolling pin, or very large socket/piece of exhaust tubing & hammering around to seat the seal in the groove.
The only thing in the video I don't do is stake the seal or use as much sealant. Be very careful not to remove too much of the rope as being correct will form a tight seal. Don't forget to index after cutting & re-seating as stated earlier & don't damage the crank with the cutting tool!
I think the OP now needs to apply the knowledge he was most likely unaware of when fitting the last couple of seals.
 
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