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  #1  
Old 04-13-2020, 04:55 PM
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Easy R.M.seal fix, Sorta.

Cleaned up skid plate and wiped underside of motor area to find oil leak. Bingo, rear main seal. No way to fix economically on this old X. SO, to stop the leak, I simply park on a forward incline, no more leaking. Of course this only works on a forward incline. Oh well. PS. To much work for 255K miles 20 year old X5.
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  #2  
Old 04-15-2020, 04:43 PM
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Quote:
Originally Posted by Bmwtvboy View Post
Cleaned up skid plate and wiped underside of motor area to find oil leak. Bingo, rear main seal. No way to fix economically on this old X. SO, to stop the leak, I simply park on a forward incline, no more leaking. Of course this only works on a forward incline. Oh well. PS. To much work for 255K miles 20 year old X5.
try using a bottle of AT-205 reseal. can improve the leaking by 20-80 percent from what I've found. it also pays to buy a second bottle, pour into a trigger sprayer, and aim it so that it can soak the outside surface of the seal if possible.

There's nothing you can really do as all seals will leak due to time. Perhaps the best way to prevent leakage is using synthetic seal materials along with synthetic oils, and occasionally adding AT-205 to the oil. But there's been no scientific tests done.

Here's some literature of interest from FALK ;
Quote:
SEAL LIFE
Seal manufacturers today will not make a public statement
regarding seal life. However, statements made several years
ago in the literature (8) indicates that “long life” is considered
to be more than 1000 hours before leakage results, that
“medium life” is defined as leakage beginning at 400-600
hours of operation and that “short life” is 100 hours. In
another paper (9) it is pointed out that a Nitrile material
“withstands temperatures of 100-200E at surface speeds of
200 fpm for approximately 3000 hours. Viton would last
longer possibly up to 10,000 hours. Information given to Falk
in 1965 by Chicago Rawhide indicated that the seal life for a
Nitrile seal at 200E was 3000 hours. Apparently their studies
did not consider seal life at lower temperatures. A more recent
paper (10) reveals data regarding seal tests where it is
indicated that a criteria of success is to operate without
leakage for a period of 100 to 500 hours, and that from a
test of 10 seals they all leaked within 1100 hours. The
following statement made in this paper can best summarize
the performance of contact seals:
“All seals will leak if run long enough at a given set of
conditions. Material, process, design and test variations
will result in variations in time to leakage.”
SEAL LEAKAGE
Information regarding degree of leakage is impossible to
obtain from seal manufacturers. The only definitive
information uncovered (8) indicates that most synthetic seals
(about 80%) leak .002 grams/hr. or approximately one drop
every 11 hours. This is not considered to be troublesome by
some persons. About 15% of synthetic seals leak .002-0.100
grams/hr. (approximately 1 drop per 11 hours to 1 drop per
11 minutes), a rate which is considered borderline. If the
leakage rate is in excess of 0.10 grams/hour the seal can be
considered defective, misapplied or misspecified.
SUMMARY
Precise performance criteria for contact seals is impossible to
obtain from seal manufacturers. The following statement is
based on the years of experience that Falk has had with the
application of contact oil seals in their products and must be
regarded as a tentative standard by which to measure seal
performance.
All contact type oil seals used in enclosed gear drives will leak
if operated long enough. The variation in time before leakage
occurs will depend on the material of the seal, the operating
temperature of the gear drive and lubricant, the type of
lubricant used, the quality of the seal-shaft surface interface
and the environment in which the gear drive operates. A
wetting of the surface may commence shortly after the startup
of a gear drive and may then progress to the formation of
droplets. Unusual operating conditions would accelerate the
leakage.
REFERENCES
(1) “Analysis of Tapered Roller Bearing Damage”, Widner
and Wolfe, American Society for Metals, Report
C-7-11.1, October 1967.
(2) “How to Recognize and Prevent Tapered Roller Bearing
Damage”, The Timken Company, Canton, Ohio, 1970.
(3) “Bearing Failures and Their Causes”, SKF Industries,
King of Prussia, Pa., 1968.
(4) “Spherical Roller Bearing Service Damage and Causes”,
The Torrington Co., South Bend, Indiana, 1960.
(5) “How to Prevent Ball Bearing Failures”, the Fafnir
Bearing Company, Form 493.
(6) “Fatigue Prevention by Lubricant Chemistry”,Mobil Oil
Corporation Publication.
(7) “The Effect of Water in Lubricating Oil on Bearing
Fatigue Life”, Richard Cantley, ASLE Paper
76-AM-713-1, May 1976.
(8) 1973-1974 Seals Reference Issue - Machine Design,
September 13, 1973, page 22, Penton Press, Cleveland,
Ohio.
(9) “The Fluoroelastomer Seal: A Stronger Link”, Daniel B.
Jackson, (Manager R & D, Parker Seal Company), Power
Transmission Design, July 1971.
(10) “Statistical Interpretation of Shaft Seal Performance”,
Leslie Horve, SAE Paper 741044, October 1974.
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  #3  
Old 04-16-2020, 01:44 PM
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May try that. Mix opinions on additives. Difficult to spray as it is under the transmission bell housing cover. Again, its not that bad, especially since parking on the incline.
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