Rear main engine seal leaking, 90,000kms after being replaced ?

Submitted: Friday, Aug 15, 2014 at 15:08
ThreadID: 109145 Views:2485 Replies:4 FollowUps:16
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Hi everyone. 90,000kms ago I had my 4.5L petrol cruisers clutch replaced.
At the time the workshop suggested they also replace the rear main seal.
The seal is now leaking to the point that it needs replacing.
The original seal lasted 3 times longer.
I'm wondering if the seal was replaced ?
I'm not mechanically minded.
Am I being unrealistic ?
Whats your experience been with this problem ?

Thank you.
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Reply By: Slow one - Friday, Aug 15, 2014 at 16:03

Friday, Aug 15, 2014 at 16:03
Bob,
most likely the crank has wear where the old seal cut into it. This is pretty common and the new seal doesn't stand a chance with the uneven surface.

This is the normal method used to overcome the worn seal area.

Have a look HERE speedy seal
AnswerID: 537719

Follow Up By: Ross M - Friday, Aug 15, 2014 at 18:47

Friday, Aug 15, 2014 at 18:47
It may be possible to find a similar seal which has the sealing lip in a different relative depth position and have it fitted, or, the mechanic to be aware of the problem and ensure the seal lip isn't placed into the same position because the same will happen again and again. Usually done by spacing the seal out from the original position if sufficient engineering will allow such a move. Always fitted with sufficient initial lubricant.

OR
maybe speedi sleeve properly fitted with ample lubrication provided for when it is started and begins spinning. Often people don't provide sufficient initial lubrication and the seal life is compromised in the first 30 seconds of it's life after the first start.
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Follow Up By: Slow one - Friday, Aug 15, 2014 at 20:15

Friday, Aug 15, 2014 at 20:15
Yep I did the same thing with my mower, installed a seal that ran in a different position on the shaft. I have also installed speedy sleeves with lots of success on a couple of different engines and axles.
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Follow Up By: Batt's - Saturday, Aug 16, 2014 at 02:59

Saturday, Aug 16, 2014 at 02:59
Something wrong if the rubber has worn a groove in the crank unless you've done an incredible large amount of k's. I would expect the seal may have prematurely failed it happens with mass produced item sometimes. Had my GQ's clutch replaced early in 2011 then the sincro went on first about 4 months later just putting up with it till I need a new clutch which could be a while off yet. Unfortunately your's will need doing because if oil can get out water can get in.
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Follow Up By: Slow one - Saturday, Aug 16, 2014 at 04:58

Saturday, Aug 16, 2014 at 04:58
Batt's,
nothing wrong it is very common for a seal to wear shafts. It was very common for Harmonic balances and axles to be worn.

Both my engines had big hours on them but the cruiser motor is getting up there also.
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Follow Up By: Batt's - Sunday, Aug 17, 2014 at 01:37

Sunday, Aug 17, 2014 at 01:37
Maybe common for some vehicles but I've never had any problems with the 10 or so cars I've owned, my current GQ has 422,000km on the clock when should I expect to have trouble if it happens beyond 500,000 I won't complain. Also never had any wear on axles either most vehicles I've had have had high km on them before I sold them. I recently done all my wheel bearings and no sign of wear you must be unlucky.
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Reply By: Life Member - Terry 80FTE - Friday, Aug 15, 2014 at 20:20

Friday, Aug 15, 2014 at 20:20
More likely the crank sealing surface wasn't prepared properly i.e. cleaned of all carbon then cross hatched with fine wet and dry paper about 800 grit.
Most important fit a genuine Toyota seal. lube lips with vaseline, (that's on the seal:)
The seal retainer should also be removed and resealed with some FIPG sealant as it can leak as well.
Cheers
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Follow Up By: The Bantam - Sunday, Aug 17, 2014 at 09:29

Sunday, Aug 17, 2014 at 09:29
Just to support that, the general consensus is on toyota motors only use genuine crank seals and timeing parts.

There are lots of good non-genuine parts out there for toyotas...but on those two items genuine is the go.

cheers
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Follow Up By: fisho64 - Sunday, Aug 17, 2014 at 22:39

Sunday, Aug 17, 2014 at 22:39
cant say Ive ever heard of cross hatching a lip seal surface-why would you do that?
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Follow Up By: Life Member - Terry 80FTE - Monday, Aug 18, 2014 at 22:00

Monday, Aug 18, 2014 at 22:00
Cross hatching helps the seal bed in, but it also holds some oil to lube the seal.
Don't try to overdo it and only use fine grade grit.

Cheers
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Follow Up By: fisho64 - Monday, Aug 18, 2014 at 22:10

Monday, Aug 18, 2014 at 22:10
as a mechanical fitter,marine engineer-I cant say I have ever heard that nor would I do that on my own engine.
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Follow Up By: Life Member - Terry 80FTE - Tuesday, Aug 19, 2014 at 21:29

Tuesday, Aug 19, 2014 at 21:29
That's how I do them as an "A" Grade Automobile Engineer and Toyota Specialist Technician with 50 years in the trade.

How do you prepare a polished but not worn/grooved surface?

A seal installed by someone that didn't get it right, less than 3000kms

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Follow Up By: fisho64 - Tuesday, Aug 19, 2014 at 21:46

Tuesday, Aug 19, 2014 at 21:46
a polished but not worn/grooved surface is how it comes new?
Just cant say I have ever heard of someone roughening up a hardened ground steel surface so a rubber seal make try to it smooth again

Its a new one on me.
In the pic they maybe "didnt get it right" but Id be suprised if a seal failed most times when the surface wasnt roughened up-it hasnt for me?

Ive had a look thru our CAT workshop manuals for 3406 and 3516 and cant find any mention of it, contrary, to polish it as smooth as possible.

Dont get shirty though, Im just saying I have never heard it and it defies logic for me.

Never mind, its not important
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Follow Up By: The Bantam - Wednesday, Aug 20, 2014 at 21:02

Wednesday, Aug 20, 2014 at 21:02
remember he is talking 800 gritt......that is pretty polished.

Lots of people linish cranks with coraser than that.

more like mildly breaking the glase.

cheers
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Follow Up By: Life Member - Terry 80FTE - Wednesday, Aug 20, 2014 at 21:59

Wednesday, Aug 20, 2014 at 21:59
Generally most people can't replicate a "New" surface finish,
I never said "roughen up"

Not sure what you mean by "a rubber seal make try to it smooth again"

The seal in the photo never failed, in fact looked new, just the sealing surface wasn't prepared properly, that's why it didn't work.

There's more than one way to play with a CAT,
I never read about it in a book either. maybe some old guy told me about it.

Hopefully not shirty, just trying to help others, some times maybe a little short and to the point.

It is important to get it right, so maybe should have added, Not to polish the surface radially

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Follow Up By: The Bantam - Thursday, Aug 21, 2014 at 08:54

Thursday, Aug 21, 2014 at 08:54
There are many precidents in engineering ( automotive and otherwise) of glazed surfaces faililing to seal well or hold oil or do other things they should beacuse they are glazed.

There is also a very real possibility that there may be material deposited either side of the area where the previous seal is running that may impare the function of a new seal.

I cant comment on the necessity of " polishing" or "Linishing" the crank surface with very fine material...but it sounds reasonable and I doubt that it would do any harm.

Remember not evrybody has heard of everything.

cheers
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Follow Up By: Life Member - Terry 80FTE - Thursday, Aug 21, 2014 at 21:14

Thursday, Aug 21, 2014 at 21:14
You're much gooder with words than me Bantam
But that's about the crux of it.
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Follow Up By: cruza25 - Thursday, Aug 21, 2014 at 21:49

Thursday, Aug 21, 2014 at 21:49
Hi all, lots of good info here in this post
the following is from skf who are one of the largest seal mfgs around.
What they say is .... too rough gives too much wear - early failure.
Too smooth (Glass type finish) .... no oil fed to seal contact point on shaft..... results in seal lip overheating due to running dry.
very very fine surface marks from grinding or linishing allows oil to form a film that lubricates and cools the seal lip.
Quote........
The lower value for Ra is a minimum value. Using a lower value will adversely affect the lubricant supply to the sealing lip. The temperature rise caused by inadequate lubrication, particularly at high circumferential speeds, can lead to hardening and cracking of the sealing lip which will eventually lead to premature seal failure. If the counterface is too rough, there will be excessive sealing lip wear and seal service life will be shortened. If the value Rpm is exceeded, the seal will leak or excessive sealing lip wear will occur...

just hope it helps people see what is really needed to get a good long lasting seal. Also needs to be lubricated well during assembly to prevent a dry start.
cheers
mike
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Reply By: Bob W5 - Sunday, Aug 17, 2014 at 15:44

Sunday, Aug 17, 2014 at 15:44
Thanks for your replies.
The seal was replaced by a specialist 4x4 workshop.
A "Landcruiser guru". I imagined that would equate to top quality knowledge and workmanship.
It's not a big deal, just a minor dissappointment. :-)
AnswerID: 537815

Reply By: Mark - Sunday, Aug 24, 2014 at 21:13

Sunday, Aug 24, 2014 at 21:13
Excessive pressures in the crankcase will also cause rear main to leak (usually the largest seal). Check for blowback when the oil filler cap is removed.
Cheers
Mark
AnswerID: 538134

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