Another new oil leak and a theory...

Lorin

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I keep developing new oil leaks :x

The order of events was as follows:

1. Had no oil leaks at all
2. Extended diff and gearbox breathers and plumbed into the airbox
3. Noticed oil in the airbox - tried to narrow down where it was coming from but when I disconnected each breather in turn no oil was found to leak from them. However there was oil throughout the whole extended breather.
4. Noticed new oil leaks from where the rear propshaft attaches both to the rear diff and the transfer box - Ian suggested there may be a link between the extended breathers and the new oil leaks.
5. After a six hour motorway drive, I've developed a quite significant oil leak from where the front propshaft connects to the diff and there was more oil in the airbox.

How much suction is there in the airbox? Could it be that where I've plumbed the breathers into the airbox it is creating a vacuum in the diffs (and the gearbox) and has blown the seals by pulling air through - hence the oil also being pulled up into the airbox?

I'm going to extend the breather further - to the top of the snorkel to remove any vaccum effect as a possibility.

Also, I've noticed that despite putting new oil in the diffs less than 800 miles ago it looks like s**t. I even drained a bit out the rear and it was shocking. How many times should I put new new oil in and drain it off to remove the crap in there?
 

Paul_Humphreys

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Lorin said:
How much suction is there in the airbox? Could it be that where I've plumbed the breathers into the airbox it is creating a vacuum in the diffs (and the gearbox) and has blown the seals by pulling air through - hence the oil also being pulled up into the airbox?


That is why I did not put the breathers into the air box. Just incase!!

Paul
 

Andrew Prince

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Lorin said:
How much suction is there in the airbox? Could it be that where I've plumbed the breathers into the airbox it is creating a vacuum in the diffs (and the gearbox) and has blown the seals by pulling air through - hence the oil also being pulled up into the airbox?

I'm going to extend the breather further - to the top of the snorkel to remove any vaccum effect as a possibility.
Bummer with the leaks, Lorin :o I think you're right in linking the start of all the leaks with the changing of the breathers.
Regarding the suction, I would imagine that there is a reasonable suction generated by the engine at high revs. If you put your hand near the snorkel intake when revving hard, there's quite a force there. I think that this is probably the cause of your problems, as you've suggested.

Lorin said:
Also, I've noticed that despite putting new oil in the diffs less than 800 miles ago it looks like s**t. I even drained a bit out the rear and it was shocking. How many times should I put new new oil in and drain it off to remove the crap in there?
How sure are you that your axle oil seals are holding and you don't have grease mixing in the diff oil? If your breathers are sucking oil out of the diffs, it stands to reason that this suction would be sucking from the knuckles/hubs :?: So grease is probably being drawn into the diff oil. For sure a bit of grease will make the oil look nasty but it probably won't cause too many problems for the diffs themselves. I would check that all the seals are good before replacing diff oil, or you could be doing this frequently. Also if grease is being drawn into the diffs, the grease volume will be declining. :?
If no grease or contaminants (water/mud down breather for e.g.) is going into the oil, then one flush should remove pretty much all the gunk, I would think...

Assuming that re-routing your breathers stops the oil suction problem, I wonder whether the seals will all be ok or whether this will mean replacing most of the seals :cry: ? Hopefully not but this could involve "school fees" here.
 

Jon Wildsmith

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A little grease in the diff oil won't do much harm but a lot will hurt after a while. Lorin mentioned the rear oil looking bad as well though.

Have you been driving through big muddy puddles? Could be as simple as you've been sucking mucky water into the axles with your breathers the way they are. As almost all of the oil comes out when you drain the diff you wouldn't really expect new oil to go bad just from that little bit left behind. Except if the front diff was full of oil/grease sludge previously but that would only affect the front of course.
 
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Dave 2000

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A few years back I had a leak free LR Discovery...............no honestly, and after I fitted breather extensions to the axles/gearbox and engine I routed them up the snorkel but drilled holes under the snorkel top and routed them out of there. A few days later I noticed a leak from between the gearbox/transfer box. About a week later the pinion seal started leaking on the rear diff but the diff was changed under warranty with Ashcroft (excellent service) and there was no more leaks. The gearbox/transfer boxes were removed and new seals fitted, and no further problems, coincidence? I did not even post it up at the time because it seemed so bizarre I thought I was imagining it and yet I have now read about this 'coincidence' on two other LR's and this is now the second '80' to have been affected.

Any further input guys/girls?

regards

Dave
 

Lorin

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I've now removed my extended breathers from the airbox. Since doing this two of my three oil leaks have simply stopped and there is no more oil in the airbox! The transfer case and rear diff pinion no longer leak at all - the front diff pinion however is knackered. I have also checked the extended breather tube several times since removing from the airbox and it remains oil free.

Given the chain of events I have experienced it appears that there is enough suction in the airbox to actually pull air in through various seals (i.e., diff pinion and transfer case extension) and pull oil up through the breather - perhaps when it is sloshing around over bumps etc. Therefore, for me at least, extending the breathers wasn't the issue, but plumbing them into the airbox was.
 

Jimbo4x4

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I've learnt a lesson there, thanks for that.
 

Roman

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Hi,

If the internal diameter of the breather pipes is too small, they will be draining oil due to capilary action, especially when hot. I've even seen it occasionally on 10mm ID pipes vented at atmospheric pressure.
 

Julian Voelcker

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I'm really suprised because I have always plumbed breathers into airboxes and never had oil seal problems as a result.

I do find occasionally on pre-aug '92 find that you can get a little oil getting blown up into the airbox, with post Aug '92 models Toyota fitted a plenum chamber to the breather to catch any excess oil before it goes up the breather.

(one other time you can get problems with breathers plumbed into the airbox is if they are plumbed in in line with the airflow into the filter housing - this can lead to suction along the same lines as the paint sprayers you had as children made out of two pipes at ninety degrees where you put one in the paint and blow through the other)

Actually on the negative pressure side of things we often find that with well serviced axles you often get quite a loud suction noise when removing factory breathers, which have valves that let the air out, but not back in leading to the negative pressure.

Something else to bear in mind, if negative pressure was an issue it would be holding the oil into the axles and transfer case, not forcing it out.


As for the leak from the axle and transfer case this may be down to the the lowering of the suspension resulting in a reduction in the length of the PTO shaft. As the PTO compressed the grease in it would have taken a while to compress out around the splines - this would have put extra strain on the read diff input and tcase output - any play in the bearings there could result in possible fluid loss. Eventually the grease will get pushed out of the way, the pressure comes off the bearings and the seals stop leaking...... well it is a slightly more plausible than the negative pressure :)
 
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