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Old 11th June 2010, 21:07   #1
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Default Axle / differential breathers - how important are they?

A question to all the 4x4 enthusiasts here:

How important is to ensure that the axle / differential breathers above water level when doing water forging?

On my reading, the understanding is that the breather helps in maintaining the pressure within the differential due to difference in temperature during operation.

If that was so, when you do water forging, you basically reduce the temperature of the casing and hence the pressure inside reduces. This will require air to be drawn from outside to reduce this pressure, but since the axle is under water, water will be pulled.

Now, water and oil do not make good friends. And an extended use of this mixture will spell disaster in the long run.

So, what have you all you hardcore off-roader's done to mitigate this?

Note: This is also true for all vehicles, 2WD or 4WD, but made a post here since 4x4 have a higher probability of their axles spending more time under water.
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Old 12th June 2010, 01:28   #2
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Happy,

The solution for this is attach a long rubber tube with a breather cap in the end (Both differentials, and gear box) You can leave the tube anywhere high above the normal water levels. The rubber tubes need to be tightened with Clips for water tightness at the Differential end.

In my Jeep the front Differential and the gearbox tubes are left inside the bonnet just next to the windscreen washer tank, and the rear breather tube inside the wheel well right at the top. (Though the rear differential breather posn is not the best, need to find other alternative position for it!)

Cheers

Nishanth

Last edited by hgnishanth : 12th June 2010 at 01:30.
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Old 14th June 2010, 10:52   #3
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Thanks Nishant! So, is this something that all off-roaders keep an eye out for? Am asking this because I have not come across any discussion of the same in the 4x4 rebuild threads that I have gone through in the forum (or maybe I just didn't notice it so far!!!). Which gets back to the question: Is this actually a point of concern that is looked at when re-building or is it something that is not to be made an issue out of?
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Old 14th June 2010, 15:42   #4
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Its a must have if you regularly ford bumper level water crossings. The alternative is to check diff/ gear oil post every OTR and if you find a frothy mess, then repoace the oil, which could prove expensive depending on the frequency and depth of the fording.

Nice to have otherwise..
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Old 15th June 2010, 12:55   #5
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I also need some info, someone told me that the OE breather caps have one way valves at the diff, which will close and not allow water to get in? Is this true?

Also whatever we do, unless the oil seals etc are water tight, water will eventually get in. This is especially true for front diff's with Lambda's FWH (esp the new ones) since they don't have seals inside.

Best is to replace oil once you do heavy water wading.
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Old 15th June 2010, 13:40   #6
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The OE caps do have one way valves but if you enter deep water with hot differentials, water is bound to get sucked in.

Aisin and Warn hubs come with seals, the Lamda ones dont. Hence prone to water leakages and also getting jammed if driven thru deep slush.
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Old 18th June 2010, 11:10   #7
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Quote:
Originally Posted by Jaggu View Post
someone told me that the OE breather caps have one way valves at the diff, which will close and not allow water to get in? Is this true?

Also whatever we do, unless the oil seals etc are water tight, water will eventually get in. This is especially true for front diff's with Lambda's FWH (esp the new ones) since they don't have seals inside.

Best is to replace oil once you do heavy water wading.
Quote:
Originally Posted by satan View Post
The OE caps do have one way valves but if you enter deep water with hot differentials, water is bound to get sucked in.

Aisin and Warn hubs come with seals, the Lamda ones dont. Hence prone to water leakages and also getting jammed if driven thru deep slush.
As part of EXAMM/AKC preps I talked to Mahindra guys and they say the same as Jaggu does. Am hoping what Satan mentions can be circumvented by probably waiting/letting the jeep cool down a bit before water fording? In either case I think an oil change is advisable post that.
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Old 18th June 2010, 11:34   #8
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Quote:
Originally Posted by Jaggu View Post
I also need some info, someone told me that the OE breather caps have one way valves at the diff, which will close and not allow water to get in? Is this true?...
Would be interesting to know what conditions trigger the closure of the valve.

Quote:
Originally Posted by Jaggu View Post
...Best is to replace oil once you do heavy water wading.
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Old 18th June 2010, 22:44   #9
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I guess there is a breather for the gearbox.

I never knew it was so important to have them.After attending an OTR i learnt it.

GURUs Please do post all your experiences so that Lay Man(s) like me can get to know
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Old 19th June 2010, 10:24   #10
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Default Breather

Quote:
Originally Posted by AVR View Post
As part of EXAMM/AKC preps I talked to Mahindra guys and they say the same as Jaggu does. Am hoping what Satan mentions can be circumvented by probably waiting/letting the jeep cool down a bit before water fording? In either case I think an oil change is advisable post that.
Hi AVR,

The Breather does not have a valve, but a spring loaded cap, which is useless in water fording or wading obstacles.

Get a 7mm Banjo & Bolt and attach a 7mm air hose as long and as high as you want, to make an efficient breather.

The Bolero and Later model Vehicles have a longer Breather Nipple on the Rear Axle and a rubber hose attached to the Chassis.

Regards,

Arka
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Old 21st June 2010, 10:24   #11
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Does this apply to gypsies as well. I know there are diff breathers on a Gypsy but I have never come accross any discussions of extending these on a Gypsy.

How do these work then?

Cheers
Ankit
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Old 21st June 2010, 19:06   #12
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Quote:
Originally Posted by ex670c View Post
Hi AVR,

Get a 7mm Banjo & Bolt and attach a 7mm air hose as long and as high as you want, to make an efficient breather.
Thanks Arka,

Had a look at my Jeep and here's what I need to do:
1) Front Diff: Will be adding the hose here
2) Rear Diff: Doesn't have any breather valve! Was told that older versions (Mine is a 1990 model) did not have breather valves. Didn't they have this issue?
3) Gearbox: The breather valve is at a pretty high position i.e. sits right under the floor plate of the gearbox which I think should be relatively easier to live with??

Cheers,
Adi
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Old 21st June 2010, 22:28   #13
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There is a long discussion about this in the water fording/snorkel thread.

EDIT:

Here's one thread:

http://www.team-bhp.com/forum/4x4-te...l-mm540-5.html (Snorkel for MM540)

Last edited by Tejas@perioimpl : 21st June 2010 at 22:40. Reason: see edit
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Old 22nd June 2010, 01:35   #14
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Quote:
Originally Posted by Tejas@perioimpl View Post
There is a long discussion about this in the water fording/snorkel thread.

EDIT:

Here's one thread:

http://www.team-bhp.com/forum/4x4-te...l-mm540-5.html (Snorkel for MM540)
That thread is largely referring to air intake for combustion which is done using a snorkel. This thread is about the breather valves that are present on both the differentials and the gearbox. Fairly different issues though largely a similar elementary solution of taking the air intake to a higher point!

Cheers,
Adi
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Old 22nd June 2010, 07:26   #15
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Quote:
Originally Posted by AVR View Post
That thread is largely referring to air intake for combustion which is done using a snorkel. This thread is about the breather valves that are present on both the differentials and the gearbox. Fairly different issues though largely a similar elementary solution of taking the air intake to a higher point!
My dear Watson, I can clearly read and understand english and i know what the two threads are about. What i said, is to do a search and you will find that this has been covered earlier. That was just one thread i had posted about. Anyways, i'm not lazy, so here you go, i'm quoting from the other threads:

Quote:
Originally Posted by ex670c View Post
Hi Alok,

Check and clean the Breather Plugs. If the Plugs are blocked, then while running, the oil heats up and the hot air/gasses cannot escape, thereby creating a High Pressure inside the T-Case and vent through the oil-seals or weaker joints (sealing).

Regards,

Arka
Quote:
Originally Posted by vinod_nookala View Post
You must change oil only when you find water in the oil sample that you take out of the diff's and the gearbox. Gurkha has tall breathers, hence it shouldn't be a problem. But it is better to check always!

Quote:
Originally Posted by Red Liner View Post
AMAZING! That was what I was coming to, and you beat me to it See image below to know how it looks. Kittu, I understand that yours was an army vehicle...they have done a great job with it. You do not need wading plugs. I would love to see the underchassis of your jeep sometime and see how they have drawn these pipes and kept them in place.
Quote:
Originally Posted by DirtyDan View Post

If you do deep fording, water is going to come into the cab thru the doors and the firewall. You will risk long term corrosion of your electricals including your alternator and lights. If you should happen to stall in deep water you may take water up your exhaust pipe and into your motor. Your differentials are vented. You may take water into them and dilute or wash out your gear oil.

My point is that if you are thinking of fording, a snorkel is not the only thing to worry about.
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