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Air coming out of diff breather diff lock problem


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Hi,

I have a problem where I press the electric diff lock button on a 2004 mack vision bogie tipper and the light on switch doesnt come on and I can hear a heap of air coming out of the rear most diff breather. I’m guessing the diff lock button light is not coming on because the piston isn’t moving to press the switch in diff?

the diff has a label which I will post picture of and another picture of the part I may need help removing to check it.

 

Can someone explain what I need to do or tips to remove this contraption out of the housing please?

 

thanks

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Edited by The Nitro
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I would think that the o-ring on the piston is broken, or possibly a cracked piston.  So then the piston is not moving which wont engage the detent ball on the end of the switch, as you stated.  I would just pull the small cover off and inspect it.. ..............  I just looked at the picture again.. maybe pull the detent switch out first and turn the lock 'on'.  I bet air comes out of the hole.  I am wondering if the bolt next to the piston housing is actually a 'caging bolt'.. used to keep the shift fork from dropping out of place..  I don't remember how these diff lock's  look inside, because I havent had one apart in a long time. However, sliding this rear end forward is not that big of a deal, in the case that you had too.   I just looked again at the picture...  I wonder if behind that small bolt is a counter bore with smaller threads, where you would screw a longer smaller diameter bolt, like an 8mmX1.25 metric bolt and it cages the shift fork..  If I remember correctly, to remove the piston housing, you would use a pipe wrench and unscrew it. Maybe get a close-up pic of the data plate.  I think its and Eaton 405,  I may have a service manual on this model, of course, I also expect a few guys to help you more directly than I can.. Jojo

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Theres 2 buttons for locking diffs. One electric which sends air to both diffs with the same looking pistons screw in thing that we can see in my pics and then theres an air type switch with hoses that only sends air to front diff 

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ok. I understand..  I guess I threw out a few old ideas I had.  Yes Meritor is right..  I know I said eaton, but I looked at the picture again,  I know that I do not have a Meritor rear end book.. Here in the last month, I bought 3 Mack books from E-bay..  There is a bunch of guys on here from youre part of the world, who are very smart, maybe one of them is familiar with the Austrailian version..  jojo

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Yes sir I understand..  I guess, for me, I would go for it because I have had many of these rears apart, just not one with diff locks in a long time.  but the inner workings are pretty standard..  I dont feel like im helping much... sorry....  jojo

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I appreciate your input mate, I’ve enjoyed looking at your posts on this website. Being a new rookie mack trucker now I’ve got lots to learn. I’ve done a couple crownwheel and pinion swaps on my 4x4 toyota with dial guages etc so know a little bit but have never fiddled with trucks..... yet! 😂

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very good..  I need to go back to bed.. I couldnt sleep so i came here...  now im sleepy again.  I will check in later. jojo

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There should be two switches. One is the interaxle lockout (power divider) and the other ( in this case ) is for what's often referred to as "full lockers"

Probably what ever form of diaphragm  ( I think is O rings in these ) is in there (your picture) is leaky. Used to be if you needed to cage them up, you removed the fitting and used a long bolt to engage the sliding clutch into the carrier.  🤔  I don't think you'll need to do that to make this repair. Usually it can't go anywhere with the axle in it.   

Edited by Mark T
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Thanks Mark.  I was trying to help him with this, and wasnt sure if the small bolt had a small set of threads inside to cage the fork, like the older Eatons did for the power divider..  I think the leak is an o-ring and/or cracked piston..  Jojo

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I'm pretty sure they have O rings and that cover with the fitting screws off... and a piston with an O ring. That bolt in the picture I believe is the cage bolt just screwed in there for when you might need it to lock the sliding clutch into the case in the event you need to remove the axle. You lock it in, cage it then take the axle out  (like for towing) Then if I remember right they're disengaged with a spring in there ???   But anyway, seems he has a leaky something (?) under that cover.

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As Mowerman has said before, They ask for advice but never say how things turned out! The Nitro, Thanks for a detailed answer to what and how the problem was solved. And now we know the rest of the story.    .....Hippy

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3 hours ago, Joey Mack said:

Awesome...  Thank you for posting the process to fix it.. I'm glad you "went for it"   Jojo

YUP TOTALLY AGREE !

please post your FIXES GUYS! This helps others and everybody learns !

That is what its all about!

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