Blown Hub Seal?

[Steelreaper80]

Hey guys, need a lifeline thrown my way. Heading back home from Chicago and stopped at a truck stop for coffee. I got out if the M925A2 and saw my middle drivers side tire was wet.......soaked in gear oil. I am 121 miles out from home. Any suggestions?


What is the issue and what parts will I need? Can I drive it at all at slow speeds? Any help is greatly appreciated!!!

 

[Elijah95]

Hey guys, need a lifeline thrown my way. Heading back home from Chicago and stopped at a truck stop for coffee. I got out if the M925A2 and saw my middle drivers side tire was wet.......soaked in gear oil. I am 121 miles out from home. Any suggestions?


What is the issue and what parts will I need? Can I drive it at all at slow speeds? Any help is greatly appreciated!!!

Is it coming from your outer seal there where the bolts attach it to the hub?

Is ctis intact? Whether it functions or not, most certainly you have a clogged axle vent and it put extra pressure on your seals during your long drive, and if the ctis seals are weak or if the outer axle gasket where it bolts together is weak, you’ll get the centrifugal sling of gear oil. Check your gear oil in that axle, and as long as hub temperatures do not exceed 170° limp her home! Carefully touch the hub with the back of your hand briefly

Shouldn’t be any problem getting home. In fact, after you get out, run atleast 20 miles without touching your brakes and try to stop without them, and recheck hub temp. As long as your brake isn’t dragging and melted the seal, then you don’t have to worry about the bearings because gear oil works just fine keeping her lubed. If it’s still about the temp of the other hubs, full speed ahead


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[Steelreaper80]

Is it coming from your outer seal there where the bolts attach it to the hub?

Is ctis intact? Whether it functions or not, most certainly you have a clogged axle vent and it put extra pressure on your seals during your long drive, and if the ctis seals are weak or if the outer axle gasket where it bolts together is weak, you’ll get the centrifugal sling of gear oil. Check your gear oil in that axle, and as long as hub temperatures do not exceed 170° limp her home! Carefully touch the hub with the back of your hand briefly

Shouldn’t be any problem getting home. In fact, after you get out, run atleast 20 miles without touching your brakes and try to stop without them, and recheck hub temp. As long as your brake isn’t dragging and melted the seal, then you don’t have to worry about the bearings because gear oil works just fine keeping her lubed. If it’s still about the temp of the other hubs, full speed ahead


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Thank you very much. Topping off gear oil now.

 

[Steelreaper80]

CTIS has been removed. It seems to be dripping from where the CTIS went into the axle. It is not leaking from the outer seal.

 

[162tcat]

Check the bolts, probably loose. That should fix it.


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[Elijah95]

CTIS has been removed. It seems to be dripping from where the CTIS went into the axle. It is not leaking from the outer seal.

There shouldn’t be gear oil coming from that port, if you remove the ctis plug in the hub and oil leaks out, your seals have failed and you need to consider getting rid of your factory military axle vents and using an open vent system with hoses routed higher, then servicing all 4 rear hubs


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[M35A2-AZ]

Look would guess it is coming form the wheel hub/ Axle bolts are loose. 10 bolts and take 3/4" wrench

 

[Nomadic]

Seal joke

 

[Steelreaper80]

I managed to get it back. Thanks for all the help. I did find out that my brakes have been dragging on that wheel so I probably fried the hub seals. I have new parts on order including new shoes, seals, and spring brake can bladder. The hub was hot, but not melt your skin off hot. It was just heat from the brakes. You could hold your hand on the hub without burning it. The axle never ran dry of oil and the differential was still full once I got it back to the shop. Do you think that I need new bearings or just re-use the ones I have if they look ok?

 

[Ajax MD]

I managed to get it back. Thanks for all the help. I did find out that my brakes have been dragging on that wheel so I probably fried the hub seals. I have new parts on order including new shoes, seals, and spring brake can bladder. The hub was hot, but not melt your skin off hot. It was just heat from the brakes. You could hold your hand on the hub without burning it. The axle never ran dry of oil and the differential was still full once I got it back to the shop. Do you think that I need new bearings or just re-use the ones I have if they look ok?

Inspect the bearings visually and spin them in your hand. I found these resources to be useful in assessing the bearings' conditions.

How to Identify Tapered Roller Bearing Damage

Recognizing causes and types of bearing damage can help you prevent further bearing damage resulting in improved bearing life and performance.

www.knowyourparts.com

There are two types of axles types- "Dry" and "Wet." The old 809 series were "dry." They used a piece of cork in a keyway to keep the gear oil contained to the differential. The bearings are lubricated by heavy grease. These axles do not have the sealing system necessary to allow the gear oil to lubricate the wheel bearings without leaking out.

Wet axles have the necessary system of seals to allow the gear oil in the differential to flow into the axle tubes, lubricating the wheel bearings. I *think* that all or most of the 900 series trucks have wet axles. If I recall, there is a procedure in the manuals that explains how far to fill the differential and get oil into the axle tubes.

I apologize if you knew all this already.

 

[Steelreaper80]

Well, pulled the hub Monday, brake shoes looked great, got excited that perhaps it wouldn't be too bad once I pulled the hub....pulled the hub today, outer bearing and seal looked good, got the hub off and the inner bearing literally fell apart into pieces. The bearing metal has welded itself to the shaft housing! Do I need an entirely new hub and how do I get the welded bearing metal off of the axle housing without destroying it? Is the hub beyond a new race and inner bearing? There is also material, which I assume is cooked grease that is in the exact shape of the destroyed bearing. I included photos. Any help is greatly appreciated.

 

[Glenngineer]

Inspect the bearings visually and spin them in your hand. I found these resources to be useful in assessing the bearings' conditions.

How to Identify Tapered Roller Bearing Damage

Recognizing causes and types of bearing damage can help you prevent further bearing damage resulting in improved bearing life and performance.

www.knowyourparts.com

There are two types of axles types- "Dry" and "Wet." The old 809 series were "dry." They used a piece of cork in a keyway to keep the gear oil contained to the differential. The bearings are lubricated by heavy grease. These axles do not have the sealing system necessary to allow the gear oil to lubricate the wheel bearings without leaking out.

Wet axles have the necessary system of seals to allow the gear oil in the differential to flow into the axle tubes, lubricating the wheel bearings. I *think* that all or most of the 900 series trucks have wet axles. If I recall, there is a procedure in the manuals that explains how far to fill the differential and get oil into the axle tubes.

I apologize if you knew all this already.

The M939 A1 and A2 Booth use greased bearings with seals to keep the oil out I believe .that hub may have been assembled incorrectly .You should check if that bearing material made it into the differential. Probably time to look at all the hubs.

 

[simp5782]

There are 2 seals one in the hub one on the inner axle. Doubtful it got past the inner housing seal if you don't have a leak there.

Member suprman used to carry some of the hubs new in the box for cheap.

 

[Glenngineer]

Well, pulled the hub Monday, brake shoes looked great, got excited that perhaps it wouldn't be too bad once I pulled the hub....pulled the hub today, outer bearing and seal looked good, got the hub off and the inner bearing literally fell apart into pieces. The bearing metal has welded itself to the shaft housing! Do I need an entirely new hub and how do I get the welded bearing metal off of the axle housing without destroying it? Is the hub beyond a new race and inner bearing? There is also material, which I assume is cooked grease that is in the exact shape of the destroyed bearing. I included photos. Any help is greatly appreciated.

That looks like a speedy sleeve may have been used on that ,take a small sharp cold chisel and see if it peals off. As suggested by simp5782 a new one may be your best bet ,your seal surface is pitted and worn .Probably the start of your failure.

 

[simp5782]

From @Suprman eBay page

M939A2 5-TON MILITARY TRUCK FRONT AXLE WHEEL HUB A-333-X-3534 M923A2 M925A2 M931 | eBay

You are viewing a front wheel hub for the M939A2 trucks. It has the port for CTIS connection. In most situations you can buy a Square Trade warranty on the item for a small fee.

www.ebay.com

M939 series REAR HUB A3-333-Z-3536 A1-333-Z-3536 | eBay

Find many great new & used options and get the best deals for M939 series REAR HUB A3-333-Z-3536 A1-333-Z-3536 at the best online prices at eBay! Free shipping for many products!

www.ebay.com

 

[Glenngineer]

From @Suprman eBay page

M939A2 5-TON MILITARY TRUCK FRONT AXLE WHEEL HUB A-333-X-3534 M923A2 M925A2 M931 | eBay

You are viewing a front wheel hub for the M939A2 trucks. It has the port for CTIS connection. In most situations you can buy a Square Trade warranty on the item for a small fee.

www.ebay.com

I could be wrong ,but I thought we were dealing with a rear hub.

 

[simp5782]

I could be wrong ,but I thought we were dealing with a rear hub.

It is. It just didn't attach both links

 

[Steelreaper80]

The M939 A1 and A2 Booth use greased bearings with seals to keep the oil out I believe .that hub may have been assembled incorrectly .You should check if that bearing material made it into the differential. Probably time to look at all the hubs.

I got the axle housing cleaned up fairly nicely with a Dremel. Not perfect but it is smooth all the way around and "should" be a nice surface for the new seal. I have never seen a bearing that bad. Outer bearing had oil only on it. No grease. I will check the differential oil once bearings and seals get here. I hate to do it but I will probably one at a time pull all the hubs.....ugh

 

[Steelreaper80]

That looks like a speedy sleeve may have been used on that ,take a small sharp cold chisel and see if it peals off. As suggested by simp5782 a new one may be your best bet ,your seal surface is pitted and worn .Probably the start of your failure.

It was the actual metal of the bearings that welded to the housing. Dremel tool took it off"mostly". It is now smooth all the way around. You can feel slight imperfections in it, I did it by had so it is not machined perfectly but it is close and smooth.

 

[M35A2-AZ]

All I can say WOW!