1969 3/4 ton breaking 4x4 hubs - need help
 

Hi every one! First post here, I have a 1969 chevy pickup 3/4 ton 4x4 stock 350 with a 4 speed manual tranny. The pickup either breaks the 4x4 warn hub or loosens up the hub bolts or breaks the bolts. Anyone come across this before? I use the truck to plow snow and I don't chain up the tires. The first time it happened I put high grade bolts back in, thread lock and torqued them down. Half hour into first snow storm I hear popping sound get out and look all bolts are loose and some missing. I replace, retighten and thread lock. I get back to plowing and same thing happens accept the hub breaks. I'm lost on this one and could use your advise.

Thanks!

Re: 1969 3/4 ton breaking 4x4 hubs - need help
 

Those old external hubs commonly have that problem. It would be worst when you are using 4WD and doing a lot of backing up under power as you are when plowing. Some people have used studs instead of the bolts with some success. The real solution it to swap in a later mode front axle that has the (smaller) internal hubs - that will solve the problem permanently.

Re: 1969 3/4 ton breaking 4x4 hubs - need help
 

I would guess that you are missing a snap ring. The bolts that hold the cap on should have no pressure on them. The bolts are only to hold the cap on, and the most pressure they should see is from the spring. If a snap ring, or a thrust washer, or the inner bearing to support the stub axle are missing or damaged, when under power, the axle would move in and out breaking the little bolts.

Re: 1969 3/4 ton breaking 4x4 hubs - need help
 

Let me clarify, the bolts that are breaking and coming loose are the 6 large bolts that hold the locking hub onto the axle. I sheared off 4 of the 6 bolts. The other 2 I assume worked their way out and feel out somewhere. I'm going to attach a picture of the hub if I can figure out the attachment process.

Thanks for your input!

Re: 1969 3/4 ton breaking 4x4 hubs - need help
 

This is an external hub axle. The bolts that hold the lockouts to the bearing hubs also transfer the power to the front tires. That is why they back out and break. As I said, the solution is internal hubs where the torque is transferred with a slug from the external splines on the axle shaft to internal splines on the bearing hub.

Re: 1969 3/4 ton breaking 4x4 hubs - need help
 

have you checked your bearings?. bad brg will cause the drum to flop and pop goes the hub
ron

Re: 1969 3/4 ton breaking 4x4 hubs - need help
 

Thanks! Where should I look to purchase internal hubs?

Re: 1969 3/4 ton breaking 4x4 hubs - need help
 

Thanks Ron, no I have not checked the bearings I will check this weekend.

Re: 1969 3/4 ton breaking 4x4 hubs - need help
 

The easiest way is to swap in an entire newer front axle assembly. In order to get an internal hub 8 lug axle, the most plentiful is a 10 bolt out of a '80 - '87 GM. A Dana 60 from a '77 - '91 K30 would be the ultimate axle if you can find one. I am assuming that you still have the drum brake front axle on the truck now, if so this swap also gets you front discs.

Re: 1969 3/4 ton breaking 4x4 hubs - need help
 

Thanks Tim, if I do the axle swap won't that mess up the gear ratio thus having to replace the rear axle also? Is there a eaiser fix than a axle swap?

Thanks again for your help!

Re: 1969 3/4 ton breaking 4x4 hubs - need help
 

the easiest way is to just fix what you have. just pull the complete frt hub assembly off and check the brgs to see if there is a problem. the worst scenario is that the inner brg has gone and pounded out the inside of the hub where the seal and brg race goes. that will mean a new hub and brgs. if not just service the brgs and put it back on and go and buy yourself a new set of locking hubs for anywhere between 75 and $125.00 and away you go
if you do install a newer frt axle 73-87 you will als have to upgrade your m/c and install a proportioning valve.
you can find newer frt axles with the same ratio. but if you do change the frt axle you might as well do the back as the newre axles do have a much larger rear brakes
ron
now just go and pull that frt wheel and find out what is wrong first before you have to alter your whole life plan

Re: 1969 3/4 ton breaking 4x4 hubs - need help
 

You need to find a used axle with the same ratio that you currently have.


Otherwise, a new set of lockouts with the correct bolts to hold them on might last you for a while. You need a really close fit between the bolts and the inside of the holes through the lockout. If there is any clearance in there, the lockout hub can (and will) rotate a little bit everytime you go from from drive to reverse or vice versa. It is this little bit of rotation (working against the heads of the bolts) that causes the bolts to come loose. I think the correct bolts actually have a pilot diameter with no threads (like a longer bolt normally would) up near the head of the bolt.

Re: 1969 3/4 ton breaking 4x4 hubs - need help
 

when you buy a new set of Warn locking hubs, everything comes with them to mount them.
the thing to make them last is maintenance, which means packing your wheel(axle) bearings regularly which means that they stay tight which reduces hub movement which takes stress off the locking hubs. It also doesn't hurt to check those mounting bolts from time to time for tightness because they can back out.
and only lock your hubs when you are actually going to use them saves a lot of wear and tear on everything
ron

Re: 1969 3/4 ton breaking 4x4 hubs - need help
 

Thanks guys, I like the quick fix solution over the axle swap. There's to much room for headaches when you start piecing things together. I'm sure when I purchase the new hubs there will be directions included but what's your thoughts on using thread lock? Advantage would be bolts may not back out, disadvantage would be if bolts break it may be impossible to remove with ezout??? Would a high grade stud be the way to go? I read that in a previous post. Oh ya, I spoke with a rancher today he said the best way to fix the problem on "those old chevy's" is to weld the hubs on. I'm not sold on the idea seems like it would create many other poblems.

Re: 1969 3/4 ton breaking 4x4 hubs - need help
 

don't use thread lock. just check them once in awhile. you have off take them off periodically to do the wheel brgs. have you checked them yet or are you still theorizing?
ron

Re: 1969 3/4 ton breaking 4x4 hubs - need help
 

still checking over all angles of the issue. I hope to find some time this weekend to check the bearings. I hope that it's a simple fix by finding out the bearings are causing the problem.

Re: 1969 3/4 ton breaking 4x4 hubs - need help
 

there are no angles.just take it apart and check it, then you know. the internet will not tell you
ron

Re: 1969 3/4 ton breaking 4x4 hubs - need help
 

I never had a problem with them on my '72 k-20 but then I don't run my hubs locked unless I need them. Anyhow, I was told that they make a tab washer of sorts that gets peened over the bolt heads to hold them from backing out. I believe this was talked about on the '67-'72 truck board before?

Re: 1969 3/4 ton breaking 4x4 hubs - need help
 

I would have this moved over to the 4x4 section (contact yukon Jack or Mudder) and maybe get more response...

Somethings not right inside the hub if you are breaking bolts like that. I would go for the hub rebuild (bearings, snap rings etc..) and fix what's broken. Is this on both sides or just one?

Re: 1969 3/4 ton breaking 4x4 hubs - need help
 

just the driver side has broke as of now. the passenger side will loosen up some of the time but has not broke a bolt or hub.

Re: 1969 3/4 ton breaking 4x4 hubs - need help
 

There are indeed "bend-tab" type washers for these hubs, but that only addersses the loosening issue. The breaking of the casting does not look normal though. I guess have something to do with the hub being loose, but loosening that quickly has to have an underlying problem.
Lool for:
Loose wheel bearings
Stiff axle joints
Bent spindle
Bad threads in the hub
etc...