Bent axle housing FR Mack MH

[Vladislav]

I started a play over my MH the other day, was going to put the hubs and wheels wich were laying painted for a while.

Did all 4 and got the jack shafts installed. When putting the flange nuts on I noted I couldn't fit one of the shafts almost in place. It touched hub's mating surface at some point and there was still the gap of 3-4 mm (1/8") at the opposit. To my big surprize I found out that contact point didn't turn over together with the hub but always stayed at the right of me - the direction front to the vehicle. That gave me a thought I wasn't glad to have.

Took the hub back off (and the opposite one) and looked through the housing...

I sure know i should swap the axle and I will do it in the future. Probably together with that strange "new style" Neway air suspension nobody could determine what it was. Although it's just a hobby truck. And the one I haven't planned to spend alot on in the nearest future.

I see no trouble about tyre wear since I planned to drive it for nearly 100-500 miles a year.

But I'm afraid it will ruin the jack shaft.

Any thoughts on how quick it could happen?

The B plan is to remove the jack and drive one axle only. I need to lock the power divider for that.

But it's a stock one, with no interlock. Does anybody know an easy way to lock it?

Vlad

[mrsmackpaul]

So am I right in the axle housing is bent ?

If so can you just pull the housing out and put it in a press and push it back straight ??? or is that a big no no ??

Paul

[41chevy]

So am I right in the axle housing is bent ?

If so can you just pull the housing out and put it in a press and push it back straight ??? or is that a big no no ??

Paul

It it done with Ford 9" and Dana 60's all the time. But you need a dummy ham with bushings in place of the bearings and the same on the axle bearing end of the tubes. A shaft to run through the all to show you when it is aligned. Clamps and a minimum of a 20 ton porta-power.

The tube is replaceable, pull it and put the tube in true. They are button welded in most times.

[BC Mack]

Vlad

have you exchanged left/right axle shafts (half shafts)..?? this would be just to prove they were both straight, if the problem moved to the other side then the shaft or flange is bent... or, set it in vee blocks on a bench and spin with a dial gauge and then roll it across the bench looking for wobble.....hmmm, just thought, are left/right same length?.. if not just take same side off other axle.

can't see the diff being twisted inside...

is the hub running true...?? dial gauge the mating face of the hub and see if there is run out... if there is the 3-4 mm you saw then you may have a wheel bearing cup in offset...

other than that... what Paul said, you probably got a bend on the axle tube... either impacted or stressed by overload.

if you want to go single drive... take the rear diff and put it in the front axle... you will need to put the front diff into the rear as the opening needs to be supported from flexing.

some guys would just add more gaskets and impact the axle in... but I know you want to do it right

BC Mack

[theakerstwo]

Easy way to check for a bent housing is jack both wheels up and paint a strip around the center of each tire as some one turns it then as its turning scrip a line in the center as its turning.Now with a measuring tape check across to other wheel the toe/in.The measure across to other wheel the top and bottom like you did the top/in.This will tell you if its bent up or down.Any difference will show if bent.

[Vladislav]

Yes, the housing is bent for sure.

After ovserving the axle shaft pay I resolved to pull the shafts out and saw a pear shape.

As I can see (and you can see it either on the last picture) the housing is bent to the rear and up.

Still wonder how the center axle could be hit so hard with no effects to the other parts.

I would say the tubes are both straight. Seems like the banjo itself is deformed.

As for the bearings and hubs I've just put new sets of Timken's into them with new seals.

The hub(s) turned freely. Until I drove the axle shaft in and tightened the flange nuts.

Right at the moment I have absolutely no lust to get the axle out and so on. I also have no press I could put it in to fix the issue.

A plan is to get the truck running by the easiest way.

BC,

Putting the rear diff into the FR housing is not the way since FR is bent.

I could change the axles but this doesn't seem worth the labour.

Getting the interaxle locked together with the semi shaft off might put that baby on the road.

At least temporary what would be quite enough for me at the moment.

I have the divider with interlock in the DMM and could put it on the MH.

Just don't want to mess up the stuff wich have enough issues of other kinds.

Thank you for the thoughts folks.

[j hancock]

If the banjo is out of shape and the axle tubes are straight, you may have junk already. That being the case, you could try using a rosebud oxygen/acetylene torch in conjunction with ratchets and chains to try to pull it back into line.

[dogg rescue]

My dad bought a '69 r-600 in '78 he was rebuilding the brakes when he noticed the left front axle didn't fit in very well, turns out the truck was in an accident were a car had hit the duals. We still run that truck and never have went through the trouble of changing out the banjo. Over the years I would estimate it has 300,000 mi. on it since then. It has been a farm truck and sees a lot of gravel roads, I have never noticed any bad tire wear, however you can see a little more wear on the axle splines from it flexing with rotation. While I wouldn't recommend running a truck this way, for a hobby truck with a limited amount of miles I would say it probably won't bother.

[Vladislav]

My dad bought a '69 r-600 in '78 he was rebuilding the brakes when he noticed the left front axle didn't fit in very well, turns out the truck was in an accident were a car had hit the duals. We still run that truck and never have went through the trouble of changing out the banjo. Over the years I would estimate it has 300,000 mi. on it since then. It has been a farm truck and sees a lot of gravel roads, I have never noticed any bad tire wear, however you can see a little more wear on the axle splines from it flexing with rotation. While I wouldn't recommend running a truck this way, for a hobby truck with a limited amount of miles I would say it probably won't bother.

That sounds optimistic. Might be depending on the degree of out of shape.

The hub on the bent spot turns heavier then the others but I can spin it over by two hands with no trouble.

I noted also one of the axle shafts is of the different style by its flange end form. Looks like someone had to change it in the past, too probably due to a failure. What I am really afraid is a shaft's break down wich will result me sitting in a middle of the road. Especially nice if it happens on a railroad cross wich are everywhere around. I can spare the shaft off my second R though.

Any ideas on how fast the shaft could be gone? I understand this question is a kind of dumb one but maybe anyone had experience?

This truck was towed for 700 km to me when I bought it and I'm sure that wheel was turning all the way.

[theakerstwo]

We have a spring shop that will straighten most bent housing and the way they do it is leave the wheels on the housing and they will move it the way it needs to be bent.I would think most large city have same thing.

[Vladislav]

We have a spring shop that will straighten most bent housing and the way they do it is leave the wheels on the housing and they will move it the way it needs to be bent.I would think most large city have same thing.

Glenn, that sounds unbelevable!

To my sorry, nothing like that here. If I try to send the axle to overseas trip it might be missed in between the coasts

[mrsmackpaul]

Vlad Im a bit ruff around the edges but I feel with a porta power some chains and blocks of you could jack it back into shape still on the truck or at least get it a lot closer than it is now with out pulling the housing out

Even if you didnt straighten the axle housing I feel it would last a long time with out any problems maybe 100000 km but thats just a guess got to think until the other day as far as you new it was all ok and you maybe worrying about something that is not a big problem ?? These axle housings are bending and flexing all the time while your driving along big loads they bend quit a lot even on rough roads they are twisting and turning as you drive along so they are designed to work a lot of there life not in a straight line anyway so it may well be ok

Paul

[Vladislav]

Paul, thank you for the suggestions.

You're right, I'm not a trucker. But mechanic. And everything deformed being working looks to me wrong.

I probaly will keep that axle as-is for some while and let myself to get the best idea.

Currenty I'm again out of time to work out that truck. Just need to put some repaired parts back together and get it on the road.

I have experience with bent axle housings on off-road Mercedes G's.

Usually it's followed by brake of an interaxle diff.

But depending on a degree of issue. Mercedes gives 0.25 mm out of center limit on its axle ends.

[41chevy]

Class 6 and 8 trucks in that period were build with greater tolerances than the Mercedes and vehicles now. Also truck with road conditions and loads have a greater tolerance of wear. I would think after a 700 KM tow and how ever many Kilometers it was driven before and the lack of odd tire wear, I'd not worry about it to much.

[Vladislav]

Ughhh... I'll let you know when it's fail.

Right at the moment the main fact that cheers me up is indefiniteness of the time when that truck will be on the road.

[Maddog13407]

theres a company near us that use to straighten rear end housings all the time, think they still do. Back In the day when they were building I90 and I81 thru New York and Syracuse I heard many of stories about poor B models being pushed with D8's thru the mud and the housings would bend backwards. my grandfather still has a few housings and trucks in the pile that have bent axles from this practice. This was long before the articulated dump trucks when everything was done with small trucks. I remember horror stories about takin a B mode, chaining on the exhaust and takin the petcocks out of the air tanks and putting in plugs so when they got pushed thru the mud, stuff wouldn't get broke off.