Differential problem, best approach?

[Naj ✝︎]

Hello, Bob,

The fact that the car drives again would suggest to me that nothing serious has happened in there. Probly, the securing bolt has just come off.

Get a bigger hammer to persuade the shaft to move! I destroyed the front tool on my sliding hammer and the shafts (both) did not budge.
I was stripping the axle anyway and I got the shafts out in the end by knocking them out from the inner ends. I would say persevere and you will get there.

naj

[ja17]

Hello Bob,

Sorry I have not been up to date on this thread. The "rear axle tour" uses a later W113 car with disc brakes on the rear. If I recall the drum brake cars require removal of some other parts. The emergency brake pulley fasteners at the brake plate (two 10mm nuts) in addition there is another bolt on the other side of the backing plate. It  goes through the axle housing and into the pulley casting and this bolt is parellel to the driveshaft (possibly 12mm).  Make sure these three fasteners are off also.  

Sounds like you have a loose bolt in the diff. All the banging and the camber change probably allowed the spines on the universal assembly to re-engage!

[cascadia]

Hello All,
Yes, the "rear axle tour" mentions those extra e-brake and backing plate bolts, I made sure those were removed.

It looks like I'm going to try the 'bigger hammer' approach. It's a little counter-intuitive to me, one of the things I love about these cars is how almost every element is elegantly assembled.  I've de-trimmed a few of these cars for paint and learned to appreciate that nothing needs to be forced apart.   The way they go back together is equally refined.

Will give it another go, if nothing else I'm getting good at drum brake disassembly!
Thanks!
Bob

[cascadia]

Gave it another shot today.  Had about 3 friends stop in throughout the day, each time I enlisted their help with a 3lb sledge, each of use hitting the angle iron on either side of the hub in unison.  No go.  I'm starting to trawl Craigslist for donor cars, here in Portland there's always a couple on CL at any given time.  What models and years would interchange?
Bob

[waqas]

Sorry to hear that. Perhaps the 'loose bolt' or whatever else is causing the problem is also obstructing the axle from sliding out. Not sure about this, but it might be useful to slide over the axle boot (without damaging it) and inspect that end for something obvious.

Most axles from the 113/111/108 series should work just fine. The only differences are axle ratio and drum vs disc brakes. Your original should be drums with 3.75 rear ratio (not sure about the limited slip though). The ratio should be inscribed somewhere on the diff housing (my 3.75 has a "3/75" inscribed on the diff rear in a semi-circular machined face).

There have been many many discussions about the relative merits of the various diff ratios, so search away. If you switch to a disc setup, you will need a rear proportioning valve in addition.

[cascadia]

Yes, mine is 4.08 so there's room for improvement with a swap.  I looked at a 64 190D finner project for sale today, but the ratio was 4.10, I'd like to go lower.

[ja17]

Hello Bob,

Did you remove that 13mm bolt on the back side of the backing plate, the one inside the opening in the lower shock bracket?

[cascadia]

Hi Joe,
Definitely did remove it, the brake backing plate is swinging loose.
Bob

[Longtooth]

Just an engineer's logical thought process... absolutely zero practical experience with rear axels and differentials except for my work on my '65 Chevy Heavy Duty (C20) pick-up's axels and bearings.

The axel splined end uses slip fit (or slight press fit) into the differential U-joint.... typical and standard in most similar applications.  The axel splines will therefore be forced out with relatively mild force --- i.e. the 3 lb slege approach among others.

Since it's not budging with that approach, nor with both sides of the bar being hit simultaneously (for symetric unbiased torque at the splines), it means that the splines "fit" (mating splines) are cinched up so to speak... friction is all that's holding them together unless the splines have been "twisted".  If just friction, then more force is needed to overcome it... so why limit the hits with a 3 lb sledge???... gee, I use a 32 oz (2 lb) hammer just for nailing.

If twisted, plus friction, the force required is greater yet, since the sliding friction is greater... but that's all.... so more force is reqiured over a greater distance of sliding along the splines to dislodge.

Now, if you can't get the axel out by the 3 lb. sledge approach, and have to consider replacing the differential / axels anyway, then why limit the dislodging effort to a 3 lb sledge?  Go for a couple of guys that can handle a 20 lb sledge each and bang on the bar (might need a heftier bar though) on both sides simultaneously 'til the axel begins to move off... then keep banging 'til it's free.

What's to lose but a few calories and perhaps some skin from a knucle or two? If you break something in the process it's still no loss as you're going to replace the differential anyway if you can't get the axel out... and even then you may find you have to replace it if you're unlucky.

The curious part is why you get engagement with high positive camber condition then no engagement with normal camber.... but that's internal to the differential.  

Brute force is necessary to unstick frictional forces when those forces are high... no matter what may be causing the high frictional forces... even if somebody used super glue once upon a time on the splines... or some other adhesive, it's still a force issue.  So.... more force is needed than you've been using.  

Get a couple of 30 lb sledges (local tool rental joint) and have at it! What am I missing here that that 'solution' hasn't been tried before resorting to puchase of another differential?

[ja17]

Hello Longtooth,

The most common point resistance is the tight fit of the wheel bearing in the housing.  Maybe some heat at that point around the housing would allow the assembly to pull out.

Another alternative is to rent a giant slide hammer tool commonly used for axle removal. Such extremes are not usually needed.

[cascadia]

My mechanic loaned me his heavy duty slide hammer, the thing looks like it's from the bronze age, I just got done with about 10 minutes of it.  Will apply some heat around the housing and see if that helps.
Bob

[Longtooth]

Hi Ja17... very good point, and better than mine ... re:
 

quote:The most common point resistance is the tight fit of the wheel bearing in the housing. Maybe some heat at that point around the housing would allow the assembly to pull out.

Yer right, of course.  Heating the housing sufficiently will expand it, reducing the frictional compression of housing on bearing outer race. But the housing has a lot of conductive (heat conductive) metal mass, so heating it sufficiently may be problematic.

Another similar approach is to shrink the bearing's outer race... squirting some super coolant on it(I don't know what's available)... or doing both (heating housing and cooling bearing race)... plus pounding while doing this.

[ja17]

Hello Bob,

I have never heard of one being so difficult!

[cascadia]

quote:Originally posted by ja17



I have never heard of one being so difficult!

That's what most people I've spoken to say as well.  It couldn't be the circlip that's hanging things up could it?  

Bob

[ja17]

Hello Bob,

Thats what I'm thinking also. Once they get out of their groove they can cause all kinds of difficulty.  At some point you should be able to overide that pesky clip!

[cascadia]

Would it help if I removed the road spring and compensating spring and angled the axle tube up?  I seem to remember a thread here where someone said that's the procedure for getting the shaft back in.

[ja17]

Hello Bob,

Having the axle hanging at an angle could cause problems. I would let it down on the ground and place a jack stand under the end of the housing and try to extract it then.

[Naj ✝︎]

Is removing the swivel pin and taking off the right axle casing complete with the axle shaft an option?

naj

[waqas]

quote:Originally posted by naj

Is removing the swivel pin and taking off the right axle casing complete with the axle shaft an option?

naj

Naj, wouldn't the 'stuck' right axle prevent the axle shaft from coming off?

Or does the universal simply slide out from the other end (diff side) once the axle shaft is removed?  In this case, the axle and the universal would need to be separated on the bench (with axle shaft stuck in-between). Not sure if this is easier... but my assumptions may be wrong.

[Naj ✝︎]

quote:Originally posted by waqas

wouldn't the 'stuck' right axle prevent the axle shaft from coming off?

Or does the universal simply slide out from the other end (diff side) once the axle shaft is removed?  In this case, the axle and the universal would need to be separated on the bench (with axle shaft stuck in-between). Not sure if this is easier... but my assumptions may be wrong.

The right casing would come off with the axle shaft. If the UJ retaining bolt has come off then it would pull out with the casing and shaft. If not, only the 'pesky' circlip would have to be dealt with. As I said earlier, I was not able to remove the axle shafts before stripping the casings.
Once they were free from the center pumpkin, the shafts were easily removed by knocking the inner ends with a wooden block and club hammer.

naj

[JimVillers]

Bob.... I am late to this thread and hate to comment after the good ideas have not worked.  My thoughts are that you have a broken outside race in the wheel bearing and it has expanded enough to become very stuck.  I cannot imagine the circlip or anything else preventing the axle from coming out with what you have already done.  

So, what next?  I see two options; borrow the big slide hammer again and pound until something gives (what I would do) or remove the rear end from the car, split the axle housings and then take the right housing to a shop with a big press to press it out.  I would doubt that removing springs or changing the orientation would help.

Heat might help but brute force should also work.

[cascadia]

Thanks for the advice.  I think I'll take the car off the lift, tuck it in the corner and keep going with the slide hammer, for the moment brute force is my simplest option
Bob

[gary ensor]

Bob, I had a similiar problem years ago on  customer's car. The sliding sleeve that the right side axle slips into had broken into several pieces and the small cylinderical bearing and pieces of the sleeve were jammed, holding the axle in the sleeve. Have you tried pushing the axle back in ? Will the right side of the axle pivot up and down ? I had to cut the axle off just inside the bearing and remove the right side tube. After removing the tube i could remove the snap ring that holds the sliding sleeve together, letting the axle and broken sleeve parts come out.

[cascadia]

I have tapped inward on the axle shaft with no noticeable results.  My mechanic who loaned me the slide hammer recommended equal impact in both directions for this problem.  Maybe it's just a matter of perseverance.  The right side won't pivot, it's stuck in the positive camber position.  Somehow, this position allows gear engagement because when the rear went out the car finally sat level.  Now that it's stuck again, maybe I should drive it until it goes out and back to level?  Might help with getting that axle shaft to release.

[DavidBrough]

Hi Bob,

You might want to try removing the compensating spring, road spring and the shock absorber then you can see how the axle tube pivots, or not as the case may be. You will need an axle stand to support the right side tube and will also have to remove and plug the brake hose on that side. You may also need to loosen off the hand brake cable. The road spring is easy but the comp spring is a bit more difficult. If you haven’t done it before Waqas has a good post showing the spring compressor to use.

A combination of up and down movement on the axle tube whilst rotating the axle shaft might help to understand/feel what is going on. As part of this you could chock the left wheel and or put the car in gear or park. I’m not sure if this will show anything but at least it’s another option to continually hitting everything with ever bigger hammers. Ultimately, you may have to drop the whole axle and cut off the rubber boot. In any event it sounds like you may have to remove the right hand tube which really means the axle has to come out anyway. If the problem is a UJ bolt that has come completely loose then you should be able to separate the tube axle and UJ together. If not and the whole things stuck then cutting the boot and delving inside may point the way forward.



David Brough
280Sl Auto with A/C & 3.46 Axle