Started the 'dreaded' half-shaft replacement

[85 DSEL]

Well I couldn't help myself today since it was one of those really nice late summer days when the weather was 'perfect', I got started replacing my passenger side half-shaft. I hope I don't regret doing it myself and not taking it to my Indy!

I've got the wheel side out of the spline but now I'm trying to get the rear cover off the diff. Do I have to lower the diff to get to the upper 15mm bolts on the cover or can I get to them with the proper socket and swivel combo? I have actually removed the hanging bracket that the rear of the diff attaches to but then realized there were four more bolts holding it up! And a couple of these puppies are not too easily reachable!

Any words o' wisdom would be greatly appreciated as I'm done for the night and may or may not do anything else to it the rest of the weekend! After all, it is a holiday!

[Brian Carlton]

The two large cap screws that you removed hold the diff mount to the diff. You'd be way ahead of the game if you removed the four screws that hold the mount to the body. Use a socket wrench with an extension and a proper socket bit (6mm??).

You probably have the diff supported already (or you'd be wearing it), so, you can lower it three inches or so for improved access on the cover. Remove all the cap screws and the cover will come off with a bit of persuasion.

Now you've got to find the clips that hold the axles in place. They are not immediately visible to a person who's never been inside of the diff, but, you'll see a tang protruding from the clip and you can grab the tang with needlenose vice grips. Pull smartly and the clip will disengage. Once the clips are off, the axles slide right out of the diff. You've already done the difficult part of removing the splines from the hub.

Make sure you transfer the spacers from the old axles to the new axles as they belong to the diff. There should be just about zero axial play in the axle after installing the clip.



When reinstalling the cover, thoroughly clean both surfaces (preferably with acetone) and use a small line of RTV around the entire face. Set the cover, screw it in place, and allow to dry for 24 hours before running the vehicle.

[Cervan]

Originally Posted by Brian Carlton

The two large cap screws that you removed hold the diff mount to the diff. You'd be way ahead of the game if you removed the four screws that hold the mount to the body. Use a socket wrench with an extension and a proper socket bit (6mm??).

You probably have the diff supported already (or you'd be wearing it), so, you can lower it three inches or so for improved access on the cover. Remove all the cap screws and the cover will come off with a bit of persuasion.

Now you've got to find the clips that hold the axles in place. They are not immediately visible to a person who's never been inside of the diff, but, you'll see a tang protruding from the clip and you can grab the tang with needlenose vice grips. Pull smartly and the clip will disengage. Once the clips are off, the axles slide right out of the diff. You've already done the difficult part of removing the splines from the hub.

Make sure you transfer the spacers from the old axles to the new axles as they belong to the diff. There should be just about zero axial play in the axle after installing the clip.



When reinstalling the cover, thoroughly clean both surfaces (preferably with acetone) and use a small line of RTV around the entire face. Set the cover, screw it in place, and allow to dry for 24 hours before running the vehicle.

Silicone or rtv will work, but 24 hours is abit long for gear oil, i would say atleast an hour.

[85 DSEL]

Originally Posted by Brian Carlton

The two large cap screws that you removed hold the diff mount to the diff. You'd be way ahead of the game if you removed the four screws that hold the mount to the body. Use a socket wrench with an extension and a proper socket bit (6mm??).

You probably have the diff supported already (or you'd be wearing it), >> Not so! There's four more points of 'attachment' that need to be removed first! These are what hold the diff up to the sub-frame. I can actually lower the hydraulic jack from under the diff and it (diff) stays right there! << so, you can lower it three inches or so for improved access on the cover. Remove all the cap screws and the cover will come off with a bit of persuasion.

Now you've got to find the clips that hold the axles in place. They are not immediately visible to a person who's never been inside of the diff, but, you'll see a tang protruding from the clip and you can grab the tang with needlenose vice grips. Pull smartly and the clip will disengage. Once the clips are off, the axles slide right out of the diff. You've already done the difficult part of removing the splines from the hub.

Make sure you transfer the spacers from the old axles to the new axles as they belong to the diff >> Thanks for this tip! <<. There should be just about zero axial play in the axle after installing the clip.



When reinstalling the cover, thoroughly clean both surfaces (preferably with acetone) and use a small line of RTV around the entire face. Set the cover, screw it in place, and allow to dry for 24 hours before running the vehicle. >> Should I also wait 24 hours before filling with fluid? <<

Thanks Brian for your much appreciated help. You have always been one of the first to the 'rescue' every time I have had an issue with my W123! You are a true asset to the forum!

[Brian Carlton]

Originally Posted by 85 DSEL

Thanks Brian for your much appreciated help. You have always been one of the first to the 'rescue' every time I have had an issue with my W123! You are a true asset to the forum!

Anytime.

But, I'm a bit confused as to why the diff doesn't fall. The subframe is held at three points, with only one in the rear, so, if the diff mount is removed, the subframe has to drop a bit in the rear (the diff drops with it). The two front mounts prevent it from falling to China, but, they can't stop the back end from dropping a good bit.

I'd wait 24 hours before filling it.........because I only want to do it once. Others might risk it after one hour.........but, they don't mind doing it twice.

In reality, letting it sit overnight is probably sufficient.

[85 DSEL]

Originally Posted by Brian Carlton

Anytime.

But, I'm a bit confused as to why the diff doesn't fall. >> There are two bolts that come down from the top into threaded holes in the front portion of the diff housing just aft the flex disk that are tuff to reach and then there are two up high forward of the diff mount that I have removed and I believe they are 19mm nuts that appear to thread onto studs attached to the diff housing that need to be removed. << The subframe is held at three points, with only one in the rear, so, if the diff mount is removed, the subframe has to drop a bit in the rear (the diff drops with it). The two front mounts >> Now where are you talking about here? << prevent it from falling to China, but, they can't stop the back end from dropping a good bit.

I'd wait 24 hours before filling it.........because I only want to do it once. Others might risk it after one hour.........but, they don't mind doing it twice.

In reality, letting it sit overnight is probably sufficient.

Thanks again

[Cervan]

Originally Posted by Brian Carlton

Anytime.

But, I'm a bit confused as to why the diff doesn't fall. The subframe is held at three points, with only one in the rear, so, if the diff mount is removed, the subframe has to drop a bit in the rear (the diff drops with it). The two front mounts prevent it from falling to China, but, they can't stop the back end from dropping a good bit.

I'd wait 24 hours before filling it.........because I only want to do it once. Others might risk it after one hour.........but, they don't mind doing it twice.

In reality, letting it sit overnight is probably sufficient.

just dont forget to fill it with fluid before you go to work in the morning :O

[Brian Carlton]

Originally Posted by 85 DSEL

Thanks again

You're thinking that the diff will fall by itself. That's not happening. The diff is attached to the subframe via the four nuts and bolts that you mention.

I'm speaking about the subframe falling with the attached diff. Three points hold it up.........two in front and one in the back. Remove the diff mount in the back and it must fall.

[85 DSEL]

Originally Posted by Brian Carlton

You're thinking that the diff will fall by itself. >> Yes, that's what I thought would /should happen. << That's not happening. The diff is attached to the subframe via the four nuts and bolts that you mention.

I'm speaking about the subframe falling with the attached diff. Three points hold it up.........two in front and one in the back. Remove the diff mount in the back and it must fall. >> This is where I am confused! I have the diff mount removed and ain't nothin' fallin' - not even a smidge!

..

[Brian Carlton]

>> This is where I am confused! I have the diff mount removed and ain't nothin' fallin' - not even a smidge!

Is the vehicle sitting on it's tires?

[85 DSEL]

Originally Posted by Brian Carlton

Is the vehicle sitting on it's tires?

Front ones only!

[Brian Carlton]

Originally Posted by 85 DSEL

Front ones only!

Well, if the back of the vehicle is supported on the body, and you remove the diff mount, the springs are going to force the trailing arms and subframe to China if they can. So, I'm really not following what you're doing with that vehicle because it's impossible for the subframe to remain in position unless the tires are on the ground.

[85 DSEL]

Originally Posted by Brian Carlton

Well, if the back of the vehicle is supported on the body, and you remove the diff mount, the springs are going to force the trailing arms and subframe to China if they can. So, I'm really not following what you're doing with that vehicle because it's impossible for the subframe to remain in position unless the tires are on the ground.

Brian,
let me see if I can give a step-by-step recount of what I have done thus far. here we go:
1) Raised car by hydraulic jack under diff
2) Placed jack stands just forward the rear wheel openings
3) Removed rear wheels
4) Loosened fill plug
5) Drained fluid
6) Removed the 8mm bolt at end of axle shaft
7) Tapped splined end out back side of wheel
8) Removed two large bolts from back of diff (in mount)
9) Removed 4 diff mount bracket bolts from cross frame
10) Loosened and / or removed several cover bolts
11) Tried lowering the hydr jack...diff does not follow!
12) ? ()

[Brian Carlton]

Originally Posted by 85 DSEL

11) Tried lowering the hydr jack...diff does not follow!
12) ? ()

The subframe with attached diff should move downward 3-4". The procedure is fine.

If it doesn't move...........I'm at a loss..........it's not physically possible

[85 DSEL]

Originally Posted by Brian Carlton

The subframe with attached diff should move downward 3-4". The procedure is fine.

If it doesn't move...........I'm at a loss..........it's not physically possible

Brian, if anything comes to mind tonight OR in the wee hours of the morning, please reply to this thread! Heck who knows, it may come to you in a dream!

Over and out (I'm going to bed!)