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MG MGB Technical - Problem trying to install axle

This is a continuation from removing axle for a new hub.....

I am attempting to reinstall the axle. Its a Mk1 Banjo rear end with the axle and hub pressed together.
I'm having a devil of a time getting the spline to mate and allow the shaft to slide fully home.

With the prop shaft locked and the other wheel on the ground, I have been rotating and tapping the hub to try and get the spline into mesh. But it doesn't want to!!
I have carefully dressed the end of the splines to ensure there are no burrs that might prevent engagement and to form a slight taper to aid in meshing. But still no luck.
Also tried lifting the opposite wheel off the ground and got someone to rotate that wheel while I moved the shaft. Quite a few times the shaft "locked" as if the splines were beginning to mesh, but then let go again. I tried hitting the end of the hub inwards with a hammer when it was "locked", but it just bounced back outwards." Am I not hitting it hard enough?
What else should I try

I've just about used my quota of swear words for the month
John Minchin

Maybe you can see something with a flashlight, or borrow a borescope. Definitely no hammering. You should expect about 1" of engagement in the splines.
Art Pearse

I think I may have stumbled onto a reason why I am having so much trouble.
The diagram in the manual, plus every photo I have found via google shows the splines on the axle shaft going right to the end of the shaft. Mine doesn't as you can see.

Is this abnormal? If the splines are right to the end, then getting the splines lined up would occur well before the hub was trying to fit onto the 4 mounting studs when there was still scope to vary the angle of the shaft a little while trying to align the splines.

John

John Minchin

I don't remember my Salisbury ones being like that, but I haven't seen a banjo one. I would have thought it would make it *easier*, as you can get the plain bit in first irrespective of rotational alignment, then while the inner end of the shaft is being supported by the plain bit you should be able to rotate the shaft to get the splines aligned. Are you sure you are getting the inner end of the half-shaft in the correct alignment both vertically and laterally to even get the plain bit in? maybe it needs a point grinding on it :o)
PaulH Solihull

Jeez that's one well worn shaft end!!!!!!
It looks like the reason it won't go in is that the worn bit has "filled" the bottom of what should be a spline. Try cleaning the burrs off with a file and try again.
Question is.. How much spline is left to transfer the load along the shaft when it's engaged in the diff?

I would be pulling the other one to check it and/or looking for a replacement... Have you pulled the diff to check the inboard bearings and cage?
Good luck... You might need it ;0)
MGmike
M McAndrew

I do not recall any OE axle having the turned down end. Assuming it IS the shaft you started with, then I suggest that the people who fitted it to the hub beat on it hard enough to mushroom the end, then turned down the end. But, the reduced part is still bigger than the root diameter of the splines in the gear. An alternative is that it is NOT the shaft you started with - there are 25 and 26 spline axles.
Should be on Barney, but I can't get his site to work today.
http://www.mgaguru.com/mgtech/

FRM
FR Millmore

Well
The shaft came out of the axle to get a new hub fitted - but as i have not yet driven the car, i have no knowledge of what the previous owner might have installed. I will check the number of spines first. I take it (from the referenced site) that the MGB should have 25 spline gear and shaft. I suppose it is possible that a PO had fitted an MGA diff with 26 spines, and the original 25 spline MGB shafts were installed? The mystery deepens!
Thanks
John Minchin

I still can't get Barney's site, so I can't check there. (In fact, about half the Internet seems down here - anyone else?) But, whichever axle it has must have the same side gears as shafts. You cannot fit mixed 25/26 sets. Since you have not driven the car, A possibility is that some DPO has fitted WW axles into a disc wheel housing, as a half-assed conversion. Since the WW housing and shafts are shorter than the disc ones, the splines may only have been engaged by the amount of the eaten off end, which is about what would have been engaged. Suggest you pull the other shaft and diff and examine the gears.

FRM
FR Millmore

FRM, that is the situation I inherited from my DPO. He put WW shafts into a disc wheel axle (MGA). Fortunately he never drove it. I now have swapped the axle case for a WW one. But as I recall, the spline engagement was about the same as the tip of John's axle, about only 1/4 inch.
John, inspect your other shaft and measure the axle case width.
Art Pearse

Art- Yep!
And John - Late MGA used the 25 spline MGB shafts. 1500 used 10 spline, and 1600 up to a point used 26. All these fit in the housing (and probably the hub) with the correct matching gears. But, all MGA and early B used fine thread hubs, later B are coarse thread.

FRM
FR Millmore

Internet working intermittently but seems OK at the moment!

Checked with a local MG wshop - compared a Mk1 WW axle shaft and hub - its the same length as mine. Also fitted a loose spare diff gear - it slid on to my the splines easy as pie. By the markings on the shafts, the position the gear takes on the shaft is fully engaged on the remaining splines - ie the turned down section is sticking out the other side of the gear and hence is of no consequence in terms of transmitting motion.

It seems that the difficulty in getting the splines to come together is because the hub plate is engaging on the studs at exactly the same time that there needs to be a bit of jiggling of the shaft to engage the splines. If the shaft was as it should be the splines would be engaged before the hub plate reached the studs.
Nevertheless, I will be double and triple checking to make sure the shafts, axle case are correct length/width etc etc

I will report back......
Thanks
John Minchin

"compared a Mk1 WW axle shaft and hub - its the same length as mine."
>>>Yes well, we already know you have a WW shaft.
"Also fitted a loose spare diff gear - it slid on to my the splines easy as pie."
>>> Good
" By the markings on the shafts, the position the gear takes on the shaft is fully engaged on the remaining splines"
>>> those marks may be from when the shaft was in the correct housing
" - ie the turned down section is sticking out the other side of the gear and hence is of no consequence in terms of transmitting motion."
>>> There is very little space on "the other side of the gear" - much less than the length shown. But as stated, if the housing is the wider one, then the engagement will be just what is "turned down"

"It seems that the difficulty in getting the splines to come together is because the hub plate is engaging on the studs at exactly the same time that there needs to be a bit of jiggling of the shaft to engage the splines. If the shaft was as it should be the splines would be engaged before the hub plate reached the studs."
>>> By the same reasoning, the reduced part would already be in the gear, acting as a pilot, hence making it even easier to engage.

It is possible that running with only a short engagement has broken the gear, and the broken piece has fallen down inside the hole where the shaft goes.
I've probably fit a few thousand of these shafts with no such problems, just push and turn.

Nevertheless, I will be double and triple checking to make sure the shafts, axle case are correct length/width etc etc
>>>10 minutes to pull the other shaft, a lazy hour to R&R the diff = less than you've spent trying to figure it out!

Best, FRM
(and internet here is awful I still can't get Barney, or any weather, or US Gov sites.)
FR Millmore

John, stick a steel tape measure down the casing and see where the diff gear starts. Then calculate how much spline engagement you will have.
Art Pearse

Did all the measurements - the shaft is 606.5mm from the hub flange to the end of the shaft (23 7/8") The depth from the mating hub flange to the pinion pin is within 2mm of the same. So I think I have a WW hub and shaft in a WW axle.
I am taking things slowly and am resisting the temptation to pull the other axle in case I can't get that back in for the same reason I am having my current difficulties. I am considering getting a replacement axle with a full length of splines, test it will slide into mesh, then have the hub pressed onto it. Are replacement axles OK? Any recommendations on suppliers?

John
John Minchin

I acquired a replacement axle shaft (2nd hand, good condition) from MG Spare Parts and Service in Sydney.
Offered it up and it slid straight into place at the first attempt with no effort.
So now I just need to press the hub onto this "new"shaft and I should be back in business.
Thanks for all the advice
John

John Minchin

John, didn't you say that it was the hub that was interfering with the insertion process? Won't this happen again when you change the hub to the new shaft?
Art Pearse

Problem solved and I think Art was on the money.
When I measured the hubs I found (amongst other small differences) the holes were smaller than the original and smaller than the studs. So it was never going to fit.
By eye it looks the same as original - would it be from an MGA?
Anyway, I just need a proper hub and I should be back in business, albeit with a spare shaft :-)

John


John Minchin

Seems odd to me! I have an MGA with 25 spline 3.9:1 diff - wire whhels, currently in pieces as am changing diff to 4.88 ratio. Axles have splines to the end, 40 mm spline length. Appears your axle was only driving on the last 6 mm and has now stripped the splines - why don't you pull the diff out and have a look?
Mike
Mike Ellsmore

With the correct hub, the shaft slipped into place in about 30 seconds - brake drum on and new wheel and spinner in place. 6 week delay but now I can move on with the last few tasks before the Autumn (Fall) gets too advanced and tempratuires drop :-(
Original shaft is a spare. Mike, the missing splines is a mystery I may never solve - not worn off in situ as the measurements show it was fully meshed with the gear.

Thanks to all for comments / suggestions

John
John Minchin

This thread was discussed between 30/01/2012 and 11/03/2012

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