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MG MGA - Rear axle and sline-hubs

I am in the midst of a soft-restoration of my MGA. So I had to learn that the wire-wheels and spline hubs are all badly worn triggering the purchase of four new wire-wheels and spline-hubs. OUCH! As I removed the old spline-hubs I noticed various issues that I would like to discuss with you.
Front axle: The front spline-hubs came off easily and I think, replacing them will go smooth. With the spline-hubs off, I checked the bearings by waggling the hubs up and down, from left to right and laterally in and out. Both front hubs were tight, no noticeable play. However, one hub spins very easily where the other hub doesn’t turn as easy.
Question 1: How easily should the hub turn? What needs to be done to correct this?
Rear axle: Removing the rear spline-hubs resulted in pulling the half-shafts out as well. It is my understanding that the spline-hubs have to be separated from the half-shafts by using a 60+ ton hydraulic press.
Question 2: When attaching the new spline-hub to the half-shaft, how much pressure should be applied? And, should I use some fixation paste like Loctite or similar?
As with the front axle, I checked the rear hub bearings also. Both sides were tight, up/down and sideways. However, the left/rear has about a 1/8 inch lateral play (pushing the hub in and pulling it out).
Question 3: Is this play tolerable? If not, what would you suggestfor a fix?
Also, when I removed the same rear/left break-drum, the entire drum and the brake pads were soaked with oil. I could not really see where the oil is coming from because it is everywhere.
Question 4: Do you think it could have anything to do with the lateral play I mentioned above? How should I conquer this problem?
I thank you in advance for your good thoughts and hints.
Sincerely, Hans



Hansueli Ryser

Q1. It should turn really easily, just the resistance of the grease. If it is stiff, need to be corrected. Could be just old dried grease. Pull the bearing, wash in paraffin or petrol until it spins freely with no chatter. If in doubt, replace it, they are cheap.
Q2. Take it to a m/c shop. No Loctite.
Q3. Absolutely not!!! The hub is retained by the axle nut which bears on the bearing race and holds it tight to the hub recess. Probably related to your oil seal failure.
Q4. Pls investigate source of play and report back!

Inspect the seal face on the axle once you have the hub off.

In the WS manual there is a nice sectional diagram of the rear hubs.
Art Pearse

There is a good page on this here which will help you understand what's going on and how things should work: Start here and work through the list on the page

http://mgaguru.com/mgtech/rearaxle/ra101.htm

This is on the timetable for me tomorrow on a coupe, so I will take photos as I go and be able to provide higher quality ones than on the page above (must be quite an old page looking at the resolution of the photos)

Question 1: How easily should the hub turn? not finger pressure but a reasonable hand effort should do it. maybe the grease has hardened from age. Try washing out with a solvent and oil the bearing to find out if it is binding. Bearings are cheap (it's a standard one, no need to buy from Moss) if it has to be replaced.

Question 2: You will need to use the same press to get the new hubs off the shafts. You just apply the pressure required to ease them into the hubs as far as they need to go - you need to leave them at the point that you can insert the cap over the end - you also need to remove this cap to press the old hub off the shaft. I thought Barney would have a page on this but can't locate it. You don't need any fixative.

Q3. This play is not normal. The bearing should be tight in the bearing carrier, and the bearing should also be a tight fit on the axle. if you can move it around easily, something is worn and you need to find what it is. This will also mean that the seal at the inside of the bearing carrier cannot work and oil will leak out


dominic clancy

Also examine the inner splines on the halfshafts, its false economy to put a new hub on a worn half shaft.
mog

Here is the Barney page that is specific to the rear spline hubs:

http://mgaguru.com/mgtech/rearaxle/ra107.htm

You should not need a 60+ ton press to change them. I think the press I used was either 25 or 50 tons, BUT it was equipped with a pressure gauge that told me exactly how much pressure was being applied. Both of the old hubs broke loose at well under 10 pounds, so it turned out I could have done the job with my 12 ton press at home. Your mileage may vary. There is no reason to use any sort of compound between the shaft and the hub. Be sure to install a new expansion plug afterward; that is what will keep oil from leaking past the joint.

The oil in the brakes is probably leaking past the seals in the inner hubs. This is a very poor design which requires removal of the bearing to get at the seal, so you may as well replace the bearings while you are at it. It's easy to mess them up getting them out, since there is no access to the outer race, and you have to apply force to the inner part of the bearing. You can buy the standard bearing du jour for about $40 (IIRC) from the usual British suppliers, or you can buy first quality SKF bearings from a bearing shop or Amazon for about twice that:

http://www.amazon.com/gp/product/B007VG9VW4/

The seal rides on the axle housing itself, and it is very common for a groove to be worn there, such that after replacing the seal, it will still leak. The cure for this is to install a repair sleeve over the axle housing, which Barney details on his site. You can buy the repair sleeves from Amazon here:

http://www.amazon.com/National-Oil-Seals-99193-Redi-Sleeve/dp/B000C5JNH4

Or you can pay about twice as much from Moss. For the seal, there is a more modern, double lip seal available (Timken 473241) that may seal better than the original. It may even eliminate the need for the sleeve repair, since the lips don't ride over the housing in the same location as the single lip of the original seal. Available here:

http://www.summitracing.com/parts/tmk-473241

-Del
D Rawlins

Also, question 3... To echo the others, there should be no play in the hub. If the bearing is loose in the hub (worn hub), and a new bearing does not eliminate the play (which it probably won't), you will need to source a hub that isn't worn. IIRC, the only difference between the disc wheel hubs, and the wire wheel hubs, is the length of the studs. So if all you can find is a disc wheel hub, you can swap out the studs with those from your existing hub.

-Del
D Rawlins

Hello fellow MGA lovers

Man, you are awesome! Thank you bunches for your prompt responses. It gave me a clearer picture of what I have to do next and what is out of acceptance.

Again, thank you so much!

Yet, it triggered a couple more questions:

- "mog" mentioned that I should also "check the inner splines on the half-shafts". May I ask, what would I be looking for? And what side of the splines are at risk, the differential side or the wheel side?

- On my car, the inner-spline's "inner lock nut" shows clear signs that a chiesel was used to open (my guess) the nut previously. Is this an acceptable method if you don't have a $80 eight-sided nut socket?

Again, I thank you for all your input.

Best regards, Hans
Hansueli Ryser

The octagonal hub nut has to be VERY tight, and you cannot possibly get it tight enough by using a chisel. If you have not seen it, there is a currently active thread on this subject. Scroll down for the thread "Rear Axle Nut Spanner".

As for wear in the splines, Mog was talking about the inner splines where the half shafts go into the differential side gears. If you've got the earlier (1500) cut square splines, I could see those possibly wearing enough to cause a problem... The later 1600 and Mark 2 cars had involute splines; they had either 25 or 26 splines which are of course, not interchangeable. I think those would be far less likely to wear. I couldn't tell from your picture, what type you have.

Not sure what would be a good way to check for wear (unless it is really obvious) without pulling the differential out... There shouldn't be any discernible slop between the side gears and the shafts.

-Del
D Rawlins

Hello D Rawlins
Many thanks for your great advice.
You know, I hate the idea of using a chisel. This sounds more distructive than a real obtion.
As to the inner splines, I will check them for obvious wear.
Thanks again for your input and best regards to you and Alaska.

Hansueli
Hansueli Ryser

This thread was discussed between 30/04/2015 and 07/05/2015

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