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MG MGA - Hub Bearings

I am about ready to insert new bearings into the front and reat hubs. Now, my local car-parts stores offer only sealed (closed cage) bearings as opposed to open-cage bearings as originally installed on the MGA. Of course, I could order open-cage bearings over the Internet.

- What is the better choice, sealed or open bearings?

- And what clearance specification should I look for (C3, C2, C0, CN)?

As always, thank you so much for your thoughts and have a great weekend,
Hansueli
Hansueli Ryser

On the front, do not use C3 as they are too loose and you will have play at the rim.
See earlier thread "Wheel bearing internal clearances" a few weeks ago.
Do you really need new rear bearings? The original R&M are really sturdy and I think the replacements have fewer balls.
The rears are oil fed so open cage.
Art Pearse

http://www.skf.com/us/products/bearings-units-housings/roller-bearings/principles/bearing-specifics/bearing-internal-clearance/index.html

See this site - SKF. I think the "C" designation is SKF specific.
C2 is what I used. Should be deep groove radial ball bearing type.
Art Pearse

Get the open caged bearings for the rear, at least. The bearings are lubricated by the gear oil from the axle housing, so the oil needs to be able to get to the bearings.

The original bearings were very good, but due to the design of the hub, it is impossible to remove the bearings to replace the seal, without pressing (or pounding) on the inner race, instead of the outer race which would otherwise be the preferred way. As such, there is a chance of damaging the bearings whenever they are removed to replace the seals. This also makes a good argument for using the modern double lip seals I linked in the previous thread, and making sure the surface on the axle housing is as perfect as possible, so you won't have to re-do the job. I personally used the new SKF bearings in the Amazon link I posted. They are more expensive, but at least you know ahead of time what you are getting, compared to whatever the usual suppliers for our cars are selling.

There may be some advantage to the sealed bearings in the front hubs on a wire wheeled car, if you don't mind replacing them periodically instead of repacking them with grease, as you can do with the open faced type. The sealed bearings might keep grease from migrating out of the hubs to end up on your wheels.

The currently available rubber-backed seals for the front hubs are not so good. They would not stay in place in my hubs on their own, and I had to glue them in with RTV sealant. Those particular seals appear to be unique to British applications, and only the one brand of seal (made in Taiwan) is available new.

-Del
D Rawlins

Thank you All for the great input and hints.

@Art: Good question. Actually, the wheel didn't have any play in any of the axes. However, the rear left wheel showed an amazing amount of oil on the brake shoes, the drum, well, oil was everywhere. To then point, I couldn't tell where the oil was seeping out. So, I felt that it could have been the seal which is "kept hostage" behind the bearing. Plus, the (too) small drainage hole behind the back plate was clogged, of course. This is why I thought I have to change the seal and therefore remove, or hard-punch-out the bearing. It took me about 20+ minutes to do that. At that poiont I was affraid that I harmed the bearing.....

@Del: I ended up bringing the 9-ball bearing back to NAPA and instead ordered the 11-ball bearing from Moss. The price was similar.
I did get the double-lip seals.
I felt very similar regarding the sealed bearings in the front. However, for some time, it seemed that nobody shared my thoughts about the sealed bearings with me, so I ended up getting open bearings again.
Regarding the front hubs/bearings, the PO must have had the same issue at some time and fixed the problem by piting the hub walls to improve the bearings' fixation. See attached picture
Well, just one other surprise....
Del, again, thank you so much for having sent such good information my ways now and in the past!


Hansueli Ryser

and another picture


Hansueli Ryser

That's a sure sign of worn hubs... Wait, those are disc wheel front hubs. You mean to say that the front also has spline adapters that attach to the hubs? That's an ass-backward way of doing it. The front is easy to convert; the wire wheel spline hubs are a direct replacement for the disc wheel hubs, and you just need to find the wire wheel brake drums and attaching hardware. None of which is uncommon.

Should be lots of WW front drums around with all the people converting to disc brakes... Paul at Sports Car Craftsmen probably has a bunch of them, or will know where to find them.

I don't normally sell my extra parts, but I have two complete spare sets of front WW drums someplace. If you can't find some closer (shipping to and from Alaska can be expensive), I would make you a fair deal on a pair, since I'm still running my car's originals, and can't imagine ever wearing out two sets. Just might take me a while to find them since I am in the process of packing up my shop to move.

Either way, it's worth going to the factory setup in the front, for simplicity's sake and you can have NEW hubs without any bearing retention issues. That's the one big advantage of wire wheels over disc wheels these days... They are higher maintenance, but at least you can find NEW parts. The rear is a tougher nut to crack, since you need the whole wire wheel axle to really make it right.

-Del
D Rawlins

Just a thought:
Bearings with shields are supplied into industry to run for 1000's of hours without additional lubrication. Is that not an improvement on relying on using oil which is shared with the diff?
One downside though could be much reduced lubrication on the lip seal since the shields will prevent the axle oil reaching the seal.
Graeme Williams

Even modern vehicles with live axles have their outer bearings lubricated the same way as the MGA. With sealed bearings, the lubricant that they start with is all they are ever going to have. Sharing the axle lube, the open bearings are continuously lubricated, and all the owner has to do is keep the axle topped off. If that's not done, then the hub bearings become the least of his worries. I would expect the open bearings to run cooler as well due to circulation of the axle oil.

The whole rationale for the sealed bearings (and universal joints) used in modern vehicles is the assumption that owners are not going to do any preventive maintenance. As such, they might make some sense in the front, if you are going to ignore maintenance, but otherwise you're better off with the serviceable ones. Unlike the rear hub bearings, the fronts are a lot easier to remove without damage, so you can simply keep re-packing them with grease at each maintenance interval. As Barney has demonstrated, they will last almost indefinitely with proper care.

I did end up replacing all of my front bearings though... One of them was seized to the spindle, and had to be cut off to remove. At that point, especially since I was also using new hubs, I felt it best to just replace them all.

-Del
D Rawlins

Del, I believe you are right, my car must have been equiped with disc originally. As I stated in my other thread "Rear hubs and hub nuts":

You know, at this point I am quite certain that the axle/hub/splined-hub combination is everything but original nor a common modification.

Here are the reasons why I think so based on what I understand today. Again, I have a 1956 MGA:
- I can't find the axle's serial number where it is supposed to be nor anywhere else on the axle
- my MGA is one of the very early MGAs (# 9631)
- my MGA has a 46 inch wide axle (from back-plate to back-plate) which indicates it is a disc axle yet, my car has wire wheels
- the half-shafts are long shafts as offered these days for ww conversion
- the hubs do not have an o-ring which seems to be in line with early MGAs yet, early MGAs are supposed to have R/H thread hub nuts however, the rear hub-nut on the left side on my car has L/H threads
- On the back, a common disc to ww conversion has the splined-hub mounted on top of the brake-drums. In my case the splined-hub is mounted inside the drums
- On the front, a common disc to ww conversion has the splined-hub inside the drums, in my case they are on top of the hub
- And, on the front, a common conversion uses a 6 bolt splined hub, in my case it has four bolts


So, it is a mess. However, I have already received the ww adapters for the front to mount them on topf of the drums as it was before. However, I will certainly convert it to wire wheel spline hubs, next time I do the bearings.

@Graeme: I think you have a VERY legit oint that a sealed bearing in the back would not be good since the axle-oil would not reach the seal lips anymore to provide the necessary lubrication. Thanks for your input.
Hansueli Ryser

One question which arises about sealed bearings is whether special purpose grease lubrication in a sealed bearing is better in terms of load-carrying and reduction in wear, than oil. Especially oil which is circulating around a number of wearing components.

Hans: If you have long, wire wheel half shafts then I'm not sure what you see as a problem. Someone will correct me in I'm wrong (please) but like the Sprite (which i do know) shouldn't the flange on the splined wire wheel extension hub be inside the brake drum anyway? On the Sprite you remove the drum before you can pull the half shaft. The problem that arises is that loosening the nuts holding the drum in place reduces the pressure on the seals between the half-shaft and the hub, so opening up the opportunity to leak oil. On the Sprite there is only a dubious small cross headed screw to keep it all tightly together!
Graeme Williams

This thread was discussed between 15/05/2015 and 16/05/2015

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