MG T-ABC

I am just about to reassemble my front hubs/stub axles with new bearings, seals and hubs. Is there a preferred sequence of assembly, - I've learned that it pays to ask before you start!

John Steedman TC 0301

Hi John,
New ball or roller bearings? Do you have the original spacer between the inner races?
Cheers, Peter

I am just about to reassemble my front hubs/stub axles with new bearings, seals and hubs. Is there a preferred sequence of assembly, - I've learned that it pays to ask before you start!
John Steedman TC 0301

John,
Just a quick reminder to have the axles maganafluxed before reassembly if you have not done so already. I had it done to mine last week and unfortunately one is cracked so I am going to replace both. It will be a bit of a delay but it should reduce the chance for problems later.
Norm Wetzel
48 TC 4924

Peter, John and Others,

The question of use of the bearing spacer has been answered MANY times. Original information 35 years ago said to delete the spacer with tapered rollers. This information was WRONG.

Please ALWAYS use the bearing spacer, suitably shimmed with shims if using tapered roller bearings, as it makes for a much stronger front stub axle.

Regards, Bob

Please ALWAYS use the bearing spacer, suitably shimmed with shims if using tapered roller bearings, as it makes for a much stronger front stub axle.

Bob, do you know a source for the shims other than using shim stock and making your own? (not real pretty)

Joe Potter

Hi Joe,
For shims, look up my article on the T-ABC web site.
Cheers, Peter

Joe, MGB shims work well.....I used them on the N type.
Terry

Don't even think of using other than ball bearings in the front hubs. Stub axles are designed for balls and rollers tended to cause two piece stub axles. I can't locate the scholarly treatise on the subject, but if I do I shall post.

I wrote something on the subject for TSO about a zillion years ago, but can't put my hands on it at the moment. The gist of it is that the strength of the spindle with the original ball bearing and spacer assembly is derived from the fact that when the spindle nut is tightened correctly the spibdle, inner races, and spacer are all locked together into what is in effect a single unit. The strength of the whole assembly is much greater than the strength of the spindle by itself. The spindle by itself is pretty weak.

Way back when, converting to tapered roller bearings sans spacer was a popular modification. The tapered rollers were thought to have a longer life, and adjustment certainly was a lot easier (just tighten the nut until the correct end float was achieved). Trouble is, spindles broke.

There is nothing wrong with converting to tapered roller bearings, but you MUST use a spacer between the inner races. To adjust end float, shorten the spacer or add shims to lengthen it, as required, and tighten the spingle nut really tight to lock the spindle, inner races, and spacer assembly together as in the original ball bearing setup. DO NOT use the nut to adjust end float.

There is also nothing wrong with using ball bearings as original. If high-quality bearings of the correct type are used, and if the hubs are assembled correctly, the bearings will last a long time. A lot of the bad press surrounding ball bearings was the result of (1) the inferior quality bearings once supplied by most of the T-Series parts houses, (2) reuse of collapsed spacers, and (3) sloppy assembly.

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Joe I think it is you that asked the question on where to get the shim for the front end, In the states you can get mm shims that will work in various size from Metric & Multistandard, 120 Old Saw Mill River Rd, Hawthorne NY l0532 800 431 2792, you need the dia, inside and outside and thickness, various, they also have BSF bolts and nuts, taps etc,. but no mad metric material Regards Dean

I disagree.
The stub axle does not know if ball or roller bearings are being used. The critical difference is that previous information was to leave out the bearing spacer and install the stub axle nut loose when using tapered roller bearings. This resulted in a smaller effective diameter stub axle than if the whole assembly was locked up using the spacer and shims and the nut fully tightened. That was the problem, not the bearings. A properly set-up front stub axle using tapered rollers, bearing spacer and shims to allow the stub axle nut to be fully tightened will result in a much superior wheel bearing assembly. Tapered roller bearings are far superior to the original ball bearings. Thats why modern cars use tapered rollers.

Bob

Two Eminence Gris of the TC world have responded and pointed out that properly setup roller bearings won't break stub axles, so I stand corrected. I'm still not going to use them :-) I've already twisted off the top of a sector shaft, writing off one more of my lives, so I will happily motor on with balls. Heh, heh.

So someone was selling new Hepolite standard size pistons on Ebay and there was nary a bid. Any comments on that? He did have a higher reserve than the $75 starters.

1. I am busy replacing the spindles in the front hubs of both my TCs as per Mike Sherrell's drawing. Can someone tell me what grade steel is recommended for this job?

2. Thanks for the advice about the spacers. I am also fitting tapered bearings. I will take the advice but I think there is a flaw in the argument. In my youth (1959 or so), I broke 2 spindles and they both snapped right at the root in exactly the same place. I don't think the additional strength derived from the spacer/bearing assembly would have helped this at all.

Rgds to all
Viv James

The reasoning behind inserting a bearing spacer on the front stub axle comes from the need to increase the effective diameter of the spindle as far as any BENDING MOMENT on the spindle is concerned. However to achieve a rigid assembly, the nut on the spindle has to be tightened hard which puts the spindle under TENSION, this stress plus the the reduced bending moment stress fatigues the spindle at the root area of the bending moment.

The tension stress is fairly constant, whilst the bending stress is variable as the wheel rolls along the road and therefore the bending stress is the greater cause of fatigue. The moral seems to be to minimise bending stress and therefore follow Bob Grunau's advise.

Regards Eric Worpe.

Just goes to show that to own a TC you have got to have balls!

As far as the pistons are concerned it's all a matter of chance. You may advertise and get six people looking for your item, on the other hand it may have no appeal that week. I advertised an MG item and never got a bite...put it back a week later and got ten people and a final bid beyond my reserve...you pays your money etc..etc. Have a nice day...we are freezing here in New York State think I will go back to bed!

Regards Geoff

Bob, (and the rest of the list also)
Do you know what the std part numbers would be for tapered bearings to replace the balls. (Speaking of which, I am glad I am not a brass monkey today in Michigan -12 F.). I may as well do the rebuild correctly as long as I am this far.

Thanks in advance to all.
Norm Wetzel

Here in the U.K. the best stock steel is EN24T (817M40) but Abingdon spares have them on the shelf, CNC machined to a very fine finish. This is far superior to the original forged steel, which was probably just a cheap carbon steel, not a chrome-moly like EN24. Has anyone ever done an analysis on an original stub axle?

I certainly agree with Bob - taper rollers will outlast baals every time. As to breakages, we have sunk many a pint of Bass or Speckled Hen debating this point. As Viv says, they always break at the root, so maybe taper rollers without a spacer allow the thin end to wave around a bit and not snap off the thick end. That's a very simplistic view, but until somebody runs a computer simulation of the stresses, we will never know for sure.

ocTagonally
Roger Furneaux ("Mad Metrics" always available)

TC front wheel bearings using Timken tapered roller bearings:
4 off-07204 cups
2 off-07079 cones
2 off-07097 cones.
Bob

Hi Viv and Roger etc,
Yes, Abingdon Spares have the stub axles, supplied by me. The steel is American/Canadian spec ASTM 4140, HT and SR. This is a very strong, ductile material and very suitable for stub axles. Yield stress is 129,433 psi, Tensile stress is 142,719 psi, elongation is 18.1% , reduction is 55.91%, BHN is 293/302. All this according to the material Mill Test report. I have the chemical analysis if interested, but its a chrome-moly steel.

The spindles are machined on a CNC lathe and are very highly finished. I made a change from the standard TC spindle by substituting a 3/4"- 16 TPI thread on the axle end ( instead of original 5/8" BSF ) , as it seemed to me to be a much stronger spindle with the better thread. Spindles are LH and RH threads as original, but you need a 3/4" late TD/TF or MGA set of front nuts ( not to be confused with balls! ).

I have raced my TC for two years on these spindles with no problem. After one season racing, my friend Frank Mount removed his stub axles, with my spindles installed, and I magna-fluxed the spindles. result, AOK.

Trust this helps.
I can supply the spindles if interested, email me for details.
Regards, Bob

The spacer loads the hub near the inside. Without it, the tapered spindle flexes.

Regards,
Ray McCrary
"Speed is Life; of course Luck and Altitude are helpful, too."