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MG MGA - MGB Front Wire Wheel Hub on A

I am converting my 1600 MGA over to wire wheels and have a pair of MGB front wire wheel hubs from a 1965 MGB will they work on the the MGA.
I checked the moss catalog and they are different part #
J Nicholas

Won't fit, the common use of B components is to replace the entire upright/kingpin assembly. Plenty of information on this in the archives I'm sure.
Bill Young

Different bearing configuration.
Rich McKIe

It has been a long time but I ran into the same situation. I believe I measured the B hub bearing fits and that the B bearings and A bearings have the same OD (not ID) so you could use A bearings in a B hub and install it on a A spindle. Not sure if the bearing spacing is the same but the B hub has larger OD studs so A wheels/brake rotors wont fit. If the hubs are not in REAL good shape I would not use them on new wire wheels anyway. Have a good day!

John
John Progess

Conversion by replacing the entire upright assembly is a straightforward job. Lots in the archives. I have had this conversion on my A for years. Used washers as spacers at the upper end.

FWIW

Larry
Larry Hallanger

Yes, you are talking ball bearings in the MGA and taper rollers in the MGB - quite different.

You can still get the new wire wheel hubs for the MGA from the usual sources and that's the easiest way to go.

If you have a good steel wheel front hub, I can tell you how to convert that to wire wheel cheaply using Triumph parts.
Bill Spohn

John, that is very interesting. That may be the answer to my dilemma of finding a set of disc wheel disk brake hubs for a conversion on the Magnette.

If what you say is true then I could fit the B hub to the A spindle and use a B rotor.

Right?

Jay, does your 1600 have disk brakes?
Wray

I seem to recall kicking this around with John Progress a couple of years ago, or maybe it was on the Magnette board. Don't think it would work because of the bearings, and I recall doing a lot of looking at parts books and parts. Gotta be in archives someplace. OK, I'll look it up again!

MGA ball bearing
Inner 6306 30mmID, 72mmOD
Outer 6304 20mmID, 52mm OD
MGB
Inner LM67048/LM67010 1.250ID, 2.328OD
Outer LM11949/LM11910 .750 ID, 1.781OD

(NOTE: the 1965 BAP catalog erroneously shows wire wheel A as having the same bearings as MGB. Wrong, though the Twin Cam/Deluxe did. This kind of error has a habit of persisting through time in listings and folklore)

Brake rotors do not have anything to do with wheel studs on MG, as the rotors mount to the back of the hub.
Rear drums fit over an enlarged shoulder on the stud; I believe the shoulder size is the same for A(mag) and B, as drums are the same part number.
I believe that A/Mag wheels, which use a 7/16 stud, will nevertheless clear the B 1/2 studs. It is too cold and deep for me to go check!
FRM
FR Millmore

Just out of curiosity, what would prevent the use of the B hubs on an A if you could find bearings of the appropriate OD for the B hub, and ID for the MGA stub axle?

Given the huge variety of bearings available, there's a reasonable chance that such a standard bearing exists.
dominic clancy

Dominic
believe I did this search a long time ago, and could not find any standard bearings to suit. The possibility remains of coming up with bearings to fit one or the other or somewhere in the middle and making spacers to suit. Lots of precision machine work, little point. Many easier and perhaps better ways to do it.
FRM
FR Millmore

Hi J.Nicholas,

I converted my 1959 A,Coupe from steels on drums over to wires on discs, I bought an MGB front crossmember from a breakers yard, complete with shockers pan assemblys kingpins etc, stripped all the components threw away anything that could not be refurbed and bought new discs, washers,splitpins,screws and bolts etc,etc,

Had to cut out a little on the inner whweel arches to get the shockers to fit as the B, shockers operate the other way round, but all in all fits just fine, I had decided not to go down the complete original road some time ago, if you want any photographs drop me your email address I can forward you a couple of photos of the setup, was a pretty straight forward cheap conversion, Graham.
G.W. MAGGS

P.S.
Just one thing though, I forgot to mention, the steering rack from the MGB will obviously not fit on to the A, so on the advice from Bob West, I shall need to get the original A rack shortened, this also is not a problem as long as you can find a good welder to cut and shut it for you, Regards, Graham.
G.W. MAGGS

GWM,
DO NOT do any welding on the rack/tie rods! All you need to do is cut about 5/16" off the threaded end of each tie rod, and adjust the track. People speak of have to put a few more threads on, but I never needed to do this.
Actually, I don't understand what you did, since I also never had to cut fender wells. Did you change the entire crossmember?
FRM
FR Millmore

Modified MGA front suspension:

http://www.mgcars.de/indexgb.html
Wim Betzel

Wm Betzel-
Nice sight, I need to go back and examine it more closely.
Did my first one like that in 1966. I did not monkey with switching shock arms to worn-out and hard to get A shocks, but relocated the mounting holes on the newish B shocks, Easy to do, each hole center needs to be moved 1/8" in or out to match the Off square pattern, which means they come out 1/2" diameter, so I then pressed in 1/2OD x 3/8ID bronze bushes to return the holes to the right side.
FRM
FR Millmore

The MGB shocks fit without any cutting of the inner fender panel or wallowing out the mounting holes. All you have to do is reverse the arms and mount the left on the right and the right on the left. You can remove the studs and replace them with bolts so the shocks slide in. To swap the arms you must grind a flat to clear the arm mounting bolt. I have had this setup on an A roadster since 88. As FRM states you must shorten the rack. I did run the threads down a little but may not have needed to. To shorten the rack put a die on the shaft backwards, cut off the shaft as needed then dress it with a grinder then clean the threads by pulling off the die.
Do NOT grind the mounting hole as FRM reccomends just mount left to right and the B shocks fit just fine.
Shock, upper arms, kingpins, hubs, wheel brgs, and brakes are all B pieces. The lower arms and pans are same A or B. I used A springs. Simply unbolt the A pieces and store them away for originality. The only un reversable part of the mod is cutting the inner tie rods.
R J Brown

I did the mounting holes on a milling machine, with toolmaker's techniques; I don't recommend freehand, and certainly not "wallowing" - these holes are front suspension location points. At the time, I was obeying the injunction "thou shalt not remove the arms, lest thee get them back wrongly and really screw things up", Also, one arm is a press fit, and I didn't have a press; it is also very bad to loose the press fit, as loose arms strip on the splines. Nowadays I would likely mark arm position carefully (the arms must be in register with the internal works) and press arms off and back on with Locktite on the splines.
FRM
FR Millmore

You may get some info from

http://www.rhodo.citymax.com/f/front_suspension.pdf
Bill Spohn

In the above article the shock bodies were reversed to increase clearance for a V-6 engine. With the shocks reversed in this manner the bolt holes were wallowed out with a air grinder to fit. Arms reversed on B shocks allows for a shock fit without grinding and a more stock appearance. Pressing on and off the one arm is not a big deal. When shocks are rebuilt it is a neccesary step. Taking care to center the arm to the shock movement is not difficult. I would definately NOT use locktight as the arms are sufficiently difficult to remove as is.
R J Brown

The A shocks currently offered as NEW are B shocks with A arms. They fit in the inner wing as long as you remove the studs and use a bolt instead. They do not need to be mounted backwards.

I don't know what the dimensional difference of the arms is, but it may be possible to use the standard B shock if you are using a B kingpin and trunnions (these are MUCH cheaper than the A setup, and can be bought as a reconditioned set for about $50 US compared to the $400 or so for the A equivalent)

Having said that, my car is still stock MGA with the B shock bodies. I still have the A shocks, which are fine apart from one leaking seal at the shaft - anyone know what the seal number is and if the metal ring is also available?
dominic clancy

The procedure detailed by Bill causes the shock to be twisted on its mountings, leading to alignment errors and side load/binding of the upper and lower pivots. Which way it goes depends on which holes you butcher. I believe I have commented on this once before, not a good method. Moving the all 4 holes half the distance equally gives correct mounting position.

I fail to see what the issue is with inner panel clearance when using MGB shocks with the body pointing outwards on MGA which had the body pointing inwards.

I seriously doubt that most drivers can discern any changes in bump steer with the requisite amount of shortening of tie rods due to the steering arm changes. It is also unlikely that the original geometry was any closer to correct than the new is, most cars aren't. These cars may be better than average as original, never tested/measured one, and neither have the vast majority of readers, and they are unlikely to do so. And, the use of longer lower arms is also unlikely to correct the "bump steer" characteristics to the OE condition, be it good, bad, or indifferent.

Most drivers can't tell if their tire pressures are within +/- 50%, or if the rear axle is cockeyed, or if there is a 300 lb load in the boot, or if the throttle cables are failing to get the carbs open more than half way. Another case of people reading books and attempting to apply arcane theory with no comprehension of reality. Anyone who actually measures these things, and understands the theory and results, and has real world experience, should know that this order of alteration is indiscernible and means zilch to most people in most situations.

The use of Locktite on press fits can result in easier disassembly as often as more difficult. See Locktite tech publications. With the required press, it doesn't matter; if you don't have a press, heating the arm to 400F dissolves the Locktite anyway, and you can readily get to 400F without cooking anything else.

FRM
FR Millmore

The seal numbers for the MGA front shock are Federal Mogul no. 470954 (.750 x 1.250 x .250) and 471267 (.875 x 1.375 x .250). Units are normally available at most bearing supply houses. I don't use a steel ring on repairs as I don't know where to find one and also the groove is often damaged on removal of the existing ring. These seals are double lip seals. Hope this helps and have a good day!

John
John Progess

"I seriously doubt that most drivers can discern any changes in bump steer with the requisite amount of shortening of tie rods due to the steering arm changes. It is also unlikely that the original geometry was any closer to correct than the new is, most cars aren't."

You've got that dead right! I've had quite a few MGs on the alignment rack and the variation between them is quite wide.

We've also found on things like Bugeyes that the stock alignment of the suspension pivots (which should be in the same axis) are so far off from the factory that when you install solid inner bushes in them the A arms seize up and will not move. The only thing that allowed them to function all those years was the complianceof the stock rubbers.

We've found variations in camber (and more amazing, caster) from side to side, and one wonders what checks the factory performed before shipping the cars.

And Mr Millmore is correct - the method I used to fit MGB shocks to the MGA can theoretically result in a slight twist one way or the other and could result in binding. We were careful to check the result through the full range of suspension movement (with springs removed) to see if there was any misalignment and binding. There wasn't on my car, but that doesn't mean that there wouldn't be on any other car and one should bear that in mind if following that method of fitting.



Bill Spohn

Why would any of you change the location of the mount holes at all when there is another way to do the conversion that works better? If you mount B shocks with the body pointing inward as the A originals were there is no need to change the mount holes.
I am not looking for an argument, just an opinion of why it may be better to change the mount holes and not the arm direction? Unless I am missing something there can only be problems created by re drilling the mounting holes.
Dominic:
with the A arms on the B shocks I believe you are mounting them "backwards" to the "B" direction.
R J Brown

FR
B shock bodies are taller than A shock bodies. If you don't remove the studs, you can't get the bodies through the gap between the studs and the inner wing. Simple really.
dominic clancy

RJB-
I think I pretty well explained it in my 12 Feb post, above, including the point that I would likely do it your way now, but maybe not.
While it may be a matter of terminology, I don't like to think about how carefully a person who "wallows" critical location holes will relocate the arms on splines. What is the correct angular compensation at the splines for the differing center to center end-hole angle between the straight B arms and the droopy-ended A ones, if that's what you are doing? What is the bump/rebound damping rates/ratio, which you reverse if you mount the damper bodies "backwards"? (I don't know, Peter Caldwell certainly will, but once in a while you come across a listing - you cannot assume that they are equal and interchangeable.) What about bumpstop mods, or whether or not they are in place at all, or have they fallen off? I'm sure you've seen cars suffering these evil things. I really don't think I want to drive one with the damper internals serving as bumpstop! I have met dampers that have had arms relocated so that they were acting as bumpstop. One of them had stripped splines, several didn't damp at all anymore. I once saw one with an arm welded on, in the wrong position - the rest of the car matched that.

It all comes down to what you trust "them", who may be "us", to understand and do based on your/our advice. I'm not trying to start an argument either, jest my opinion, and trying to keep everyone safe and happy!
FRM
FR Millmore

This thread was discussed between 07/02/2007 and 15/02/2007

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