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MG MGA - MGB rear brake drums on an MGA 1600 MK.2
|Has anyone ever tried to fit MGB banjo axle rear brake drums onto an MGA 1600 Mk.2, and if so do they work?|
|AFAIK the wheel studs are a different diameter.|
There may be other differences.
|Dave O'Neill 2|
MGB wheel studs are as Dave says one size up from the MGA. This means that the holes in the drums are bigger, so you will not have the locating effect of the studs, and will be relying on the small retaining screw to locate and hold the drums centric on the hub.
MGB brakes are also adjusted from the rear of the backplate, so will be also missing the hole on the front of the drum that gives you access to the brake adjuster on the MGA
So with two major problems (and I have no idea if there are other dimensional differences - but would guess not as the brake drums for the MGA were apparently designed in the 1920's) I reckon the answer is no.
The B drums do have larger stud holes in it but it is not those that locate the drum. It is the machined recess inside the drum that fits over the end of the half shaft. They are only slightly different ( half shaft bigger ) but the B drum will not fit the A - I have tried - but it was a 1960 1600 and not a mk 2. They do have the adjusting holes in them - or mine did from MGB hive.
|A J Dee|
|Change all brake parts to early MGB parts starting with the backing plate. Use parking brake cable from MGB. The MGB internal brake parts may work with MGA hubs and drums (but I haven't tried it yet). Otherwise use the early MGB bearing hub and halfshafts with larger studs to match the B brake drum. Use differential sun gears that match splines on the halfshafts. You could end up with different size lug nuts front and rear. For wire wheels you might end up with different threads on the knock-off nuts front an rear.|
I know that there are differences in the hub arrangements between wire and steel wheel cars. On a steel wheel car, the drums are located by the studs as there is no other protrusion through the drum. The end of the half shaft sits under the drum.
I would be surprised if this is also not true for the wire wheel cars, as the drum is also held to the hub with four bolts and the drums are the same for both wire and steel wheel cars. On converting from steel to wires or renewing hubs on wire wheel cars, it has never been apparent that the drums are located by anything other than the studs / bolts through the hubs and drums, which are always a snug fit.
I converted disc to Wire Wheel using the standard disc axle. The brake drum is different in this conversion. It is dished towards the centre; the studs have to be shortened and fitted with thinner nuts.
Drum is located on end of half shaft which is machined to fit recess in drum. See attached picture. This is an A drum on an A shaft. The B drum will not fit because the recess in the drum is slightly smaller diameter than the end of the A shaft. The studs stop the drum rotating on the shaft but do not keep it concentric rotationaly
|A J Dee|
This thread was discussed between 17/02/2016 and 19/02/2016
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