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MG MGA - Prop shaft removal

How easy is it to remove the prop shaft. According to the Haynes manual, it seems very straight forward.
However, I remember using Haynes to remove the rear shock absorber. 'Just undo and remove three bolts, and remove from chassis.' It didn't mention that it would be stuck, and a b****y big hammer was needed!
Nigel Munford

It is not difficult if you can get under the car, with the rear wheels in the air, so you can turn the shaft to get to all the bolts...You may have to wedge the rear wheels as you go around the flanges.
Edward
Edward Wesson 52TD

Nigel
Its a very long time since I did it and I am sure someone will be along soon with chapter and verse. But I just thought it may help that I do recall I was advised to mark the ends before it is taken off, to be certain to put it back in exactly the same place.

Good luck, Graham
g Victors

Hi Nigel,
Graham's recommendation to mark the flange on the prop shaft with the transmission flange is good advice. By doing this, you are assured to maintain the balance of the shaft. I put a permanent mark on each flange to be sure that they went back in the same position as they were taken apart. If you are removing the front universal, be sure to mark the shaft with the flange so the spline will be assembled in the same position.

George
George Raham [TD4224]

At the factory when the cars were made, I am sure they picked up a prop shaft, put it on, and that was it. I doubt they tried each position (of four possible on the rear end, and very many at the front splined end) to find the position with perfect balance. Why in the world would it need to be marked? If anything, the shaft itself would have been balanced as a subassembly before going to be installed, but the orientation in the car would not matter.

No?

JIM in NH
AJ Mail

I do however, remember reading something about you want the U-joints to line up rather than be at 90 degrees to each other or some such...no reference handy, though. Can anyone comment?

JIM in NH
AJ Mail

http://chicagolandmgclub.com/driveline00/0404/drshafts.html

Here is the article on prop shaft alignment.

JIM in NH
AJ Mail

Hi Jim in NH,
I recall when I first removed the drive shaft from my TD some 50 years ago, my next door neighbour who was a mechanic, suggested I mark the flanges so they can be put back in the same position. I did as he recommended. Years later, when I did my frame up restoration, I completely forgot about the markings, and reassembled the shaft without paying attention to them. When the MG was completed, the first road test resulted in a vibration that I had not had before. After looking at everything that rotated, I remembered the markings on the drive shaft and sure enough, they did not match up. When matched, the vibration disappeared. This experience has tells me it is a good practise.

George
George Raham [TD4224]

The propshaft is balanced as an assembly before installation. For early and mid 1500 type there is no flange in front, just 10 splines. There is no way to mark the spline orientation before removing the propshaft. Those fo together in any one of 10 different orientations relative to the gearbox mainshaft, and it doesn't matter which spline you catch.

For the late 1500, 1600, 1600-MK-II, Twin Cam, and all MGB, the end flanges have a rectangular bolt pattern, to it can only be assembled two ways 180 degrees apart (at each end). It is impossible to assemble it 90 degrees out from original. Again it doesn't matter which way it goes.

If you swap out the gearbox, the propshaft or the differential (which I have done all multiple times on my car), you would have separated the original set. In that case trying to align the flanges with some prior mark is totally nonsensical.

The one thing you do have to abide by is having the front and rear U-joints aligned with each other. This does not apply to the one-piece propshaft where the end yokes are welded in place. This does apply to the two-piece propshaft with two flanges and an intermediate sliding spline.
http://chicagolandmgclub.com/driveline00/0404/drshafts.html
Barney Gaylord

If as a point of principle it was thought necessary to have the 1500 prop shafts 'in phase' can someone please explained why the 1600 prop shaft has been designed 'out of phase'.
J H Cole

The one-piece 1500 propshaft is welded together and cannot be assembled out of phase. The 1600 propshaft is not "designed out of phase". It is correct design and originally assembled in phase. If you disassemble the sliding spline joint just aft of the front U-joint, you can reassemble it out of phase, which will result in vibration when running. How it works (or doesn't) and how to assemble it properly is covered here: http://chicagolandmgclub.com/driveline00/0404/drshafts.html
Barney Gaylord

I never understood why BMC did not take Murphy's Law into consideration.
(If something can be done incorrectly it will be done incorrectly).
Note the solution to misaligned U-joints in the rear axle half shafts on Triumph cars.

Mick


M F Anderson

Surely it was Hardy Spicer who made the propshafts?

Alex
Alexander R

Most parts on cars are made by specialist manufacturers but they do it to designs specified the car companies.
Why are BMC conrods different from Triumph ones, Jaguar ones or Aston Martin ones? The same applies to pistons, crankshafts etc...almost every part on the car.
It includes the significantly different designed propshafts and half shafts.
Car companies do the design then contract out the supply of the components.

Mick
M F Anderson

Barney, the reason why I thought that the 1600 prop shaft was designed 'out of phase' was because I looked at my set up and made the rash assumption that it was correct! It now seems that I've been driving for years with the prop shaft out of phase. Is the simplest way of correcting it to release the rear UJ, let the prop shaft drop down enough to pull it out and then reposition the splines? This assumes the tunnel cross braces will not get in the way.
J H Cole

That should work. If it is assembled with all the right parts, you would need to unscrew the knurled packing nut at the back end of the front yoke. The smooth shank for the seal there is smaller diameter than the OD of the splines. There is a cork (originally) or maybe rubber (replacement type) seal and a split steel backup washer that will not come off over the splines. So unscrew the thin knurled hand nut and leave it on the shaft as you separate the shaft from the front yoke. See attached illustration.


Barney Gaylord

This thread was discussed between 24/07/2013 and 31/07/2013

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