Some TA Clutch Tips

Recently, I have had quite a few technical queries about clutch problems on TAs with MPJG engines.

The clutch plate on a TA has 46 corks of roughly 1 inch diameter, which are lubricated by engine oil via the rear of the crankshaft and holes in the 1st motion shaft. These clutch plates last quite a long time (60k to 80k miles or more) but can give problems if the car is left to stand for a long time (i.e. several years). The corks then become stuck to the flywheel and are often difficult to free up. In the past, quite a few owners re-corked the plates themselves using corks from wine bottles (a good excuse to drink more wine!). Nowadays, it is easier and better to have your plate re-corked by a specialist company like Charles Cantrill of Aldridge http://www.charlescantrill.com Some owners have used Kevlar to replace the corks on the clutch plate. I have no experience of this material, so do not feel qualified to make a judgement.

Ed’s note: Kevlar is the registered trademark for a para-aramid synthetic fibre, related to other aramids such as Nomex and Technora. Developed by Stephanie Kwolek at DuPont in 1965, this high-strength material was first commercially used in the early 1970s as a replacement for steel in racing tires. (Acknowledgement to Wikipedia).

Now back to Brian……….

The last time I changed the clutch plate, the one I removed must have covered at least 50k miles and still had plenty of life left in it. I only changed it as a ‘belt and braces’ job because I was off on a long trip up to the Scottish Highlands.

Accessing the clutch

Now let us look at getting the clutch apart. You can replace it, either by taking the engine out of the car, or by removing the gearbox from within the car. The big problem which most people hit is in separating the engine form the gearbox – it seems ‘un-separate-able’. The way to separate the two is to remove the clutch operating arm from the shaft on the side of the bell-housing (located with a straight pin and woodruff key), then rotate the shaft anti-clockwise so that the clutch fork can clear the release bearing. The TA clutch is fairly unique in that the clutch fork pulls the clutch release bearing back towards the driver, whist in most cars the fork pushes the release bearing towards the engine. One thing to remember just before separating the gearbox from the engine is to put a tray beneath the bell-housing as about a pint of oil will pour out when you separate them!

Replacing the clutch plate

You do not need to strip the pressure plate assembly down if you are only replacing the clutch plate, just unbolt it from the flywheel (12 bolts). Make sure you remove the large circlip from the three little bosses on the spigot bearing carrier before removing the old clutch plate, and take care of the three little springs behind the plate when you remove it. These little springs and the large circlip are not available from any supplier now, so take care of them!

Before you fit your new clutch plate, please make sure you soak it in new engine oil for at least 24 hours. Also, check the clutch release bearing, if it runs free with no binding leave it alone. However, if you do decide to replace it, make sure that you fit it with the ‘thrust face’ facing forward towards the engine. If you fit it the other way around, the first time you come to use the clutch will result in all the balls being forced out of the race and into the bell-housing and you will have to strip the whole lot down again!

If you have removed the clutch thrust bearing to look at the 12 clutch springs, make sure you clean out the pressure plate cover, especially the 3 gauze oil strainers. New standard clutch springs are no longer available, but SVW Spares in Hull sell 10% uprated ones. However, I have never found the need to change standard springs.

Before mating the gearbox and engine together, there are a couple of important things to check. The clutch operating shaft in the bell-housing is a weak point, the driver’s side operating shaft was badly designed and is prone to breaking (see photo)

New improved shafts (see photo) are available from the MG Octagon Car Club (part number SGC022) which overcome the problem.

Old (broken) and new clutch operating shafts

Also, it is worth considering fitting a small lip seal on the outer end of the bell-housing where this shaft protrudes (please refer to the article in Issue 19, April 2013 of TTT 2).

It is best to scribe (or use Tipp-Ex) a horizontal line on the end of the shaft to show when the clutch fork is horizontal; this helps when assembling the bell-housing to the engine, you can see the position of the clutch fork externally. If you are not sure of the clutch layout, it is helpful to study the diagram on Bill Davis’ TA website www.billdavis.org/MGTA/Cork.html

For ease of reference it has been reproduced here.

Don’t forget to use a new gasket (and sealant) between the bell-housing and flywheel housing or the joint will drip oil!

When you have assembled everything back on the car, don’t forget to adjust the clutch linkage for 1 inch free play at the pedal. Whilst attending to this, check also the condition of the clutch operating linkage. If it is in a poor way (I have seen several that have been broken and been welded back together again) (see pic of old and new linkages) you can now purchase a new one from the MG Octagon Car Club (part number SGC049).

Brian Rainbow

A new TA clutch shaft from the MG Octagon Car Club

http://www.mgoctagoncarclub.com/Parts/parts.html

and an old one.

Ed’s note: Reference was made earlier to Bill Davis’ website. The previous reference was for the clutch layout. To access the whole site (not to be missed if you are a TA owner) please go to:

www.billdavis.org/MGTA

6 thoughts on “Some TA Clutch Tips

  1. Jan W. Garnaes Johnson says:

    As is usual, we TA owners on this side of the pond, are “teased”
    with the numerous spares available from the Octagon Car Club and would love to have the above noted “improved” pieces, but they won’t sell to North America! Jan/Fairfield,Ohio/USA

  2. Richard Little says:

    Easy to read and understand; well done! TA1326 and I are grateful!

    Would it be possible to have the Octagon Car Club find a single contact in the US to whom they then could ship? (Sort of like an agent) We would all try to be honorable and cooperate. The cars merit our support here and a marketing policy change by the Club would really help.

    Obviously their replacement parts look superb.

    • John James says:

      Hello Dick,

      It is not so much a marketing policy change that is required – the Club would, I am sure, love to supply spares to members in the US – but the cost of insurance is prohibitive.

      I will forward your “agent suggestion” on to Brian Rainbow. Brian is currently on an MG Tour right around the North of Scotland coast.

      Kind Regards, JOHN

  3. Tim Parrott says:

    If you have dismantled the clutch then on reassembly the orientation of the clutch cover and pressure plate is fixed by the spring pressure. These two items need to be aligned so that the three cutouts in the pressure plate fit the flywheel and the 6 bolt holes on the cover line up. I used the flywheel before it was installed to assemble the clutch. The technique is to use overlong bolts with additional nuts. Align the cover and pressure plate with the bolts as studs and then tighten down the nuts to compress the clutch springs. You need to fit the clutch plate otherwise the central boss on the pressure plate will not protrude far enough to fit the bearing and collar. Now fit the washer, release bearing and collar. I am now concerned as to whether the bearing has been fitted correctly!

  4. Tim Parrott says:

    If the horseshoe circlip is beyond redemption then three e-clips are an acceptable substitute. The internal diameter required is around 5mm. I reckon that I used 4.8mm ones from a “come in handy” parts bin. The clutch plate will sit a mm or so further out. We also made three springs by cutting down a larger one as my originals are now somewhere in a large washing tank. NTG have a spring and circlip set in their catalogue.

  5. Tim Parrott says:

    No mention is made of the clutch pedal return spring, nor was there any evidence of one on my car. From the Frame Up have the two brackets and the spring in their catalogue and a picture on their tech tips listed under Springs. Easy to make the brackets yourself.

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