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MG TD TF 1500 - MGA rear end in a 52 TD

I just purchased a 52 MGTD with steel wheels. - I also have a 62 MGA rear end with a full set of wire wheels that are extra. I would like to get opinions if I should convert my 52 to wire wheels and the higher ratio rear end? I want the look of wire wheels but do not know if they were an option for that year or are they the correct size? Will there be any engineering problems with the conversion? What will this do to the value of the car? How hard is it to change the ring and pinion gears? I feel comfortable swapping the entire rear end but if I just changed the gears I don't know if I could check for backlash etc.
Any advice would be appreciated.

I also have an entire modified 1962 MGA MKII that is about 1/2 completed if anyone is interested. I can give full details upon request. The body and exterior are in good condition with no rust, the frame has been modified to have complete coil over adjustable shocks in both front and back. There is a custom four bar rear suspension and adjustable power steering in front. The frame, firewall, brake, clutch cooling systems are all custom modified to handle the high performance Ford V8 Cobra engine, 5 speed alum transmission and rear end. The drive train has been narrowed, shortened and balanced by a local race shop.
I have most of the chrome, trim, all major gauges and components. Due to the purchase of the above TD I really need to sell one of my projects.

e-mail for details

R. Bardsley
R. Bardsley

Mr. Bardsley:

I would stick with keeping the TD, all TD, at least in appearance. Changing the ring & pinion is a lot more acceptable and a lot easier than converting the MGA axle & wheels to fit. The ring & pinion is a bolt in swap. Make sure it has the 4.3 ratio. Get the conversion book by Carl Cedarstrand. It outlines the entire procedure, step by step. I have done our 52 TD and it was more time consuming than difficult. My machinist did the setup with the dial indicators, but I did all the mechanical work myself. The gear ratio swap is a reversible operation, if you ever want to go back to factory stock.

Wire wheels were never an option while the TD was in production. I understand that there was a dealer installed kit available after the TF was introduced for retrofitting wire wheels on the TD. I loke the look of wire wheels too, but since the car was never produced with that option, our car will always have the original steel wheels.

If you decide to convert the ratio, there are a number of tools and jigs noted in the Cedarstrand book that make the job much easier. Without them, the job is almost impossible. I built them and used them for our car and they are in storage in the garage. I would gladly sell and ship them to you, if you desire to tackle the project. E-mail me for details.

John M.
John Masters

The problem of using the entire rear axle from a MGA is that the spring mounts are further outboard. These have to be cut off and rewelded in the correct locations for the TD/TF. The rear brake drums are also bigger, changing the braking ratio between front and rear. The track is also wider, making the tires slightle protrude from the fenders.
A better solution is simply replacing the hubs and drums with the TF wire wheels ones. BOLT-ON, since the differential housing and axles are the same on the disk and wire wheel versions.( Unlike later MG's).
The wire wheels are 15 inch like those used on MGA's, and most other sports cars of the era. New hubs and drums are available, as welll as used ones. Moss even sells a complete kit with wheels (Not the bolt on the disk wheel studs conversion) ( Not cheap! but used hubs and wheels tend to have badly worn and corroded splines).
One may also want to change the rear axle ratio, using the MGA ring and pinion. Not a "bolt-on" since some precision machining, measurement, and alignment is necessary, but Cederstrand has shown us how. This conversion makes driving at expressway speeds practical without having to run our engines in excess of 4000 RPM. Better for the life of the engine!
Don Harmer

I have to disagree with the previous posters. I converted my TD using an MGA rear axle, and have been very pleased with the results.

It is necessary to move the spring perches; this cost $25 at a welding shop. With a little grinding the MGA perches can be made to look like TD perches, and the same parking brake setup is possilbe. I also had a stud welded to the back of the banjo to mount the 3-way brake fitting.

My rear tires fit just fine under the fenders; I haven't noticed any difference in appearance from the stock setup.

I also installed MGA front disks, so with a complete MGA braking system there's no balance problem. But I think any such problem would be relatively minor and could be corrected by installing an adjustable proportioning valve and/or by choice of brake shoe compounds.

Another advantage of the MGA rear axle, besides being stronger and lighter, is that it's almost a quick change rear end. I've got both 4.3 and 4.55 pumpkins, and one day I'll get around to installing a set of TD/TF 4.875's in an MGA pumpkin. You can swap ratios in an afternoon.

The MGA half shafts may be stronger and more reliable than the TD/TF half shafts; I don't know.

Finally, there's the matter of cost. I wanted to convert my TD to wire wheels, and this was a much cheaper solution. Plus, there are real costs to converting a TD rear end; it is a bolt on operation, but a non-trivial one. Not every shade tree mechanic is capable of pulling it off, and the prices I've seen for having the work done are substantial.

True, it's not original, but the differences in appearance of MGA vs TD/TF brake drums are pretty minor. I've got the original stashed away, and if I ever sell the car (a circumstance I can't forsee) I'll re-install it if that's what the buyer wants.
Jack Williamson

Further to Jacks comments - I installed a Morris Oxford rear end in my TF, and had to shift the spring mounts also, quite an easy job.

I discovered very early that the rear brakes would lock up, and cured this by installing smaller diameter wheel cylinders. Im afraid I forget what size. A proportioning valve would work as well, and is probably easdier to get nowdays.

I converted the 4 stud to 5 stud wheel studs by making an adaptor plate that was bolted to the bearing hub, knock out the existing studs and drill and tap to 7/16 unf I think. Mount new wheel studs in the adaptor plate and bolt on the original TF wheels.

Advantage over the crown and pinion conversion is that with a whole axle conversion I got to keep the later design multispline half shafts, and never wound off an half shaft end.

IanF
Ian Fraser

The major problem with the half shafts of thr TD/TF era arose from the quality of the steel used to make them.
The modern replacement half shafts essentially never break, since the steel used is much more resistant to the shearing forces.
My point in suggesting the conversion of the TD rear axle ratio vrs the use of the MGA was essentially twofold.
Just changing the axle to the MGA one is cheaper, my conversion of the TD/TF cost $125 for the ring & pinion from an MGA plus about $ 100 for all new bearings and seals ( Our club members did the machining and about 3 hours labor)
The second point is that one should do more than just install the MGA rear axle, one should install the MGA front brakes also. This should also involve lengthening the tie rods to accomidate the longer MGA steering arms. One should also use the MGA shocks, mounted backwards, ( reverse the shock arms) to get the front end geometry right. A much more extensive (and expensive) proposition tha just cutting and rewelding the spring brackets on the rear axle.
In addition, the rewelding of the tie rods creates a real safety hazard as the are likely then to break at the weld unless a really good welder does the job.
One of our club members bought a TD converted in this manner. On restoration it was found that both tie rods had cracks where they were welded. The car was eventually restored to the original brakes and rear axle.
These changes, if just to get wire wheels, are going to get more expensive, and a hazard without some real engineering and care to maintain the front end geometry.
One could also look at the effect on value and saleability of the car. Around here you just devalued the car by $3000 to $5000 dollars unless you find an unknolegable buyer.
We also have in our club one such who bought a concours looking TD at a premium price, only to learn later that what he had was an MGA engine, transmission, and running gear, with the fire wall cut away and replaced by a shelf to hold the brake and clutch master cylinders and the MGA heater. The mechanical work was not well done. What he has is a bad MGA with an excellent TD body and upolstery. (it even has the MGA instruments).
But then I am one for "Maintaining the Breed" and keeping my T-Cars as original as possible. Just my point of view, ( Note for you Jack about our disagreement)
Don Harmer

Don, I agree, reasonalble people sometimes have divergent opinions about originality matters.

Again, it seems to me that any brake balance problems caused by larger MGA rear brakes could be handled with an adjustable proportioning valve (about $50 from any street rod parts vendor) and / or by choice of brake shoe compound.

My experience with installing MGA front suspension and disks differs somewhat from that described in the previous posting. With the slightly longer MGA steering arms I found that my tie rods were a little too _long_. I solved this problem by mounting each tie rod end on a stud, holding the stud in a collet on a lathe and then turning about .125" off the face where the nut seats. I also shortened each tie rod by a couple threads. Of course I did all this with some trepidation, but the tie rods still screwed into the ends to a little more than twice their diameter, and the strength of a connection with a threaded fastener does not increase past 2x. Also there's plenty of thread left on each tie rod for adjustment. Just to be extra sure I drilled the lock nuts for safety wire, which is moored to the zerk fittings on the rod ends.

Perhaps there is a slight change in the front end geometry. However, the MGA king pins are the same length, the and knuckles are identical (although the MGA knuckles are steel, not bronze). So I can't see a geometry problem arising from these components, and hence no reason to change shocks. The stub axle locations and angles also looked the same to me, the only difference being (as I recall) the larger thread on the MGA pieces and one side having a left hand thread.

So what possible consequences of the charge are left? 1) the bump steer characteristics, and 2) the Ackerman (which I think is measured from the rod ends to an imaginary point in the center of the rear axle. I haven't actually checked these, but there's been no unusual tire wear, and I haven't noticed any handling changes in some farily hard driving before and after. This is what I expected from a small change in the position of the tie rod ends.

Mike Goodman once told me MGA disks / front susp was a fairly common conversion. His suggested solution was to bend the steering arms so the ends were in the TD position, but I don't like bending steering arms.

I certainly agree with Don that welding tie rods to lengthen them is ill-advised, although an FAA certified welder using a proper fish-mouthed reinforcing tube over the rod complete with rosette welds, etc could probably do a safe job. But I just would never feel comfortable driving such a car. A better soultion would be to use an internally threaded tubular coupler of some sort. Millions of cars have been made using this type of coupler on the tie rods as alignment adjusters. The best solution would be to simply turn new, longer rods out of some nice alloy steel and have it properly heat treated. But, I found this all to be moot--my rods were a little too long.

Finally, if I was to do this all again, I'd use an MGB front suspension. From what I've heard, this is a safer, stronger design and has been sucessfully used on TD/TF's. The T series parts have a nasty reputation for breaking, although there may be some elements of urban myth in these reports.

I also agree with Don about engine transplants. For example, I don't think there's any question that an MGA/B engine is "better" than an XPAG/XPEG, if ordinary automotive engineering criteria are applied. A nicely installed 5 main 1800 with a cross flow head would doubtless make for a quick, strong car. I just don't happen to want one in TD24784. Transmission swaps strike me as equally tasteless, except for the going-back-in-time installation of a TC box. When you get all the way aft, I don't know why, but a rear-end swap just doesn't offend my T-series aesthetic.
Jack Williamson

Just want to call attention to the article in current (Winter 99) issue of Moss Motoring magazine concerning installation of an MGB front end. The article describes tie rod end, tie rod shortenening similar to that discussed in my posting above.
Jack Williamson

This thread was discussed between 13/11/1999 and 22/11/1999

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