Restoration of 1952 MG TD 2



Author: Bob McCluskey
First posted: 1 Sept 2000
Last amended: Dec 2015
Please email Bob McCluskey
Car No TD/11935
Engine No XPAG/TD2/12333
Body Type 22381
Body No 11301/78948






PEAR Suspension Having taken out the axle, you can take the opportunity to inspect and recondition the shock absorbers as appropriate, and to replace the rubber seating pads and the rubber bushes in the shock absorber linkages in any case.

Have a look at the springs first, because you've really got to take these off anyway before you can check the dampers.

rs_oldTake them off and measure the camber: it should be 10.4 cm unloaded. If it's significantly different, or if the two sides aren't the same, you'll want to get them reset by a suspension specialist. If the camber is OK, take the opportunity anyway to dismantle, clean and paint the spring and replace the rubbers throughout.

During disassembly you'll have to undo the locknut and the nut itself from the locating bolt in the middle of the spring set (because the head of the nut is cylindrical, you may have to resort to vice grips here). This bolt is interesting: it looks as though its function is to hold the spring leaves together, and that is indeed part of its job. But it's real job is to fix the axle locating plates, and through them the rear axle, into their proper fore-and-aft position. On one dark and stormy night in the Blue Mountains, I drove through a deep pothole which I couldn't see because it was filled with water, and I sheared this bolt on the left-hand-side. It had an immediate, powerful, and interesting effect on the steering: instead of being applied to both wheels equally to drive the car, the power was now applied more easily to the left wheel only making it slide forwards on its spring. This in turn made the rear of the car slew to the right, and the whole car steer to the left. As I took my foot off the accelerator in panic, the engine braking was applied first to the left wheel, making it slide backwards on the axle, and the car slew to the right. Now you'ld think that an enquiring mind would want to know whether you could steer the car this way, just by using the accelerator; but I'm sorry to say my sense of self-preservation overcame my scientific curiosity.

On reassembly, use a new locating bolt if at all possible, remember the cylindrical head goes on the top of the springs, and don't forget the locknut!

Now look at the dampers.

There should be a total movement of 70 degrees - 35 degrees each side of centre. The arm should move smoothly and evenly over its whole range. The manual specifies deflection rates of 20 degrees p sec at 250 lb/in torque on compression and 20 degree p sec at 400 lb/in torque on rebound, and one hopes the Nuffield Group were better at choosing dampers than they were at communicating units of torque. In any case these specifications don't make a useful basis for testing by amateurs. They correspond to 0.08 degrees / sec / in.lb on compression and .05 degrees / sec / in.lb on rebound - it is significantly faster on compression than on rebound. A housebrick - nominal weight 8lb - hung from the end of the six-inch lever arm does provide a useful test; using an approximation factor of 0.9 to allow for the effective shortening of the lever arm as it deflects (because somehow these days its harder to integrate the secant function than it used to be), this leads to a deflection rate of 3.5 degrees / sec on compression, or just about 20 sec to move through the entire range, and about 33 seconds on rebound. If the body is still on, you'll find that rigging a test for compression will be an interesting challenge, and perhaps you'll be satisfied with measuring just the rebound time.

If the rates are significantly different, or different side-to-side, or not even over the range, the only remedy open to amateurs is to check the fluid level. If that doesn't fix it, hand it over to professionals. This decision was easy for me: all dampers, front and back, were seized solid. But I had learnt from the chassis experience, I did check them out again this way when I got them back and found them at least within a bull's roar.

rs_newDuring reassembly, with new shackle pins if necessary and new rubbers anyway, do remember that rubber and steel slide over each other relatively easily if you keep them wet with water/detergent mixture (about the consistency of washing up water). Good luck. The diagram in the manual shows the pin through the Silentbloc bush at the front going from inside outwards; but mine was the other way round with the nut on the inside, and I found on reassembly there wasn't enough clearance to do it the way the book shows. Put the bolt through from the outside, don't forget the washer, do use loctite, and tighten it up. The shackles aren't supposed to be tightened until they're under load so that the rubbers are correctly flexed; but if the car is in the process of restoration it may be some time before they're fully loaded by the weight of the car; in that case it might be better to tighten them unloaded, or better still to leave them loose until the restoration is finished and the load comes onto the suspension. DON'T FORGET TO TIGHTEN THEM IN THE END.

After the axle is in place and the U-bolts tightened, you'll have to compress the springs to be able to bolt up the rebound rubbers. If the body is off, it'll take about 400lb (or 50 housebricks at a nominal 8lb p housebrick) to compress both sides.

PRONT Suspension The front suspension and steering is a little more tricky than the rear, but not enough to worry anyone. The only really tricky bit is that the manual uses a number of terms interchangeably, which makes for some confusion - for example swivel pin interchangeably with king pin, outer fulcrum bolts with wishbone-to-link bolts (these are the bolts through the upper and lower king pin swivel links, or trunnions), and lower fulcrum pins with wishbone pivot. It gives specifications for camber angle, castor angle and king pin angle, but since there is no provision for adjustment, I prefer not to know. The judges aren't going to look there.

fs_oldOnce again I was lucky because I didn't have to make decisions about how much to dismantle: everything was seized up, and I was clearly up for dismantling the whole assembly. As well as the slightly agricultural state of the steering and suspension, this picture also shows some of the damage to the dumbirons and chassis.

There is a lot of discretion in the order for disassembly. I took the steering rack out first, because I thought that would take longest to fix. In the event, it all came apart so quickly that it wasn't an issue.

Take off the track rod end ball joints using any of the traditional methods, which usually involve a large hammer, or alternatively, as I did, slacken off the locknut then wind the track-rod out of the track-rod ends with a spanner on the flats. This leaves the track-rod ends in the steering arm, where you can apply the traditional methods later with less risk. With the track rod ends undone, you can evaluate the steering rack: any problems here are almost certainly beyond an amateur's capacity - any play in the tie-rods, transverse or longitudinal, or any rotational play in the pinion, you must take it to a specialist. Unbolt the radiator support member, and undo the flange at the bottom of the steering column. Now you can unbolt and remove the steering rack: turn it over, slide it out through the holes in the dumb-irons, first towards the passenger's side till it clears the hole on the drivers side, then back, up and out towards the driver's side.

fs_loadTo get much further you have to take out the coil spring. This is much easier if you dismantle the hub and brake assembly first. Then, especially if the body is off or the engine out, you'll need to compress the springs. Again, 50 house bricks did it for me (actually, this picture was taken during reassembly, which is why it all looks so nice and clean).

Remove the outer fulcrum bolts, top and bottom, keeping the split pins, nuts and spring washers, and remove the kingpin assembly. Make a note of how the bits come apart - rubber seals and retainers, spacer tube and thrust washers, and fulcrum bolts. Now you can gradually unload the springs, then push down on the lower wishbone unit and pop the spring out.

Now you can undo the four bolts (two front, two back) which hold the lower wishbone assembly together on each side, and remove the spring pan. Undo the nuts on the ends of the wishbone pivot and remove the lever arms. If this is an all-nuts-and-bolts-off restoration, you'll want to undo and remove the fulcrum pins, and the rebound rubber. Now here is a serious piece of economy: unless something is radically wrong, don't buy a new rebound rubber, but using coarse emory paper, rub off the rough, oxidised outside, and tart it up with Armorall. Believe me, the judges can't tell the difference, and neither can the car.

All that's left now is the damper. Because mine is a relatively early car, it has the early Luvax Girling dampers, not the more recent Armstrong dampers. The manual gives the deflection rates, still using wrong units for torque. Like the rear units, they should have 70deg deflection, 35deg each side of centre. Using the housebrick deflection test described above, the rate should be about 4.4 deg / sec on compression, or about 16 sec for the entire range - a bit less than the rear suspension - and about 33 sec for rebound.

Clean up all the parts, examine for wear, and decide which bits you're going to replace. If the damper isn't right, you must take it to a specialist. Measure the spring - it should be 9 5/8 inches free length (it should also be about 6 3/8 in when loaded to 1095 lb, but I have no idea how you'ld measure that). If it's significantly different, put it in the box along with the dampers and steering rack to go to the specialist. Now have a look at the swivels. If there is any play on the kingpin you need to replace the swivels. The manual says if there is play in the spacer tube, you can rebush the swivels, but the concensus is that if they're worn enough to allow play in the spacer tube, the threaded faces will be worn too. In my case, I put new swivels, and new spacer tubes, thrust washers, retainers and seals, but I kept the kingpins and fulcrum bolts. This had the additional advantage that I didn't need to take the steering arm off the kingpin. I sand-blasted and painted all components with powder coat except the new bronze swivels, naturally masking off all bearing surfaces and threads.

It goes back together in the same order it came apart, naturally using new rubbers throughout even if you don't use any other new bits.

Bolt the rebound rubbers and dampers in place first. Then bolt on the lower wishbone pivot; all the bolts go from the top, except the two inner back bolts, where there isn't enough clearance to go from the top. Preferably use Loctite. Make sure the hydraulic pipe is clipped in place - this can be a real bugger. Slip on the new rubber bushes, remembering that rubber and steel slide over each other easily if they're lubricated with a dilute water/detergent mix - about the consistency of washing-up water. Place the lower wishbone levers over the pivot, and insert the outer rubber bushes. Loosely bolt the spring pan in place between the levers (I had bolted the spring pan together before painting, so that it could be painted as a single piece. Silly, because I had to take it apart again to fit it to the lower wishbone pivot; but you can at least have one lever bolted onto the pan, so it's painted as two pieces. The nuts go on the outside.). Press down on the spring pan, grease the ends of the spring, and slip it into place. Now transfer the jacking point to the end of the wishbone, and load up the spring as shown above. When the lower wishbone is horizontal, you can tighten up the spring pan bolts and the lower wishbone pivot nuts, remembering the flat washers and new split pins. Try to make sure that the rubber bushes stay equally spaced as it tightens up by tightening the wishbone pivot nuts and spring pan bolts evenly.

To reassemble the kingpin, assemble the lower swivel first. Slide the dust excluders (which will fit into the groove on the swivel) onto the kingpin, then grease the bronze swivels and the threads on the kingpin, and wind the swivels onto the kingpin. There is a trick to this: there is a groove all the way round the kingpins, top and bottom, in the centre of the thread, where the spacer tube fits. Wind the swivels on until the groove lines up, then slide the spacer tube into position. Wind the swivel up and down to the limit of its travel (about three complete turns) and wind it back to the approximate centre. Assemble the thrust washers and rubber seals and retainers; do use new parts here, because they're so cheap and to re-use parts would be false economy. Bolt the lower swivel into place on the lower wishbone, remembering that the swivel is turned so that the bolt is towards the inside on the bottom swivel, and towards the outside on the top swivel. If you get this wrong, as I have done, there is no great drama: you will simply find that you can't assemble the brake back plate properly and you will have to dismantle it and do it again. The bolt goes in from the front, with the nut to the rear. Tighten it up, not forgetting the flat washer and new split pin. Swing the kingpin upwards, assemble the top swivel the same way, and bolt it into place.

fs_newReplace the steering rack in the opposite sequence to disassembly: hold it upside down, slide it through the holes in the front dumbirons, passenger side first, then back through the hole in the drivers side, turn it over, and bolt into place. Bolt on the chassis cross-member, and screw the steering tierods into the balljoints using the flats on the tierods.

Reassemble the brake and hub assembly, and you're back in business.

Easy.

This would be a pretty good time to fit the bracket for the engine steady rod. It goes on the drivers side, using one of the bolts for the damper, one bolt into a captive nut just under the steering column, and one nut and bolt through the chassis. If you choose not to do it now, don't leave it too long.

Although there are advantages to fitting it much later.

For example, I didn't fit the steering column until the car was almost fully assembled. The steering column fits onto the rack and pinion with three bolts, which have castellated nuts which are wired together. Because assembly was so far advanced, it was difficult to fit the nuts, and I dropped one. I thought it had fallen onto the floor and disappeared into the layer of crap when it fell from my nerveless fingers. I spent a long time looking for it, under shelves, behind boxes, everywhere. I swept out the whole garage, and went meticulously through the garbage; but in fact it had fallen onto the chassis and rolled into that little space behind the mudguard and beside the front shock absorber. I found it there much later when I was taking off the front valence and driver's side mudguard in order to fit the bracket for the engine steady rod. If I'd fitted the bracket at the right time, I wouldn't have had to take off the mudguard, and I would never have found the castellated nut. On the other hand, if I'd fitted the steering column at the right time, I'd never have dropped the nut in the first place.




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