MG TA Rear Telescopic Shock Absorbers

1 May

The original Luvax shock absorbers are increasingly difficult to source and repair, and become problematic quite quickly thereafter. This applies to both front and rear units. In fact, my original Luvax were useless so I had them rebuilt for around £300 several years ago by an “expert”. Despite replacing most of the internals, one seal leaked and I could not get similar damping rates despite adjusting the internal screw. My car already had telescopics on the front and they are excellent.

This article describes suitable brackets for installing telescopic shock absorbers to the rear of the TA. I see no reason why the same brackets and shock absorbers should not fit the TB or TC in a similar manner. No modifications are required to TA original equipment and it would only take an hour or so to replace the original Luvax units.

The drawing (Figure1) shows the bracket measurements for one side, the other side being a mirror image. Details of the suggested shock absorbers are shown on this drawing, and cost around £85 the pair delivered (Jan 2012). As I received two different units initially (one black, one grey, different serial numbers) please check you receive two identical units, preferably painted black. The kit for one side is shown in Figure 2, and the lower bracket assembled in place in Figure 3. The finished rear axle compartment is shown in Figure 4.
The bolting can be bought from your usual supplier and does not have to be BSF, but I bought these anyway, at around £5 per set of bolt, nut and plenty of thick washers. Any competent blacksmith can make the brackets, mostly from offcuts lying around his shop. The bolt head welding position is not critical, but the bolts do need to be approximately perpendicular to the angle brackets. I suggest you do the drilling yourself, preferably with a pillar drill, use sharp drill bits and be patient.

You should be able to do the whole lot for under £200, and much better they will be too.

Notes:

(1) The lower brackets could be shortened by one inch, but 6″ looks just fine. If you want to shorten them, after offering them up to study clearances from all other equipment, cut off the excess with an angle grinder before drilling the holes. Note they are assembled on the outside row of bolts. (Inside bolts causes interference with the chassis and petrol pipe). Also, the lower plate on my car curves slightly due to the fixing bolt tension, and this provides just the right amount of angle to align the bottom shock absorber bushing.

(2) Don’t tighten up the large nuts until everything is assembled on the car. This allows the rubber bushes to take up the slight out of vertical remaining after all the thick washers are added.

(3) I did consider re-using the existing lower mounting bracket but this would mean the top of the shock absorber would be 90 degrees out from the bottom. I don’t know much about shock absorber design but this can’t be good practice, can it?

(4) There is an alternative method, with the mounting bolts pointing along the car rather than across. This is possibly a more elegant solution, but the geometry and fabrication is more complex. I cannot see that it makes much difference. Whichever method is used there is very little room to do anything and avoid everything else.

(5) Please note that telescopics are not acceptable for VSCC events, should you be thinking of this. I’m not in to competition, just road use.

I hope all the above is clear enough. (Polite) comments are welcome, to improve the breed!

Ian Linton
April 2012


Figure 1

Fig 2 (above) & Fig 3 (below)


Fig 4 – the finished rear axle compartment

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5 Responses to “MG TA Rear Telescopic Shock Absorbers”

  1. Gordon 07. May, 2012 at 1:20 pm #

    In selecting the telescopic size what stroke have you gone for and how does this compare to the full compression to full rebound movement of the axle? It seems vital that the shock absorber sould not be acting as the stop in either compression or extension since they are not designed to do that.

    • John James 08. May, 2012 at 8:37 pm #

      Ian Linton has provided the following answer:

      I was recommended to use this model shock absorber by another T-type owner and it works very well. The relative axial movements will to some extent depend on how good the back road springs are. In my case they are in excellent condition, even though around 45 years old (I renewed them then). So the at-rest length of the shock absorber is 320 mm. The space beneath the axle to the lower bump stop is 40mm and above is about 75mm. Using the extended and compressed dimensions on the drawing this means there is an excees for downward axle movement of some 30mm, but the upper movement is a little short, 5-10mm. However I cannot conceive how in normal road use the axle could get anywhere near the upper bump stop (although one of these allowed me to get home all those years ago when the axle fixing plate gave way!). If you want to be really sure the shock absorber cannot compress fully then add 1/2 to 1″ to the height of the upper bracket. On my car there is still 2″ headroom before touching the axle cover board so there should be room. However this extension will make the whole bracket more flexible, and possibly render the original Luvax support plates more liable to fracture.

  2. Martin Moore 08. May, 2012 at 2:44 pm #

    Dear John ,

    out of interest I can confirm that my late TA was fitted with a very similar telescopic shockabsorber arrangement when purchased in 1960 . One of the rear shockabsorbers was leaking last year and I fitted a pair of adjustable Konis saved from a racing Mini ( I never throw anything away ! )

    I do believe but only hearsay that telescopics were available as an ex factory option .

    Yet another fascinating TTT2

    Best regards Martin

  3. Gordon 08. May, 2012 at 9:42 pm #

    I can confirm that after-market telescopic shock absorbers were marketed by Newton. There were adverts in the 1928 Autocar showing fitment to the Austin 7. They were standard fitment on the 1928 Singer Junior and on some Morgan 3 wheelers. By the time you reach 1935 they were standard fitment on many American cars so I would suggest that they are an in period modification. Of course the Lancia Lambda had these from the start and the prototype Lambda was built in 1918. However the VSCC, in their infinite wisdom have banned them in racing!

  4. Martin Lane 13. May, 2012 at 7:56 pm #

    Hello all, We also followed Ian’s advice for the rear shocks, but with minor modifications. Ian’s design clamps on just one side of the leaf spring, so we made the lower bracket a bit wider from a sturdy piece of C channel halved. This meant that the lower bracket was bolted through with 4 bolt rather than two. Although it probably isn’t necessary, we also used 5/8″ Ø bolts to add a bit more strength and a larger welding area. They too work very well.

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