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Part 3 Rear Suspension Links
The rear axle is connected to the body of the car by a four-link system and the rear springs. The link system comprises two upper and two lower trailing radius arms. Most problems occur
with the lower arms in relation to excessive wear on the bushes. Much has been said, and written, about the relative merits of hard and soft bushes. I have tried both with V8 conversions and my own 8 and have come
to the conclusion that it is a matter of personal preference. Hard bushes transmit noise and vibration from the drive train (particularly with coupes). Soft bushes can induce 'wind up' on hard acceleration with the
V8 and will wear out more quickly. A
compromise is to fit a soft front bushs and a hard rear one. As my 8 only does a maximum of 3000 miles per year, and I like comfort, I have opted for soft bushes all round.
Post article -I have been advised that a third type of bush is now available for the trailing arms. For a number of years, yellow superflex polyurethane bushes have been available for
Dolomites, Triumph 2000s, Stags and the like. Now they are available for the TR 7 and 8. As I understand it, they are somewhat softer than the hard bushes currently available and have a much longer life. Also they
are much easier to fit. The centre steel bush can be removed before pressing the main bush into the arm and then replaced without much difficulty. The only downside is that they are approximately 50% more expensive
than the standard hard bushes. A set is being used on a TR7V8 FHC and I understand that there is no increase in noise levels on the original soft bushes. Rimmer Bros. have included them in their latest price list
and I believe S&S are also offering them. If anyone has had first hand experience of fitting these I would be very interested.
Following the same pattern as the previous articles, all the parts should be available before commencing the strip down. Parts required:
Lower Arms
a) 2 x front bushes -soft -part no. ULC1579 (Unipart)
hard -part no. ULC1580H (Rimmers)
b) 2 x rear bushes -soft -part no. ULC 1580 (Unipart)
hard -part no. ULC1580H (Rimmers)
c) 4 x 7/16" UNF bolts -part no. BH607241 (Freight Rover)
d) 4 x 7/16" UNF Nilok nuts -part no. NY607041J (Jaguar)
e) 8 x 7/16" washer -part no. WM803
Upper Links
a) 4 x bushes part no. UKC5514
b) 4 x 7/16" UNF bolts -part no. BH607241 (Freight Rover)
c) 4 x 7/16" UNF Nilok nuts -part no. NY607041J (Jaguar)
1 x bottle of washing-up liquid
1 x bench vice.
NOTE: I have included all the nuts and bolts as they may have to be replaced after removing the arms. Now that all the parts have
been assembled, it is time to carry out the work. I have endeavoured to put it into chronological order for simplicity.
1) Disconnect the battery -earth lead first.
2) Loosen the nuts on both rear wheels.
3) Block the front wheels.
4) Jack up the car under the centre of the axle (hopefully a trolley jack is available).
5) Support the car on axle stands at the Jacking points -not on the trailing arms or axle.
6) Lower the jack so that the axle stands take the weight of the car but leave the jack in place to take the weight of the axle.
Remove the road wheels.
7) Lower the jack further until the springs can be removed.
8) Raise the jack again to bring the trailing arms to somewhere near their original position and, for additional safety, position a
second set of axle stands under the axle.
9) Remove the four nuts and bolts attaching the anti-roll bar to the trailing arms and note the position of the shim if one is
fitted.
10) Now the tricky bit -and the reason why I suggested not tackling the replacement of the shock absorbers and the bushes on the
same day. The bolts holding the bushes can ,grow' into the steel part of the bush and be very difficult to remove.
11) As we have now reached the difficult stage, I would suggest that each of the four arms is refurbished separately beginning with
the lower arms. The car can then be returned to the road relatively quickly.
12) Initially, by the obvious way to remove the nuts and bolts, with spanners, but remember to use unified not metric (7/16"
UNF).
13) Hopefully, the nuts will come off and the bolts can be pushed out without too much trouble. Note the way they come out.
14) If the bolt is stuck in the bush, the only effective way is to cut the head and tail of the bolt off with a hacksaw blade. Both
ends need to be cut to allow the arm to slide out of its retaining bracket at the front end. This can be a long and arduous task but I know of no alternative. WD40 may work in the long term, but trying to burn it
out with a welding torch is ineffective because it does not remove the centre steel part of the bush. Another solution is to use an angle grinder, if you can get in, but use extreme care as they can be lethal in
confined spaces.
15) Once the arm has been removed from the car it is time to replace the bushes.
a) If the soft bushes are being used it is a relatively simple operation. First push out the old bushes (they may even fall out!)
using a vice and a suitably sized socket. Next fit the front bush (ULC1579) making sure that the two outer ears of the bush are parallel to the line of the arm. Use washing-up liquid (Not grease) to lubricate the
rubber and gently squeeze it into position using the vice. Use the same method for the rear bush (ULC1580) but you will need to clamp a jubilee clip round the raised boss on the arm to help locate the raised outer
edge of the bush as it enters the arm.
b) If the hard bushes are being used, the only real answer is to have them pressed in using a large press. Various methods have been
employed to squeeze the bush before it enters the arm but I have yet to find an effective one that does not tend to destroy the outer edge of the bush. The ideal answer would be to have a tapered tool especially
made so that the bush can be wound in with a large bolt and washer -unfortunately tools of this type tend to cost a considerable amount of money.
16) With the bushes in place, refit the arm to the car. Make sure that copper grease is used on all the bolts to ensure that the arm
can easily be removed in the future. Do Not tighten the bolts at this stage.
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