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GTM Libra History 2000 to 2017 (sidewinderforge.co.uk)

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Refurbishing the Suspension, April - July 2011

Latest Update: 21/11/2012
Rear spring problem, see page 11, now resolved.
Sat 09/07/2011, Car passed MOT, tax disc ordered!
Sat 16/07/2011, Road test completed OK.
Nov 2012 Due to a knock on the drivers side rear when turning sharpley, further searching for replacement suspension bush has been ongoing, a new source of rear suspension bush has been found, although not as the origionals, figures in brackets are for origional,  - sourced in USA, body diam 40.2mm (40mm), centre hole 12mm (12mm), centre bush width is 9mm narrower (like Merc ones), bush main body is correct width. It has been possible to skim the body on a lathe from 40.2 to 40mm. Now waiting for a suitable time slot for doing the work.

Monday 18th April 2011 - At the age of 11years it had become obvious that the suspension was not working as it should, it turned out that one of the rear springs had broken in 2 places, this was not seen until we removed the rubber gaiters (these are as used on off road/trials motor cycles).

The inboard end bushings of the front suspension arms were very stiff, however sourcing these bushes proved impossible - the 16 replacements items have been turned [very carefully] on a lathe from Polyurethane Rubber "shore A90" material. The front suspension of the car has now been totally refurbished. (see update on page 11 ).
The rear suspension has now got new springs (locally sourced) & refurbished shocks from AVO. At this stage we decided we would like to try the redesigned (by RDM Coventry) trailing arms. We never liked the Land Rover style ball joints. A second hand set of Mk3 version arms has been purchased, these are not however suitable for use with the origional Raceline 205 width wheel/tyre combination. We therefore faced further complications, could we modify these to use them with  the 205 width wheel/tyre, we think we can do this, but then could we source the pivot bushes in case we need to replace one at some time, but nobody has the definitive source information. We believe that there could be upto 3 versions of the trailing arms, the origional GTM Mk1, RDM's Mk2 which had been strengthened to become the Mk3. Various source possibilities have been put forward by other GTM Libra owners. Current information from RDM indicates that they are from a Rover 75. We extracted one of the bushes from one of the upper arms to see it in the "flesh". It appears that it is not from the mundane CDTI or 1.8vvc but from the rear suspension of the 4.2 litre Rover 75 V8 or MG ZT260 which is rear wheel drive (only about 900 were produced, will this be the basis of the new MG6? in 2011), hence the suitability for rear wheel drive Libra's.  Rimmer Brothers have them listed but they have no stock & non on order. A bit like trying to find Rocking Horse Sxxt. Meanwhile modifications to the upper trailing arms are being carried out, modifying the tubing, then adding 3mm plating top & bottom to give more strength. This plating adds to the unsprung weight but we think this is acceptable for our road only car. Below is the bush which we extracted from one of the upper arms. Despite others saying that they are retained in place by circlips this one did not have any such retaining system, it was purely a tight fit - we used a 10 ton hydraulic pully extractor to remove it, the bush will need to be put in the freezer for a couple of hours to refit it.
Further online research has gone on today to try & find a bush that we can use & we have decided that one from a Mercedes [several models use this bush] will be useable, with much help from GSF car parts in Sheffield.
It is not overall as wide as the "Rover" part,  but the body is the same diameter & the same width, the centre hole is 14mm instead of 12mm, spacers & a tube sleeve should solve these problems.
(see photo's below).
22nd April 2011 - Suitable tube sleeving is available at B&Q 14mm OD x 1mm wall thickness giving 12mm ID - needs a little bit of work on the inside wall which is a bit rough, to make it easier to fit the 12mm bolt. A 1metre length is enough.
2017 Note: Another correct size bush has now been found, as fitted to MGTF rear suspension, number to come ..................
Tip, use plenty of Waxoyl with steel when assembling.
Below are pictures of the process, tools used etc.


Extractor used


 Bush partially extracted



Close up showing bush being removed
downwards



The origional bush extracted from the arm, (the arm is
shown next but one photo below).
Width 57mm, Diam 40mm, hole 12mm.
Possibly Rover V8 or MG ZT260.



This is the Mercedes bush we have sourced
from GSF car parts.
Width 48mm, Diam 40mm, hole 14mm.



Mock up "jig" used to see why 
205 wide wheel/tyre would not fit.



View of orional setup.


205 wide wheel/tyre showing "bind" point
at front of wheel (on the left looking at the picture)
.


Another jig view.


New tube work shaped & taped in place ready for welding.


Arm & bush.


Parts in preparation for welding


Arms back from the welders 28/04/2011
===============================
Saturday 30/04/2011
The bushes had been cooled in the freezer for about 4 hours, then they were refitted into both modified upper trailing arms. They where pressed back into their housings using a 4 inch engineers bench vice.

We then fitted the offside arm into our test rig, the results are very good. See photos below.
We have refitted the hub back onto the car so that we

can turn the car around to get to the back of the end easier. We will have to remove the internal rear trim so that we can get to the mounting bolts
.


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Photo Gallery


The clearance between tyre/wheel & upper arm is now evident as the photos show


Sunday 01/05/2011

Today we have turned our attention to the lower arms, we have discovered that two of the bushes have damage to the "boot" at one end, one has obviously been damaged as it was fitted into the arm - the boot locating groove on one bush has been distorted & squashed, see photos 1 & 2.

The other had minor metal damage & the boot was split, photo3.

Photo1.

Photo2


Photo3

Photo4

This shows component parts of the 2 damaged bushes.


Our kit of bits to turn the Merc bush into
Libra bush as shown in the next photo.
Short sleeve 14mm to 12mm reduction,
 with brass top hat spacers 25mm diam 4.5mm thick
 & a small 14mm to 12mm insert.

Merc bush with above kit added to make

it look like an origional Rover bush in photo below.

Wed 4th May 2011

Removed Mk1 arms & started to fit our Mk4 arms

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