Bumps in the night: the terrifying case of suspension failure

Pictures and Words: Andrew Regens

Tales of the supernatural always include the nerve-jangling story of the mystery bang in some poorly lit corner - and you always wish that the protagonist never went off to investigate... but here, investigation of this alarming noise proved well founded - as I'll let Andrew take over the story...

Hi, Well I have one sick F.
One of my rear shockers has pulled our from the locating hole [n/s rear] and the complete attachment bracket has pulled away from the body on the other side! This happened last week, a day before we were due to use the Philip Island Circuit for a driver training day.
Since the harder shocks have been fitted the car has only done a few events it would seem that my car has a huge problem, which will be costly and it is way past any chance of a warranty claim.
I am trying to have this all fixed for our M.G. Club Challenge on the Queen's Birthday long weekend in June which is at Sandown, a Supersprint and at Rob Roy a Hillclimb. In August our club night is on the 11th but on the 22nd we will have a Hillclimb and a Regularity Sprint Competition at Morwell.

A few pictures of the damage. I think a warning should be mandatory for anyone fitting harder shockers ! ...

Peering in: damper upper mount visible in centre of picture - but ripped from mounting.

A close up of the damage: damper mount and surrounding metal ripped apart

Damper removed: gaping hole is left

We used sketches from Rover Sport for the MG F Trophy racing development information booklet some 77 pages and I had my local garage ( Link Automotive) make them and the body shop weld them in.

You can see they are much larger and more parts than the currently available 'off the shelf' kits.

Not Andrew's car obviously, but showing early stages of repair: the damper bracket is removed, and the holes patched with fresh metal

Looking backwards: new substantial mounting bracket welded in place

Side-on view

Looking forwards from the rear of the car

Because we made a reinforcing plate to go under the turret which as the originals were removed and replaced by "new" (the new came from this) it was an easy fix to do as the turret were not in situ. We then added bigger bracing bits as per the racer. I think the rest of the vehicle will collapse before the rear does again!. This is the start of the seventh week without my car I have missed two major sprints Phillip Island, a very fast track. Sandown where I had hoped to be able to judge how much faster the car is since fitting some new bits and bobs, plus Rob Roy hillclimb. The next event for me will be on 11th July a Motorkhana including some circle work held on a skid pan which will be wetted for part of the event. I hope this gives me enough time to reassemble my car as everything from the rear bulkhead and I mean everything was removed so they could pull out the old and weld in the new.

Job nearing completion: the bracket has been painted up, and the wiring loom has been re-installed

A close up of the repaired area: it is a very neat job

Another view of same: if you didn't know that the suspension mounts had been substantially modified, you wouldn't realise from a casual glance

What is the moral of this story?

Big thanks to Andrew for the story and the pictures... so what is the moral to this tale? If you plan to use very stiff, non-standard dampers, beware. The standard mounts were designed for use with shock absorbers with very weak compression resistance. After market dampers tend to have far greater stiffness, and therefore impose a far greater load. If you get a knocking sound from the rear suspension, investigate - you may have a problem similar to Andrew's...