Rear Suspension Failure

[AndyInOz]

Thinking more about this, I'm still alarmed at the "worn springs" suggestion. I've heard of "broken" springs but never "worn", as the physical nature of a spring is that it can only really become weakened by over-extension (impossible on a car) and never by excessive compression when acting as a shock absorber. Yes dampers do wear out and very occasionally so do bushes but I have only had this problem once in years of motoring. Given the general reluctance of Mitsu to repair anything under warranty I doubt the OP actually had the springs changed unless it is easier/cheaper to do this when replacing a faulty damper by putting in an entire new strut assembly.

As far as I can see from an example on ebay the car has trailing arm suspension with Macpherson struts which seem to involve a number of bushed joints - so difficult to know which are being referred to, but I don't recall anyone having this problem on this forum. Therefore, not sure that this can be described is a well known issue with the PHEV.

I'm not sure that this is true.

When working for the Navy, I had to buy some valve springs.

The particular engine was no longer being manufactured, and we had no spares.

Because we had no technical data on the spring, we requested the return of some springs from one facility that still had some in stock, so that we could get new ones manufactured 'by sample'.

After distributing the newly made valve springs, we immediately received a flood of complaints because we were sending out 'worn out springs'.

It turned out that the repair facility, had supplied 'worn out' springs to us to use as a sample, rather then release their precious spares...

D'Oh!

I also had to replace the 'worn out' coil springs on my twenty year old car, because they were no longer able to keep the car at the appropriate height. (i.e. had weakened over time)

 

[jaapv]

Could the NCT failure be triggered by the fact that the car has cross-camber by design?

 

[ThudnBlundr]

I've had worn springs on a car, but it was an early '70s sports car in the late '80s and it was droopy on the driver's side. The leaf spring was still intact, but was definitely a different shape to the other side. Constant stressing will cause them to move very slowly over time, but it certainly shouldn't happen with modern materials over the period of a few years.

 

[MrPastry]

I have seen plenty of vehicles with weak coil springs. Very common on heavy 4x4's like the classic RangeRover.

 

[GeePHEV]

I'm curious to know how suddenly these bushings or Pins have sign of wear? I have just had an MOT fail today on the Central rear upper suspension component. My last Service at a Mitsubishi accredited service last Dec 2020 made no mention of any problems on rear or front which also failed and came up as an advisory on last MOT ( light misting) October 2020
I use my car as a Private hire vehicle with stringent checks. last full service was only 2,000 miles ago so surely this wear and tear would have been evident then?
As for the car itself it drives fine..... no noise and apart from regular speed humps in London is pretty smooth.

 

[IrelandHS]

I'm curious to know how suddenly these bushings or Pins have sign of wear? I have just had an MOT fail today on the Central rear upper suspension component. My last Service at a Mitsubishi accredited service last Dec 2020 made no mention of any problems on rear or front which also failed and came up as an advisory on last MOT ( light misting) October 2020
I use my car as a Private hire vehicle with stringent checks. last full service was only 2,000 miles ago so surely this wear and tear would have been evident then?
As for the car itself it drives fine..... no noise and apart from regular speed humps in London is pretty smooth.

Hi there

I'm no expert like the others on here but I don't think the part that causes the suspension fail, the bushes, has actually worn out. I think it is in the original design of it that it causes too much movement and is failing testing. I have since heard of dealers in Ireland replacing the bushes with ones from a different car model before onselling.

 

[KevinK]

I'm a bit puzzled by this thread. The Eire fitness for purpose testing procedure is on line: Google (nct_manual_july_2018_v4.pdf). It's an interpretation of the EU directive on vehicle fitness to operate. It is full of bureaucratic prose translated so that we ordinary mortals can understand it!

Last Summer I moved from a 2008 MY Volvo XC to a 2015MY PHEV because of the impending £12.50 per day London Toxic Car tax triggered by the Volvo's Euro4 Diesel engine.

The two cars weigh about the same and I'm using the PHEV just as the XC was used. The PHEV suspension is probably 'as built' without any signs of maintenance. The springs have sagged a bit and the ride height is slightly down. The Bushes and Bearings are about as worn as I would expect from a 2+ ton 65,000 mile all wheel drive car. The Shockers are not yet showing any signs of failure.

I'm sure I'm going to have to replace most of the suspension's wearing components in the next 3 years as mileage heads towards 100,000. The Volvo had 210,000 miles in my care and pretty much everything in the suspension department wore out twice in that time- Factory parts were used in every case. It did help that the Volvo shared it's Chassis with Land Rover's Freelander II, so parts were readily available.

As for the Eire fitness for purpose testing (nct_manual_july_2018_v4.pdf): the electronic suspension evaluation plates check geometry by measuring induced side forces against Manufacturers Homologation Data and also tests for misalignment induced by worn/loose components. The suspension is further checked with all 4 wheels hanging down unloaded using traditional methods. Shock absorbers are visually examined for leakage but there is no 'Bounce' test in the procedure.

My experience was that the Volvo's geometry wandered off from book and had to be reset every year. Yes I was guilty of using the car for it's intended purpose. The PHEV is getting the same treatment, only tempered by Covid-19 restrictions, so I'm expecting to have the same annual task.

The rear suspension of the PHEV is so much easier to get at than the XC's and I could probably work kerbside on most things. The front is a bit more restricted but both are simplicity itself (as far as I can tell) when compared to the XC.