Suplex suspension WARNING

[cjmillsnun]

After I bought my MGF Trophy 160 I discovered that the hydragas had been replaced with Suplex suspension

I had a problem in that the suspension always seemed to bottom out.

Then about a month ago I heard a ticking sound from the off side rear...

This is what I found.

The dampers were not adjustable, but the standard dampers included with the kit.

The problem is the dampers themselves. As discovered by David "Aiketgate" on another forum, the dampers are a copy of the Monroe OEM ones. This means they have two issues.

1. They damp only in rebound. (proven by the fact there is little or no resistance when compressing the damper but a fair bit more when pulling it apart.) This is fine for Hydragas as it's designed to do the damping itself, but springs need damping in both bump and rebound.

2. The bottom bushes are not fit for purpose.

However there was one modification made to compensate for the springs.

(this next picture is not mine but is David Aiketgate's. I'm sure he won't mind me linking this)



A bump stop was added to the top of the damper. The problem is that the slightest bump causes this bump stop to be hit. and all the force goes through, you've guessed it, the top mount. This causes it to flex and metal fatigue cracking is the result.

This has happened on at least 2 Fs with the standard Suplex supplied dampers. Mine and David's. Mine is a Trophy, and if it was just mine, you could argue that the system wasn't optimised for my car. However David's is a Freestyle, which runs standard ride heights.

Both of us have switched to GAZ adjustable dampers and have noticed a massive improvement, as they damp in both bump and rebound and do not have those bump stops. Instead if the suspension bottoms out, it hits the bump rubber attached to the spring mount (the same as on Hydragas) and bottoms out on the suspension arm, putting all of the force on the subframe which designed to take that kind of load.

My personal recommendation is to repair your hydragas system if at all possible. If not, you have to add the cost of a full set of adjustable dampers to a Suplex kit. Do NOT run the dampers provided by Suplex I find about 8 clicks rear and 5 clicks front (on GAZ Dampers) gives decent damping in both bump and rebound without overstressing the mounts. Any more, then you need to strengthen the damper mounts (preferably to cup specification).

[Rob Bell]

Thanks for this heads up. :Thumbsu:

Have you approached Suplex with these findings?

[cjmillsnun]

I have and am awaiting their reply.

[adrianclifford]

Thanks for details of this Chris, I've heard rumours about this but now I've seen the evidence.

[Taki]

I am following this thread here and in the other MG forums, as I am running on Suplex for the last 3 months.
My car is not a Trophy but a standard F, so should I worry more about the top mount problem? I have checked carefully and for the time being I haven't seen any damage.
As I have some clonking from the front units on uneven roads, mostly at low speeds, I would like to know if this stops when using the Gaz shocks (apart from the better handling).

[Rob Bell]

I think I'll need to speak to Dan directly - I'll try and let you all know what transpires.

[Taki]

Thank you Rob. It would be great to have a definitive answer from the manufacturer that covers these issues.
For the time being I stay with the shocks supplied with the kit, since changing those seems that voids the 12-month guarantee of the kit.
I do not know of any way to tell if the shocks I have are the earlier version or not.

[cjmillsnun]

Taki

As you're within the 12 month warranty of your kit, look closely at the dampers.

Take a rear wheel off and look just under the suplex sticker.

If you have stamped in "SUPLEX MGF F" and underneath a sticker saying REAR, then you have the old style dampers. These are the ones that can cause the issue. You'll also find that at the front you'll have stamped on the damper "SUPLEX MGF R" and a sticker saying FRONT.

Newer dampers are correctly stamped and don't need the extra sticker to label which end of the car they should be fitted to. From what I gather (and Rob seems to have confirmed this) the later dampers are made by GAZ. You'll probably be alright with these.

[cjmillsnun]

Thanks for details of this Chris, I've heard rumours about this but now I've seen the evidence.

It was a bit of a shock to say the least Adrian. The air turned blue for a few seconds until I was able to determine that the damage was weldable.

[Taki]

Thank you for your suggestion.
I will check the markings but I am sure the dampers have the oval yellow stickers FRONT and REAR (or this is on the units? ...I will check and see)

[Taki]

I have checked the dampers without removing the wheel and I have black labels with yellow letters stating FRONT and REAR

This is a front

[Taki]

It seems the dampers that came with my kit are not made by Gaz. They are made in France by a company RECORD.

[Rob Bell]

I'll chase this up when I get back from Holidays - but the French dampers were certainly the ones that were supplied with the original kits...

[Taki]

The signs are getting worse. I now get the ticking noise from the RH rear. From a first check there is no obvious damage but I'll have the car checked next week, as it seems the noise comes from below the top mount bush. Also the clonking from the front units keeps increasing.