MGF Suspension Problem

[firedevil666]

Hi all my name is Damien and im new to this site and new to the world of owning my own MGF, witch i have only had for two week. (and really love)

My suspension seems to be really bouncy, Driving normally down the road even though theres no bumps in the road and like always in the middlands the roads are still very uneven my mg just bounces all over the place and creating a very hard and violent ride, if i was going over a speed bump i have to drive at walking pace other wise it would feel like im in a car crash or gone off road. if i push down on the back of the car, It Springs Like any normal car and so on when i do the same on the front oof the car.
if i push the back end of the car it still moves once i have let go, also when i push down on the back end of my car the front of the car rises up, could this be down to fulty shocks or sehere's, and is there a cheap and easy fix if it does happen to be the sehere's.
I will be working on my mg all or part of tomorrow to try and get this problem sorted out but any help i could have from you guys on here would be much appreciated, im not really sure with common fults with the suspenion on the Mgf so im begging for help plz.



I really hope someone can help my with getting to the bottom of my Suspension Problem
Thanks....

[cath's mg]

Hi Damien, you have definatly come to the right place for some advice. The thread link may be helpfull, if not there are lots of people on hear who will give you some great advice. These cars are great fun to drive dispite the niggles.
viewtopic.php?f=8&t=8404#p69352
Gary.

[firedevil666]

thank you gary that link was a big help, when i push down on each side of my car there is movement do im gonna replace my dampers first and see what happends just as a nice and cheap option. i rang up (we love mgfs) and they told me secondhand seheres would cost me about £100 but also £400 inc fitting what a joke why do they quote a stupid price like that to do a very easy job, (ie) not very hard.
Is there anyone on here who is mobile and has a pump or does anyone have a number to someone who could come out and pump my suspension back up for me just incase i do end up changing the seheres.
Im ws11 cannock way on.

[cath's mg]

You might be able to find somone on here
http://www.hydragas.co.uk/
but im sure someone will know a mobile near you. We re-gassed Cath's last year using someone mobile and i think it cost about £40.00 (cant remember the exact price) and it made a real differance with the comfort of the drive.
The suspension height should be 368mm measured from the centre of the front wheel to the lip of the arch.
Have you got any photo's of the car?

[firedevil666]

Thanks for all your help so far every one but i need to be clear on somthing acording to the site that cath posted its possible to refill the hydragas in the spheres if so why are welovemgf's trying to sell me some new seheres, oh and i would like to tell you all im sure it is my spheres that have gone and not my dampers because when i try to push down on the car now im sure it is just the tyers that move, when i did my checks last time i was only just looking for movement and was not really taking any notice. shame on me i should be taking notice as i plan on keeping this car for a very long time as i really do love it.

By the way nice car cath same color as mine i really love that color and thats the only reason why i had it in the first place, it came in as a part x and soon as i seen it i just new it was mine, i have fell in love with it now and i would not change it for the world.
ps........ i will put up a pic of my car soon

[Rich in Vancouver]

You have to be careful not to replace parts that don't need replacing.
Remember that the dampers and spheres each do separate tasks.
Basically, the spheres hold the car up.
If the suspension height is correct (368mm for a standard car) and stays there the spheres are usually ok and doing their job.
The dampers do just that, damp the suspension movement.
You can check them by pushing up and down on each wing. After you stop pushing if that corner of the car keeps going up and down by itself
the damper isn't doing it's job. If the movement stops after one cycle it is OK.
Replacing the dampers is a simple job and inexpensive.
Replacing the spheres is more complex and expensive.

In short; Pump your suspension up. if it rises to 368mm and stays there then,
Test the dampers by bouncing each corner.
Only replace the parts you have to.

[Reckless Rat]

I agree with Rich. Don't go and buy a set of dampers for the time being. This sounds very much like you've got a car that's sitting on it's bump stops because the suspension is deflated. The first thing you should do is to measure the ride height from the centre of the FRONT wheels to the top of the wheel arch. It should be roughly 368mm. If it isn't, then the first job is to have it pumped up. You may then need to have a four-wheel alignment check done to ensure that everything is as it should be - MGFs are very sensitive to incorrect suspension height & tracking - it seriously affects the handling of the car.

So, go and find somewhere you can have it re-pumped and then take it from there. There's info on places at the top of the tech forum.

[firedevil666]

The ride hight is fine I taken the car into welovemgfs last week and he had all the suspension repumped it has not lost any since that has been done, the bloke at the mg place said it was too high to start with by about 1inc, its still at the right high now after one week. when im pushing down on the car now its very hard to move it and I was before I took the in and that's why I took it in the first place. im feeling really stuck now and don't really know what to do and how to fix this problem.

[nigelandjo]

If the ride height is fine, have you checked the tyre pressures (as F's and TF's are very fussy about running at the correct tyre pressure)? Do you have the same make of tyre on each axle? What brand of tyre does your car have (again they are quite fussy)? I'm not 100% certain what the problem is from your description as you said the ride is very bouncy, but then said it was very hard and violent...

[firedevil666]

Ok here we go i have changed the dampers about an hour ago and the ride is still the same, the tyre pressures are fine and the suspension is pumped up to 368mm and stays there but, im still getting a very hard and bouncy ride and what i mean by hard and bouncy ride is that the suspenion is that hard if feels like every time i hit a bump in the road it feels like the wheels are coming off the ground, its really hard to explane its one of them things you would have to see for yourself.
Does anyone recommend me changing the spheres or is it possible to get them refilled with hydragas, im not really up on this and im not 100% sure how the spheres work but im im right not saying im am, but im under the inpression that the spheres hold (Hydrolastic fluid and Hydragas)

[Tipper]

It sounds like you have lost the nitrogen gas fill above the rubber diaphragm (fluid below). This means that to get the correct ride height more fluid has had to be pumped in and as the fluid is not compressible whereas the gas is you have effectively lost all suspension travel other than the bounce in the tyres and maybe a little in the rubber of the spheres themselves.

I think new or 'regassed' spheres are needed. Alternatively convert it to Suplex spring kits or TF spring coilover subframes.
Just one of the downsides of MGF ownership when they are getting long in the tooth!

[firedevil666]

Thanks tipper i have been doing some reserch just after your post and i think your right.
does anyone know how i could convert my mgf to mgtf suspention and what would i need to do this.
or could anyone lead me in the right diretion on how i could get my spheres regassed.


Pic for cath
Thanks all

[Tipper]

TF conversion is basically buy some TF subframes complete and swap them over.

I do believe there may be a little 'body fettling' around the TF top shocker mounts to allow the subframes to fit but that is all.

[Reckless Rat]

Was that picture of your car taken before or after you had the suspension re-pumped, because it still looks low to me?

Given the current resale value of a 96/7 mgf I hope you are capable of tackling subframe changes yourself because it's going to cost you an arm and a leg if someone else has to do it for you - far more than the car will probably ever be worth irrespective of its condition. Even the suplex conversion is going to cost you just under a grand, plus fitting. Replacement hydragas spheres are considerably less, and of course you can have the existing ones re-gassed if you have a facility whereby you can weld a schraeder valve into the top of the sphere. Then all you need is a garage that can pump it full of Nitrogen to about 350psi. A cheaper option would be to source a set of second hand spheres from a breaker. There ARE new ones about but they're as rare as hen's teeth these days. Trophy ones are more readily available but you'll need some other mods to fit them to your car. Please note that front and rear spheres are NOT interchangeable. They are slightly different.

The symptoms you describe are those similar to fluid lock in the spheres caused by nitrogen loss. The suspension is effectively solid and the only give is in the tyres. That's why a new set of dampers won't make any difference (and hasn't).

[firedevil666]

Thanks Reckless for the info im gonna do some reserch into getting my spheres regassed or just change them over i think the best thing to do will be getting them gassed up and fitting some valves.
leave it with me and i will get back to u all in a few days and let u know how i get on.

[firedevil666]

Hi every1 the problem is solved, i got the car up on the ramps today and changed the spheres then had my new best mate come out and pump up the suspension for me then took it a drive and guess what no bumps and no bouncing, the proplem was that my passenger side sphere had jammed up the drivers side was fine but i still changed it anyway just to be on the safe side.

Anyway thanks for all the help, the contact details of the garage repummed my spheres, very helpful and saved my skin, if it was not for chris my car would of been suck on the ramps lol.
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C.R.S. MG & Classic Cars
Restoration Specialists
Bednall Head Service Station
Cannock Road
Bednall Head (on the A34 between Stafford and Cannock)
ST17 0SG
Tel : 01785 663 751 Mob: 07773 500 502 email: rodgers.chris61@yahoo.co.uk

[Steve Chitty]

This description seems to mirror the problems I am now getting. 1998 F with just over the 100K on the clock. Bought a year ago having been garaged for 18 months. Very low suspension that was re-gassed (fluid) and ride and handling were fine. The car went into my local MG specialist (who are honest enough to admit they don't really understand the F suspension) for a fair amount of work for one reason and another. Garage fitted 2 new lower suspension arms, 2 rear top ball joints 4 nylon lower shock bushes and pumped her up to 368mm.
The car rode so badly that my better half was reluctant to get in it (my chest hurts...and no she wasn't laughing). Having done some basic forum snorkling I thought it worth bleeding a little fluid to see if that would help. What came out was foam not fluid. Took the car back to the MG boys who drained it completely while scratching heads about the foam. They have said they think they may have used the wrong fluid (one hydrogas pump used for one thing only...how does it get the wrong fluid?) Anyway pumped up again and running at 368mm the car was long legged and bouncy and just not as comfortable as when I bought her. Ride height has dropped a little since I collected last week.

Theories

1/ Lowering knuckles have been fitted by a previous owner and the ride height is therefore set too high ( I have no idea what PSI they pumper her up to )
2/ Sphere failure

From the string I am following on from you mention "changing spheres" but not which ones. The car sits level, it bounces once when pressed on each corner but clearly something is wrong and I have no clear idea how to be sure if its front, rear or all four spheres that need replacement.

I have seen a lot of info on the "schrader valve weld in to re gas" option but is anybody with the skills and the tools now doing this with second hand spheres to create "reconditioned" units? I can get 2nd hand from Martin Smith but again no idea how to know if the units are any good.

Is there such a think as a simple step by step diagnostic process that can be followed in order to be sure of the fault and where it lies?

Any help, hints, photos and biscuits gratefully received