Topic

Ok, my first how to, be kind!

Those of you who have had to replace a hydragas sphere due to failure in recent times will know that new stock of front displacers is limited and new rears are non-existent. Sphere production ceased in 2002 and with no known plans to produce new stock, this leaves F owners in a dilemma. Personally I love the hydragas system but with even second hand Trophy spheres almost impossible to get hold of and having had one fail when I was touring Tasmania, 2000 km from home and now with a second one gone, I needed something reliable where I wasn’t wonder how I was going to continue to keep my car on the road. Enter the coil spring conversion kit for MGF’s!

This kit was developed by the Sydney MG Centre as a direct swap replacement for the hydragas system in conjunction with Murray Coote (ex Australian rally champion) of MCA Suspension who has an excellent reputation. It consist of coil springs mounted in the car’s hydragas sphere mounting bracket and adjustable dampers utilising the F’s existing secondary damper mounting points. This also leaves open the option of should spheres ever be produced again of changing the suspension back should one wish.


The replacement for the sphere consists of a “top hat”, a coil spring and an adjustable base plate.

The top hat is made of aluminium and turned from a solid billet.



The “brim” fits into the car’s existing mounting clamp.



Inside there is a raised centre for location of the spring.



The springs are produced by King Springs, Australia’s largest aftermarket and performance spring manufacturer. I’ve used King Springs on a number of my previous cars with excellent results and they produce a quality product.
The springs themselves are made of X5K spring steel which apparently is a “Micro-Alloyed high strength spring steel enhanced by additions of silicon, chromium, and vanadium nickel, along with lower carbon than conventional spring steel grades. Material difference allows these springs to withstand higher operating stresses with superior resistance to sag and improved toughness and corrosion fatigue properties. It allows a reduction in the amount of steel required in a spring, making it substantially lighter (by approximately 30%) and reducing the solid height therefore increasing travel.” Had never heard of it before but sounds good!

Front and rear springs are different with the front being slightly taller and thinner.



The adjustable base plate is turned from steel and allows for significant height adjustment. If you like the 4wd look you can have it!







The replacement for the sphere assembled.



The kit comes with GAZ adjustable dampers but I believe you can purchase the kit without them if you already have adjustable dampers. May reduce freight costs too.

What you will need:

The kit.



One of these, or similar. (note: I haven't fill the passenger foot well with concrete, it’s a failed rear hydragas sphere. )



One of these.



A couple of these.



Some of these.



Some of these



Some of these.



Maybe some of these.



Possibly one of these.



And not forgetting a workplace supervisor.



The process.

Jack up one side of the car supporting it on car stands. DO NOT rely on a jack alone to support a vehicle! Depressurise the hydragas system on the side you will be working on using a hydragas pump or other method. If not using a pump be aware that the fluid in the suspension is pressurised to around 400 psi. Be careful!

Remove front and rear wheel.

Front

Remove the plastic wheel arch lining. It is secured by a number of metal screws around the edge as well as plastic screw clips.



To improve access to the hydragas bracket bolts, remove the damper first. Assuming you’re top damper bolts aren't seized like mine were.

The bottom damper bolt is undone by a removing the 17mm nut while holding the 13mm bolt.



Remember the order of the fitting. Goes bolt, suspension, brake line bracket, spacer, washer, damper, concave washer, nut.

The top bolt is accessed on the passenger side by removing two bolts and moving the fuse box aside to allow greater room.



On the driver’s side unbolt and disconnect the horns.



Now comes the tricky part, holding the rectangular top of the damper bolt with a 7mm spanner, undo the bolt. In my case the top started rounding off without the bolt budging, hence my having to use a hammer drill.

With the damper removed it’s a straight forward process of removing the four bolts holding the mounting bracket. The bottom two bolts have fixed nuts behind the bracket, the securing nuts on the top two bolts are loose. If you have ABS there is a bracket held on by two of the bolts which also needs to be removed. It holds the ABS sensor wire.



Now undo the hydragas pipe which enters the sphere. On the driver’s side this is easily reached but I found the brake master cylinder was in the way on the passenger side. I ended up removing the pipe from where it meets the pumping valve.



Once disconnected the displacer can be levered out of the mount. The spring on the knuckle should also be removed.



Using the supplied lube, smear a small amount of grease on the baseplate threads.





Screw the top plate right down onto the bottom. The instructions suggest cutting 15mm off the top of the knuckle but I found by fitting the baseplate over the knuckle first this was not necessary. Whether this is the case with F’s which don’t have lowered knuckles, I don’t know.

Next mount the spring (making sure it is one of the front springs; these are taller than the rear) and top hat on the base plate and slot into mounting bracket making sure the top hat is recessed completely.



At this point the instruction suggest cutting a slot in the removed front plate and then reattaching. Height adjustment is then effected through the slot, useful if you want to play around with the height. I chose to adjust first to the suggested height and then refit the plate. Adjustment occurs by inserting the two tools into the holes in the upper and lower baseplate and turning until the require height is reached. On the front this is suggested at 8 mm between the plates.



Don't forget to reattach the ABS bracket if you have it! Bolts should be torqued to 25 nm.



Remove the top nut, bush and two washers from the new damper. Preferably with two people, have one hole the damper from beneath, passing the top bolt through the mounting hole while another secures it with the two washers, bush and nut.
Reconnect the lower damper bolt and torque both it and the top nut. Front done!



Rear

The rear is more difficult due to the limited access. Remove the bottom damper bolt as per the front ones.



Access to the top bolt is more difficult. On the driver’s side, the coolant bottle needs to be moved. It is secured by two bolts. Remove these and the top inflow pipe being careful not to spill coolant everywhere. Carefully move the bottle aside. This should allow access to the top bolt and the rear nuts of the sphere mounting bracket.







The passenger side is more problematic. This involves removing the ECU and its bracket. You may wish to disconnect the battery at this point though I understand it’s not strictly necessary. Remove two upper bolts on the bracket and slide the bracket upward so as to release the bottom rubber mount. Undo the electrical sockets (number and type will vary depending on ECU in car) and remove ECU and bracket.





Now, depending on your car, you may have a number of things still in the way. In my case I had to disconnect and move more electrical cables and two fuel lines. Depending on the air filter setup in your car, this may also have to be removed. Either way, access to the hydragas sphere is still extremely limited.



After removing the damper, you may wish to release the antiroll bar to allow extra suspension movement, though I found this not to be necessary on the second rear I did.



With difficulty, remove the four bolts securing the sphere mounting plate, remembering the top two nuts are not fixed, and remove the plate.

As per the front, undo the hydragas pipe from the sphere. If you do not plan on removing the pipes completely it would be worthwhile securing them to something at this point so they don’t flap around.

The sphere can now be removed, through the engine bay on the driver’s side and out the bottom on the passenger side.

Once again lube the bottom adjuster plate and fit to knuckle then mount spring and top hat. It’s a tight fit!





Again I chose to adjust first, raising it by the suggested 20mm.



Fix front mounting plate.
Install new damper. Damper suggested settings are 10 all round to begin with and adjust for preference from there.

Refit wheels, drop car, do other side and......

Done!



Thoughts

I found the most difficult part (apart from seized bolts) to be getting the hydragas spheres out. The new springs went in very smoothly. Second side of the car took half the time of the first.

Using the suggested settings, the front is sitting at 350mm (basically Trophy spec). The rear seems a little high but will wait and see how it settles after some driving before adjusting. Due to the adjustment, both front and rear could be dropped further, though due to my using the car as a tourer I prefer having a slightly higher ride height, means I’m not bottoming out on every neglected back road I use!

The ride is very smooth. Being use to Trophy spring rates, I’ve developed an automatic reaction where I brace for every bump or pothole I see, but with this setup that’s no longer necessary. On a nearby road I avoid due to it feeling like I’m riding in a jackhammer, the F now floats across the bumps – really impressed. The car feels like it rolls more in cornering but that’s expected with a softer spring rate. Need to play with the damper settings to see what I can achieve with them. Also does tend to pitch more than with the hydragas due to the loss in self levelling capability but no more than most other cars I've driven.

The reason I like this setup over the suplex is that if you did decide you wanted a firmer spring rate it’s just a matter of having another set of springs made up. I’ve taken measurements and thanks to Dieter’s assistance have a current spring rate figure to work off. Also helps that King Springs are about 45 min down the road. If you did choose to go down that track, with practice I don’t see it taking more than an hour to swap between spring setups.

I'll continue to update on how this conversion goes as I put some k's on it. Any questions just shoot.

Awesome, comprehensive 'how to'. Thanks.

Your organised tools set up made me sick with envy.

Fantastic write up, mate!
Really keen to hear how this setup copes with the famous Oz roads!


Two questions spring to mind.

1/. I know that some people who have replaced the standard shocks with uprated/adjustable versions have experienced failure of the top mounting on the rear.
Have you beefed up this mounting?

1/. What do you think would be the outcome of retaining the original dampers with the new spring conversion?
Just thinking that if you could just replace the spheres initially,and that this would spread the cost.

My F is fitted with the Aussie kit and I've now done some 3000km of country touring since fitting it. I can echo GIR's comments on the handling of rough roads. As our car is used primarily for touring I've not set the car too low preferring to have sufficient ground clearance. Its cannot be over stated just how lousy our back country roads are out here in Oz. The highways are OK but get off them and you'll encounter conditions that the Brits and Europeans reading this could not imagine. The F now tackles these conditions easily and competently.

I am using Bilstein Shock Absorbers on our car which are brilliant and as such the car handles brilliantly. A word of warning, its a good idea to strengthen the rear upper mounting points if you are using rough roads. It may not be all that necessary in Europe but in Aus and South Africa its a must do.

The best aspect of this conversion though is the peace of mind that it provides when touring. To my mind the biggest worry when touring in the F was the ever present prospect of sphere failure. Every time in our F's history when a sphere failed it was while touring. As such the car was always 500km or more from a garage with the ability to recharge the hydra-gas system. Its was a constant source of annoyance (& considerable expense) to have to truck the car to another garage to have this done. So to me the availability of replacement spheres is irrelevant. The issue was the fragility of the spheres and the knock effect of their failures. Of course when I bought the car new none of this was known.

On my recent trip to australia i perchased this kit and lugged it back in my suitcase!!!

So i will be testing it out on the uk roads.

The kit itself is very well made and feels as good as it looks.

As for price its cost me £1050 because i saved the $300 to $400 postage
and the shocks are made in the uk so they were sent directly to me.

im very gratefull of the how to.........but you dont have the salt and corosion in aus that we are used to in the uk
so im expecting to add a saw/grinder and a canister of release agent to my pics

thanks paul

Sidders wrote: wrote:

On my recent trip to australia i perchased this kit and lugged it back in my suitcase!!!

So i will be testing it out on the uk roads.

The kit itself is very well made and feels as good as it looks.

As for price its cost me £1050 because i saved the $300 to $400 postage
and the shocks are made in the uk so they were sent directly to me.

im very gratefull of the how to.........but you dont have the salt and corosion in aus that we are used to in the uk
so im expecting to add a saw/grinder and a canister of release agent to my pics

thanks paul

I'll look forward to a how to on a British car then!
Paul

David Aiketgate wrote: wrote:

1/. I know that some people who have replaced the standard shocks with uprated/adjustable versions have experienced failure of the top mounting on the rear.
Have you beefed up this mounting?

Not yet but will be getting done along with other engine maintenance work now that she's back on the road.
I figure better as a preventative measure than having to deal with a whopping big hole in the chassis!

David Aiketgate wrote: wrote:

1/. What do you think would be the outcome of retaining the original dampers with the new spring conversion?
Just thinking that if you could just replace the spheres initially, and that this would spread the cost.

I've read that the GAZ adjustable on their softest setting are supposed to be the same as the original dampers, that said when I was playing with the originals after removing them I found that the bound was very soft but the rebound was significantly stiffer than the GAZ.

I've been playing around with the damper settings and found at 20 (about half maximum adjustment) it corners much more like a Trophy should with significantly less body role but still is quite compliant over bumps. Have to start playing around with different rates on the front and rear to see what that does.

Sidders wrote: wrote:

On my recent trip to australia i perchased this kit and lugged it back in my suitcase!!!

So i will be testing it out on the uk roads.

The kit itself is very well made and feels as good as it looks.

As for price its cost me £1050 because i saved the $300 to $400 postage
and the shocks are made in the uk so they were sent directly to me.

im very gratefull of the how to.........but you dont have the salt and corosion in aus that we are used to in the uk
so im expecting to add a saw/grinder and a canister of release agent to my pics

thanks paul

Will be very interested in this kit and the fitting "how to" especially as there is already a SIMPLEX set on Roger Parker's (MGOC) MGF, this is the british version being sold currently for £876 including VAT by the MGOC and B&G ~ the Simplex units are black anodised to stop the units corroding

Im aware they will corrode a little so they will be sprayed with a waxoil....and the kit from b&g is plus vat so its not to far from what i payed....

Im going to install it this weekend.....sprayed all the bolts with plusgas in preperation.
cheers paul

Sidders wrote: wrote:

Im aware they will corrode a little so they will be sprayed with a waxoil....and the kit from b&g is plus vat so its not to far from what i payed....

Im going to install it this weekend.....sprayed all the bolts with plusgas in preperation.
cheers paul

Thank you, good to see that you are using Plusgas!!! so many think WD40 will do Plusgas is a must. i would personally paint them with POR15 from Frosts (what Daz uses on his subframes) waxoil is good but they are going to be messy to fit good luck with the job

Great How to GIR, I'll be doing the conversion if and when Mine fail. A pity about the failure when you were in Tasmania, I may have been able to offer some assistance. Next time you're down this way give me a call and I will organise a private practise at Symmons Plains.

Craig

Sidders wrote: wrote:

Im aware they will corrode a little so they will be sprayed with a waxoil....and the kit from b&g is plus vat so its not to far from what i payed....

Im going to install it this weekend.....sprayed all the bolts with plusgas in preperation.
cheers paul

Sorry to harp on about the price for the SUPLEX kit B&G are advertising the kit in the current MG magazines for £876 Including VAT @20% ~ the MG Owners Club are also selling it for the same price. I think the AUS kit looks awesome and look forward to your results.