MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGF Technical - Suspension trouble

I noticed that my car was sitting about 2 - 3 " lower than another F which I was parked next to. My man at the garage has checked and says that I have no pressure in the hydragas system. Is this going to cost a lot of money. Also someone told me that recharging the hydragas system requires removal of the sub frame - can this be true. Hope someone can give me some good advice on this.
David M Smith

Do you know if it has always been that low, as some owners have it lowered by letting out some fluid. On the other hand, others have it pumped up far too high.

On my car I can put 2 fingers between the front wheel and the wheel arch, on others I can put my whole hand there.

This means you can get a hight difference of about 2 -3" on different cars. Maybe you could check with some pictures on the web. The hight from the centre of the wheel hub to the wheel arch is standard 365 MM, on mine it is 335MM.

As far as I know, the hydragas suspension needs to be pumped up through nozzles under the bonnet.

Johan
Johan Slagter

David,

It is likely that over time the system can de-pressurise. It is quite usual and should merely require dropping into any garage which is able to service Metro's to have it pumped up. There are two tyre type valves beneath the plastic shroud under the bonnet to pump up the system. It usually takes 15- 20 mins and should cast between £30-40 depending what part of the country you live in. The system is normally charged to 400psi, this will correspond with 368mm wheel centre-wheel arch on the front wheels. (the rear wheel arch is a different profile so will have a slightly shorter dimension). Allow the car to settle before taking a final dimension, this can be speeded up a bit by driving the car over some speed bumps (not too difficult to find in London).

Many people prefer the look of the car when the pressure is low and so release the pressure from their systems. This is not to be recommended as the pressure in the system is a major contributor to the cars handling. If you do prefer the lower look you can fit lowering knuckles to the car which reduce the height by about 20mm but still maintain full pressure in the system.

Tim
tim woolcott

Completely agree with what Johan and Tim have said.

I'd advise against letting your dealer pump the suspension up for you: they charge too much, and rarely do they pump the suspension up correctly. IMO you'd be better off taking it to a specialist for attention - be that B&G, Mike Satur or Techspeed (I suspect that of the 3, Techspeed are the most convenient, with them being off the Fosse Way... :o))
Rob Bell

FYI, mine has exactly the same problem and is going into B&G on Saturday - they've said about £25 to sort it out. But did say "of course, we'd need to find out why it's leaking". Well that can come later!

Rgds

Ade
Adrian Collis

Mmm, I put up another thread this morning with a similar sort of Q. Between which set of tyres is the H-system linked? Front to rear, each side, or side to side, front and back?

I ask because I've got a significant drop (3/4") on the nearside... could system depressurisation cause this?

Ta,
Col
Colin McIlwaine

The system is linked front to rear.

If 1 side is lower you may have a leak in 1 of the spheres, especially if it a bit sudden.

Johan
Johan Slagter

I've got it booked in to my "local man today. He looks after quite a few F's in the area and has always done a good job (Including recent HGF). Thanks for all the advice guys - where would I be without it? (no sarcasm intended).

David Smith
David M Smith

David, let us know how you get on with your 'local man'. I'm booked into Rover tomorrow to have my system repressurised... I'll be taking measurements thereafter to determine whether I've a nearside leak.

Col
Colin McIlwaine

To add to this thread ... I have noticed that with the drop in temperature from 30C in the summer to just above freezing today my suspention has dropped about 20mm.
I have been monitoring it with temperature variations up and down ... the ride height goes up and down as well.
I read somewhere that the measurement of 268mm is at 18C ... so there appears to be some expectation that the ride height will change with temperature.
Therefore, I suspect all F's drop a bit in the winter months ..??????
Richard Lane

Gents,

The Hydragas on F has been successfully repressurised by Rover... and I must say they were very precise about it, back and forth with the measuring tape until it was just right.

(Also, quite stunningly for rip-off Ireland, I was only charged 34.50 euro, about Stg£23.)

Only downside is... now she's back to the factory settings, she looks *way* too high. Lowering knuckles it is ;-)

Col
Colin McIlwaine

Colin, it might settle down a bit, but with a change in temperature it might rise again !, see eatlier reply .
Mike (@home)

It's all fixed,, by my local man, at a cost of only £20. The car was around 2" lower than factory settings as measured from centre of wheel hub to top of the wheel arch. I must say that the car not only drives and handles better, but also looks right now (In my opinion). There are no signs of leaks or other damage to the components so I suspect that the system has been neglected over the years to the point where it became really noticeable. I know that on aircraft landing gear struts, which work on a similar oleo/pneumatic principle, that the gas pressure is usually set using a graph based on strut extension versus ambient temerature, such a graph for the F would ensure that when pressurising the system a more accurate setting could be achieved taking account of temperature differentials, I suppose that that would be wishful thinking though. Once again thanks guys for all the help and advice.

David
David M Smith

This thread was discussed between 22/02/2004 and 02/03/2004

MG MGF Technical index

This thread is from the archives. Join the live MG MGF Technical BBS now