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 - front of car grinds over speed bumps-Faux Chassis?

Hello All

I became an owner of a 1999 VVC MGF last Friday and am glad for this great resource.

Unfortunately i didn't go over any speed bumps when i test drove the car, now when i do i notice a quick metallic grind from the front of the car as it comes down over the raised road surface.

I took it to the not so local garage in Switzerland and was told that the 'faux chassis' was at fault - and that the front left hand wheel had moved slightly back from its original position so that it rubs the back of the steering weel on a full left hand lock. He said this was not good, but also not bad. The piece making the grinding noises were symetrical spurs from the bottom of the faux chasis.

Question 1 - is the faux chassis french for front subframe (thats the only equivalent i could see from diagrams)?

Question 2 - is this just an annoyance or does it really need to be fixed - the garage was trying to warn me away from doing the work

Question 3 - the garage estimated 14 hrs to do the work and 1500 GBP for the part - does this sound right? Is there a difference between frames for LHD and RHD?

Really appreciate any help as the language barrier here is not ideal
A CLAPPER

As your car is 'Swiss' then it will not have been 'modified' from the original build such as lowered or different wheels/tyres which are the common causes of 'bottoming'.
The suspension height is controlled by fluid pressure in the Hydragas system and is checked by the measurement from the centre of wheel to the wing.
This is needs a pump that is also used on earlier Minis.
Search for 'Ride Height' in the Archives.
The 'Rub' is seen on a lot of cars as the liner is only plastic but may be worse if the car is riding low.
Have you spoken to the local members of MG Car Club Switzerland. http://www.mgcc.ch
Geoff F.
Enjoy your new car !!
Geoff Farthing

If the car drives OK I would say that it's unlikely that the car has been damaged. I would do as Geoff suggests and check your ride height.

1) Place the car on level ground and let it sit for a little while.

2) Bounce on the front and rear of the car (watch and not damage it- open bonnet and boot) and then roll it back and forth a metre or so. This will get the fluid down to ambient temperature and "relax" all of the suspension parts.

3) Measure from the centre of the FRONT wheel to the underside of the same wheel arch (suspension connected front and rear so you only need to measure front wheel). It should be 368mm +/- 10mm at 17°C. Allow 0.6mm for every degree difference in ambient temperature (if it's warmer the ride height will be greater).

4) If it's out of spec take it to someone that has a suitable pump and get the ride height adjusted.

It's quite common to have the inner edge of the wheel rubbing on the plastic liner. This usually happens when the suspension is low or wider tyres have been fitted to the front (you're should be 185s)

David Clelland

Hi,
Speed bumps are a pain. Our F will catch them too.
Question 1.
What catches is the towing 'Ears' which stick down from the subframe. They now look like they've been a couple of rounds with Mike Tyson.
Does your's have these ?
I had the car tracked with a laser alignment setup that did all 4 wheels and the front was out but is now rectified.
Question 2.
If the garage guy says it's probably OK then perhaps it is, He'd tell you if you should leave it at home and walk in future.!!
Question 3.
certainly the price is stiff.

Does the car drive ok ?,
is it Pulling off to one side - if not it's a good sign
are the tyres wearing oddly / badly - if not it's a good sign
Use ramps or axle stands, NOT a jack on it's own &
Look underneath at the towing ears and down pointing bits and see what's been grinding the tarmac, look for ground off paint or bare metal - the towing ears don't really matter much.
Check in the wheel well to see where it's rubbing and check the tyre.
I assume you've not got larger profile tyres on ?

Then go and park next to a similar model and compare like with like, look at the gap front and rear of the wheel in the wheel arch, the owner will probably be happy to chat.
Our's drives fine again once the tracking was set, but now instead of straddling speed bumps I run one wheel up a bit to keep the subframe ears off the tarmac.

Gramh

whilst looking for bits that ground - don't overlook the mudflaps - these were the only bits I could find that ground when coming down from a speedbump
Will Munns

I had a problem like this when I first got my Abingdon MGF last year. Coming out of my driveway I would also get a small grating noise as the car came into contact with the ground.

I had the Ride height of the car checked and the Hydragas suspension need pumping up after that no problems to date.

Like others have suggested above check the ride height of the suspension, maybe your suspension needs pumping up.

Hope it helps and you are enjoying your MGF.

S J Sibthorp

I had the same problem, had the suspension pumped solved the problem. As a VERY crude guide, if you make a fist it should just fit between the tyres and the body. The only true way of course is to measure with a tape messure, but this is a quick guide.
Brian
Brian

This thread was discussed between 01/07/2008 and 15/07/2008

MG MGF Technical index

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