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MG MGF Technical - Mind of it's own!
|Please help me restore my love for my F!|
Quite a while ago I had just my front right hydrogas unit sink, this seemed to coincide with the handling going completely strange, which you'd expect. I had it pumped up again (& new rear NC30's fitted) after about a weeks careful driving.
I've now done many miles on my rear tyres and the suspension hasn't sank again. The only problem is that the handling is still completely sh@gged, when on fast undulating roads the front end of the car seems to wander when coming off the bumps. When braking from speed the front of the car doesn't dip straight down it seems to go down and to the left, it's also very keen to follow the camber or any grooves in the road especially under braking.
I've already had my MGR dealer investigate the problem but all they could come up with was that they could feel what I was talking about but the problem wasn't excessive?!?!? They suggested having new front tyres, but I don't need them and fail to see how that could help solve such a fundamental problem!
My tracking, balancing & ride hight are all set to the recommended figures and I've got NC30's all the way around. Thought about getting wheels toe'd in but can't find anywhere willing to do it.
I'd be eternally grateful for any helpful suggestions, as I'm totally out of idea's and my interest in my F is fading fast!
Cheers, Mark - BRG, 1.8mpi, R120KDK.
|Sounds like tracking/ride height to me.|
I take it that the ride height is set to Rover specs, ie 368mm +/- 10mm measured from the centre of the front wheel to the underside of the wheel arch.
AFAIC this is on the high side aesthetically and is set at this level to prevent inner rim tyre wear rather than to make the car enjoyable to drive.
Assuming the ride is correct, preferably around the 358mm mark, the next most obvious cause is tracking. Standard MGR settings promote understeer and vagueness in the steering. By getting the front re-tracked to 0/5 toe in you will gain a lot of feedback from the steering wheel, the car will feel more responsive and this will i feel solve a lot of your concerns.
Is the car out of warrantee? If so than there is no reason an aftermarket tyre place shouldn't set the tracking up so. The basic idea is that the motion of the car pulls the front wheels into or close to parallel, giving full contact with the road and therefore more control over the car. MGR settings increase the toe out when in motion creating poorer contact with the road and therefore more understeer and less control over the car. To quote Mr. Spock, 'Logical Captain'. You are after an independant place if possible, you don't want an ignorant grease monkey quoting official figures back at you, you want someone who is experienced and will listen to logic. So, large chains like Kwik Fit et al are unlikely to produce results. A small independant garage is probably your best bet.
Another avenue worth travelling is to fit rear compliance washers from B+G. Last time i checked they were only 10.00 and they stiffen up the rear suspension removing some of the play in the set up, thus increasing accuracy.
Lastly, your choice of tyre will also pay dividends, standard rubber (NCT30) are barely passable. Excellent results have been had by people on this board with Yokohama and more especially Bridgestone SO2 / SO3. The latter are 'recommended' generally by the majority of BBS users and will noticably increase grip levels.
|Methinks wear and tear to bits and pieces of the suspension - sorry I can't be more specific, but I'm sure someone with more idea will be able to say what parts may be suspect. Although your car's not that old it's ot unheard of for suspension components to deteriorate on the F prematurely, I'm pretty sure now this was the ongoing cause for uneven tyre wear on my previous VVC. This also at times had signs of sloppy handling compare with a newer and lower mileage F. Now fixed permanently for me buy replacing the car with a TF - no signs of ANY uneven wear - the only perisistent problem I had with the F.|
|There you go - Andy beat me to it! LOL.|
Basic point is, although the tracking readings etc. all fall within tolerances when set, they can of course change if there is any play in suspension components due to wear and tear. Hence you drive down the road or a couple hundred/thousand miles and bang you are out of spec again and handling and uneven tyre wear becomes a problem again. Personally I would also go with the suggestion of using Techspeed, Mike Satur or B&G to look at and sort the wear problems. Unfortunately, main dealers do seem a bit hit and miss when it comes to the F's suspension. :(
You say you only had the front right hydragas unit sink. This is a bit strange as the units on each side are interconnected so if there was a leak of fluid on one of the two hydragas units on one side then both ends of that site would sink. Did yoou see any traces of leakage? If not I suspect that the nitrogen sphere inside your front hydragas unit has broken. Do you know to what pressure you pumped up the car to get it back to normal height? I sugeest you take the car to a dealer (or someone with a hydragas pump with a pressusre gauge) and ask them to perform the test detailed in the manual to check your right front unit. Chances are you need a new one. This will also explain the car leaning to the left under braking. Try bouncing front of the car by yourself and check if both sides feel the same.
|Sounds like shocks are shot,say that quick? Could be play in ball joints,painful 8-( Mileage ?? Try alternative tracking/alignment settings, see archives, HTH|
|Cheers for the suggestions! I was also very confused by Spyros's point. How can just one hydrogas unit sink when the front & rear are connected? Stranger still, if the nitrogen sphere leaked how can they now be level again? Surely no matter how much HG fluid you pumped in it would never replace the missing nitrogen, meaning the difference between front and rear would be there until the knackered unit was replaced?|
Think I'll get MGR dealer to check the HG unit properly. If that's okay I'm gonna try changing the front suspension bushes and getting the tracking toe'd in (good excuse to have the lowering knuckles added aswell!)
|Has anybody tried changing the rear compliance washers themselves? Was wondering if you need any special tools to get the old ones out / fit the new ones? My Dad's a mechanic so he should be able to do it, right?|
This thread was discussed between 29/06/2002 and 30/06/2002
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