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MG MGF Technical - 'Cracking' sound from front suspension?
|From the front nearside wheel/suspension area, when driving over a speed hump or dropping into a small dip or rise I get a definite "cracking" sound, it doesn't seem to affect steering or anything else, its just concerning.|
Iv'e had the car jacked up and there is no wheel movement (fore and aft) and everything "appears" clean and tidy.
Any suggestions would be welcome.
|Hydragas or coil spring suspension?|
|2001 MGF 1.8i - Double wishbone,inter-connected Hydragas units, shock absorbers and anti-roll bars.|
(quote from spec)
|Be happy, will never be the coil spring then :)|
May be dampers upper fixture need to get tightened.
Other well known are:
- bonnet hinge
- lower ball joint or track rod ends (you would have felt this while your wheel check)
At last I'd look for brocken weld dots at the sheetmetal below the driver side wiper arm.
|I had this then on the front right anti-roll bar where it connects to the wheel hub gave way! Only a few quid for the new part.|
|Hope you find the cause of the cracking noise John and|
can let the rest of us know the outcome because I have had the same noise for three years on my 96'F' and it defies me and the garages. My car has passed three MOTs
with this and numerous rides on a two poster ramp and
still it evades us. Good luck and please post outcome or I fear my car will take its secret to the grave !!!
|iain mitchell 1|
|>on my 96'F' |
>I fear my car will take its secret to the grave !!!
Please excuse my ignorance. Are you new to this Board ?
If so, please check the archives for *crossmember bar*, or have a look here
(This is for old MGF only. Latest haen't got this problems)
The bid U-Shape clamp was a good solution for several owners.
Then think about whether you are very sure that the noise comes from the suspension. The body transports noise often in a confusing way.
|Thanks chaps for the various suggestions - this is a mystery and I'm still pretty sure its somewhere on the nearside suspension.|
Iv'e noticed that where the rubber bump stop is , at some time it must have had full travel as the top of the metal (below it) has a dark rubber "impression".
Can't think this would produce the "clunk" I get but out of interest I will put a piece of Bluetack there and see if it gets "squashed" (the weakest link?!!)
Will keep you posted.
this mark on the upper suspension arm is normal.
No worries about it.
.. as long as there's not another smaller about 1" behind it from metal_2_metal impact.
This would mean that your ride height is to low and the displacer bracket hits the upper arm.
|Thanks Dieter - your picture is exactly how mine looks.|
At least that's not the problem !
|>> From the front nearside wheel/suspension area, when driving over a speed hump or dropping into a small dip or rise I get a definite "cracking" sound, it doesn't seem to affect steering or anything else, its just concerning. <<|
This sounds similar to the noise I was getting from the front of my '96 MGF. Couldn't track it down either - I don't recall it coming from one side or the other though - but definitely from the front, and worse when encountering a broken road surface. Not noticed it since I had the subframe mounts replaced with solid TF items though - which is interesting - perhaps pointing to the source of the problem???
|Hope my "problem" doesn't have to go as far as that Rob.|
Taking it into a Garage next week to get the car up in the air to have closer look - do you know if any garage would have "elliptical" rollers on a rolling road to enable problems like this to be more easily simulated or am I expecting too much?
|I think it would be rather unlikely that any garage would have equipment like what you describe John. :o(|
I had my subframe bushes replaced for altogether different reasons (better steering/ better geometry control), but the loss of the annoying 'clunk' was a very postive side effect!
As our Technical rep, you more than anyone should know how to eliminate such noises!.
Turn your Stereo up!!!!!!!!! :o)
|I have had this noise on my 1997 MPi and recently it got much worse after I fitted polyurethane bushes to the shock absorbers. |
I noticed at the time I fitted them that the stainless steel liners in the lower eye bushes were a looser fit on the mounting bolts than the originals.
If the clamping force applied to the ends of the liners by the mounting bolts is insufficient, the liners can move on the mounting bolts under extreme loading crating the metallic cracking noise.
I have re-tightened the mounting bolts and significantly reduced the noise but not entirely eliminated it.
Anybody know the correct torque setting for these bolts??
|Andy, the lower shock mounting nut should be 45Nm. |
John, have you tried putting the car on axle stands and then jacking up the hub assembly? If the noise is related to suspension travel, this might provide clues.
My '96 car has a similar noise over moderate undulations, which I'm now reasonably sure emanates from the crossmember - having stripped & rebuilt the entire suspension front & rear with Powerflex bushes & new shocks the noise is still very much there.
I did raise the car up last night and then put my hydraulic jack under the wheel hub, raised the suspension further with this and then released it quickly but - not a sound !
By accident I happened to "bump" the inner black wheelarch lining and noticed it sounded similar, I then purposely pushed to flex it and it sounded again like it (aka Rolf Harris's widgery board !)- I wonder if the front of the car can twist just that bit enough to give the "crack" sound ? anyway, I'm just about to have a look at the other side to see if its the same.
Results to follow !
|For those following this "cracking" thread this is the latest.|
The car went to the garage and a good hour was spent with it in the air but nothing obvious was spotted - except - it was noticed that the ball joint (see Deiters web picture from thread above)seemed to be sitting slightly higher on one side than the other, and on the problem side (nearside) with a screwdriver you could just "lift" the ball slightly from the socket (Deiters picture beneath the orange "washer"). Deiters picture shows grease around the ball joint and also slightly raised as mine, but mine was as clean as could be so a liberal amount of grease was applied to the nipple above it. - Question - does grease get to the lower part of the ball joint from a track via the nipple above ? or is it a greased for life part by MGR ? if yes did they forget it !?
If mine was dry could this have caused the clunk ?
On the run out of the garage the "clunk" seemed to have lessened but occasionally it was heard but not quite so bad.
I was told that the ball joint movement was safe, thus hopefully not needing replacement.
The opportunity was taken to remove brake pads and check this area and all was OK.
Over to you oh wise ones.
the grease at the shown ball joint and the height relates to a _broken_ knuckle joint.
Yours will/should look like this:
This is the usual suspension knuckle mounted from the factory.
(There is another short one availiable from aftermarket suppiers to get the suspension lower)
I think the mm difference you saw was the upper rubber gaitors hose-part. App 25mm diameter and just slipped over the aluminum piston)
This knuckle gets no grease from the grease nipple. And if it looks like the link in this post, then it is OK.
In comparison with the far above linked picture you can see that the lower rubber part came off upwards from the suspension arm.
This is a picture of the dismantled knuckle
Anyway, this one usually never makes suspension noises cause its under high pressure from the hydragas diplacer connected to th upper part. App 8-10kN "spring"-force press it on the upper arm.
The only case of noise coming from there is, if the upper shaft of dk_DCP_5376.jpg sticks in the aluminum cylinder due to a forgotten washer between rod and aluminum part.
Unusual, if the knuckles never got removed at any service.
OK, back to the mentioned other noise sources.
You and your workshop obviously tried to everything with moving parts and had a look to the weel house cover.
- how sure are you that it cannot be any static body part and suspect weld spot ?
I mentioned already. Just crack noises may appear anywhere and steel leads the noise to anywhere else.
I have some crazy instructions, if you say *not sure*
Need to look up for images from what my friendly dealer did to my car 5 years ago.
Will be back when I found them, or took new from this still visible subject at my MGF.
Btw. if you start exploring my silly webside you may get on this site.
Please notice, that was with early MGF only. Should not be valid for a MY2001 MGF. The noise produced from this trouble appeared as suspension related from direction right or left wing, but finally it wasn't.
There was another owner at this board who had a creak just behind the steering wheel fixture. This noise was different and easier to locate.
|Deiter - thanks for taking the time and trouble with such a lengthy reply.|
I'm pretty confident that the ball joint is not broken and it does look pretty much like your illustration, I have a picture I could e mail you if this would help (don't know how to post it here)
Suprisingly, having injected a copius amount of grease into the nipple and putting Duck oil around the ball joint the "cracking" sound doesn't seem so loud although it is still there when the nearside wheel goes over a bump, dip, or kerb. I'm still sure its from that area and not travelling from somewhere else
A favourite expression when I had my TVR S2 was - " they all do that sir" - perhaps this could be passed onto the F - !!
Thanks once again - I will keep looking out for the source of the "annoyance"
send the picture to
Three pictures are on there way.
didn't arrive. May be to large for that email account.
Please try alternative:
(good for huge file attachments)
Just e mailed to the alternative address, hope you receive them OK.
(our time 6.10pm)
Thank you. The images are at
Can't see anything bad.
However, my above long post reffers to the inner knuckle joints.
Your pictures from nearside suspension show the big upper ball joint at the hub. I think I was on the wrong subject ?
Anyway, upper all joints at the hub of course can fail also.
I know from BBS messages that it's quite difficult to find out.
A final analysis could be made _there_ only with de-pressurised hydagas system.
Anyone with more ideas ?
|Dieter - thanks for your comments.|
I expect this particular "noise" may remain a mystery for some time.
Having mentioned earlier about greasing the upper swing joint (via the nipple) and putting oil around the ball joint (around the orange coloured ring on the lower picture)the "cracking" sound does seem to have reduced although it hasn't gone away completely so perhaps I'm heading in the right area !?
It was this joint that I was asking if there was an oil track from the swing joint above.
This thread was discussed between 14/05/2005 and 26/05/2005
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