Rumbling Citroen AX - Richard Hall
Car - Citroen AX10 Debut, 1995, 95,000 miles. (Yes, that one - I found a straight bonnet and scuttle panel the right colour for £45).

Fault - a regular knocking/rumbling, which sounds as though it is happening once per wheel revolution. Only happens when accelerating out of a corner, easier to provoke on left than right hand bends. Even turning the steering wheel 20 degrees left and accelerating will result in this rumbling sound. Never happens on a trailing throttle or freewheeling through a bend, no matter how tight. Never happens in a straight line either.

My first thought was a failed CV joint. The right hand joint had suffered a split boot (twice) so I reckoned it might have got some grit in it, although it felt fine. I fitted a GKN reconditioned driveshaft - no difference. The driveshaft the other side feels OK with no excess play or rough spots. I have jacked up each corner of the car and checked each wheel bearing - all perfectly smooth with no play.

I have had the car up on ramps and checked that the exhaust is not vibrating against the bodywork or rear axle.

So my thoughts now are:

1. Left hand driveshaft - may be faulty even though it appears OK.

2. Right hand driveshaft - replacement might have the same fault as the original (unlikely)

3. Differential - excess play in bearings allowing the diff assembly to move sideways in the casing under load so that the crownwheel bolts foul the casing - but in this case, wouldn't it happen in a straight line as well? The transmission has a fair amount of play in it - there's a noticeable 'clonk' when letting the clutch out, as the free play is taken up - but it has been like that since new. (I tried to get a new gearbox under warranty, but the dealer's demonstrator had an even worse gearbox than mine, so I accepted his explanation that 'they're all like that, Sir'.)

This one really has me baffled. Anyone come across the same problem on AXs before? I don't want to start changing major components at random, but I'm running out of other ideas...

Richard Hall
Rumbling Citroen AX - Mondaywoe
Not something simple like a worn brake pad / warped disc? Could still be a bearing - sometimes they don't show up unless the weight of the car is on them - cornering eg. When the seal goes, water gets in and knackers the bearing very quickly.

Plenty oil in the gearbox?

Alternator bearings? Water pump? Iffy pulley?

Just thoughts....!

Rumbling Citroen AX - Amin_{p}
with 90% certainty its the driveshaft. I have an AX, 1.4 TGD J reg with 140k. the exact sound you describe appeared in my car after I replaced the right hand shaft due to a failed tripod joint. This is unlikely to be a diff porblem, and i doubt its also a gearbox problem. The gearbox on mine is also loose and the slack is there unless you change gear very slowly and let the freeplay be taken before the clutch is up completely. I wouldn\'t spend too much time messing with bearings because mine are gone, however this noise was not present until i changed the shaft. my shaft was also reconditioned, however i lost my faith in them after they bought back my old shaft from me for £5. i think they just open them, stuff them with oil and pass them on. I know for a fact that the old driveshaft in my car had `wrapped\' due to a hit, because once i replaced that, a very annoying vibration also disappeared, however you have to ask yourself if they are going to `straighten\' the shaft out, which i doubt very much, or just recondition it and sell it knowing (or may be not, because i didn\'t tell them) that the shaft is not straight. Freeplay on joints is not the only important thing on shafts. Also jacking the car up, will not generaly regenerate the noise because the engine and the system is not under load. The best test is still to go around in full lock on first gear and easily accelerate (without shooting off the road). anyway hope this helps. If you manage to fix it, keep me posted because i would like to know what is exactly the problem.
Rumbling Citroen AX - Richard Hall
Thanks Amin for that. I took a friend out with me to see if he could pinpoint the source of the noise. He reckoned it was coming from the front nearside, so I've got another driveshaft on order - I'll let you know if that fixes it.

I think you're probably being a bit harsh about recon driveshafts - GKN is a very reputable supplier, and I would expect them to check the shaft for straightness and fit new CV joints (which GKN manufacture themselves I think).

Richard Hall
Rumbling Citroen AX - Richard Hall
Amin, I owe you a beer. Driveshaft changed, noise gone. Shame that it blew a hole in the top radiator hose on the test run. First thing I knew about it was when the temperature warning light came on (no gauge on the poverty-spec models). I now wait with fear and trepidation to see whether I have cooked the head gasket....

Richard Hall

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