Hello all. Glad to see the forum has survived the GSF departure - definitely a cash saving bonus for us all. This place has saved me a few quid over the last few years.
Anyway, onto the problem.
I have a 1995 Pug 405 1.9 td with 196,000 miles on the clock.
About a month ago completely out of the blue it developed a nasty vibration (not there when I got home from work Friday night, but there Monday morning).
I have four brand new tyres on (all changed since the vibration started), and tracking has been checked and rechecked. I can safely eliminate tyres/road wheels as the cause.
There is no play in the wheel bearings whatsover, and they're all free of any signs of roughness.
The vibration only surfaces when under power. There is no vibration when the engine is not generating any "pull" at the road wheels. It appears when at high speed, especially riding over those gentle undulations found on British A roads (seemingly when the car "lands"). But it is most noticeable when applying power on a roundabout - it feels as if I'm wobbling the steering wheel back and forth - except there is no feedback through the steering wheel - it's the car that oscillates. On coarse worn out roads it is almost absent, but on newly surfaced, bowling green-style tarmac, it's considerably worse. It's a lot worse with a front seat passenger - adding a drivers side rear seat passenger makes little or no difference (possibly counter-acting the front seat passenger).
The frequency of the vibration is directly proportional to the road speed - it's a slower oscillation on roundabouts, but more pronounced (like a bigger wobble), but at high speed it's a lot like a wheel out of balance.
To me as driver the vibration appears to be in the seat and floor (nothing in the steering wheel at all). A front seat passenger suggests it's in front of the passenger seat footwell.
I replaced all the front suspension bushes and wishbones a couple of months ago for the MoT, and just last week changed the track rod ends.
So, the $64,000,000 question is this - what's the most likely cause?
I reckon I've narrowed it down to three possibilities;
(i)A trailing arm bush (but unlikely due to the speed related nature of the vibration).
(ii)A driveshaft out of balance - possible after changing the wishbones and suspension bushes (possibly showing up any slop elsewhere in the system, or even a slight change in geometry).
(iii)The last idea is the lower engine mount - the possibility that the engine is wiggling in its mountings - this makes sense as the problem is only there under power.
Can anybody suggest which of these I should try to fix first?
Or is there something else it could be???
405 Vibration...
Moderator: RichardW
While I can'tanswer your question Stevie,it sounds not too dissimilar to this:
http://www.frenchcarforum.co.uk/forum/v ... hp?t=16276
Which is happening on my car.
Ken.
http://www.frenchcarforum.co.uk/forum/v ... hp?t=16276
Which is happening on my car.
Ken.
Cheers Quinny - yes sounds very similar. I had all four wheels rebalanced before I had the new tyres, and it didn't change at all with the new tyres fitted (and balanced again), so I kinda know it isn't a tyre problem. The garage I use is very good too, and they know me, so I doubt any kind of issue in that respect.Quinny wrote:While I can'tanswer your question Stevie,it sounds not too dissimilar to this:
http://www.frenchcarforum.co.uk/forum/v ... hp?t=16276
Which is happening on my car.
Ken.
The problem with vibrations is detecting exactly where they're coming from. The only constant I have is that passengers all feel the vibration beneath their feet.
I'd make the order of preference, firstly check the engine mounts (upper and lower) which may be causing the vibration to be exagerrated via the exhaust system touching under certain circumstances; I found this recently on a BX where the bottom bolt had dropped out and besides thumps that sounded like the transmission coming through the floor, it also gave some fairly harsh vibrations particularly around corners. A new clutch was about to be ordered too. 
Second port of call if they prove to be OK would be a drive shaft as I have seen CV joints to also cause this. I had one on my 16V that was emitting a strange noise when I first bought it which turned out to be the drive shaft that hadn't been pushed fully over the locking spring clip when someone had obviously fitted a new boot. I had driven the car approx 1500 klms in one go with no noises but it popped up next day when I took off at an intersection where I had to turn sharply and this apparently caused enough stress to pull the ill fitted retainer out of position.
Alan S
Second port of call if they prove to be OK would be a drive shaft as I have seen CV joints to also cause this. I had one on my 16V that was emitting a strange noise when I first bought it which turned out to be the drive shaft that hadn't been pushed fully over the locking spring clip when someone had obviously fitted a new boot. I had driven the car approx 1500 klms in one go with no noises but it popped up next day when I took off at an intersection where I had to turn sharply and this apparently caused enough stress to pull the ill fitted retainer out of position.
Alan S
RIP Sept 19th 2008.
She said "Put the cat out" She didn't mention it was on fire!!
She said "Put the cat out" She didn't mention it was on fire!!
Cheers Alan.
Luckily I already have a lower engine mount. I bought one shortly after I bought the car (6 years ago) but never quite got around to fitting it. I might as well give that a go. I had planned to do it this weekend anyway, but a busy driveway and the call to beer put the mockers on that.
One other suggestion that had been made to me was that the bearing on the intermediate driveshaft (the one in the bottom engine mount) may have worn, but this is another bearing that feels nice and secure when I swing about on it beneath the car
I regreased the inner CV joints when I replaced the front arms (the fight to release the balljoints successfully popped the rubber boots off anyway, so I was already halfway there). This adds to your second suggestion about the boots. Maybe I didn't re-secure them properly and one has moved - they look okay, but maybe I should take a closer look - while I'm changing the lower mount. The offside one did seem to ooze a lot of grease back out very quickly, even though I know I hadn't overpacked the joint.
Has anybody known the spring in the CV joint to break? Would it cause the driveshaft to move excessively if it did?
Luckily I already have a lower engine mount. I bought one shortly after I bought the car (6 years ago) but never quite got around to fitting it. I might as well give that a go. I had planned to do it this weekend anyway, but a busy driveway and the call to beer put the mockers on that.
One other suggestion that had been made to me was that the bearing on the intermediate driveshaft (the one in the bottom engine mount) may have worn, but this is another bearing that feels nice and secure when I swing about on it beneath the car
I regreased the inner CV joints when I replaced the front arms (the fight to release the balljoints successfully popped the rubber boots off anyway, so I was already halfway there). This adds to your second suggestion about the boots. Maybe I didn't re-secure them properly and one has moved - they look okay, but maybe I should take a closer look - while I'm changing the lower mount. The offside one did seem to ooze a lot of grease back out very quickly, even though I know I hadn't overpacked the joint.
Has anybody known the spring in the CV joint to break? Would it cause the driveshaft to move excessively if it did?
Yeah, that's the one I meant Alan. Having seen these when regreasing teh CV joints, I wondered how strong they might be, and how much of an impact a broken one would have.alan s wrote:I've seen it left out without causing any real big issues, that's the spring that holds the end tension I presume you're talking about.
Alan S
As it is, I've confirmed both are still intact, by putting the steering on full lock each way, and pushing and pulling at the driveshafts. Only about 0.5 mm movement, but you can feel the springs pulling the shaft back into place.
I've also had a member of the family watch the lower engine mount, whilst I gently engage the clutch in first gear (and footbrake firmly applied!).
It seems as though the mount is moving around 10-20mm backwards into the fork that steadies it. Seems to me like the rubber is shot. Cheers for pointing me in the right direction Alan. I had the head gasket oil leak a coupe of years ago which soaked everything in that area on a daily basis, so I imagine that's finally taken its toll.
What's the job of swapping the lower mount like? It looks reasonably easy to swap out the whole unit, but how easy is the disc-only swap? I imagine the old one is a real b*tch to extract from its housing. It's going to be a Saturday morning job, and with the British weather performing its usual pre-winter test of everything it's got, I don't want to be under the car for too long.
I have never changed a disc in one but from what I hear, don't try to use Marquis of Queensbury rules when doing it unless you own an hydraulic press and the right sizes drift.
Remove from car, hold solid (preferrably in a vice, and carefully cut the steel surround that is the outer edge of the disc. Tap out using a flat ended punch. Clean out the hole it came out of, and apply a thin smear of grease on the outer area of the new discs outer surround as well as the inner mating edge of the alloy mount and press together in the vice.
If you want to make it a bit easier, don't grease the alloy part, but warm it to a temperature just above what you are capable of holding in your bare hand and using a pair of leather gloves to take it to the vice(or may even work this way on a piece of wood on the floor,) press the disc into it. The warming will cause it to expand but the secret is, don't heat it too much or it can damage the rubber in the new disc. (Common sense required)
Either a blow torch or if you have a wife or mother with a good sense of humour, the oven, (preferrably not whilst she's baking a sponge cake)
Alan S
Remove from car, hold solid (preferrably in a vice, and carefully cut the steel surround that is the outer edge of the disc. Tap out using a flat ended punch. Clean out the hole it came out of, and apply a thin smear of grease on the outer area of the new discs outer surround as well as the inner mating edge of the alloy mount and press together in the vice.
If you want to make it a bit easier, don't grease the alloy part, but warm it to a temperature just above what you are capable of holding in your bare hand and using a pair of leather gloves to take it to the vice(or may even work this way on a piece of wood on the floor,) press the disc into it. The warming will cause it to expand but the secret is, don't heat it too much or it can damage the rubber in the new disc. (Common sense required)
Either a blow torch or if you have a wife or mother with a good sense of humour, the oven, (preferrably not whilst she's baking a sponge cake)
Alan S
RIP Sept 19th 2008.
She said "Put the cat out" She didn't mention it was on fire!!
She said "Put the cat out" She didn't mention it was on fire!!
Cheers Alan (again ).
If I need to remove the whole mount to extract the disc, I might as well change the whole mount. Seeing as I've got one kicking about here.
Thought it was worth asking, as there might have been a knack to getting the old one out "in-car".
I'll report back when the new mount is installed. More blood and gearbox oil spilled methinks.
).If I need to remove the whole mount to extract the disc, I might as well change the whole mount. Seeing as I've got one kicking about here.
Thought it was worth asking, as there might have been a knack to getting the old one out "in-car".
I'll report back when the new mount is installed. More blood and gearbox oil spilled methinks.
Well, the mount is changed. What a nightmare that turned into... 
The old one doesn't actually look too bad, just a little frayed around the edges. It does seem as though the rubber is a lot softer though, so maybe that's the sign that it's on its way out.
I had intended to give the car a trial run before work tomorrow, but the battery has gone flat on me. Enough to keep the radio playing all day, but when I come to start up, not enough oomph to turn the engine over. So that's on charge now. I'll get a new one tomorrow. I just hope it'll start in the morning.
I'll report back as soon as I know whether the new mount has done the job.
The old one doesn't actually look too bad, just a little frayed around the edges. It does seem as though the rubber is a lot softer though, so maybe that's the sign that it's on its way out.
I had intended to give the car a trial run before work tomorrow, but the battery has gone flat on me. Enough to keep the radio playing all day, but when I come to start up, not enough oomph to turn the engine over. So that's on charge now. I'll get a new one tomorrow. I just hope it'll start in the morning.
I'll report back as soon as I know whether the new mount has done the job.
I'll let you know mate. Need to swap cars around on teh drive in a bit, so I'll post back here after I've been for a blast.Quinny wrote:Hopefully,if that's sorted your problem Steve,it may be the same one I have on my 99 406.
Ken.
Battery is now charged and running. Looks like that's getting tired just in time for the cold weather, so I'd better pick up a new one tomorrow.
One thing I noticed about the mount is that the smaller vertical rubber bush mounted into the fork (I saw it called something like the "torque bush" on a 406 the other day), is in almost perfect condition. I suppose it's protected, being tucked away an' all, but after ten years and 197,000 miles I would've expected it to be in a worse state.
Another thing I noted whilst playing earlier - with the car on axle stands, front road wheels removed, right hand ball joint split from wishbone, engine running and first gear engaged, if I pushed the hub towards the engine (compressing the CV joint), I felt something resembling the feeling through the car that started all this off. Presumably it's the rings in the CV joint touching the deepest face of the cup, three times per revolution. It would certainly explain the sensation I had been feeling.
If it turns out not to be the engine mount, then I'm going to suspect the new wishbones I mounted a few months ago. Maybe the balljoint hole is just a few mm short of where it's meant to be, and with some sideways swing of the engine, is allowing the CV joint to close up too much.
I've only done a few miles today, but the problem appears to be sorted. Cheers Alan.
I might find it's only massively reduced when I do more miles tomorrow, but at least I can eliminate one more possible cause.
Whether it's fixed it or not, I think it's time I changed my car. It seems lady fate has decided this car must die soon, so I need a replacement.
V6 406 anybody? Are they worth the lower mpg? More fun? More comfortable?
I might find it's only massively reduced when I do more miles tomorrow, but at least I can eliminate one more possible cause.
Whether it's fixed it or not, I think it's time I changed my car. It seems lady fate has decided this car must die soon, so I need a replacement.
V6 406 anybody? Are they worth the lower mpg? More fun? More comfortable?
Well, I've given the car a good few miles today. The vibration is still there, just 
.
If anything it's now very subtle, and more pronounced as a problem at the rear. But still only there when under power.
I think I'll have to live with it until I get a replacement car. The weather is now unbelievably nasty here, and I don't think I can be bothered with any more frozen fingers to repair a car that is rapidly turning into a money pit.
.If anything it's now very subtle, and more pronounced as a problem at the rear. But still only there when under power.
I think I'll have to live with it until I get a replacement car. The weather is now unbelievably nasty here, and I don't think I can be bothered with any more frozen fingers to repair a car that is rapidly turning into a money pit.
Right then gents, the vibration is back.
Exactly as it was before.
Initially it only seemed to be the high speed vibration, with nothing on roundabouts, but soon enough the roundabout problem surfaced too.
Two things to note, that may cast some light on things -
Firstly, This morning I was negotiating a large roundabout, and pushing the car to bring on the vibration (still trying to ascertain it's location). I changed from 3rd to 4th gear, and as soon as I engaged the clutch and accelerated, the top of the gear lever jolted about an inch backwards - no noise, just a violent jolt.
Secondly, this afternoon, whilst in a local council car park, I had to negotiate three large speed bumps (those metre-long flat-topped ones). After the last one I found I couldn't change gear. Almost as if the whole gate had shifted. As soon as the car had composed itself (revs dropped etc, all four wheels level etc)) everything returned to normal. Immediately after this happened I circled a small roundabout and the "wobble" I mentioned in my first post returned stronger than ever. The whole car shook quite violently.
My question is - could it be the gearbox mount that's causing this? I had a feel of it some months ago when the engine started to kick a little more than usual under acceleration, but as you can't see it without removing the battery, I was going on feel alone.
It would make sense that it's a mount that's causing it, as on cold mornings the problem is almost gone. It's only as the day/engine bay warms up that it gets to be a problem.
Any more ideas out there? We have a promise of relatively pleasant weather here tomorrow, so I ought to make the most of it.
Exactly as it was before.
Initially it only seemed to be the high speed vibration, with nothing on roundabouts, but soon enough the roundabout problem surfaced too.
Two things to note, that may cast some light on things -
Firstly, This morning I was negotiating a large roundabout, and pushing the car to bring on the vibration (still trying to ascertain it's location). I changed from 3rd to 4th gear, and as soon as I engaged the clutch and accelerated, the top of the gear lever jolted about an inch backwards - no noise, just a violent jolt.
Secondly, this afternoon, whilst in a local council car park, I had to negotiate three large speed bumps (those metre-long flat-topped ones). After the last one I found I couldn't change gear. Almost as if the whole gate had shifted. As soon as the car had composed itself (revs dropped etc, all four wheels level etc)) everything returned to normal. Immediately after this happened I circled a small roundabout and the "wobble" I mentioned in my first post returned stronger than ever. The whole car shook quite violently.
My question is - could it be the gearbox mount that's causing this? I had a feel of it some months ago when the engine started to kick a little more than usual under acceleration, but as you can't see it without removing the battery, I was going on feel alone.
It would make sense that it's a mount that's causing it, as on cold mornings the problem is almost gone. It's only as the day/engine bay warms up that it gets to be a problem.
Any more ideas out there? We have a promise of relatively pleasant weather here tomorrow, so I ought to make the most of it.