Funny vibration on ZX TD - got me baffled at present!

uhn113x · Unread post by **uhn113x** » 23 Nov 2006, 17:13

OK - here we go:

Between about 15 and 70mph, in any gear, if you really put your foot down, the gear lever starts to shake; do it a bit more, and the whole car shudders.

It pulls, starts and runs fine.
There is no mechanical noise.
The vibration is not rhythmic (so not like driveshafts).
It is possible to drive so it does not do it.
Started suddenly (during a downpour

) and has not gone any worse.
It is not like a misfire.
Pulls away smoothly (mountings OK?)

I have had a quick look around the driveshafts and engine mountings - seem all OK.

Someone did mention the rubber on the gearbox mount near the centre driveshaft bearing housing - do you think that is a possibility? It looks OK with a cursory inspection - too cold to get under now!

Anyone had this?

TIA

jeremy · Unread post by **jeremy** » 23 Nov 2006, 17:30

May be the lower mount - it can be examined by crouching down by the front of the drivers door and peering inderneath. The centre bit breaks away - and if it has you may be able to see excessive movement.

Another possibility is the gearbox mount - on the top of the gearbox - connecting to the battery support. Its a bit difficult to see but worth a look.

wrinklet1 · Unread post by **wrinklet1** » 23 Nov 2006, 17:57

Hi,
Have you had one of the front wheels off?
If you have, have you put it back on properly?
A friend f mine had the same problem on her Zx and it turned out that the wheel had been taken off and refitted incorrectly, there is a stud that goes into a hole to help mount/align the wheel. It hadnt been put on right and the stud wasnt in the hole, therefore, the wheel didnt go round correctly and caused a vibration.

Paul

citronut · Unread post by **citronut** » 23 Nov 2006, 18:03

or maybe a suspension arm bush,or warped brake disc/s
regards malcolm

Stewart(oily) · Unread post by **Stewart(oily)** » 23 Nov 2006, 18:20

X cured a Xantia of a very similar affliction after many tries by replacing the nearside driveshaft, I replaced the gearbox mount, offside shaft intermediate bearing, stripped the diff

there was not a lot wrong apparently with the shaft i replaced but that effected a cure.
Stewart

wrinklet1 · Unread post by **wrinklet1** » 23 Nov 2006, 18:28

Uhn113x
Maybe before going down the mountings and driveshaft way, just check up on my idea, the costs are zero!!!
I am not saying I am right but you never know!!!
Paul

uhn113x · Unread post by **uhn113x** » 24 Nov 2006, 08:04

Thanks folks

Paul
Wheels have not been off for ages, and it only does it under load; is no different at any speed either. It also started doing it suddenly.

Malcolm
Would have thought that if the disc(s) were warped, it would affect braking and be the same with no load? Doesn't seem like a suspension thing, as the engine shakes before the car does! Would have been spotted at MOT as well.

Stewart (Hi!)
Maybe, but it is not rhythmic and is not affected when steering.

Jeremy
I think you are on the right track; my money is on the mounting(s). I might have a look this weekend, or live with it until weather is warmer.

Will let you all know what happens.

jeremy · Unread post by **jeremy** » 24 Nov 2006, 08:23

Its also worth checking the wheel bolts (easy - but I had one work loose on my BX and got it recovered as I thought the hub had broken up!)

I have also had 2 cambelt - side engine mounts fail - one when I bought the car and its replacement. This can be checked by inspection and by lifting the engine. There should be little triangular rubbers each side of the bracket with a little clearance. The (front?) one will be under load when accelerating.

uhn113x · Unread post by **uhn113x** » 24 Nov 2006, 08:50

Looked OK at a cursory glance, but I will have a closer look; especially as I did the cambelt last year and took the mounting off.

citronut · Unread post by **citronut** » 24 Nov 2006, 09:27

you should be able to see if any of the mounts are week or gone with the engine running,from under the bonnet blip the throtle and you should see if the engine moves to freely
regards malcolm

jgra1 · Unread post by **jgra1** » 24 Nov 2006, 12:12

Hi, i had this on a friends ZX

only when under load, esp in high gears, when the car would rather shake than accelerate..

It was the inner tri ax joint on one of the driveshafts, in this case Offside..
I tried everything to fix it, all eng. mountings, wheel balancing, new tyres, suspension bushes..

trust me, break the (larger) Gaiter sealing rings, pull gaiter back, and look at, check, both tri-ax joints .. if either are gone, there will be some loose needles lounging about

Dont bother with the CV joints at this stage..

what is happening is the torque on the driveshaft is causing the wobble, which then shakes anything connected to it, i.e. hubs engine/gearbox (and lever)

John g

zxb29 · Unread post by **zxb29** » 24 Nov 2006, 13:08

yeah as above sounds like the lower mounting on the driver side where the driveshaft goes though, its bolted to the back of the engine at the bottom.

i had the same problem when i had my td mileage was about 145k i was quoted about 70 quid for that part as the rubber mounting thats inside it has to be compressed in.

citronut · Unread post by **citronut** » 24 Nov 2006, 13:34

zxb29 wrote:yeah as above sounds like the lower mounting on the driver side where the driveshaft goes though, its bolted to the back of the engine at the bottom.

i had the same problem when i had my td mileage was about 145k i was quoted about 70 quid for that part as the rubber mounting thats inside it has to be compressed in.

that price would have been for the hole mountting,GSF do just the bush for aprox 6 squid
regards malcolm

Unread post by **Peter.N.** » 24 Nov 2006, 14:05

Without actually driving it, I would go with driveshafts or the o/s driveshaft centre bearing. I had a similar vibration on my CX estate but only when warm and the hotter it got the worse it got and that turned out to be the inner drive shaft joints.

uhn113x · Unread post by **uhn113x** » 24 Nov 2006, 20:15

jgra1 wrote:Hi, i had this on a friends ZX

only when under load, esp in high gears, when the car would rather shake than accelerate..

It was the inner tri ax joint on one of the driveshafts, in this case Offside..
I tried everything to fix it, all eng. mountings, wheel balancing, new tyres, suspension bushes..

trust me, break the (larger) Gaiter sealing rings, pull gaiter back, and look at, check, both tri-ax joints .. if either are gone, there will be some loose needles lounging about

Dont bother with the CV joints at this stage..

what is happening is the torque on the driveshaft is causing the wobble, which then shakes anything connected to it, i.e. hubs engine/gearbox (and lever)

John g

Gulp!