Shudder (at speed)

[Pyoor_Kate]

Hey folks, it occurs to me that someone may have a suggestion on what's at fault with Rebecca; she's had this problem for about the last 6 months.

Prior to this, in say a situation where it was entirely legal, I'd be happy to do 80+ in Rebecca when required, but now that's just plain not safe, and holding 70 is uncomfortable...

Rebecca had 155R14's on the front and 145R14's on the rear (which I know is 'backwards'). Anyway, I hit a pothole, in the dark, at about 50mph, after which the suspension / tracking / toe-in / ride-height / something at the front wasn't right. She started to scrub the front passenger side tyre very badly, and pulled to the left.

Took her down to the Mog Centre and they said "the torsion bar had jumped one spline, so the ride height was wrong; and the toe-in was wrong" this was corrected, the front and rear wheels swapped over and off I went.

A few days later I discovered that at 65+ I got this god-awful shudder through the steering, like the wheels were out of balance. Started gradual, got worse and worse if I held the speed. Got the front tyres balanced, nothing doing, got the rear tyres balanced, no improvement, took it to the Mog Centre and said "'ere, there's sommat wrong"

They rebalanced the front tyres, rechecked the front suspension, checked the tracking and all that and changed the prop-shaft.

The shudder got less bad, was still quite noticable.

So I went back and said "'ere, it's *still* doing it". They changed the prop-shaft *again*. This time the shudder sort of got much less noticable. Then they suggested that other causes would be "Gearbox or Diff" and there was no *way* I could afford to change them then (or indeed now) so.....

....but anyway, the problem's still here 6 months later, and I'm wondering if there's anything else people can suggest - or if there's anything they can suggest toward checking what's knackered - 'cos it's a bit wearing this shudder, and I can't really even hold 70 for any period at the moment.

[rayofleamington]

Did they replace the torsion bar and suspension arm? There is no way it could jump a spline if it was in a safe condition.
If you had a propshaft vibration then maybe the big bang helped knock off the balance weight or something worse.
If the propshaft is unbalanced you will get severe wear on the plain bush in the end of the gearbox. Changing the propshaft for one that is better balanced might make it seem better but won't fix it as the clearance in the bush will allow runout.

However these things can be a complete red herring and it may be a dented rim, or a miss shaped tyre etc.. etc..

[Pyoor_Kate]

The following parts were replaced....I can only decode the first one, whoever did the invoice didn't bother to put what the items were, and bizzarely the one item I can decode of the two was not, as I recall, mentioned to me. But I have a poor memory, so it may well have been mentioned and I forgot it. Anyway, if anyone's got a newer version of the Charlie Ware book o'bits (mine's what, 11 years old) they might know what the second one is (or maybe I'm just being blind):

SUS136 - Lever, steering, L/H.
FTS102 - Not in my book, as far as I can see.

Otherwise the only thing that was changed was the actual prop-shaft...

Both those items were changed *before* I complained of the judder.
The judder then appeared (I don't think it was present even when the suspension was horribly out and the car was pulling to the left).
The prop-shaft was then changed, twice....

[Kevin]

I had a friend who car developed a shudder starting at lower speeds than yours and that turned out to be caused by an overtightened gearbox steady cable, it could also be worth checking the engine steady rubbers, I know neither of these are directly connected with the start of your problem but the can give some strange symptons and are easy to check, the gearbox steady cable should just be done up so there is no slack and not bow tight as in my friends case.

[newagetraveller]

I typed FTS102 into Google and it came up with a parcel shelf.
Can this be right????????

[Kevin]

Well I must admit I have not come across a parcel shelf causing the sort of vibration Kate is suffering from, maybe Charles Ware knows something we dont.......

[brixtonmorris]

cant jump a spline. i think thats rubbish.
how about a realy badly worn trackrod end or sterring rack?
a buldge in the tyre as ray mentions espically after the bump.
but they should have noted it when the wheels were balanced

[rayofleamington]

but they should have noted it when the wheels were balanced

Yes they should! A lumpy tyre is very dangerous (internal damaged may lead to a complete tyre failure at speed etc.. )
However I've seen people balance wheels and not take any interest to the dodgy shaped tyre so I check them manually every now and then. I've had at least 3 lumpy tyres so far and been in someone elses old Merc where his tyre started to give way.
The Merc had vibes at 80mph , but then they got much worse and he had to drive at 50 - we stopped to look and one tyre had developed an nasty 'growth' that would have blown out big time before the end of the journey.

[winger300]

mine has a little bit of judder at 70mph. It doesn't feel unsafe, but 65-67mph is much smoother. I did find however that using Super unleaded plus octane boost sorted it out, perhaps as the engine had more power at lower revs and changes the resonant frequencies between suspension/engine vibrations.

[Willie]

I once had a very bad vibration ( on a MINI) which only became
apparent on the M1 after about five miles of fast running, it turned
out to be a bulge on the tyre which only appeared when the tyre
got hot enough to produce this 'bubble ' on the tread. So, the question
is, does your vibration appear as soon as you hit the high speed or
only after prolonged running at high speed. If the latter then it is
definitely tyre related. I agree with the previous replies, there is
no way that you could jump a spline on the torsion bar, if it was that
worn you would quickly be resting on the rubber bump stop as it
continued to 'slip '.

[Chris Morley]

I think the propshaft is a red herring. Immediately after hitting the pothole I assume you didn't have the severe vibration at speed - it only started after the front and rear tyres were swopped around by CW? In which case swap them back (and try using the spare) and see what happens.

[Peetee]

I had a car that had hit a pothole after which it pulled to the left until the tyre was replaced and the tracking was adjusted. After that the car ran straight but understeered badly on right hand bends. A secondary inspection showed that the whole upright had shifted back about 3". It was plain to see when comparing the position of each wheel in its wheel arch but was missed by the mechanic the first time.
Check this hasn't happened to yours.

Also try:

fitting the spare wheel (front and back) to see if the problem goes.


I'm tempted to think that the wheel and suspension components have recieved a huge aft load that has either bent the assembly backwards (either permenantly or momentarily) or damaged the eyebolt rubbers or eyebolt fixing in the chassis leg.

But then if changing the propshaft has reduced the problem it suggests that the rear is where the damage is. The propshaft may have been dampening out a vibration caused elswhere by a bent or ovalised componant. Maybe a driveshaft or UJ.

[Pyoor_Kate]

I'm fairly certain I didn't have the hideous vibration at speed problem prior to getting the tyres/scrubbing/ride-height fixed. It was a long time ago for me now (my memory is at best bad).... So mmmm, swap the wheels back. Yes. That sounds like a nice easy starting point.... I may do that tomorrow (presuming absence of rain). I checked the tyres over when I did the service, and when cold there's certainly no bulges. The rims also look okay (tatty, but okay

I'll also have a nose when I come off the motorway tomorrow. It certainly gets worse if you persist at 70. Or at least it gets a bit worse and then stays steadily worse.

I'm fairly certain the suspension components are all okay. I may get out there with a measuring tape however, but it doesn't *look* wrong, and it was checked a few weeks ago due to the whole did it again, scrubbing tyres, situation. Lots of bushes/etc have been replaced this time around as apparently she's now only "just" within tolerance at the front. Which leads me to suspect that maybe there was some damage there....? But was not something that they mentioned the first time around - so maybe that's damage from the second pot hole experience (perhaps I'm better off not living in the middle of nowhere!)

Anyway, I'll try and get a look at it tomorrow, or thursday, otherwise you can all come and stare at my car on Saturday

And it *is* a parcel shelf, I knew I bought one so I could make a complete hash of fitting it when I did it somewhat later ;-)

[Cam]

otherwise you can all come and stare at my car on Saturday

Any chance of a pic of your car so we can find it?? Or will we find you next to Nikki's car??

[Multiphonikks]

Hehe

We'll have to make some kind of plaque....

"Here be Rebecca and Hebe...."

Kate's will be the Trafalgar Blue '69 4 Door sitting next to the Rose Taupe '65 2 Door with questioinabaly painted wheels (I'm not the best when it comes to paint...)

Nikki

[Pyoor_Kate]

I would do a picture.... but I haven't finished setting up my machines as webservers, so I've not got any webspace atm.

[Pyoor_Kate]

Thanks to the enormous generosity of Nikki:

http://www.multiphonikks.com/car/mog2.jpg

Only, um, she's a bit tattier now (tattier?!) - what with y'know, there having been two years and somewhat more miles inbetween this photo and um, how she looks now.

So kind if, more of a streaky brown look to the grille, and my RAC and AA badges got put back on, I have actually polished the hubcaps since then, but they are somewhat less than, um, entirely shiny.

And since this photo was taken both rear wings have been hit.... so I've got some really nice scrapes on them.

[rayofleamington]

I see it's one of those grilles that was spray paintd on the car.. ;-)
Have 2 years changed it a lot? Riley has been ok, but mainly due to a decent car shampoo with wax in it and also because it gets left on the drive most days..

crumbs - I've just realised Riley has done less than a mile (from the back road to the front road) in the last 7 weeks! I think I ought to blow away some of the cobwebs before the weekend. Too many cars so little time.

I need some sympathy today - I just lost in court over an accident in 2002. Apparently if the other guy comes on to your side of the road round a parked car and causes an accident, it ISNT necessarily their fault.

[Pyoor_Kate]

Um, no, actually. The grille was a replacement and was sprayed before fitting...

Rebecca gets used every single day, come rust-bearing-salt & ice or dry-dusty-sun. And since I work, usually 6 days out of 7 I didn't have much time for cleaning her. Don't have much time..... So the salt got to the grille and has made it kind of rusty-blotchy.... So 2 years of fairly hard use, with very little time to do any maintainance and not even sight of a garage has rather taken its toll on tired paint and old chrome....

[Peetee]

Hang on, you say you have different tyre sizes front to rear. Is that still the case? Has a mechanic swapped one of the fronts for a rear perhaps?
That could cause a vibration as the diff struggles to cope with wheels revolving at different speeds.