New wheel wobble

[Hasbeen]

The 8 has suddenly developed a large deflection low frequency wheel
wobble at 75 to 82 Km/H, as distinct to the normal high frequency
unbalance shimmy from 95 to 100Km/H. I have never had this wobble
at this speed in any of my 7/8s.

I had the fronts balanced, off car, & this did nothing, or perhaps
made it slightly worse. I watched the balancing, & the wheels ran
true.

We then adjusted one wheel bearing, about a 1/16Th of a turn of the
nut, & adjusted the rack, by removing a 10 thou shim, which
dampened out most of the wobble, but made the rack slightly stiff
from about half lock on the left turn side.

Then replaced the 10 thou shim, & removed a 5 thou, which made the
rack spot on, but allowed a bit more wobble to come back.

I have checked everything in the front end, & found nothing wrong.

The worry is that it has appeared just a day after the bloke who set
up the injection computer had driven the car, without me in the
car, to keep an eye on things.

I will get an on car balance in the next few days, & see what that
does.

Hasbeen

[Underdog]

You could try swaping frt to rear. That would possibly point out if it is indeed a wheel tire problem.

Jim Underwood
72 MGB BRG
80 TR8 Persian Aqua
If women don't find you handsome, they should at least find you handy.

[PeterTR7V8]

Are there road work signs on your street? Is the wobble due to a lack of a seal on the road?

Alright, apart from the ridiculous the only other thought is it may be brake related.



The map: http://tinyurl.com/wedgemap . The blog: http://www.forum.triumphtr7.com/topic.asp?TOPIC_ID=8548

[Beans]

Or "the bloke" hit something like a curb [B)]

<center>
<font color="blue"><i>1980 TR7 DHC (my first car, now restored and back on the road)
1981 TR7 FHC Sprint (better known as 't Kreng)</font id="blue">
<b>[url="http://www.tr7beans.blogspot.com/"]<u><b><font size="2"><font color="red">My Weblog</font id="red"></font id="size2"></b></u>[/url]</b></i></center>

[Hasbeen]

Yes Beans, that is the worry, & was my first thought. However, I
have checked out very carefully, everything I can see, including
going over the tyre side walls, & can't find a thing. Out here in
the bush there aren't any curbs, & it's a long way to even find a
centre island, & they have angled curbs, anyway.

You would have to drive straight over an island to do much damage, &
that would take the spoiler off the thing.

No road works Peter, & it's while just cruising down the road,
nothing while using the brakes.

It does stop, as soon as you turn the steering wheel, even a couple
of degrees, which indicates to me it is a slight unbalance, which
is allowed to get a bit of movement going because of some slop in
the front end somewhere. Turning the wheel would preload against
any wobble getting going. That's why I adjusted the rack.

However, I can't find anything worn, anywhere in the front.

I'll just have to keep looking.

Hasbeen

[Bobbieslandy]

I'd be slightly more blunt and go back to the guy who drove it saying somthing along the lines of "you've ****** my car, sort it now" I'm sorry but a car doesn't go in to a garage in one condition then come out worse. Hasbeen, with your experience it's unlikely to have been happening before it went in so something must of happened. Bearing in mind the guy had lots of time to cover his tracks, you wouldn't find anything. Good luck mate, i hope it gets sorted.

Rob.

[Hasbeen]

Bob, it didn't go in mate. He was the only recomended bloke I could
find, with a lap top which could work with the old computer
program. It had to run Doss on a Windows 95 or older system, to
hook up, & work. I'm trying to find one to buy, to keep on hand.

He cane here, twice, & only drove the thing up & down our road, so
although I'm suspicious, I don't really think I can lay the blame
to his door. If I really thought it was him, I'd be right with you.

I still may, if after getting the thing balanced by a good shop,
it's still there. It does feel like a thrown weight, & the local
country shop who I had balance it, is better with tractors, than
cars. Still thanks for the advice, & the feeling, which comes
through your post quite clearly

Hasbeen

[jclay (RIP 2018)]

Check the wheel hubs for cracks or egging around the outer bearing area.

Clay

[url="http://web.mac.com/jclaythompson/iWeb/Site/Welcome.html"]My Triumph Site[/url], [url="http://web.mac.com/jclaythompson/iWeb/Technical/Intro.html"]Technical Stuff[/url], [url="http://homepage.mac.com/WebObjects/FileSharing.woa/53/wo/HJMTK8gsojtwKleP.1/0.2.1.2.26.31.97.0.35.0.1.1.1?user=jclaythompson&fpath=Triumph_Articles&templatefn=FileSharing4.html"]Download Page[/url]

[John Clancy]

With the car stationary get someone to turn the steering wheel and listen at the front road wheels for a 'clonk, clonk, clonk'. This was the problem with my car and it's an indication of worn strut top mounts. Robsport just repaired this and now there is no wobble (or shimmy as it is sometimes called.)

I feel this is unlikely to have been caused by the chap driving up and down the road. It's such a common problem it's bound to be just one of those coincidences.

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[Hasbeen]

Thanks John. What speed was your wobble at. I have nothing at the
usual 100Km/H, 60 MPH balance shimmy. It is a little above 70 Km,
about 45 to 50 that this one is at.

We did look at everything, but I will try listening as well.

Thanks Clay, I'll have a look for that too.

I really do think it's something that has just fallen off, or packed
up, suddenly.

Hasbeen

[John Clancy]

My wheel wobble was only very slight most of the time but around 45 to 60mph.

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[Hasbeen]

Sorry I’ve taken a while to report on this, the computer caught a
cold, & none of the “expertsâ€￾ in our neck of the woods seemed to be
able to wipe its nose, so I’ve been off the air for a few days.

The bloke at my favourite wheel balancing place, that does on car
balancing, is on holidays. Damn.

I went to a good place with a new balancing machine that loads the
tyre with 250 Kg of pressure to simulate the cars weight. The car
was no better.

What I did notice was that the wobble stopped, when I had a moderate
amount of lock on, turning left or right. It was worst when rolling
straight, under no load. Could it be wheel alignment, with
excessive toe in, causing it to grip on alternate front wheels?

Could it what. On the Wheel aligner it read just over 8mm toe in,
almost a third of an inch. No wonder it was wobbling.

The exotic new balancer is not as good as the old “on carâ€￾ job, &
there is still a little unbalance shimmy, at 95Km/H, but very
slight.

How did it suddenly get so far out on alignment, when it was done
when these tyres were fitted, only 650Km ago? I can’t really point
the finger at the computer bloke, but never again will anyone drive
one of my cars without me in the car.

Hasbeen

[Beans]

Over 8 mm of "toe-in" is very much indeed and can only be caused by hitting something,
or something on the suspension was/is loose, like the the lock nuts for the track rod ends or the inner ball joints of the steering rack.

<center>
<font color="blue"><i>1980 TR7 DHC (my first car, now restored and back on the road)
1981 TR7 FHC Sprint (better known as 't Kreng)</font id="blue">
<b>[url="http://www.tr7beans.blogspot.com/"]<u><b><font size="2"><font color="red">My Weblog</font id="red"></font id="size2"></b></u>[/url]</b></i></center>

[Hasbeen]

Yes Beans, my thinking exactly.

However, nothing is or was loose, & I can detect no excessive wear
or damage. That's why no one will drive the car without me, or my
son, in future.

I have had cars, in the past, with excessive toe in, which wandered
a bit, particularly over bumpy roads, with first one wheel
steering, then the other, but never this wobble, as alternate
wheels took control.

Still sorted now, but it was a bit of a worry.

Hasbeen

[nick]

Hasbeen,
These wobbles are the damnedest things. The other day I had exactly the same problem as you. The new tires have about 1k miles and had no wobble. And from one day to the next, wobble. So I shifted the tires front to back. No change. I couldn't remove the nut on the damper which holds the spring and shims so I just tightend the plug a bit. That seems to have taken care of about 80% without degrading the steering.


nick
'79 TR7