940 Alignment

[arctan]

'97 940 with Volvo alloys...
At about 40 or 50 mph, when braking, on a slight down hill, I get a bit of vibration. There is no one sided pull, it's more of a wobble. Not awful, but not healthy! On the recent MOT, one of the advisories suggested slight damage to a front alloy. I swapped it for the spare afterwards, and the quality of the vibration has changed, and lessened a bit. I think between my wife and my self there may have been a bit of kerb stuff happening, as hard as I try to avoid it. I've had warped disc/s in earlier times, and changed them (to Brembo), being now careful about the wheel nut tightening sequence and torques thereafter. On the motorway there is no 'vibration at a certain speed' going on. Also on the MOT, I had an advisory 'lower left front suspension ball joint has slight play'.
I'm thinking- get the wheels balanced, and steering alignment done whilst I'm at it. There is a National Tyres place near me who I like, compared to yer average tyre shop. When they were fitting new tyres last year, out came the torque wrench. If was difficult to have input into the situation, but I asked the torque settings after seeing the fitting through the glass and they said 40 ft/lbs- which is better than a 'nut case' with an air gun. I re did them later that day (the values I have are -1 3 5 2 4 pattern, once at 33 ft/lbs, then 66 ft/lbs).
The online pricing for alignment comes out at £15 after using a discount code, and then probably some more for the balancing.
What I think I need please, are the alignment values, if anyone can help?
I'd much prefer someone here's figures to the tyre shops!
Also, any thoughts about the 'slight play' lower suspension ball joint- should I sort this first? I think I've seen a Lemforder part for under £20.
I'm thinking get the above lot sorted, and, if it's still going on, look in to the brakes...
John.

PS These days I'm a semi retired low income dog walker, with a slipped disc- so I have to exist carefully both physically and financially! Two days ago I had the classic cracked plastic radiator game, the 4th radiator I've replaced in my time. Three of them have been on 900 series! I had to buy a no name radiator from Braydons, and fitted it in an hour. And now the back is playing up. I'm wondering if one of those new fangled silicone hoses would be better from a lower vibration point of view :-)

[360beast]

See my how to guide about halfway down are the wheel alignment figures

https://www.volvoforums.org.uk/showthread.php?t=297897

If a ball joint has play it would be worth getting it replaced before doing the wheel alignment.

The 'spaceship' bushes were shot on mine so when I braked it felt like I had warped discs but I knew it was the bush as the cause. Now I have polybushes the warped disc feeling has gone when braking. It would be worth checking the condition of them as they seem to be the most common failure on these cars.

The wheels probably do need balancing if you have vibration while driving along, I have found it is usually over 60mph the vibration starts on cars I have had that needed the wheels balancing.

Wheel torque setting mine are stamped on the actual hub face as 66lbft or 90Nm.

[Laird Scooby]

What Luke suggested above! ^^^^^

Luke, are those toe settings figures for 15 or 16" wheels? Most tyre shops do the alignment to a degrees, minutes and seconds setting rather than mm.

The degrees, minutes and seconds is 0d, 18' 0" +/- 8' toe-in which should cover all wheel sizes.

John, just to reinforce what Luke said about the ball joint, that will cause wobble as you drive especially if it's a track rod end (T/R/E) ball joint and will show up during setting the wheel alignment.

Also the "spaceship bushes" will cause problems so make sure those and whatever ball joint the MoT tester referred to are all spot on before wasting your £15 on a wheel alignment.

Last thing you'd want is to put it in, pay for it then for them to say "Sorry we can't finish it because this or that component is defective!"

Alternatively, invest about £70 and learn how to do it yourself :

https://www.ebay.co.uk/itm/Trackace-...r/300814333955

They work well and there is a fair amount of bending involved which i know won't help your back so you have to "pick your battles" as to what day you choose to do it. The procedure is fairly simple although needs a lot of words to explain so seems more daunting than it is.

It will pay for itself fairly quickly, my local ATS (who i wouldn't trust with a wheel barrow!) charge £36 for a wheel alignment check or adjust per end.
On one of my beasts, it needs the back end checked/adjusted before doing the fronts so just one alignment pays for it!

Even just doing it now and checking it again in a few months time (after many potholes have been encountered!) will pay for it on that basis!

[360beast]

I can't remember what size that is sorry Dave, I don't think it even said, I imagine due to the higher profile of the 15" tyres they are the same.

I just did my wheel alignment on Thursday in my half hour lunch, adjusted the Trac rod ends one flat each and got it bang on! I was over the moon! In your email to me you were saying about centralizing the rack, the way I do it is on the grease plates.

Turn to the right so the drivers wheel reads 20 degrees and check what the left wheel reads, mine read just shy of 20 degrees. Then turn to the left so the left wheel reads 20 degrees and see what the right wheel reads, mine read 19 so I adjusted it up to the just shy of 20 degrees. That way you know the track rod ends are in the exact same position, then I clamped the steering wheel in the central position with the wheels pointing forwards. Adjusted it and it drives beautifully now and the steering wheel is bang on.

Sadly our tracking gauges only reads minutes/degrees and imperial so I had to convert it from minutes to imperial to metric!

[Laird Scooby]

You'd think as long as the rolling radius of the wheel/tyre combo was the same, it wouldn't make any difference really but it does :



As i'm sure you know Luke, the toe measurement is the difference between two measurements, both taken at the height of the centre of the wheel, one at the front of the wheel on the rim, one at the back on each side.

Let's call the distance between the inner edges of the rims at the front "b" and the distance between the inner edges of the rim at the back "a". The total toe setting might be 2mm toe in so for example, a = 1462mm and b = 1460mm. Without altering the angle of the hubs, fitting larger wheels is going to make the difference bigger for the same angle/toe setting or reduce the angle for bigger wheels.

What i was saying about centralising the rack is slightly different to what you've done, it's usually only necessary if the rack has been changed or the steering wheel has been off. With the 7/9xx life is fairly easy as it's 3.5 turns lock to lock so 1.75 turns from the centre of the rack to either lock.
As long as there are 1.75 turns to either full lock when the steering wheel is in the straight ahead position then the rack is central. Then check the track rods have roughly equal amounts of thread showing out of the track rod ends, clamp the steering wheel in the straight ahead position and check/adjust the alignment/tracking.

[derek vivian]

Not sure if this is in any way relevant, but on a 1000 mile journey to Italy recently using only motorways I got steering wheel vibration. But this only came in when I lifted my speed up from around 65 to 70 mph to around 75. Also the tacho was at 2K then up to 2.5K when the vibration started. It cleared when I brought the speed down again. This was with a full holiday load with two people(wife and me). On our return to UK we travelled to Cambridge using M25 then M11 and again the vibration started at the same speeds then clearing on getting back to 65 ish. And this time with no full load just us and overnight bag! Anyone else had this? My car by the way is 1997 V90.No vibration at normal around town driving.

[Laird Scooby]

What about if you took the speed up to 80-85mph - did the vibration disappear?

[derek vivian]

Hi Dave,
I don't know as I didn't go that fast (to save petrol!), but I see there was a technician's comment at the last MOT in July (just before my trip) which said there was 'slight play in front anti-roll bar bushes'. Would you know if that was the cause? Derek

[Laird Scooby]

Play of any description in the front anti-roll bar bushes won't cause wheel vibration Derek.

Because yours comes in at a certain speed which is directly related to how fast the wheel itself is turning, it's almost certainly a wheel balance problem.

If the anti-roll bar bushes are really bad, you will hear knocking from the front end, particularly over eneven surfaces, moreso when it's uneven from side to side - eg when one wheel goes over one of those "half-width speed humps" and the other is one the flat still.

Because it's most likely a wheel balance problem, there will be a certain frequency at which the weights (or lack of) to balance the wheel cause the most impact or wobble. This frequency is obviously directly linked to road speed so if you take it for the wheels to be balanced, it's likely they will ask you the problem and then ask "Can you drive through it?" meaning if you speed up further, does it disappear.

That takes the wheel speed and hence the frequency of the vibrations past the point where they effect you most.

Putting energy into the car only to make the wheels wobble is a waste of energy/petrol and won't do your wheel bearings many favours either so the sooner you get the front wheels checked and/or rebalanced, the better all round. If you can find a half-decent road that is smooth enough to get it up to 80-85mph just to see if the wobble eases/disappears will confirm the balance problem.

Also you'll often find that if a wheel wobbles at say 40mph it's ok between there and 80mph at which point it will wobble again but it may be only half as bad or twice as bad, likewise at 120mph but that might be barely noticeable or three times as bad.

[Ian21401]

If you are able to drive through it it is highly likely to be wheel balance.