assembling sliding pillar

[DavidHill]

ref rubber bushes in the steering...they are all new - still rubber, but all new. so don't think it is that.

Today I put three different wheels on the front, so including the original two, that's five different wheels and got the viscous wobble with them all...so do not think it is the wheels...unless they are all bad (possible of course!)...what I did notice was that when I took a front passenger with me I did not get any wobble... and when I put 4 galls of petrol in the tank and drove it on my own again I got really severe wobble...so I have concluded it is sensitive to weight on the front wheels, the more weight on the front, the less likely the wobble is ... does that make any sense - point to anything in particular?

[davidwheeler]

Once upon a time it was possible to balance wheels on the car.  I do not know if this still happens but it might be worth exploring.

[Raahauge]

Although I have not had any trouble with wheel balance on Aprilias or Augustas I have with other cars over the years.
The discussion has mentioned balancing but without reference to the accuracy used. Garages will normally balance to 10gms, particularly if they think it is only an old car, whereas a 5gms (or better) may be what is required for Lancia sliding pillars with little friction in the system. I have sometimes had to be insistent to get this extra precision. 
Wobble coming and going is, I think, due to a small inbalance on both front wheels which changes depending on where the wheel are in relation to each other and therefore compensating or compounding any error. Unless it is well balanced then a small bump can set it off.
Important that there is some toe-in or toe-out and worth experimenting with this and tyre pressures. Tyre wear also has affect.
It can be elusive, as you have found, but very pleasing when sorted.
   

[DavidHill]

morning All,

ref wheel balancing, the wheels have been balanced to within 5g's, all the tyres and tubes are new and i have rotated through a further 3 different wheels (from my spare set) onto the front wheels...and seen no change in the really bad wobble. I have also checked the tracking and set it at 0. All the steering bushes are new too. The wobble moves the whole front of the car - its not just a vibration through the wheel, it feels like the wheels are about to fall off - its that bad and its random, not coming in at a particular speed...bumps seem to set it off...but not consistently.  I guess it may be the brake drums (as they are  not perfect) and it would be good to get the wheels balanced on the car just to finally close this avenue off....but the only company i can find to do that are based in Oxford (60 miles from me) - so i would have to get the Aprilia trailered there and they charge £160...

i now suspect its still the damping and plan to have another look at the damping rods to make sure they are working correctly..

[GG]

An odd thought....

- if its not the wheels, and if random, probably not brakes out of balance either.
- if steering linkage all seems tight
- not wheel bearings or anything else you can check
- and if its really random

So what else could it be? 

In the Aurelia with a perfectly good balanced tire and brake assembly, sometimes brake use gets a big wobbling, feels like everything is out of balance - a shudder - which goes away w more pushing on the brakes. Likely brake related - doesn't seem like your problem.

Might it be a looseness in the pillars? Years ago I saw in Italy that they were remaking the main bottom internal fitting in the Aurelia sliding pillar - saying it wore over time. The problems we see with the pillar were typically related to the seals and the small little floating discs not working right - but this suggests some (!) may have extensive wear internally.

Only suggested, not sure at all about this. 

[Kari]

Difficult to give a diagnosis from a distance. May I suggest following:

With the car on it's wheels, stand outside the driver's seat and check how much you can move the steering wheel left / right before a movement can be seen at the front wheel. Should be less than an in. If an exessive play is noted, that can be: The play inside the steering box; a loose drop arm at the steering box; worn excentric pins on drop arm, drag link and track rod, or a sum of all play in the steering circuit.

With the car on it's wheels, have a person moving the steering wheel both ways with some force while checking from underneath the attachment of the steering box at the frame, loose steering arms attached to each sliding pillar. You might have to remove the radiator grille to see the attachment bolts. Cracks around the steering box and if there is a flexible coupling near the steering box, condition of it. Might be splines though.

Have a person shake the car sideways by brute force that much that the sliding pillars move considerably. Check for undue side movement. Only up and down movement permitted, (except turning of course) Check attachment of the front axle at the frame, perhaps torque of the bolts.

Probably a bit far off, but if the rear axle has some undue movement, would that have an influence for inducing a wobbling at the front?

I hope that helps

Karl

[Raahauge]

David, I don't know the Lancia recommendation for toe-in but the "Trader" service data for the Aprilia has it as 0 to 2mm and I would set it to 2. Experience tells me that it might help.
Mike

[DavidHill]

thanks very much for all the suggestions...today I reset the toe in at 2 degrees...but no improvement gained...I then also checked the steering play...I have about 2 inches of steering wheel movement before I see movement at the wheels.  So this evening I removed the steering box. It was firmly attached and there was no cracks in the body, so no issues there. Next step is to adjust the steering box to hopefully remove all play and re fit...

[Sebastien]

There is an Aprilia steering box just now on PrewarCar.
Might be an opportunity!

[simonandjuliet]

That is certainly too much movement in my opinion, they are easy to adjust but take care not to overtighten them because you can get nasty tight spots when you turn the steering wheel

Try filling with nice thick "grease/oil" at the same time. Penrite do a version

[DavidHill]

Thanks Simon, will take a look..in the meantime can anyone advise me on which way to turn the eccentric bush on the underneath of the steering box (see pic). I have removed the large locking washer and turning the bush either way requires a quite a bit of force applied by a hammer and screwdriver, and either direction does not move very far...

[Kari]

David,

I just sent you a PM with a copy of an Aprilia Service booklet attached which is to large a size to be attached here.

Please make sure that the steering is not binding at each end of travel as most wear on the gears is around the centre position.

Karl

[DavidHill]

Many thanks for forwarding Karl, but the servicing doc does not describe which way to turn the eccentric bush to remove play...clockwise or anti clockwise??

[Mikenoangelo]

I have no knowledge of the Lancia box but my Salmson has a similar eccentric bush on the droparm shaft which when turned, moves the shaft radially to reduce or increase the clearance between worm and wheel. There is only one close clearance position so it does not matter which rotational direction you approach from. I can adjust this and when refitted to the car can check the result by turning the road wheels from lock to lock thus spinning the steering wheel and can  easily tell when it is all free with no tight spots and minimum play.

Mike Clark

[LatheJon]

Hi David,
Before the suspension work did the Car drive OK. If it did, It must be something to do with the rebuild. I would be inclined to have another go at the repair.
Do both sides bounce the same, pushing on the front wings.
regards, John