Technical Steering is stiff

[nzbobc]

I replaced most of the steering components last year, including the idler bushes. But, the steering is still really stiff: I'm constantly having to adjust the wheel since the car won't straighten out by itself coming out of corners.

I'm fairly certain it's the new idler bushes that are creating all the drag. If you've replaced these, how long did it take before they broke in?

My local 500 mechanic says I should give some thought to having some hard plastic bushes made up that will reduce the amount of drag.

 

[fiat500]

It won't be the bushes unless perhaps you tightened them when the steering wasn't in the straight ahead position. Or maybe the bolt through them is loose or the bushes themselves are a poor fit in the alloy casting.
It might be that the toe in is not right.
The principle seems to be that the torsion put into the bushes as you turn is what assists the self-centreing
Good luck with sorting that, it must be very annoying.

 

[nzbobc]

Hi Peter,

Thanks for those thoughts. I forgot to mention that I have had an alignment done.

I did follow the Haynes manual when replacing the parts such as having the wheels straight when tightening the bolt and tightening it with the specified torque.

I'll have a think about the other possibilities you mention. Thinking out loud, I wonder if I could add some grease between the bushes and the idler arm.

 

[F123C]

I'd agree with Peter (fiat500) re the idler arm bushes are designed to be in tension when the steering is turned and should be tightened up only with the steering in the straight ahead position.

So I wouldn't use grease anywhere near them but you could try loosening the bolt so the idler arm can turn freely and roadtest the car to see if it's any better.

After that I'd be inclined to suspect stiffness in the kingpins/bushes. If you can disconnect the trackrod ends at the steering arms/hubs, the kingpins can be easily checked for binding.

Although you mentioned having a wheel alignment carried out, I wonder if castor angle was checked. Incorrect castor angle can cause wandering/pulling/frequent steering corrections as can incorrect toe-in (as Peter has said).

And don't forget to double-check your tyre pressures! (btdt )

Al.

 

[nzbobc]

Good thoughts guys, thanks for your help!

I pulled the front end apart yesterday and the drag is definitely associated with the idler arm bushes. The steering box and king pins are all fine (I did re-build the box and put in new king pins when I redid the front the end). The alignment guy also checked and adjusted the castor. I did have this stiffness problem before and after the alignment and new tyres.

Taking out the idler arm yesterday was helpful in that I spent time seeing how it functions. The bushes are lined up with the bolt, too. With the base in a vise, it's a lot of work to move the arm. It does relax when it returns to the mid-point (i.e., the wheels straight ahead). I've backed the nut off so it's not at the specified torque. This has eased up on the tightness. I'll see how that feels next time I'm out in it.

On an aside, the new bushes weren't even close to fitting into the idler bracket. A machinist had to ream the bracket before press fitting the new bushes.

 

[fiat500]

Hi Bob, there do seem to be a variety of bushes supposedly to fit this application. The originals have a very obvious, toothed machining where they contact the idler arm itself.
I had that problem trying to squeeze the first set that I bought. I gave up and bought from another supplier and they were a perfect interference fit.
As you turn either way, the rubbers are being wound up and want to return to centre. If you slacken things slightly you are losing that torsion and introducing a non-lubricated bearing surface between the bolt and the inner sleeve of the bushes.
Are you sure that the casting hasn't been over- reamed? It sounds like the bushes might ne rotating slightly in their housings.