Hi all!

I own a 1988 FIAT Uno SC / 1300 cc
This car has a problem with the front suspension. When I push the gas pedal, the front wheels try to go underneath of the car.
I have changed all the suspension pats, but nothing better happens.
I suspect that the front suspension arms (the ones that go from the body/chassis to the base of the struts are moving due to a metal fatigue of the body.
The apparent solution is to add somethink like a frame for the lower suspension arms.
Do someone have had the same problem and/or a hint of how to fix that? Maybe some kind of bar between the lower suspension arms?
By request, I can send a video.

Best regards from Costa Rica

You say all suspension components have been changed but have you changed the lower track control arms? These locate the bottom of the hub and are known for rusting through. The balljoint end can actually break off leading to the wheel flapping all over the place when you try and drive the car.

Only other things it could be are the steering rack not secured (this would upset the steering and you'd feel it through the wheel quite dramatically) or bolts missing/ loose in the hub to strut carrier. Whatever it is it sounds like the car is dangerous to drive. Get it seen to asap!

As for the bar between the two suspension arms you're thinking of an anti-roll bar. This won't stop you're problem, it will only stop the car from leaning as much in corners.

Welcome to the forum, lmontero

Chas, I'm a bit worried that our new friend is referring to a different front suspension set-up - the 'bar' between the control arms would be what we call the subframe, I think. I've never been sure if the Brazil-built Uno has the same front end setup as the European Uno, or whether it has something more like the FIAT 127 where there is a slim cast-iron control arm running to each footwell and an antiroll bar tying the two together. The back suspension is definitely 127-style.

I feel that we really need a photograph or two taken underneath the affected vehicle, or a video taken from underneath, so that we can see what we're dealing with. It may be just that you have incorrect suspension struts fitted, so the wheels may have a positive camber (wheel 'in' at the bottom, 'out' at the top) - this would cause the front end to do odd things on acceleration. Or it could be body flex as you said - but not if your Uno has a subframe like ours do.

If the balljoint were to break free of a rusty control arm, the wheel would be completely dislocated and would jam into the wheelarch (driveshaft would pull out of the gearbox) - I don't think that's likely to be the problem! The suggestion of loose strut bolts seems a likely explanation.

Speaking of driveshaft, I had an Uno once where the Tripode joint (three-roller-bearing inner driveshaft joint) on one side had lost all its needle rollers. When driving off, the driveshaft would pop out of the gearbox, then back in. The effect was a sudden 'jump' at the front of the car. Maybe just check that the driveshafts are properly located in the gearbox - try to 'wiggle' them - there should be no slackness.

Sorry to be clutching at straws but I don't have many ideas

-Alex