My 2000HF has too much lateral bump steer. Rear shocks and bushings in good shape. Shocks are Tecno Suspension circa 2018. Not sure what to do to keep the rear wheels on the ground. I've posted on other Flavia/2000 forums but have not heard back. Any advice appreciated.
I'm also posting this on the Fulvia forum as the rear axle is nearly identical and there's got to be some that have been track prepped.
Rear axle hop
Re: Rear axle hop
What do you mean with lateral bump steer?
Re: Rear axle hop
You should check the rear shock´s.
If i remember correct the Shocks from tenneco are montube. There ist the possibility that the Cut-off piston between
oil and gas is defect. This is a standard defect on monotubes. So you don´t have compression force.
Also referred to as gas-oil migration inside the damper. No oil loss can be detected on the damper.
Easy to check. Remove the shock and check if you have in compression no force. The pistonrod has to come out
by itself after you have push it complete inside the shock.
Regards Andreas
If i remember correct the Shocks from tenneco are montube. There ist the possibility that the Cut-off piston between
oil and gas is defect. This is a standard defect on monotubes. So you don´t have compression force.
Also referred to as gas-oil migration inside the damper. No oil loss can be detected on the damper.
Easy to check. Remove the shock and check if you have in compression no force. The pistonrod has to come out
by itself after you have push it complete inside the shock.
Regards Andreas
Re: Rear axle hop
On moderate speed curves the rear end hops sideways over bumps. It's worse over high frequency small displacement bumps (like expansion joints) than low frequency large displacement bumps. The wheels are definitely losing contact w/ road surface. On washboard surfaces it's a handful.
Unable to determine by butt feel which mass launch (sprung or un-sprung) is too fast/far. I don't feel a lot of initial impact transferred through the body. More the after effect of the bump.
I'll disconnect/test shocks today and report back (I'm in USA). I've checked and leaf springs appear to slide OK. No obvious stiction when jacking. All bushings in good shape.
Unable to determine by butt feel which mass launch (sprung or un-sprung) is too fast/far. I don't feel a lot of initial impact transferred through the body. More the after effect of the bump.
I'll disconnect/test shocks today and report back (I'm in USA). I've checked and leaf springs appear to slide OK. No obvious stiction when jacking. All bushings in good shape.
Re: Rear axle hop
You have to check both shocks. Depent on the gas-oil migration inside the damper the rebound normaly works more
or less but the compression not.
And as you describe you loss contact to the ground.
Means fast deflection because there is no compression damping force and slow rebound due to functioning rebound damping. And, depending on the road conditions, this results in different behavior
regards Andreas
or less but the compression not.
And as you describe you loss contact to the ground.
Means fast deflection because there is no compression damping force and slow rebound due to functioning rebound damping. And, depending on the road conditions, this results in different behavior
regards Andreas
Re: Rear axle hop
I agree with Andreas. First check the shock absorbers. I would not want any shocks other than monotubes on my Fulvia or Flavia but they have their challenges.
Other items to check:
- the shackle block (the rubber at the top of the shackle)
- is the Panhard rod still straight?
- if the rubbers are original, they are not good even if they look ok. The Lancia quality was exceptional but 50 years is a lot for hard working rubbers.
Other items to check:
- the shackle block (the rubber at the top of the shackle)
- is the Panhard rod still straight?
- if the rubbers are original, they are not good even if they look ok. The Lancia quality was exceptional but 50 years is a lot for hard working rubbers.
Re: Rear axle hop
The shocks seem about the same in bump and rebound. Working but not very stiff. Someone did not use shoulder bolts- threads a bit hammered.
Rear tires over-inflated; 31 psi hot. Manual says 28.6.
Springs and shackle blocks painted over, so I'll have to pull them and inspect/replace rubbers. I did lever and also jack each end- no obvious movement.
When you say don't run other than monotubes, does that preclude Spax or HRW adjustable, which are both twin tube?
Any idea where I can get front upper control arm bushings? Mine are obviously perished. They seem to be un-obtainium.
Thanks for the help.
Rear tires over-inflated; 31 psi hot. Manual says 28.6.
Springs and shackle blocks painted over, so I'll have to pull them and inspect/replace rubbers. I did lever and also jack each end- no obvious movement.
When you say don't run other than monotubes, does that preclude Spax or HRW adjustable, which are both twin tube?
Any idea where I can get front upper control arm bushings? Mine are obviously perished. They seem to be un-obtainium.
Thanks for the help.
Re: Rear axle hop
We have recently worked on two Flavia 2000 coupés. Both had the same problem as you have. On one we only put new shocks. The car behaved a lot better. The shocks we specially make for the 2000 coupé to very high standards following the De Carbon principle of high pressure gas monotube shock absorber.
On the other one we also rebuilt the springs, changed all the rubbers front and rear, replaced or repaired bend parts (Panhard rod, lower wishbones), new wheel bearings, replaced outer CVJ's, skimmed discs, reduced disc wobbling to less than 30 micron and some other things. AMAZING. There is no car in the world with a better ride. No sir. AMAZING AMAZING AMAZING. Oh and of course straightened the wheels and mounted 165HR15 Michelin XAS tyres. Ready to wander all over the continent for the next 50 years. Every mile with a smile at any speed. Better than that. Every meter with utter pleasure. And we converted the wishbone bushes to silent blocs. I will add a picture in a new posting.
The high pressure monotube shocks (the De Carbon patent) need a lot of force to compress. I can't by hand. But I am not the big brother of Arnold Schwarzenegger. I use a tool. If the tool is released the shocks go to maximum length immediately.
On the Flavia it is important to have the wishbone bushes in very good shape. If not you may break a drive shaft when turning at low speed on a small road.
On the other one we also rebuilt the springs, changed all the rubbers front and rear, replaced or repaired bend parts (Panhard rod, lower wishbones), new wheel bearings, replaced outer CVJ's, skimmed discs, reduced disc wobbling to less than 30 micron and some other things. AMAZING. There is no car in the world with a better ride. No sir. AMAZING AMAZING AMAZING. Oh and of course straightened the wheels and mounted 165HR15 Michelin XAS tyres. Ready to wander all over the continent for the next 50 years. Every mile with a smile at any speed. Better than that. Every meter with utter pleasure. And we converted the wishbone bushes to silent blocs. I will add a picture in a new posting.
The high pressure monotube shocks (the De Carbon patent) need a lot of force to compress. I can't by hand. But I am not the big brother of Arnold Schwarzenegger. I use a tool. If the tool is released the shocks go to maximum length immediately.
On the Flavia it is important to have the wishbone bushes in very good shape. If not you may break a drive shaft when turning at low speed on a small road.
Re: Rear axle hop
Huib,
That's how I want my car to be!
I read the write-up on your website and it sounds as if the DeCarbon's provide additional springing as well as damping? If Lancia intended the shocks to supplement the springs, then twin tube would definitely be inferior. Will they change the ride height? Can you tell me who supplied them?
Also, who supplied the front upper wishbone bushes? My lowers have been replaced, but not the uppers, which I assume is because they are hard to find.
Are you familiar with Dominick's in White Plains New York? I'm told they are the premier Lancia specialists in US. I usually do all my own work (mostly Porsches) but maybe I should take it to them and have them redo all the suspension and steering components. The car was restored in Italy in 2018 but I'm finding it was mostly cosmetic.
Thanks.
That's how I want my car to be!
I read the write-up on your website and it sounds as if the DeCarbon's provide additional springing as well as damping? If Lancia intended the shocks to supplement the springs, then twin tube would definitely be inferior. Will they change the ride height? Can you tell me who supplied them?
Also, who supplied the front upper wishbone bushes? My lowers have been replaced, but not the uppers, which I assume is because they are hard to find.
Are you familiar with Dominick's in White Plains New York? I'm told they are the premier Lancia specialists in US. I usually do all my own work (mostly Porsches) but maybe I should take it to them and have them redo all the suspension and steering components. The car was restored in Italy in 2018 but I'm finding it was mostly cosmetic.
Thanks.
Re: Rear axle hop
Huib,
Thinking on this more; given the volume change from full bump to full rebound in a Decarbon monotube, the gas is compressed a lot. This would explain why Lancia mounted the shocks at such a steep angle, which has been puzzling me (52 deg from vertical at full bump). A twin tube adjustable like a Spax will definitely be less than ideal.
When you release them on a benchtop I assume they restore quickly at first and slowly at the end. Do they just barely make it to the bottom? Trying to get a feel for how much lift they will induce at normal ride height when they are at 41 degrees.
Please tell me where I can get a set or, if you can purchase from your supplier and sell them to me, that would be fine too.
Thinking on this more; given the volume change from full bump to full rebound in a Decarbon monotube, the gas is compressed a lot. This would explain why Lancia mounted the shocks at such a steep angle, which has been puzzling me (52 deg from vertical at full bump). A twin tube adjustable like a Spax will definitely be less than ideal.
When you release them on a benchtop I assume they restore quickly at first and slowly at the end. Do they just barely make it to the bottom? Trying to get a feel for how much lift they will induce at normal ride height when they are at 41 degrees.
Please tell me where I can get a set or, if you can purchase from your supplier and sell them to me, that would be fine too.