Looking fro suspension recommendations

[Jred]

1970 Avanti II and its a bit white knuckle on these Los Angeles freeways with the Avanti.

Looks like it has some monroe shocks on there now. The car feels like a small boat as is hitting the woops and humps at freeway speeds. Tail wants to bounce one way and the nose wants to sway another. I was thinking of starting with just replacing the shocks but curious if there are any other upgrades that have been popular additions?

 

thanks

[studegary]

For starters, do you have a matched set of tires and the proper amount of air pressure in them?   

[Jred]

16 minutes ago, studegary said:

For starters, do you have a matched set of tires and the proper amount of air pressure in them?   

Yes

[Avanti83]

I have KYB's on mine but be sure that the front suspension is in A1 shape. Both of my Avanti needed rebuilding when I bought them so I did it in my polebarn. With good shocks, 17" radial tires and the newer suspension components it rides surprisingly well. I also did the rear bushings at the same time.

Edited April 24, 2021 by Avanti83

[Jred]

@Avanti83 Thanks.

 

Most the bushings besides the those on the shocks look acceptable from what I could see. I'll have to get it up in the air to really see.

The overspray on the leaf springs is a tell that they are original to the car. They look very flat and Im wondering what kind of arch they should have?

On Avantiparts I'm seeing replacements for every corner. Curious if anyone has used these items and what their impression was. Im sure itll ride much nicer with fresh components.

 

[Gunslinger]

It would not be surprising at all if the front coil springs have compressed and require replacement.  The same goes for the rear leaf springs.  One way to test the shock absorbers is to start pushing up and down on the fender...let go and it should go down once, come up and stop.  If it rocks more than that the shocks need replacing.  

Also...don't expect your Avanti to handle like a modern car with a modern suspension...it's a 1953 design chassis and simply cannot keep up with modern suspensions...you might be comparing to your modern car and it will come up wanting.  

If you need to replace the leaf springs, I would suggest getting a set of composite leaf springs from Flex-a-Form.  They're comparable in cost and weight much, much less.  

I always found with an Avanti to keep four psi less pressure in the rear tires than the front...it helps some with the car's inherent forward weight bias.

[Avanti83]

Be careful about loading the rear shock mounts with a lot of weight from load leveling shocks as it not that strong. Let the rear suspension do the work and the shocks control rate.

A complete front rebuild kit with refurbished king pins is about $1000 in parts if required. Rear bushing another $100 or so.

When I rebuilt the front on my 74 I used Delrin bushing on the A-arms and urethane on the sway bars which also helps firm it up.

Gunslinger is right about the handling being a 50's design but if the suspension is in top notch shape they are reasonably capable road cars when on good radials.

Edited April 26, 2021 by Avanti83

[Jred]

Thanks @Gunslinger and @Avanti83 for those tips and info.

Both front and back do rock when pushing down on the fenders. Totally understand that this is old tech. Im kind of comparing the suspension fatigue to my experience with an old Landcruiser I got back on the road a few years ago. I know its apples to oranges but after upgrading the shocks to new "foam cell" shocks and some fresh leaf springs the truck rode amazing compared to the stock leafs and shocks. I actually just got back from the Nursery with 4 1'cubic bags of cactus soil in the trunk and there was an improvement in ride, HA.

I'll assess the kingpins and go from there. Thinking I'll order some coils and leafsprings from Avantiparts and talk to a few shops here locally about shocks.

Edited April 26, 2021 by Jred

[Jred]

Found this shop and made a visit. The owners Avanti has unmodified suspension and it was night and day compared to mine. Much more stiffer with out the bounce.