Ariemanthony

both my 928s ride a little rough over bumps. Is this normal or am I due to replace the shocks, struts and/or bushings? The ‘82 is all original and I believe they are the originals since the car’s mileage is approx 26k. the ‘83 is worse on bumps and is at 56k miles. Can anyone suggest what I can do or look for?

The Forgotten On

Replace it all. The rubber changes properties over time and doesn't dampen the way it was intended.

Same goes for the shocks, seals dry out and gas leaks etc. Only issue with those is that the rears have spotty availability.

gazfish

A specialist replaced all my suspension rubber and shocks last year, it transformed the handling and feels so planted. But these cars don’t glide over bumps they just feel solid. Old tires that have gone hard will also add to the poor ride.

jpitman2

If the 83 has M474 Sport suspension (Bilstein shocks, harder springs), thats the way it should behave - over anything but perfect surfaces. Most of my 'ordinary' passengers remark on the hard ride on suburban roads. At speed, its a magic carpet.
Other than that, agree with above advice.
jp 83 Euro S AT 57k

Petza914

See if you can find Bilsteins for your fitment. They work great.

icsamerica

Tires:
A good quality GT focused tire will help. Stay away from UHP tires, most tires shops will see "Porsche" and $$$ and push you towards UHP tires where margins are higher than an all season GT passenger car tires.

Bushings:
Replace all the bushings, UCA, LCA, Rack and check the sway bars. When bushings are bad it allows for lash and undamped movements that create very harsh feedback

Shocks:
The black / gray Boge shocks offer good damping and ride. Bilsten shocks are orientated towards performance and will add some edginess to the ride. I would change shocks last unless they are leaking or not working. I've noticed on other cars that Blsteins can sometimes fail stiff while other shocks fail loose so its worth checking them.

Ride height:
Make sure the ride heght is correct, most 928's are set too low n the front and this can create some slight crashing over road imperfections

This thread has some more detaled info.
https://rennlist.com/forums/928-foru...uspension.html

Speedtoys

I dont think he wants stiffer shocks..

Ariemanthony

I appreciate the info. I’ll start a list of items to replace and connect with Roger at 928srs.com

GregBBRD

Hold on....
Low mileage cars require a different approach than high mileage cars.

Start with tires.
What is the manufacturing date on the tires on the cars? Sidewalls turn to stone after about 5 years.
If your primary goal is ride, buy a set of Pirelli P7's. Very soft sidewalls makes for very soft ride....I call them "Jello" tires.

Front shocks on these early cars is a snake's nest....venomous snakes.
Early model front shocks are like finding the Holy Grail. And the later model shocks are made for a different suspension design. You'll need an assortment of different parts to make them work, including new springs (for sure), on the '82.
I've resorted to dyno testing old shocks and dealing with this mess, only if the are bad.

As mentioned, the '83 might have a more aggressive suspension. More information required

Ariemanthony

Thanks for this. I’ll start looking for the parts needed.

any idea if this is an afternoon job, weekend job or winter job? This is my first time working on my 928. Both cars have been to my mechanic for timing belt, gas tank, clutch and gear shift ‘linkage’. Mr Merlin said I need to learn to do it all myself so im gonna jump in and replace the bushings.

should i do all the bushings, check the ride and then decide if i need to replace the shocks or replace the shocks at the same time?

I appreciate any tips on what NOT to do and what to look out for.

Ariemanthony

I like this approach to take first. I’ll check the tire dates and see if new tires are needed and can do the trick.

I know the ‘82 sat for at least 5 years before i bought it and it was from the original owner that only put 24k miles on it as he had tons of other cars.
The ‘83 has more miles (55k) and tons of maintenance records from 2006 but, no mention of suspension maintenance.
So im assuming they both have all original suspension.

I haven’t bought new tires for either since I bought them in 2021. So, I’ll try new tires and see how the ride changes.

Thanks for the advice and direction, Greg.

Speedtoys

If you replaced _everything_

Two long weekends on a lift and with a GOOD press at arms length to use too.

GregBBRD

You could also switch the tires and wheels from the first set of tires you buy and do some back to back comparison...

GregBBRD

If you get to the point of replacing control arm bushings, buy the entire assembly from 928 International...the difficulty of replacings your own bushings isn't worth the effort, in my opinion. (We buy the complete rebuilt arms, for use in my shop, and keep ​​​​​multiple sets in inventory, virtually never changing bushings.)

There's also a whole song and dance on installing the lower arms and tightening them, which very few people understand and thus end up ruining the rear front lower rubber. This will result in the car sitting like an "off road" race truck for thousands of miles and requiring multiple alignments, as it very slowly settles.

depami

Please correct me if I'm wrong, but I believe you need to leave them a little loose and drive the car, or otherwise settle the suspension, then tighten them in the settled position.