Volvo C70 2.5T Coupè 1998 Suspension Comfort Problem

[tony209]

Originally Posted by reise

Can you write here your chassis code (8 digit)?

2.3 T5
M61S4MS5. Dynamic springs have a brown identification code.

M6 is the Dynamic front damper/spring.
S4 is the rear damper/spring

2.4T
M51N4MS5 Comfort front springs have a green paint code but there are other paint colours for different markets.

M5 is the comfort front damper/spring.
N4 is the rear damper/spring

2.0T Collection
M71N4MS5
M7 is a dynamic front damper/spring

All cars have the same rear spring, except for cars fitted with the factory lowered suspension.

[reise]

4th digit of chassis code is rear shocks

5th digit of chassi code is rear springs

All your cars have factory rear comfort springs.

In this case Dynamic Chassis of Coupe and Cabriolet is different. Equal commercial name, but is different.

My C70 Coupe Dynamic Chassis have:

Front orange factory springs

Rear yellow factory springs

(or vice-versa, because i see my old springs some days sgo to take misurement and i saw in a axle is orange and on another axle is yellow).

In any case my C70 is a low car. Expecially at rear. Equal result with original and KYB.

But some days ago is installed all new engine mounting Volvo Genuine. But comfort for my sensation was equal.
Yesterday i replace the wheels:

Ursa 7 x 16 205/55 16 91W Dunlop Sport Marxx RT DOT 2015 at end of life

Changed for

Canisto 7.5 X 17 225/45 19 94Y Good Year Eagle F1 Asymetric 5 DOT2021 Made in Germany (factory shipped)

Confort is dramatically improved. In strange, normally 16 inch wheels have best comfort than 17 inch wheels (on some vehicle with equal wheels size of course) while this Asymetric 5 is extraordinary comfortable. But sensation may be influenced beacuse old tyre have 6 years and end of life and the actual tyres is new.

Excuse me for very bad english. I'm italian.

[ASt85]

Originally Posted by tony209

The KYB springs are not suitable for the cabriolet, unless you want a lowered very hard ride and very light and twitchy steering!

Try going to partsforvolvos online and a going for the LESJÖFORS springs - they exceed the OEMs which had a manufacturing fault in the 2003 to 2006 C70s causing them to break @ around 40 to 60K miles!

Phone them, or use their online catalogue with your VIN number and you will get the right springs in the correct length and diameter for your car ie the spec will match the OEMs but be of much better quality than the originals.

Take a look at this thread and you will find some useful info. https://www.volvoforums.org.uk/showt...=278271&page=2

[tony209]

The chassis on the cabriolet differs to that on the coupe, presumably because it's a heavier car.

The KYB springs don't work well on the cabriolet because they don't change the ride height uniformly - assuming the springs have the same compression rate.

Stock Vs KYB
460-442= 4% reduction in ride height
430-400= 7% reduction in ride height

On cabriolets with Dynamic suspension, only the front springs are Dynamic, all cars have the same rear spring. C70 Coupe with dynamic chassis, probably have Dynamic front and rear.

I don't know what the spring lengths are for the factory lowered cars but I would suspect that they are a uniform reduction front to rear.

[tony209]

Originally Posted by ASt85

Try going to partsforvolvos online and a going for the LESJÖFORS springs - they exceed the OEMs which had a manufacturing fault in the 2003 to 2006 C70s causing them to break @ around 40 to 60K miles!

Phone them, or use their online catalogue with your VIN number and you will get the right springs in the correct length and diameter for your car ie the spec will match the OEMs but be of much better quality than the originals.

Take a look at this thread and you will find some useful info. https://www.volvoforums.org.uk/showt...=278271&page=2

This was the point I was trying to make regarding the KYB springs, they are not right for the Cabriolet, they make the car too low at the back. This upsets the front of the car, making it too light - this is fine for town driving but at speed it'stoo twitchy, the front end of the C70 already lifts due to poor aerodynamics and the KYB spring make it even worse.

My factory Dynamic front spring have done 130k and only have surface rust where the plastic coating has pealed.

[reise]

From brochure of some years, the Kurb weight:

Coupe 1450kg
Cabriolet 1565kg

Intended boot in basic (and equal) configuration

115kg of more weight for the Cabriolet.

[reise]

Originally Posted by ASt85

Try going to partsforvolvos online and a going for the LESJÖFORS springs - they exceed the OEMs which had a manufacturing fault in the 2003 to 2006 C70s causing them to break @ around 40 to 60K miles!

Phone them, or use their online catalogue with your VIN number and you will get the right springs in the correct length and diameter for your car ie the spec will match the OEMs but be of much better quality than the originals.

Take a look at this thread and you will find some useful info. https://www.volvoforums.org.uk/showt...=278271&page=2

On LESJÖFORS website, i find spring for C70, but not present info about lenght, weight, ecc.

[reise]

Hello I have bought Koni Special Active front struts for my C70.
I think to install it on front and leave rear new Sachs.
Actually i not happy for the new Sachs front and rear (oredered time ago with some original spare part code of original). But i think is low quality struts.
With new Koni Special Active i think comfort is dramatically best (i hope).
But time ago i was read about not is really recessary to replace too the rear shocks.
I ll try with only front struts. If comfort become excellent i not will buy rear shocks. If i ll notice problem at rear axle i ll buy too rear shocks.
Is right?
Or is necessary too equal rear shocks?

[reise]

I changed my mind:

Buyed too rear Koni Special Active.

In next weeks i'll have Koni Special Active front + rear.

Now i need to select best bump stop for confort.
Actual was ordered from Polar Parts. I think is low quality product.

[ASt85]

Originally Posted by tony209

This was the point I was trying to make regarding the KYB springs, they are not right for the Cabriolet, they make the car too low at the back. This upsets the front of the car, making it too light - this is fine for town driving but at speed it'stoo twitchy, the front end of the C70 already lifts due to poor aerodynamics and the KYB spring make it even worse.

My factory Dynamic front spring have done 130k and only have surface rust where the plastic coating has pealed.

Thanks for the info - I can't comment re the original rear ride height of my Cabrio as the rear springs were broken when I bought it....hmmm I thought it had been lowered at the rear!

The LESJÖFORS are the OEM spec and really have the car driving/handling well; the rear is significantly lifted from when I bought it, there's no steering indecisive wandering or tramlining - but then it has still only got 41K miles on it from new!