C70: Rear springs?

[tony209]

I've just had delivered 2 x KYB rear springs for my T5. According to VIDA, C70s where fitted with two spring numbers with the same suspension code "4". Volvo spring numbers are 8614554 and 8628145 (no sizes or descriptions). VIDA says, CH - 15999 is 8614554 and CH16000 - is 8628145, my CH is 64xxx so I ordered spring matching this number, the KYB springs are 400mm.
When I bought my T5, the previous owner had just replaced one rear spring to get the car through an MOT, this is a Suplex 38100, equivalent to 8614554 whish should be 430mm - I'm assuming the other spring is original and 4300mm as the car is level. Not sure now which size spring is correct, 430mm or 400mm, I'm now thinking 400mm are "lowered" springs.

Any input appreciated.

Added a picture of my car, does the rear look too high? (Ignore the wheels, they are going to be painted!)

[ITSv40]

Your car looks about right to me.

As a comparison my C70 on comfort suspension - and as it left the factory -stands very similar to yours. In some angles it looks high at the back, but I think that is because the lines through the side rise as they get towards the rear bumper. The bottom of my sills are absolutely parallel to the ground when standing on a flat level surface, so that could be a quick and easy test for yours. hth.

[tony209]

Originally Posted by ITSv40

Your car looks about right to me.

When you have the chance and your car is on level ground, could you measure the distance between the centre of the wheel and the wheel arch. My other C70 always did look lower at the rear than this one but I thought it was down to this car having oversized tyres on the rear (235 x 45).

[ITSv40]

Hi Tony,

I have measured my car: standing on the lift which is spirit level level, 225/45 tyres, empty car with spare wheel and tools in the boot and half a tank of fuel.

Centre of wheel to arch: nearside front 385mm, nearside rear 385mm, offside front 380mm, offside rear 380mm.

From ground to bottom of sill weld seam - where sill joins the floorpan: nearside front 185mm, nearside rear 180mm, offside front 180mm, offside rear 175mm.

Hope that helps to determine how yours is sitting.

[tony209]

Originally Posted by ITSv40

Hi Tony,

I have measured my car: standing on the lift which is spirit level level, 225/45 tyres, empty car with spare wheel and tools in the boot and half a tank of fuel.

Centre of wheel to arch: nearside front 385mm, nearside rear 385mm, offside front 380mm, offside rear 380mm.

From ground to bottom of sill weld seam - where sill joins the floorpan: nearside front 185mm, nearside rear 180mm, offside front 180mm, offside rear 175mm.

Hope that helps to determine how yours is sitting.

Thanks,

My car with similar load and same tyre is 360mm all round for centre of wheel to wheel arch and floor to sill seam is 185mm rear and 175mm front. Compared to your measurements, it doesn't make sense!
Attached are pics of where I measured to see if we are on the same page.

[ITSv40]

Tony,

I measured from centre wheel to the bottom of the painted metal wing - not sure if you went to the bottom of the plastic liner, but if you did it doesn't match that difference in distance.

With the sill measurement, I went from the floor to the bottom of the metal flange between the sill and floorpan, so that could explain the difference in measurements there.

[burgess]

VIDA crossmatches the data plate alpha-numerical suspension code-elements to the Volvo colour code and Volvo part number. If you can identify the Volvo colour code on the original spring you can cross reference that to the part number.

On Autodoc, Suplex 38100 springs:
Length 430mm; Thickness 11.75mm; Diameter 128mm.
fitment includes
2.3T5, Year of Construction 07.2002 - 10.2005, 2319ccm, 245 PS
KYB
Length 400mm; Diameter 128mm; Thickness 11,75mm

Springs get tiered with age, so yours might be sitting lower than when new.

[tony209]

Originally Posted by burgess

VIDA crossmatches the data plate alpha-numerical suspension code-elements to the Volvo colour code and Volvo part number. If you can identify the Volvo colour code on the original spring you can cross reference that to the part number.

On Autodoc, Suplex 38100 springs:
Length 430mm; Thickness 11.75mm; Diameter 128mm.
fitment includes
2.3T5, Year of Construction 07.2002 - 10.2005, 2319ccm, 245 PS
KYB
Length 400mm; Diameter 128mm; Thickness 11,75mm

Springs get tiered with age, so yours might be sitting lower than when new.

My car has two new front springs, KYB standard springs with no change in ride height from the dynamic spring, one fairly new rear aftermarket spring fitted by the previous owner and the other rear is I think original.

The confusion is with Volvo listing two springs for the cabriolet with the same VIN plate suspension code "4", neither having a colour code. Some spring manufacturers offer a 430mm spring equivalent part No.8614554 as the correct spring for the C70, some offer the 400mm spring, equivalent part No.8628145 as the correct spring.

VIDA suggests cars with chassis No. 1600> have the 8628145 spring. According to my car's chassis number, it should have this spring but appears to have the other spring fitted.

Since making the first post, I've discovered that the "dynamic lowered" rear spring for the C70 is 375mm, so the 400mm spring being offered by KYB, and others, is not the equivalent to the Volvo lowered spring.

[burgess]

In march 2017, I had a pair of new rear springs fitted by Volvo, genuine Volvo part number V08628145
Rear suspension code "N"
Front suspension "H8" the spring is Dynamic (brown) 3546644
Length [mm]: 473
Diameters [mm]: 13.00, 128

As the Volvo OEM shocks are Sachs, the spring probably are too.
Sachs rear coil spring OEM 8628145
Length [mm]: 430
Diameter [mm]: 11,75, 128

[tony209]

Just a follow on to this. I spoke to KYB because their 400 mm rear spring raised the front ride height and made the steering very light - I had to lower the tyre pressures to 32psi to get a positive feel.

KYB technician said that KYB spring heights are a compromise but was concerned about the lower height rear spring causing the front to go light and offered a refund if I wasn't happy with the springs.

I've now taken the KYB rear springs off as the rear ride was too hard - car did look better lower though! I know realise that the apparent high rear with the correct height 430mm springs is due to the front KYB springs I fitted being 442mm rather than the 476mm.