Suspension: 70: C70 Cabrio front suspension

[burgess]

I'm re-posting this, hope that's ok, I'd posed in the wrong section

I’m about to replace the front suspension on my 2001 C70 Cabrio

I’ve a pair of new Sachs shock absorber struts 82 4903 553 058 (oil pressure); which are said to be comparable to the original Volvo Sachs 82 4903 553 021 struts.

Volvo list the springs as OEM 3546644 dynamic spring (brown colour coding), however, most all of the after market vendors list coil springs OEM 3546642 (green colour coding).
I have a pair of Kilen springs 3546644.

The following details from P.P.S.
3546644, wire diameter 13.00mm, spring diameter 143mm, length 473mm
3546642, wire diameter 12.75mm, spring diameter 142mm, length 442mm
The dimensions for the 3546642, indicates less stored energy in the compressed-fitted state, would seem to indicate a softer ride than the more robust 3546644 springs.

Anyone have experience of 3546642 springs on a C70?

[tony209]

I've changed from the brown dynamic spring to the green comfort spring on my T5, I found the front end suspension too hard, there are a lot of speed bumps around where I live, which my 2.4 (with comfort set up) rides a lot better.

The difference in handling was very noticable on the T5 but I got used to it and learnt to drive the car to match the new dynamics. I haven't decided yet if the trade off is worth it though.

[ITSv40]

My C70 is still on the original components. Comfort suspension, 17'' comets with 45 profile Michelin tyres.

It drives very precise with a nice soft wallowy ride which I like. Rough surfaces and small potholes do catch it out, but since fitting a front strut brace has stiffened the scuttle up and much improved ride.

[burgess]

Originally Posted by ITSv40

My C70 is still on the original components. Comfort suspension, 17'' comets with 45 profile Michelin tyres.

It drives very precise with a nice soft wallowy ride which I like. Rough surfaces and small potholes do catch it out, but since fitting a front strut brace has stiffened the scuttle up and much improved ride.

Thanks for responding.
A precise softer rind sounds interesting.
Do you know the alphanumeric coding xxxxxxxxx in the lower right hand column of the data plate on your GT?
The first two characters denote the front suspension shock & spring; fourth denotes the rear spring, fifth denotes rear shock absorber.

Volvos green colour coding OEM 3546642 springs, and shock absorbers OEM 9173850, both correspond to data plate first two characters C9.

If C9 are the first characters, can you tell me what the fourth and fifth characters are, or all four if different please, from those I can ascertain the suspension geometry for year of manufacture.

[burgess]

Originally Posted by tony209

I've changed from the brown dynamic spring to the green comfort spring on my T5, I found the front end suspension too hard, there are a lot of speed bumps around where I live, which my 2.4 (with comfort set up) rides a lot better.

The difference in handling was very noticable on the T5 but I got used to it and learnt to drive the car to match the new dynamics. I haven't decided yet if the trade off is worth it though.

Thanks for responding Tony.
When you dropped out the struts, was there any lost motion at the two fixing holes strut to steering knuckle.

Reason for enquiring:
VIDA info: 1994 models the fixing screws 12.1mm replaced with 13.00mm. Also steel tubes to reduce clearance in the steering knuckle holes.

A while back, I obtained set of new fixings from Volvo, screws part number 982845, are 12.1mm.
VIDA 2014 parts catalogue does not show any sleeves, as shown in procedure section.

[ITSv40]

Originally Posted by burgess

Thanks for responding.
A precise softer rind sounds interesting.
Do you know the alphanumeric coding xxxxxxxxx in the lower right hand column of the data plate on your GT?
The first two characters denote the front suspension shock & spring; fourth denotes the rear spring, fifth denotes rear shock absorber.

Volvos green colour coding OEM 3546642 springs, and shock absorbers OEM 9173850, both correspond to data plate first two characters C9.

If C9 are the first characters, can you tell me what the fourth and fifth characters are, or all four if different please, from those I can ascertain the suspension geometry for year of manufacture.

My plate reads: M71N4MS5

The 2003 brochure states that the 2.0lt and 2.4lt was fitted with Comfort suspension, both the same whether T or GT. The T5 had Dynamic suspension.

Hope this helps.

[burgess]

Hmm, interesting. I had a look at the 2003 brochure.
I had a look at the Volvo Product Training Volvo Convertible 34 page brochure,
which speaks of three chassis variants.
The Volvo C70 Convertible with low pressure turbo (LPT) engine is equipped as
standard with the Comfort chassis.
The high pressure turbo (HPT) engine has the stiffer Dynamic chassis as standard.
The Dynamic Low chassis is the stiffest chassis for sporty driving and is an option for both models.

Going by your data plate, according to VIDA, M7 corresponds to strut 8600901 and spring 3546644, which is the dynamic spring.

Mine C70 is a 2.0 LPT variant.
My Data plate: H81N4MS5
Equates to:
(H8) front spring 3546644 and shock 8600901
(4) rear spring 8628145 and (M)shock 9173851

Quite confusing. If only Volvo would list full technical details.

The original front springs on my C70 seem to be sagging and have some corrosion. I’ll go ahead and assemble the all new struts using these Kelin OEM 3546644 springs.