replacing shock oil to increase stiffness

[Raceeend]

Hi,

I was wondering if it is possible to replace the oil in the volvo 360 gle stock shock absorbers for a thicker grade oil. I saw on other forums this is sometimes done on other brands of cars but i wonder if this is also possible with the volvo 360 shocks.

If this is possible, could anyone tell me the viscosity of the default shocks and what viscosity is recommended to fill the shocks with? I would rather have koni's but they seem to be rather hard to find for a decent price.

[jamie_stafford]

if your after rear shoks ive just fitted front shoks from a landrover defender, they cost me £35 new from ebay and theyre a perfect fit, ive heard of putting diff oil in the front shocks but im not sure how to yet.

[Jason B]

dampers.... - sorry, I'm a stickler for using the right word to describe what the part does

Plenty of people have done it, no idea if it works well and everyone will say something different. like saying landrover dampers being great - though ironically the word shock could possibly be used for landy dampers on a 300... as I'm dubious as to whether the 300 is actually heavy enough to get them working as dampers and not springs.

Replacing damper oil is easy.... remove the strut, remove the spring etc from the strut, undo the damper nut that holds it into the strut, remove the damper unit, pour out the oil into a measuring container, refill with the right amount of a concoction of your choice and refit everything... and crucially don't let anything else get into the strut tube as it could lock the valves out apparently - jobs a good'un

[filthyjohn]

Changing the oil weight should in theory make a big difference to the damping. I've never done it to a car, but used to change the oil in my bicycle forks regularly. A difference of just 5w was noticable on a Marzocchi Z4 fork, so changing to 80w gear oil should significantly alter the damping of a 300 strut.
Does anyone know what oil is used in the dampers as stock? To get a good result the oil weight will have to be appropriate for the spring stiffness. Going back to the sus forks, they were air sprung so you could alter the effective spring rate by changing the pressure, then take an educated guess at the right oil weight to get things right.
This is essentially the same as fitting a stiffer spring to a volvo, then trying different thickness oils in the dampers.

[Bazboy]

If you removed some of the oil/put less back in would this make the shocks sit lower?? cause i was reading somewhere that when you lower a car(springs only) the shocks will start to leak after awhile as there not meant to be compressed all the time. So would removing some oil help stop this?? Or am i being silly.

Cheers Dan

[filthyjohn]

Removing oil won't let it sit lower, the spring would still be the same length.

[Raceeend]

Thanks for the answers. In a few weeks i wil try to replace the oil by 80w or something near that and i'll tell here if it works.

@bazboy. the reason why it may start leaking is because suddenly a whole diffrent part of the "shock rod" (donnu the correct name) is used, that may have some dirt, rust or stone chips on them. that is rather bad for your oil seals. If you would brand new stock shocks after lowering no leacking will occur. but because the shock absorption is rather low compared to the possible travel of the shock (it is already pretty far compressed) you may hit your bump stops once in a while.

@jason: dampers is a literal translation of the dutch version of shock absorbers. But normally i am also kind of a bitch when it's about correct naming of technical parts and it's functions, so thanks for the correction

[Jason B]

hehe, didn't realise you were dutch as your english is far better than lots of british nationals that post on here and other forums! - though I should have guessed from the mention of konis I suppose

In which case I apologise for correcting you so bluntly!

[Chris_C]

@jason: dampers is a literal translation of the dutch version of shock absorbers. But normally i am also kind of a bitch when it's about correct naming of technical parts and it's functions, so thanks for the correction

You're Dutch!? FFS, now we just need to get English taught as well over here. I wish I had that level of fluency in a 2nd language.

On the important matters, I'm interesting how your test goes, I'm thinking something similar for mine atm, but am still dubious!

[WooDooUK]

I have EP80 Gearbox oil in my front struts, i was a little disappointed at first, i tried my best to bleed them the same but the car would still dive about under heavy breaking and they didn't seem particularly hard.

However i just left them and continued to use the car and they sorted them selves out and got much stiffer, works well with the landrover dampers on the rear.

Key is to be patient after you have done them.

[Raceeend]

@woodoo, now that they have had some time to gain their proper level of resistance woould you recommend going even thicker than 80 oil or do you think it is good enough now? I'm a bit too lazy to change the oil twice if i'm not happy ;P


@chris. In holland english is tought from about the age of 11, so it's almost my native language

@Jason, I'd rather be bluntly corrected than ignorantly continuing to use the wrong words

edit: and even though i was corrected i kept using the wrong term during my other posts lol

[classicswede]

The problem with changing the oil to a thicker one is that you are increasing the bump performance but reducing the rebound response. That is why you are much better with a correctly set damper using thin (fast responding) oil and suitable sized valves. Best dampers will be gas pressured not just oil filled.

I'm not saying that thicker oil will not be an improvment but it's still not going to be great.

[WooDooUK]

@woodoo, now that they have had some time to gain their proper level of resistance woould you recommend going even thicker than 80 oil or do you think it is good enough now? I'm a bit too lazy to change the oil twice if i'm not happy ;P

All depends on what your after tbh, i just use mine as a fast road car with the occasional trackday, it doesn't help the understeer at all but the car is much more stable.

[Raceeend]

well i want to make it a nurnburgring worthy car. so i'd rather use proper shocks like koni's, spaxx or something like that. but i haven't found any proper front shocks yet. i saw spaxx and landrover shocks for the rear but i didn't see any good front shocks yet.. hints or sellers are appreciated.

btw if you have understeer in a volvo 360 you just forgot to force it into oversteer clutch dumpt etc are essential for keeping the 360 under controll. especially if you have stuff like a welded diff (what will happen to mine). Best is no oversteer or understeer, but if you must choose between understeer or oversteer (which is the case with the 360) oversteer helps you getting round corders mutch faster than understeer. so an occasional clutchdump, handbrake etc will even improve your lap times when you have a rather stiff volvo 360 (so with stiff springs, dampers, and stiff body) that experiences too mutch understeer.

[trabitom99]

I may be putting a set of new adjustable Koni 86-2182 front dampers / shocks, whatever, on the bay or on marktplaats soon. 'Fraid I won't let them go for small money though, they cost me an arm and a leg a few years back ...

My GLT needs a lot of work and next year both the GLi daily and the Merc are due for their tough two-yearly German MOT checkup so I will probably be selling some stuff soon. No point having bits in the garage and no road-worthy car to put them in

Tom