More Caster in 740s

[Renny_D]

So without going to camber plates - though that is a good option - how can we add more caster to 740s. I was just looking under the hood and it doesn't look like you could redrill the holes further back as they are already pretty far back. Could the struts be rotated and then drill new holes? I haven't looked at how the spring seats up there so that may not be possible. I've heard of people shimming the lower arm forward? I don't auto cross so I can deal with having more steering effort and I'd really like to get more high speed stability and a little more grip in the corners. So what have people done or what can be done?

Thanks
Renny

[JE Jr]

There are different lengths of the lower control arm. I think the longest was on 940's with 16" wheels from factory, but since you got a 90 740T I thing you should have got Hydras on it, and maybe you got them too??

I hope someone with VADIS can help you out on this one.

[Renny_D]

Is it possible to shim the control arm forward? If so how do you do that? Bkdr wanna make adjustable arms?

Renny

[blarf]

Also, bigger bushings. I believe IPD redesigned their strut rod bushings to be a bit closer to normal size within the past few years. OTOH, the other places like FCP Groton may still sell the oversized strut rod bushings.

[Janspeed]

I shimmed them by putting 2 concave rings (like a 5mm shimstack) behind the (in my case IPD-)control-arm bushing.
You need to completely remove the reaction-arm in order to be able to place the rings.

Volvo also supplied OEM-Taxi-reaction-arms which are a bit longer (don't know the VADIS-number though) The have the same increased caster-effect.
For the 240 Volvo had a similar OEM-mod available.

It looks a bit iffy because the wheel is pushed forward and is no longer located exactly in the centre of the wheelwell but the benefits in cornering are well worth it.

[Renny_D]

Originally Posted by Janspeed

I shimmed them by putting 2 concave rings (like a 5mm shimstack) behind the (in my case IPD-)control-arm bushing.
You need to completely remove the reaction-arm in order to be able to place the rings.

Volvo also supplied OEM-Taxi-reaction-arms which are a bit longer (don't know the VADIS-number though) The have the same increased caster-effect.
For the 240 Volvo had a similar OEM-mod available.

It looks a bit iffy because the wheel is pushed forward and is no longer located exactly in the centre of the wheelwell but the benefits in cornering are well worth it.

Cool do you have any pics of the work? Where did you get the shims/rings that you used? Also If I push the bottom forward and move the top back hopefully I could gain the same caster and keep the wheel positioned somewhat close to centered. So is it possible to rotate the top and redrill the holes? Does anyone know?

Thanks
Renny

[SteveMD]

I have heard it is possible to pound out the 2 strut top mount studs and move the strut top to where you want it then drill holes in the mount via the existing holes in the strut tower.

[Janspeed]

Those rings I used are very common in chassisapplications where they are used to retain rubber bushings. They are shaped like dish. I just picked them up at a local garage.

I have to admit that making the adjustements on top is technically the better option (no messing up of the ackerman-geometry when adjustments of caster and camber are made on top.) but much harder to do too.

[JE Jr]

I checked with my local dealer today, there are an acessory control arm that are 396mm. costs ~500SEK =~$70 each.

Stock ones are 385mm, or 388,5 or 390 depending on version, if the car have had problems with unstability during braking and so on...

[kiwibrick]

Don't know about the 740 but on both my 760'a the 2 bolts on top of the strut aren't symetrical, so I unbolted the top rotated the seat and bolted it back, hey presto an eyeballed increase of about 5deg of castor, wheel is very close to the same place and I can feel the difference through the steeringwheel.

[Renny_D]

Originally Posted by kiwibrick

Don't know about the 740 but on both my 760'a the 2 bolts on top of the strut aren't symetrical, so I unbolted the top rotated the seat and bolted it back, hey presto an eyeballed increase of about 5deg of castor, wheel is very close to the same place and I can feel the difference through the steeringwheel.

Cool, please post pics as I'm definately interested.

Thanks
Renny

[blarf]

Originally Posted by Renny_D

Cool, please post pics as I'm definately interested.

Rotating the strut the 'wrong' way will change the caster (not camber) from ~5 to ~3 degrees. The easiest, and cheapest, way to increase cater would be with the bigger bushings and bigger strut rods. The 5.5mm difference makes a 0.8 degree difference in caster.

To change the camber, you'd want to drill the strut tower and/or mount.

Are you looking for more camber or caster?

[k4dje]

Now for the excuse I have never had a volvo strut off the car, Looking at the tops of the towers It looks like the caster would go the wrong way IE more negative. Well I will have mine apart soon cause my struts are worn out. My alignment settings are pretty standard for all my junk. As much positive caster as possible along with .5 to 1 deg negative camber. Gives good handeling with decent tire wear. Same settings both sides. Toe, I usually go with factory preferred.

[Renny_D]

Originally Posted by blarf

Rotating the strut the 'wrong' way will change the caster (not camber) from ~5 to ~3 degrees. The easiest, and cheapest, way to increase cater would be with the bigger bushings and bigger strut rods. The 5.5mm difference makes a 0.8 degree difference in caster.

To change the camber, you'd want to drill the strut tower and/or mount.

Are you looking for more camber or caster?

I'm looking for Caster. My original thought was to rotate the top of the strut 90 degrees then redrill but I wanted to know if anyone had done that?

Thanks
Renny

[k4dje]

Looking at my struts rotating the top will give you less caster. Positive caster is when the top is trailing the bottom. To give more caster you want to move the top of the strut rearward, or the bottom of the strut forward.

[Renny_D]

Originally Posted by k4dje

Looking at my struts rotating the top will give you less caster. Positive caster is when the top is trailing the bottom. To give more caster you want to move the top of the strut rearward, or the bottom of the strut forward.

I wish I could draw it. I ment turn the bolts 90 degrees from their current position then move the strut top rearward and redrill the holes. There is no room to just redrill the holes further rearward from the current position. It might be possible to slot them slightly but that would net me very little. I may just hold out for some one to invent a cost effective camber/caster plate setup.

Thanks
Renny

[k4dje]

Now it makes sence It could work. Go to a bone yard and try it on a junker. I think getting the longer arm would be a better rout. My .02

Originally Posted by Renny_D

I wish I could draw it. I ment turn the bolts 90 degrees from their current position then move the strut top rearward and redrill the holes. There is no room to just redrill the holes further rearward from the current position. It might be possible to slot them slightly but that would net me very little. I may just hold out for some one to invent a cost effective camber/caster plate setup.

Thanks
Renny

Yes, they can be moved and redrilled have done this many times 86 forward 740's 89 forward 780's for 1" to 2" suspension drops. However, adjustment is limited by diameter of upper strut mount first, then diameter of spring in extreme drops.

There is an issue strut towers moving with age making alignment more of PITA.

Suggest, when you get the alignment where you want it, brace everything even if you have to fabricate your own braces.