'Limp' nearside rear corner?

Unread post by **Dommo** » 31 May 2010, 17:39

Hi folks

Something I've noticed with my activa is that the nearside rear wheel is always quite limp when in the drive, even when I put the car in service high theres a good 4cm difference in the gap between the rear wheels and the rear arches, with the nearside being lower.

I had noticed that the nearside rear strut/shock was floppy as anything when I changed the rear corner spheres (I used the servicehigh method to loosen them so I didn't damage them that way).

Any thoughts?

Cheers.

Xaccers · Unread post by **Xaccers** » 31 May 2010, 18:20

Unless rusted, the rear struts rotate and can wobble with the back off the ground and depressurised.

DickieG · Unread post by **DickieG** » 31 May 2010, 19:23

Is the car level? The balancing mechanism may need tweaking.

Unread post by **Dommo** » 31 May 2010, 20:33

Not especially no, would it be wonky even when the engine turned off if the roll corrector isn't set up correctly?

Cheers.

Unread post by **CitroJim** » 31 May 2010, 20:51

So Dom, if I understand you correctly, what you are saying is that when parked up, the car leans and this lean continues even if on high.

This would suggest to me that as Richard suggests, the Activa roll corrector mechanism needs a check and set-up.

Be warned though that the process is incredibly tricky and frustrating. It's more an art than a science and takes practice...

It is possible for the system to be wrongly set-up and yet the car be level at normal ride height but tilting as the ride height changes. This would account for the lean on hight as the rams can pull one side down so that on that side full height is not achieved. If wrongly set, the car will have a tendency to tilt when parked up.

Firstly, ensure the roll corrector mechanism is very free in all ways and well lubricated. Any stiffness either on the pivot or the sliding plates will make it impossible to level correctly.

Then check that both rods are correctly set so that a clearance of 6mm exists between the rod and the back of the anti roll bar clamp bracket. Adjust by loosening the 13mm bolt in the wishbone and moving the rod fore and aft to achieve the clearance.

Then set the two bottle screws ( Caution, one side of each has LH threads) so that there is a measurement of 74mm between the extreme ends of the threads on the rods.

With the car up on ramps, start up and check level at normal ride height. Adjust each bottle screw by SMALL EQUAL AND OPPOSITE AMOUNTS until the car rides exactly level. Ensure this level is maintained on full height. Be sure that you adjust the correct way so that some pre-load is maintained in the roll corrector plate springs.

It sounds easy when described but it is a rotten, horrible and long job. You'll end up doing and redoing it for ages until you are happy.

Be aware that a worn rear ram bush and worn rods/guide blocks will all conspire to make a less than perfect set-up...

Unread post by **CitroJim** » 31 May 2010, 21:17

Dom,

What I described above is the "official" method.

There is another method. Set the car on high and place an axle stand under each sill jacking point at the front. Each stand must be precisely the same height. This is vital.

Then set the car to low so that the rear falls right down and the front stays high on the stands.

Check the ARB bracket to rod clearance as described and loosen the bottle screw locknuts. Ensure the roll corrector mechanism is very free in all ways and well lubricated as already described.

Now, raise each front wheel to normal ride height (three fingers between arch and tyre) and hold it there using a block of wood of exactly the right thickness. You are aiming to get both front wheels sitting at precisely normal ride height. For this to work you need a smooth, level driveway and identical tyres on each side carefully blown up to the right tyre pressures.

This done, now look at the alignment holes in the roll corrector mechanism. Adjust the bottle screws until the alignment holes precisely align and you can easily place drills of suitable diameter in them without actually moving any part of the corrector mechanism. Ensure the plate springs retain a little pre-load.

This method should get you in the right "ball-park" but you may still have to do a small correction to achieve precise level.

This method worked for me on Project Activa and is good to get it roughly right if the whole roll corrector mechanism has been completely dismantled. As with setting height. a small adjustment makes a big change in level.

The other benefit of this method is the engine does not need to be running, wasting a lot of fuel.

Unread post by **Dommo** » 01 Jun 2010, 00:13

Thanks for those guides Jim. If this is the issue I'll have to get that checked, and sorted! I assume with both methods you need the drive to be as flat as possible (something we don't possess

)

One thing me and my brother did notice - that I forgot to mention before - was that when we pulled or pushed the roll corrector linkage, the nearside rear wheel didnt move much in the wheel arch, whereas the other three wheels all moved a fairly decent amount. Which suggests to me that it's not a badly set up roll linkage, as surely us pushing the linkage away slightly from the nearside/towards the offside should account for a badly setup linkage if it's leaning towards the nearside, am I right??

It really looks as though it's just not able to move like it should, or not sitting where it should at least. If it's definately roll corrector linkage related then I'll get it sorted when possible, but as you'd imagine I don't fancy setting the linkage up if it turns out the rear end is wonky, so I'd have to set it up again when/if the rear end gets fixed!

Thanks again Jim, those guides must have taken a while to write up so I greatly appreciate it! Dom

KevMayer · Unread post by **KevMayer** » 01 Jun 2010, 19:39

This may be due to a faulty nearside rear drop link (possibly... that's if I understand your description correctly? ).

Could the ball joint at the top of the droplink be siezed and so the rear ram will be changing the height of the rear offside and kind of hinging around the nearside rear corner.

It may be worth having a look at this nearside droplink to see if anything is obvious.

When you go to high setting you'd expect the rear suspension cylinders to extend fully so, it's surprising to hear that there's play in the nearside rear.

Unread post by **Dommo** » 01 Jun 2010, 19:56

Thanks for the response Kev

I did have a look at the nearside droplink as it happens, I only saw that it was attached at the bottom end, didn't look into it much further to be honest, but I will do either later on today or tomorrow, so thanks for the suggestion, it sounds unlikely but you never know do you?

Also - you may have misunderstood my description of the nearside rear cylinder, it was only floppy when up on stands on servicelow, it may be floppy normally on servicelow but I only noticed it when on stands. What I meant was that I used the servicehigh method to loosen the rear corner spheres, basically to say that I hadn't damaged the cylinder myself - but someone else could have damaged it for all I know!

Thanks. Dom.

Unread post by **CitroJim** » 01 Jun 2010, 20:18

Dommo wrote: Also - you may have misunderstood my description of the nearside rear cylinder, it was only floppy when up on stands on servicelow, it may be floppy normally on servicelow but I only noticed it when on stands.

As Xac says, that's normal Dom. The other cylinder will be kept tight(er) on an Activa due to the action of the ram.

Have you noticed that if you support the rear on axle stands and drop low, one wheel will always sit higher that the other when relieved of load. IO can't recall which now, even after observing it 100s of times...

Unread post by **Dommo** » 03 Jun 2010, 15:28

Well I had a looky under the car yesterday, and in going from servicehigh to low, or low to high, the ball joints on the nearside rear ARB drop link don't appear to move. But should they, does anyone know whether they should??

And Jim - how floppy are they supposed to be exactly? It was very very floppy. I assume they're similar to a front strut under the gaiter, only smaller?

Thanks.

KevMayer · Unread post by **KevMayer** » 04 Jun 2010, 17:36

The rear drop link ball joints should move as the height changes.

The rear ram length should remain fixed and act like a second drop link.

The lower end of the rear droplink is connected to a short arm on the suspension trailing arm, so, as the trailing arm moves up and down this short arm pushes and pulls on the drop link. The top end of the drop link then acts on the anit roll bar, which is mounted high up on the subframe, to make it rotate.

Unread post by **Dommo** » 04 Jun 2010, 19:32

KevMayer wrote:The rear drop link ball joints should move as the height changes.

The rear ram length should remain fixed and act like a second drop link.

The lower end of the rear droplink is connected to a short arm on the suspension trailing arm, so, as the trailing arm moves up and down this short arm pushes and pulls on the drop link. The top end of the drop link then acts on the anit roll bar, which is mounted high up on the subframe, to make it rotate.

If I film the movement (or lack of) of the nearside rear drop link, would you be able to judge from that whether the drop link looks OK or not?

Thanks Kev. Dom.

Unread post by **Dommo** » 04 Jun 2010, 20:17

You can't see the movement in the videos I've made as the camera's so rubbish, but in these pictures you can clearly see movement in the top ball joint. So that rules that out as a possible cause for the height differences?

KevMayer · Unread post by **KevMayer** » 04 Jun 2010, 20:23

The movement looks like what you'd expect to see.