Rear Toe

[black eclat]

Bit of a puzzle here.

I was out driving my 521 Eclat earlier and the rear felt strange going through corners, almost as if it was steering itself, and not in a good way!

When I got back to the garage, I checked front toe and it was toe in 1degree. all good there.

Checked the rear and it was 3 degrees Toe Out, 1 degree on nearside and 2 degrees on offside.

No inner washers on the rear radius arm mounts so I have no adjustment left.

Nothing seems loose or bent on the rear suspension

No idea what to do next!

Anyone experienced this before?

[EXCEL V8]

Is this a newish car to you?  Do you know it has been OK in the recent past?  What sort of condition are the front trailing arm bushes in?  Do you have the reinforcing bracket across the rear diff mounts?

Pete

[black eclat]

A bit of background,

I have the car 15 years and its always handled well once driven within its limits.

October 2022, I had a crackling outer diff bearing so the diff was removed and both outer bearings replaced.

All other rear suspension parts checked and spacers on the diff noted. All bushings were replaced in 2021 and I have only covered 5k miles since then.

The radius arm washers, then, were all on the outside of the radius arms. (radius arm tight to rubber mounting).

A reinforcing channel is fitted across the diff mounts.

I have driven it since October and didn't notice anything amiss with handling but it was just a test to check that the crackling had disappeared when turning sharply.

Since yesterday, I put the car on the lift, slackened all suspension components, rolled it backwards and forwards on the floor several times with 80Kgs ballast in the boot.

I torqued the suspension again, whilst on the floor.

When I apply the tracking gauge again, it reads the same.

I don't doubt the tracking gauge as it reads correctly on the front toe and against my calibration gauge.

I cant see anything wrong, out of place and I am thinking I might need to "alter " my diff reinforcing channel.

Any feedback welcome.

 

[jonwat]

Have you  checked the radius arms have not rusted? If the steel is getting thin they'll deform under load 🤔

[black eclat]

I hadn't considered that.

They don't appear rusted.

[EXCEL V8]

I'll dig out my old radius arm bushes over the next couple of days to remind myself what would happen to the toe if the rubber started to perish.  Have you checked the camber yet?

Pete

[drdoom]

You're wise to heed what the car's handling, what the toe settings are speaking to. I'd look at the diff output bearings, U-J's, and the hub carrier bearings straight off. Yes, do inspect the trailing and lateral arms, if beginning to fail due to corrosion you won't want to be driving much at all before remediation.

[black eclat]

Don't have the means to measure camber but from an alignment check late 2021, LH Rear was -00.40 degrees and RH was -01.52 degrees.

[Dunc]

I suspect diff output bearing failure. Had a funny "wiggle" develop on mine when I lifted off the throttle. Partially dialled it out with adjustment, but its still there. Got in and out play on the lhs of the diff of about 1cm...

Still not fixed it/investigated any further.

[EXCEL V8]

I had a look at the old radius arm bushes today - if they were to go very soft for some reason or started to disintegrate they could certainly affect toe, but even my old ones are pretty solid.

By the way - you can't "alter" the diff reinforcing channel.

Do the vertical sides of the chassis look flat? - there is reinforcing inside the chassis at the radius arm mounting point - might be worth checking that it hasn't become "bowed" at the attachment point.

Any play in the wheel bearings?

Pete

[black eclat]

Diff bearings are ok, recently changed.

Wheel bearings are ok.

Small, almost imperceptible play in diff and U/J's. All U/J's greased and not rusty

Radius arm bushes are old but not soft or perished.

Radius arms look straight as much as I can tell with them on the car. Put a spirit level along its length and shows to be straight.

Chassis looks square and flat.

I have booked it in for 4 wheel alignment check this coming week so I will see what that tells me.

[Dunc]

any update on this post alignment check Michael?

[black eclat]

Well, I had to cancel the alignment check as I was invited to present the Eclat for a photo shoot to appear on a You Tube channel called Johns Garage.

I spent a considerable amount of time polishing and buffing the car in preparation for that.

It was a 200km round trip and the car was fabulous and it didn't rain. 

Part of the photo shoot was a spirited drive for some action shots and it was very well behaved.

However, I still intend to get the alignment check done, soon.

 

 

 

 

 

[jannickz]

On 03/02/2023 at 02:36, EXCEL V8 said:

I had a look at the old radius arm bushes today - if they were to go very soft for some reason or started to disintegrate they could certainly affect toe, but even my old ones are pretty solid.

By the way - you can't "alter" the diff reinforcing channel.

Do the vertical sides of the chassis look flat? - there is reinforcing inside the chassis at the radius arm mounting point - might be worth checking that it hasn't become "bowed" at the attachment point.

Any play in the wheel bearings?

Pete

Checking for play in the wheel bearings is crucial. Excessive play can indicate wear and tear and should be addressed to prevent further damage. Consider measuring the distance between the radius arm mounting points on both sides. This can help identify any asymmetry that might indicate chassis issues. You may want to consult a workshop manual or professional mechanic for specific instructions on how to properly check the chassis and wheel bearings.