Checking VCU, is it OK?

emoose · May 17, 2012

Changing the disc & pads I noticed some windup jacking up the rear wheels. Mentioned it on here and it was suggested I check the VCU.

Jacked up one wheel in neutral and tried turning it.
By hand I can rock the wheel back and forth and see the prop start turn.
With a breaker bar I can rotate it further and see the prop move but it stiffens up a lot and springs back partially when I release it.

Should it keep rotating? Or is it just turning partially enough to say the VCU is OK?

Also checked it by driving in a tight circle in a car park (felt like being a teenager again!) and it felt fine, no jerkiness or tyre scrabbling.

Took a couple of videos:
Rocking the wheel back and forth by hand 20120516_190206.mp4 - YouTube
Using a breakerbar 20120516_190244.mp4 - YouTube

jamesmartin · May 17, 2012

if you have one front wheel up and you cant turn it it ,should keep going round v/c is seized

pariah · May 17, 2012

There is a test procedure in the Common Faults and Questions section.

emoose · May 17, 2012

jamesmartin said:
if you have one front wheel up and you cant turn it it ,should keep going round v/c is seized

I can turn it a certain amount, say 20 degrees, and see the prop shaft rotating. But then it stiffens up and wants to bounce back.

If I keep pushing I can keep it going round but it takes a lot of effort and it wants to spring back a bit when I release.

Datatek · May 17, 2012

emoose said:
I can turn it a certain amount, say 20 degrees, and see the prop shaft rotating. But then it stiffens up and wants to bounce back.

If I keep pushing I can keep it going round but it takes a lot of effort and it wants to spring back a bit when I release.

If you can keep it turning then the VCU is OK

It should take a lot of effort and it will spring back a bit when you let go/collapse

emoose · May 17, 2012

Just had another go, neighbours must think I'm mental, and got it rotating smoothly.

Where I think I was going wrong was in just grabbing at it and expecting it to turn. This time I just built up pressure on the breaker bar and maintained it, then after a few secs it started to go round slowly.

Not as quickly as this guys, Range Rover 4.0 V8 P38 Viscous Coupling Test 2 - YouTube but it did go round, got about 180 degrees of rotation in the end.

Near side wheel seemed easier to move then offside...

pariah · May 17, 2012

you didnt use the official test then?

emoose · May 17, 2012

pariah said:
you didnt use the official test then?

You mean from http://www.landyzone.co.uk/lz/f38/definitive-freelander-vcu-testing-thread-99163.html ?

Well I didn't put any tape on but effectively did the same thing (first page).
I didn't lash up the metre bar and weight arrangement, I think I'm proving that its sound by rotating it, it's certainly a long way form locked solid.

Would the weight and forces for a freelander not be different for a Range rover?

Datatek · May 19, 2012

emoose said:
You mean from http://www.landyzone.co.uk/lz/f38/definitive-freelander-vcu-testing-thread-99163.html ?

Well I didn't put any tape on but effectively did the same thing (first page).
I didn't lash up the metre bar and weight arrangement, I think I'm proving that its sound by rotating it, it's certainly a long way form locked solid.

Would the weight and forces for a freelander not be different for a Range rover?

If you can turn it 180 degrees I would say it's OK for the moment. I check mine at every service.

Checking VCU, is it OK?

emoose

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jamesmartin

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pariah

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emoose

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Datatek

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emoose

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pariah

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emoose

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Datatek

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