Freelander 1 VCU and Carrier Bearings Replaced - New Noise...

I've done a fair bit of maintenance on my TD4 FL1 of late. It's a 2002 with just over 70k on the clock (my late grandfathers car). It was parked on wet grass on a farm all it's life so it's "crusty" underneath but recoverable!

Anyhoo - having replaced both front driveshafts, water pump (that is FUN on a TD4....not!) front bottom arms, arb drop links, full service - I've just replaced the VCU and carrier bearings as a single unit from Bell Engineering.

I swapped the VCU etc as the bearing bushes were gone - propshafts could move about 3/4" up and down - and given the VCU is the OE original to the car and you could occasionally feel it tighten up in a car park I thought might aswell replace it at the same time.

Now - this VCU made no noises, no other part of the transmission did, so apart from the oddness in one car park - it appeared to be fine.

Having swapped it out yesterday - the car drives just fine in a straight line at any speed - but a moderate bend in the road there's what sounds like a grinding noise possibly from the rear (hard to tell and sound travels and all that) kind of the same as if a stone gets caught between a disk and a brake shield - ie it's not a "substantial" grinding noise, but a "quietish" noise.

So - no noises before hand with a 20 year old VCU, but a refurb from a reputable firm (Bell Engineering) and now I have this.

A moderate bend or a car park manouver causes the rear wheels (and fronts naturally) to have a difference in speed left to right, regardless of what the VCU is doing - the rear diff / IRD at front allow for the different speeds across themselves - so whether a VCU is siezed up or fails open - I'm stumped to see how it could cause this noise.

About all I can think of is maybe my original VCU had failed such that it never passed torque through to the rear diff, now it does - maybe my pinion bearings in rear diff had gone? But why would a car on perfectly dry roads pass torque through to the rear if there's no loss of traction?

What I'm curious to know is - has anyone ever had this before where a "new" VCU triggers the car to make a new noise?

I rang Bell Engineering this morning and he's never heard of it either but will investigate my old unit to see how / if it failed and whether the new VCU has exposed a problem I didn't know I had.

I'm trying not to blame the last thing that was done (replaced VCU) as being the thing that caused the problem - but the car has certainly never made this noise before.

Any ideas?

Pull the rear drums off and check the brake shoes, and levers, when i had the two union bearing changed at (Bell Engineering) before i realised how easy the job was, i had a grinding noise after they were fitted, same as you i fitted new drive shafts and VCU.
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It turned out to be the shoes and old drums once replaced all was ok.
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Well I never! did yours only do this when turning?

To be fair - I'm sure the drums and shoes need doing as they are looking pretty sh** from the outside but I'd never have thought this could be the cause. I wonder how that's possible........

Have you checked the front mount on the read diff and did you line the support bearings up as they were before?

Its worth doing a 1 Wheel Up Test on the recon VCU - its rare, but not unknown for them to be delivered faulty.

GrumpyGel said:

Have you checked the front mount on the read diff and did you line the support bearings up as they were before?

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The front mount on the diff is in the same state as was before - not moved, so it's status should make no difference to this noise that only happens when turning (a car park say or moderate bend in the road) is my thinking? remember the only components changed are the VCU and the carrier bearings and the car made absolutley no noise whatsoever before (though the bearing bushes were indeed knackered which is why I swapped them and the VCU in the first place).

Given the noise is ONLY when turning, then the shafts are running in the same position regardless of any manouvering I'm doing considering the relative fixed positions of the IRD, VCU and Rear diff, so if there was a problem with alignment here then it (the noise) would happen all the time not just when turning?

The bearings are indeed lined up but not necessarily as they were before - but definitely 90 degrees to the shaft as per Rave:

GrumpyGel said:

Its worth doing a 1 Wheel Up Test on the recon VCU - its rare, but not unknown for them to be delivered faulty.

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I'll give that a whirl for the time it will take, it may help inspire confidence but it won't be any use in my conversations (should I need further) with Bell Engineering as he puts zero stock in the OWUT as per here: https://www.bellengineering.co.uk/fault-symptoms:

"Myth 2 - It has been reported on some internet sites that it is possible to test the VCU by jacking up one back wheel........"

I think @Arctic2 is onto something - as I had mucked around with handbrake briefly just prior to setting off thinking back to last night on the test drive. If the shoes on it are in the same state as the front pads were before I swapped them (they'd gone rotten and cracked all over) then it could cause the noise I was hearing on turns etc I guess.......

It's probably the brake shoes but still worth testing the vcu with the one wheel up test. If for no other reason than to give you a yardstick as to what it should be.
Nobody can understand bells stance on the test and they never tried to defend it.
BTW vcu"s failing in the way you mentioned is so rare it's very unlikely. If you took one apart you'd understand why.

nickb834 said:

The front mount on the diff is in the same state as was before - not moved, so it's status should make no difference to this noise that only happens when turning (a car park say or moderate bend in the road) is my thinking? remember the only components changed are the VCU and the carrier bearings and the car made absolutley no noise whatsoever before (though the bearing bushes were indeed knackered which is why I swapped them and the VCU in the first place).

Given the noise is ONLY when turning, then the shafts are running in the same position regardless of any manouvering I'm doing considering the relative fixed positions of the IRD, VCU and Rear diff, so if there was a problem with alignment here then it (the noise) would happen all the time not just when turning?

The bearings are indeed lined up but not necessarily as they were before - but definitely 90 degrees to the shaft as per Rave:

I'll give that a whirl for the time it will take, it may help inspire confidence but it won't be any use in my conversations (should I need further) with Bell Engineering as he puts zero stock in the OWUT as per here: https://www.bellengineering.co.uk/fault-symptoms:

"Myth 2 - It has been reported on some internet sites that it is possible to test the VCU by jacking up one back wheel........"

I think @Arctic2 is onto something - as I had mucked around with handbrake briefly just prior to setting off thinking back to last night on the test drive. If the shoes on it are in the same state as the front pads were before I swapped them (they'd gone rotten and cracked all over) then it could cause the noise I was hearing on turns etc I guess.......

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You suggested the old VCU may have failed open - this is highly unlikely. However, the new VCU will be transmitting different stresses and it will be transmitting them more so when you corner (its not just right to left, its front to back as they take different lines). 1 of the items that picks up these stresses is the front mount on the diff. Its one of the feelings of the forum that an overly stiff VCU will take out the diff's front mount. So regardless, there will be different stresses, maybe they are now not allowed to give through loose bearings, maybe what ever. Maybe they are now showing up a perished diff front mount.

Its also possible that a binding rear brake is putting stresses through the rear diff, which might show up with a faulty front mount.

Your front mount may be fine. It was a suggestion - and I think you should check it.

Lining them up square to the shaft on the VCU is pretty obvious, not sure why Rave feels the need for such a graphic! I meant did you line them up as before when you fitted them to the car. I know of at least 1 instance where someone installed them where they thought they should be only to loosen then and put them back in the original alignment. Forget the specifics but he thought they should be in a straight line with the props, but they should be straight in the car (front to back) or vise versa. There can't be much difference, but it caused him problems.

Most agree that Austen does good recon VCUs. Most also agree that he is wrong, and rather 2 faced, about the 1WUT. Most of us are not engineers - so can't categorically say whether the 1WUT is any good, so I asked those that are. You can read it if you like, it waffles like any forum thread, but the only responses were that it was a decent enough test for the purposes of getting an idea if the VCU is any good...

https://cr4.globalspec.com/thread/101113/Testing-a-Viscous-Coupling

The test has been used to identify at least 1 faulty VCU supplied by Bells. I am not knocking the Bell product, they are good and any problems rares.