DIY VCU service

Yes it still feels tight when reversing but not enough to stall the engine if not using any throttle.

New gkn ones have what peeps call a "tight" feeling on reverse anorl.

MEANWHILE...




Going to give it a go!

Good man! Go for it, I really enjoyed doing mine up, even cleaning the gunge off the disks was very therapeutic. If you can weld then do it properly and cut the end off, I don't believe anyone can clean it out properly by squirting stuff into it. There will be too much old fluid still in it between the disks, so the result will be a mix of old fluid, new fluid and cleaning fluid. I cut mine at the existing weld as I figured that was probably the right place.

My intent is to do the following:
1) Drill two holes 180 degrees apart
2) tap them at 10mm, produce short bolts with copper washers
3) Pressurise one hole and blow as much of the fluid out as possible with compressed air
4) Fill it with brake cleaner, seal it and drive it for an hour or two with lots of reversing around in circles to spin the VCU at speed.
5) Open the drain plugs, the remains should now run out - let it mostly dry and then contemplate taking it for a spin (or jack up one side of the car and spin the prop up) and let centrifugal force do its work if it won't all come out.
6) Refill with silicone.

When I drilled mine and left it overnight I had less come out than in your photo so that was not an option for me.

Alibro said:

When I drilled mine and left it overnight I had less come out than in your photo so that was not an option for me.

Click to expand...

Ah fink I may have been lucky, my vcu has been sat on the garage floor for three months, so I deliberately drilled it on the side that had been sat pointing downwards - gas pressure started expelling the fluid.

I'll see in the morning where its gotten to and get another hole drilled 180 out to let air in.

If you do put brake cleaner in after a lot of the fluid has come out then there won't be much resistance so yer will probably be able to turn the vcu by hand. So no need to drive it on the FL.

Hippo said:

If you do put brake cleaner in after a lot of the fluid has come out then there won't be much resistance so yer will probably be able to turn the vcu by hand. So no need to drive it on the FL.

Click to expand...

The fluid had become more like glue in mine so it would have been very hard to get the brake cleaner in between the disks.
If you do try to turn it by hand make sure you keep it horizontal as the weight of the plates resting on each other will make it very hard to turn.

Quite a lot of fluid came out overnight with just one hole, probably about 50ml or so.

I've drilled a breather hole now, filled it up with brake cleaner for a while and then left it to drain again:


Thanks for the tip about spinning it while it's on its side, will try that when I've left it to drain for a few days.

So, it's back on the car now - what did I do?

When a good proportion of the fluid was out I filled it with brake cleaner, left it overnight and then inverted it, left it for a weekend.
So much fluid came out, it was everywhere.

I then drilled both holes out to 8.5mm and tapped them to M10
Acquired some M10 copper washers and started the refill procedure, clear 100,000cst fluid.

I had to refill it 3 times and that small funnel took two hours to flow into the vcu, I was in no rush.

Eventually it overflowed out of the other hole after being left a couple of evenings. Took the funnel out, laid it on its side and let a little flow back out so that there would be air in there.

Acquired some GKN bearings:



Fitted them and dremel'd some M10 bolts up, one of the threads I cut not quite straight but that's what the copper washers were for, they allowed my brute attack with a drill to be corrected:

All ready to go back on the car.

The M10's will allow me to service it again in a month or so once the fluid has had time to scrape out the existing crud in there

I've refitted it but ran out of time before I could take it on a test drive. It needs a week of commuting I think before I do the one wheel up test - if it proves a bit stiff I can take the bolts out still on the car, drain a little fluid and then retest.

Any updates? Have you tried the one wheel up test yet. As you said there will be a mix of good fluid, old fluid and brake cleaner now so once well mixed it would be interesting to check.

Alibro said:

Any updates? Have you tried the one wheel up test yet. As you said there will be a mix of good fluid, old fluid and brake cleaner now so once well mixed it would be interesting to check.

Click to expand...

We've been out all Saturday so far so I'm itching to go take it for a drive in a minute and see what's what. Any remaining brake cleaner should have boiled off in the final stage - it was open to atmosphere for the last three days. The stuff that initially flooded out had returned to its usual viscous state.

So I've just taken it out and thrashed it round the roundabout circuit for an hour then brought it back and done the OWU test.
Tried very had to make it wheelspin on wet tarmac/leaves/etc and it just wouldn't do it so the VCU is transmitting/locking as expected.
No vibration at 70mph so my drilling/tapping/bolts must have been accurate enough.

Results are consistently 25 Seconds at 5KG weight.

I'd call that a success to be honest, it's nearly as good as an OEM unit from what I can tell.

Good result and a hell of a lot cheaper than a full refurb unit, however I'd still do a fluid change in a month or two anyway as there will still have been a fair bit of the old fluid in between plates. I guess once it has mixed with the new it should be less Glue like.
BTW what fluid did you use?

Took the first steps to reconditioning my spare VCU tonight - disconnected it from the props. Small step - but started anyway - they came off a lot easier than I thought. I sprayed them with WD40 a couple of days ago (don't know how much difference that made) and used this video from Freelander Specialists as a tutorial which was spot on...



The support bearings on the VCU are in very good condition, but need to be taken off to recon the VCU. Does anyone have any advice on a way that they can be removed without damage so they can used again?

GrumpyGel said:

Took the first steps to reconditioning my spare VCU tonight - disconnected it from the props. Small step - but started anyway - they came off a lot easier than I thought. I sprayed them with WD40 a couple of days ago (don't know how much difference that made) and used this video from Freelander Specialists as a tutorial which was spot on...



The support bearings on the VCU are in very good condition, but need to be taken off to recon the VCU. Does anyone have any advice on a way that they can be removed without damage so they can used again?

Click to expand...

I did mine with a bearing puller. They are not on super tight unless they are rusted on.

Madmustang said:

I did mine with a bearing puller. They are not on super tight unless they are rusted on.

Click to expand...

Were you removing them to replace them? Did you notice whether removal damaged then at all?

A bearing puller is the thing to use.


Once off. You can decide weather to change the bearing inside the mount.


This is the bearing you need.

Nodge68 said:

A bearing puller is the thing to use.
View attachment 115985

Once off. You can decide weather to change the bearing inside the mount.
View attachment 115986

This is the bearing you need.View attachment 115987

Click to expand...

Cheers for the pic and info Nodge - pictures and 1,000 words and all that.

The hub puller I've got is a cheap one and I don't think its going to be able to get in behind it - I'll have a look in daylight tomorrow and maybe ring round some mates to see if they've got one.

I didn't even think about the actual bearing going - I was thinking more about the rubber perishing (which looks OK). I'll check them out.