always best "to keep an eye on it"
Alibro
Well-Known Member
True but my 2002 car with 120k took 2 minutes so I whipped it off straight away. I thought I read somewhere a new one should be around 40 seconds therefore if correct our friend Bandit should have a few years of happy motoring before needing to worry about it.always best "to keep an eyes on it"
Anyone remember what the time should be for a new OEM VCU?
Nodge68
Well-Known Member
Mine is about 45 seconds on the same test. I also did the bench test as shown by Bell. Mine was a couple of seconds longer than there's. So a long way from being past it. I was planning on changing the fluid this summer but after the bench test, I decided not to for the moment.
Tony Reeves
Well-Known Member
Maybe you are about to...
From page 89 of my RAVE
"
GENERAL DATA
Rear Axle and Final Drive
............
Viscous coupling
Rating: ⇒ Max ⇒ Min
440 Nm (325 lbf.ft) @ 75 rpm 360 Nm (265 lbf.ft) @ 75 rpm"
Looks pretty definitive to me.
I do plan to check mine against this test some time. Worked out that if I crank over on the starter (may need plugs out) in 4th gear with front wheels free and a torque wrench holding a back wheel I can check it. I have a manual so it should work.
I tested My Daughter's which had a new GKN VCU fitted 10k miles ago - at 20degC ambient - 1.2Metre bar - 8Kg - 12secs reducing to 11secs after 5 runs.
5kg - 25secs reducing to 24 secs after 5 runs
Nodge68
Well-Known Member
That is the definitive test for VCU function. Sadly I can't see many owners having a power source Eg an industrial lathe, that would be capable of providing 440Nm of torque at 75 RPM. This makes the definitive test worthless. Hence the need for coming up with something that can be done at home by all owners with minimal tools, preferably without removing the VCU from the vehicle.
I'd be interested in how your test goes with the starter cranking test. If it works for you, well done. Sadly a starter cranking test, if it works, is only any use on a manual. This means those with automatics still need another solution.
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Alibro
Well-Known Member
OK so as I always use a 5kg weight when testing it is fair to say approx 25secs is the benchmark for a perfect VCU. I can also say that 2 minutes is not bad enough to kill the drive train as that is what mine was and everything is fine. Therefore my theory is anything between the two is safe but getting less so the nearer you get to 2 mins.
I wonder what the maximum time is before permanent damage is done?
Alibro
Well-Known Member
I think some peeps are getting overly stressed by the lack of a simple definitive test. The test doesn't have to be definitive, all we need is one which is good enough to tell us if the car is about to sh1t itself.
The one wheel up test is good enough for this so I don't see the point in pursuing perfection just for the sake of it. Remember whatever test you use is only a snapshot of the situation at that point in time, in 12 months it might have changed significantly depending on how the car is used, tyres etc.
Maybe ignorance is bliss. Look at all the hundreds of thousands of people who have owned Freelanders and never heard of a VCU. The vast majority never had a problem with it.
Nodge68
Well-Known Member
The VCU will cause most damage I.e transfer most torque when the front and rear props are rotating at the greatest speed difference. So if all the tyres are identical, the drive train will last longer with a stiffening VCU than if all the tyres are a mix and match of different makes and tread depths. This is why it's vital that the tyres are all matching in type and the least worn on the back.
Alibro
Well-Known Member
True but when I bought my project car it had mixed tyres with the newer ones on the front and a VCU which took 2 minutes to do the OWU test. Even with this, less than ideal situation the drive train was fine, so there must be a fairly wide window of OWU test time which is still acceptable.
We get peeps here quoting test times of around 45 secs and they are worrying about it. Are they right to worry? I don't think so but don't have much data to base my conclusions on.
Alibro
Well-Known Member
You should speak to my wife, she never does that.I agree with Alibro
Nodge68
Well-Known Member
My time is 45 seconds for 1.2M @ 5kg. I was planning on rebuilding the VCU this year. However after I saw the test results, I've decided to leave it for this year.
Like mine thenYou should speak to my wife, she never does that.
Alibro
Well-Known Member
LOL, I really should read the post above more often. Just as well I didn't say anything too insulting.
Test results. I am unsure as of yet whether i need to remove it ASAP, or plan to do it in the near future. Some feedback would be appreciated. Cheers.
Model: TD4 Manual
Mileage: 86000 miles
Bar Length: 1.2m
Weight: 5kg
Test 1: 59s
Test 2: 62s
Test 3: 55s
Test 4: 62s
Test 5: 61s
Test 6: 58s
Average: 59.5s
Note 1: The first few tries where jerky, it took a few trial runs for it to smooth out. I recorded the tests and checked all my measures afterwards, so despite the fluctuations in the results there should be little margin for error.
Note 2: There are/where symptoms of VCU failure prior to the test, however, they could in fact easily be down to [past] 'hard use' of the vehicle (evident heavy towing and salt water exposure).
Model: TD4 Manual
Mileage: 86000 miles
Bar Length: 1.2m
Weight: 5kg
Test 1: 59s
Test 2: 62s
Test 3: 55s
Test 4: 62s
Test 5: 61s
Test 6: 58s
Average: 59.5s
Note 1: The first few tries where jerky, it took a few trial runs for it to smooth out. I recorded the tests and checked all my measures afterwards, so despite the fluctuations in the results there should be little margin for error.
Note 2: There are/where symptoms of VCU failure prior to the test, however, they could in fact easily be down to [past] 'hard use' of the vehicle (evident heavy towing and salt water exposure).
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Alibro
Well-Known Member
What do you mean by that? Was the inside wheel skidding when reversing in a tight circle?
I'd have thought anything around a minute was fine, my 02 car with 120k miles took 2 minutes when I bought her but no signs of any damage or serious wear.
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Rear subframe mount cracked [OSF] leading to centre diff mount+seal failure, so i'm bit paranoid about the VCU right now. Not that tight while turning and the VCU stays cool while driving on roads.
It's the way it juddered/stalled on the first few tests that concerned me more than the results, though it does seem a bit higher than other peoples units, including your own. You reckon i can get away with a couple of months use (with regular checks)? It would give me time to gather the funding for a GKN unit without having to go 2wd. If it's too much risk i'll whip it off tomorrow.
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