DIY VCU service

This site contains affiliate links for which LandyZone may be compensated if you make a purchase.
I still reckon that by the time yu have found and bought a suitable fluid and trialled and errord the amount (its critical) in the VCU, yu could have bought 4 or 5 replacements at least.
 
The Mad Hat Man said:
I still reckon that by the time yu have found and bought a suitable fluid and trialled and errord the amount (its critical) in the VCU, yu could have bought 4 or 5 replacements at least.
Click to expand...

I hadn't realised the amount of fluid was critical until I re read your previous post.
Each to his own but personally I couldn't risk the VCU not working when it was needed offroad.....there might not be any trees around to attach the winch to ;)
 
jedi said:
Excellent!!! work Jonaf:banana:.....This is what I like to see, The thickness of the VCU casing looks quite thick? :biggrin1: looking at the photos you have posted, How far in does it go, before your reach the plates inside?

What sort of fluid did you use to refill them?
Click to expand...

The end walls of the VCU are 10mm thick. The easiest - but also the slowest way to drain the unit is to drill out the steel balls and let the fluid run out by itself. This takes several days. Getting the last drop out takes weeks if you do it this way. Heating will speed up the process.
I do not think it is necessary to replace all the old fluid. Diluting the stale fluid with some fresh thin silicone will loosen up the VCU and make it work OK again. I did it this way with the first one I did and it worked fine.
 
jonaf said:
The end walls of the VCU are 10mm thick. The easiest - but also the slowest way to drain the unit is to drill out the steel balls and let the fluid run out by itself. This takes several days. Getting the last drop out takes weeks if you do it this way. Heating will speed up the process.
I do not think it is necessary to replace all the old fluid. Diluting the stale fluid with some fresh thin silicone will loosen up the VCU and make it work OK again. I did it this way with the first one I did and it worked fine.
Click to expand...

Useful tips, have you tried vacuum pumps?

I was even thinking of drilling holes in the outermost edges, then add a suitable solvent and centrifuge the remaining fluid/diluent out the holes!
VCU could even be left in situ, take it for a test drive (or place on stands) and let the transmission/prop centrifuge out the rest of the gunk for you.
 
after drilling and pumping out some of the fluid 8 weeks ago and replacing it with a silicon oil then re-welding the holes i got my vcu to pass the wheel up test
lucky i had x2 vcu's to play with it takes 40-50 miles for the silicon to mix with the old silicon
first attempt to little oil was replaced so 2nd vcu i removed and replaced with more silicon oil
it is trail and error depending how thick each vcu's oil has gone
i am in the process when i get time to re-do the first vcu
Ron
 
Hi,

Just to add some info. The recon VCUs from Bell are cut at the top, cleaned out, refilled, re-welded together and re-sprayed. Nice neat job.
 
bugsb said:
after drilling and pumping out some of the fluid 8 weeks ago and replacing it with a silicon oil then re-welding the holes i got my vcu to pass the wheel up test
lucky i had x2 vcu's to play with it takes 40-50 miles for the silicon to mix with the old silicon
first attempt to little oil was replaced so 2nd vcu i removed and replaced with more silicon oil
it is trail and error depending how thick each vcu's oil has gone
i am in the process when i get time to re-do the first vcu
Ron
Click to expand...
i should add always measure how much fluid you remove so you replace it with the same amount
Ron
 
bugsb said:
i should add always measure how much fluid you remove so you replace it with the same amount
Ron
Click to expand...

With grease nipples it is easy to adjust the fluid amount. A few extra strokes with the gun makes the VCU stiffer. If it becomes to stiff, just press the ball valve with a thin crosshead screwdriver and let some fluid out.
 
jonaf said:
The end walls of the VCU are 10mm thick. The easiest - but also the slowest way to drain the unit is to drill out the steel balls and let the fluid run out by itself. This takes several days. Getting the last drop out takes weeks if you do it this way. Heating will speed up the process.
I do not think it is necessary to replace all the old fluid. Diluting the stale fluid with some fresh thin silicone will loosen up the VCU and make it work OK again. I did it this way with the first one I did and it worked fine.
Click to expand...

I'm sure I read an old thread of yours on another LR forum on this very thing.
Interesting reading. I've been thinking of trying it myself.
 
bugsb said:
after drilling and pumping out some of the fluid 8 weeks ago and replacing it with a silicon oil then re-welding the holes i got my vcu to pass the wheel up test
lucky i had x2 vcu's to play with it takes 40-50 miles for the silicon to mix with the old silicon
first attempt to little oil was replaced so 2nd vcu i removed and replaced with more silicon oil
it is trail and error depending how thick each vcu's oil has gone
i am in the process when i get time to re-do the first vcu
Ron
Click to expand...

Is the VCU fluid simple silicone oil? I don't think so.
As far as I know it's a non newtonian fluid. This fluid has special properties the make it thicken when agitated. It is more complicated than that. Agitation causes local heating of the fluid, this heating causes the thickening. Or the localised thickening causes heating. Which ever way it is, normal silicone oil doesn't behave like that. Silicone oil gets thinner as it warms up in the same way that mineral oils do.
Silicone oil is now used in radio controlled car shocks so is, cheap, easily obtained and is available in a wide range of viscosities, non of them much use in a VCU though.
 
Last edited:
Nodge68 said:
Is the VCU fluid simple silicone oil? I don't think so.
As far as I know it's a non newtonian fluid. This fluid has special properties the make it thicken when agitated. It is more complicated than that. Agitation causes local heating of the fluid, this heating causes the thickening. Or the localised thickening causes heating. Which ever way it is, normal silicone oil doesn't behave like that. Silicone oil gets thinner as it warms up in the same way that mineral oils do.
Silicone oil is now used in radio controlled car shocks so is, cheap, easily obtained and is available in a wide range of viscosities, non of them much use in a VCU though.
Click to expand...
the oil is mixed with the old fluid to water it down that is all
it is pure silicon oil
Ron
 
Nodge is absolutely correct.

The stuff you are using is not suitable for the application.

You are ****ing in the wind. It might help, but it ain't the correct stuff. It's like putting engine oil in a gearbox -" it's oil, right!" It might work, but it isn't as good and it won't do what is required long term. If yu don't mind checking yo VCU every weekend then that's fine, but it's a bodge. It cannot be recommended.
 
The Mad Hat Man said:
Nodge is absolutely correct.

The stuff you are using is not suitable for the application.

You are ****ing in the wind. It might help, but it ain't the correct stuff. It's like putting engine oil in a gearbox -" it's oil, right!" It might work, but it isn't as good and it won't do what is required long term. If yu don't mind checking yo VCU every weekend then that's fine, but it's a bodge. It cannot be recommended.
Click to expand...
not recommending it to any one it was a lets see if it works or put them in the bin but it worked fine i do check it every 2 weeks and am interested to see how long it will work for so testing in progress
Ro
 
The Mad Hat Man said:
Certainly worth a try, at yo risk. Be interesting to see your results.
Click to expand...
i will be keeping an eye on it for the next at least 6mths so far i have done around 2000miles but have not used the car much in the last 2-3 weeks as i needed the van
on a 100mile trip to work first thing i do is check the temp by hand so far its just been luke warm to touch one wheel up test is fine if it got stiff i have the tools with me to whip it off
Ron
 
All you've done is turn your car from a viscous 4WD, to FWD, with a rear end that just adds drag

It'll never "fail", and as has been said time and time again, the "rear wheel test" will only test if the VCU has totally locked up, it gives no indication of proper function


Either fit a new VCU, or just remove it and gain a smidge of mpg
 
Just freeing up the vcu a bit whether it be with silicon oil, new vcu fluid or even dog **** is a fix for me:)

You only gets 12 warranty from a reputable reconditioner anyway......what happens after that?:rolleyes:

Has anyone had any problems with a recon one?:eek:
 
DastardlyDan said:
All you've done is turn your car from a viscous 4WD, to FWD, with a rear end that just adds drag

It'll never "fail", and as has been said time and time again, the "rear wheel test" will only test if the VCU has totally locked up, it gives no indication of proper function

Either fit a new VCU, or just remove it and gain a smidge of mpg
Click to expand...
It's the "one wheel up test" and it's a measure of the resistance across the vcu. It's give us an analogue reading which varies from vcu to vcu. There are some vcu's where it won't give a reading but that's because the owner is too lazy to perform the test. Other than the "turnip test" there is nothing betterer than the "one wheel up test."

Reconditioners may advertise the test is bollocks, but they forget what they said when they ask you to drop by so they can use it to convince you to part with yer money when they test yer vcu with the same test.
 
You must log in or register to reply here.

Similar threads

pwood999
Freelander 1 Drivetrain knock when turning
Replies
3
Views
165
andyfreelandy
andyfreelandy
MollyNomad
Freelander 1 VCU Test
Replies
4
Views
906
MollyNomad
MollyNomad
M
Propshaft refitting
Replies
4
Views
436
MGT
M
andyfreelandy
Freelander 1 Front brakes still hot, new calipers and pins. Intermittent.
Replies
19
Views
597
andyfreelandy
andyfreelandy
D
FL2 Power steering strange issue after flywheel & clutch replacement.
Replies
0
Views
440
DanHughes92
D
Back
Top