DIY VCU service

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Don't get me wrong - we need peeps to experiment - but at this stage it is still that.


This is my latest experiment.
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I thought the idea was to cut the weld, strip it, clean it, put fluid in and weld end back on.
That's what the reconners are said to do. I would assume they would need to spin it in a lathe or similar to check it's been welded back straight.

I cut my old vcu open by mounting it in wood, then turning it while a fixed 1mm angle grinder disk cut into it.
 
In a perfect world I would have a lathe to cut it open and a welder put it back together and be able to balance it.
I would have the correct fluid and my IRD would be in perfect condition to take the strain. Either that or I would be able to afford to buy a new/recon one.
In my very imperfect world I don't have a lathe.
I have a welder but my welding is so bad I wouldn't trust it.
The fluid is probably close enough to correct but from everything I have read I am erring on the side of safety with 60,000.
I can afford a recon one but with all the money I've thrown at it these last few months I don't feel inclined to.
Having found the VCU currently very much locked up and signs of oil leaking from the IRD I suspect some harm may have been done so I would be concerned a recon VCU might finish it off hence going for a looser option.
Once fitted I will do the one wheel up test and post the results.

With regards to white spirit I will not be using it. I don't want to leave an oily residue inside the VCU.
 
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That's what the reconners are said to do. I would assume they would need to spin it in a lathe or similar to check it's been welded back straight.

I cut my old vcu open by mounting it in wood, then turning it while a fixed 1mm angle grinder disk cut into it.

Nice Idea but as I said earlier, with my welding skills I would probably screw it up completely.
 
In a perfect world I would have a lathe to cut it open and a welder put it back together and be able to balance it.
I would have the correct fluid and my IRD would be in perfect condition to take the strain. Either that or I would be able to afford to buy a new/recon one.
In my very imperfect world I don't have a lathe.
I have a welder but my welding is so bad I wouldn't trust it.
The fluid is probably close enough to correct but from everything I have read I am erring on the side of safety with 60,000.
I can afford a recon one but with all the money I've thrown at it these last few months I don't feel inclined to.
Having found the VCU currently very much locked up and signs of oil leaking from the IRD I suspect some harm may have been done so I would be concerned a recon VCU might finish it off hence going for a looser option.
Once fitted I will do the one wheel up test and post the results.

With regards to white spirit I will not be using it. I don't want to leave an oily residue inside the VCU.

Have you changed the oil in the IRD? Did it come out grey - indicating ground down bearings?

I presume you've removed the props until you sort the VCU.

When you put your shiney recon VCU back on (you've got to clean and paint it so its a 'real' recon unit) - I'd be inclined to replace the bearings in the rear pinion on the IRD. The teeth on the gears in the IRD are probably in serviceable condition - but I believe its the bearings on the rear pinion that go fastest and then lead to gears slipping, cases cracking etc. So you can leave the IRD in place and just remove the rear pinion and get the bearings changed in that. The bearing kits are quite cheap - I paid about £130 for a full kit. As you won't need the oil cooler, other bearings and seals (unless they're shot if its leaking) it wouldn't cost hardly anything and will put your unit back to almost the same state as a fully reconditioned unit.

Well worth doing!
 
Have you changed the oil in the IRD? Did it come out grey - indicating ground down bearings?

I presume you've removed the props until you sort the VCU.

When you put your shiney recon VCU back on (you've got to clean and paint it so its a 'real' recon unit) - I'd be inclined to replace the bearings in the rear pinion on the IRD. The teeth on the gears in the IRD are probably in serviceable condition - but I believe its the bearings on the rear pinion that go fastest and then lead to gears slipping, cases cracking etc. So you can leave the IRD in place and just remove the rear pinion and get the bearings changed in that. The bearing kits are quite cheap - I paid about £130 for a full kit. As you won't need the oil cooler, other bearings and seals (unless they're shot if its leaking) it wouldn't cost hardly anything and will put your unit back to almost the same state as a fully reconditioned unit.

Well worth doing!

Yes, changed oil in IRD. Don't remember it being grey, more black than anything.
Painting it goes without saying.
Don't suppose you have a part number for the bearing kit your talking about.
 
With regards to white spirit I will not be using it. I don't want to leave an oily residue inside the VCU.

"Silicone fluid is highly soluble in hydrocarbon solvents such as toluene, xylene, ligroin, and mineral spirits as well as in chlorinated hydrocarbons. However, it is insoluble in ethanol, methanol, and water."

White spirit is 'uncoloured' mentholated spirits. It's an alcohol [ethanol alcohol = deadly to consume]. It will evaporate completely. However, from reading the above I can see my idea re white spirit is incorrect.

Brake cleaner /carby cleaner are petroleum products. These things dissolve surface deposits and allow them to 'run' off, leaving the surface clean & degreased.

Dow Corning make a silicone solvent: OS-2 Silicone Cleaner and Surface Prep Solvent.
 
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Thought I'd do my bit for the cause!
1 vcu. Pretty much solid removed from a customers vehicle and swapped for a known good one.
So far I've put it in a lathe and discovered the welds are dammed hard. Most of my cutting tools won't touch it.
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I ended up running the lathe backwards and using an angle grinder with a thin slitting disc to cut into it.
Eventually I got through
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Nice.
Only issue I see doing it this way is that once through the outer skin the silicon will fly everywhere making it impossible to collect and measure. How will you ensure you refill it correctly without knowing exactly how much should be in it.
If I drill a hole and measure what comes out I can I replace it with the same amount of new stuff.

Edit: Ahhh, now I see. :)
 
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The fluid is like glue. It won't dissolve in brake cleaner and it takes a lot of levering to get it all apart. It is literally stuck together. Seeing how it's done and whatever the grease is like I doubt it'll wash out well enough.
 
Nice.
Only issue I see doing it this way is that once through the outer skin the silicon will fly everywhere making it impossible to collect and measure. How will you ensure you refill it correctly without knowing exactly how much should be in it.
If I drill a hole and measure what comes out I can I replace it with the same amount of new stuff.


Believe me it won't come out! Even with the lathe spinning it hardly comes out!
 
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