catastrophic UJ failure?

wammers said:

Don't forget the VCU check or you may end up with another knackered prop and a shot front diff.

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Wammers when I was taking the broken yoke off the gearbox end I tested the VCU as you said by putting a socket on the nut (27mm I think it was)

I put quite a bit of pressure on the rachet to try and turn in a 'tightening' direction. I had the feeling like it wasn't going to turn....??

unless it was a 2-3ft in length it would feel like that

jamesmartin said:

unless it was a 2-3ft in length it would feel like that

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Ah I'm glad you said that! I didn't want to keep trying because I had a short extension on the ratchet to reach the nut so it was making the socket come off the nut due to me pulling down on the ratchet (if that makes sense)

nuts 30mm socket you need 3ft breaker bar to check properly it should feel stiff with a slow pull

No the VCU should turn on the output flange with only 27 pound feet of torque applied to it. Not having the gearbox in park may help. You need quite a lot of force to turn wheel with prop on, around 95 pounds feet, but nowhere near as much on output flange.

jamesmartin said:

nuts 30mm socket you need 3ft breaker bar to check properly it should feel stiff with a slow pull

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Ok mate I'll do a proper check of it, me new prop will be a few days to arrive anyway.

What if I find the VCU is siezed after the check, is it easy to swap and are they expensive? (I'm guessing they are &#128557

yes it is easier than at the wheel but it will feel very tight with std rachet,we allways bench tested with 3ft bar where you can feel the drag but arent busting a gut to turn it,and they where mostly new ones

wammers said:

No the VCU should turn on the output flange with only 27 pound feet of torque applied to it. Not having the gearbox in park may help. You need quite a lot of force to turn wheel with prop on, around 95 pounds feet, but nowhere near as much on output flange.

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I had it in neutral, handbrake on. Just used a standard 1/2in ratchet and 30mm socket with small extension bar.

Maybe I'm not pulling it long enough, put about 8 seconds of pressure on the ratchet. Because it was pulling the socket off the nut I kept having to reset to socket on the nut.

scott02464 said:

I had it in neutral, handbrake on. Just used a standard 1/2in ratchet and 30mm socket with small extension bar.

Maybe I'm not pulling it long enough, put about 8 seconds of pressure on the ratchet. Because it was pulling the socket off the nut I kept having to reset to socket on the nut.

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OK just get the right socket. According to Ashcrofts you need to apply 27 Nm 20 Lb ft of torque for one minute and it should turn 20 to 30 degrees. With transfer box in neutal. If you can't get any turn you need a new VCU. Or just leave front prop off til you get one. Don't fit another prop if it is seized.

we was shown by borgwarner it was there test ,and the pull wasnt great but better than trying to force a short one,alot of p38s are going to be near if not seized now if not been changed 10 years was good for a classic and mileage would have been less yearly than p38 id imagine for most

jamesmartin said:

yes it is easier than at the wheel but it will feel very tight with std rachet,we allways bench tested with 3ft bar where you can feel the drag but arent busting a gut to turn it,and they where mostly new ones

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Ok James see what you mean. This this one is seized that's what's done the prop in.

wammers said:

OK just get the right socket. According to Ashcrofts you need to apply 27 Nm 20 Lb ft of torque for one minute and it should turn 20 to 30 degrees. With transfer box in neutal. If you can't get any turn you need a new VCU. Or just leave front prop off til you get one. Don't fit another prop if it is seized.

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Ok I'll give it another go. When you say 'transfer box' in neutral you don't just mean put the gear selector in neutral (auto)?

wammers said:

Ok James see what you mean. This this one is seized that's what's done the prop in.

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You recon mines siezed?

scott02464 said:

You recon mines siezed?

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Can't think of any other reason that a UJ that has no apparent corrosion, would fail like that. Looks like it has been under considerable load. As far as i am concerned VCU is the only thing that would cause that. The front end, diff or prop will always fail first if VCU is seized, due to the large forces applied on lock, specially if you have good grippy tyres fitted that don't skip easily. Give it a good checking, you must be able to turn it, if you can it will be fine, if you can't it's seized. New one i am afraid.

scott02464 said:

Ok I'll give it another go. When you say 'transfer box' in neutral you don't just mean put the gear selector in neutral (auto)?

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Fit a 10 amp fuse in position 11 on side of drivers seat. Switch ignition on after a moment you should get a message transfer box neutral on message centre. Hand brake on then try it.

wammers said:

Can't think of any other reason that a UJ that has no apparent corrosion, would fail like that. Looks like it has been under considerable load. As far as i am concerned VCU is the only thing that would cause that. The front end, diff or prop will always fail first if VCU is seized, due to the large forces applied on lock, specially if you have good grippy tyres fitted that don't skip easily. Give it a good checking, you must be able to turn it, if you can it will be fine, if you can't it's seized. New one i am afraid.

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Ok mate thanks for that. When I took the yoke off earlier today that had the failed uj attached, it was very apparent that it was dry. It had literally melted one arm on the uj. And the opposite arm had gouges in where the roller bearing had worn grooves into the steel. This is why I'm thinking you were right before about neglecting the UJ's. I took a close up pic of it before I threw it in the bin, wish I could upload it for you but I'm texting this on me phone.

Will certainly check more thoroughly the VCU though

wammers said:

Fit a 10 amp fuse in position 11 on side of drivers seat. Switch ignition on after a moment you should get a message transfer box neutral on message centre. Hand brake on then try it.

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Ah ok wammers I didn't do that earlier!

scott02464 said:

Ah ok wammers I didn't do that earlier!

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To be honest the UJ looked dry, that would cause it to break up. But check the VC properly not worth the risk really. Any sort of turn will be ok.

wammers said:

To be honest the UJ looked dry, that would cause it to break up. But check the VC properly not worth the risk really. Any sort of turn will be ok.

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It was that dry it made me cringe as I know better than that

Thanks for the info mate I'll post to say how it went! I got a second hand prop from emmots £25 delivered, going to replace both UJ's when I get it and both on rear prop too.

Thanks for the info wammers

Tony, why the transfer box neutral? It's not necessary, if you can test just by jacking one front wheel then you can test just by turning (or attempting to turn) the front output shaft as long as the gearbox is in neutral for a manual and not in park if it's an auto.