AVM Heavy Duty Free Wheel Hubs

I have a pair of AVM Heavy Duty branded Free Wheel hubs on my 109 5 door.

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Recently, I have found that when set to the unlocked position, they have at times managed to partially rotate when the vehicle is in motion, so that they end up somewhere between locked an unlocked. This worries me as I don't want the mechanism snatching when engaging at speed or chewing the ends off the half shafts. This behaviour has only become noticeable after a recent swivel ball drain and refill. (I also had some oil leakage through the hubs after refilling - possibly due to over filling and a blocked breather).

So, my questions are 1) has any one else had this locking problem, 2) what did you do about it and 3) does anyone have a schematic of the locking hub mechanism for this particular hub? (AVM are not being particularly responsive here)

BTW, I am aware of the pros and cons of FW hubs and so don't want to get into a debate about that in this thread. I'd just like to resolve the problem.

Many Thanks,

PM

imortim1 said:

I have a pair of AVM Heavy Duty branded Free Wheel hubs on my 109 5 door.

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Recently, I have found that when set to the unlocked position, they have at times managed to partially rotate when the vehicle is in motion, so that they end up somewhere between locked an unlocked. This worries me as I don't want the mechanism snatching when engaging at speed or chewing the ends off the half shafts. This behaviour has only become noticeable after a recent swivel ball drain and refill. (I also had some oil leakage through the hubs after refilling - possibly due to over filling and a blocked breather).

So, my questions are 1) has any one else had this locking problem, 2) what did you do about it and 3) does anyone have a schematic of the locking hub mechanism for this particular hub? (AVM are not being particularly responsive here)

BTW, I am aware of the pros and cons of FW hubs and so don't want to get into a debate about that in this thread. I'd just like to resolve the problem.

Many Thanks,

PM

Click to expand...

I have had landrovers for nearly 40 years, and I had never heard of AVM until I read your post.
Internet search reveals that they are a Brazilian company, which may explain it. And why you are maybe having trouble getting info out of them.
It may not be easy to resolve a problem which doesn't actually seem to have happened yet, from my reading of your post.

Sorry I can't be more helpful, hope one of the other members has actually met AVM hubs before.

They aren’t heavy duty hubs. They are just free wheeling hubs. Which should offer very minor mpg gains, if you are covering enough miles a year in your 109.

An option would be to ditch them and return to stock. All problems solved then

As originally stated and seen in the picture, they are branded as AVM heavy duty Free Wheeling hubs. This is very different from heavy duty hubs, which are non-selectable and permanently engage the wheel to the drive train.

Again, as I stated in the original post, I don't want to get into a debate about how useful FW Hubs are or not. For my circumstances they are and being told to ditch them isn't helpful or wanted. I just want to get an idea as to why they have started mis-behaving and if anyone else has had similar experiences (and possible fixes). If anyone has any ideas as to why that is the case, I would be interested. Otherwise, please can we keep focused on the original question and refrain from debating the usefulness or otherwise of freewheeling hubs, which isn't the subject of discussion here.

Turboman, AVM are indeed a Brazillian company, though they sell a lot of Free Wheeling hubs for a range of different vehicles here in the US (particularly for pickups). However, the Landy was already equipped with them when I purchased it nearly 20 years ago (whilst I was still living in the UK) and it followed me here so equipped when I moved over about 15 years ago. So they must have been sold in the UK at some point. I believe that the regular model for Series Landies was AVM Model 405, but these look different. I have contacted AVM, but they don't (or won't) give any information and just say that they are discontinued. Obviously, being based in Brazil. there is a language issue and so we may be be at cross purposes in our discussions. (He doesn't speak great English and my Portuguese is non-existent!). AVM gasket kits are available for the model 405's through various parts sources in the UK, but I haven't seen any for these types and haven't been able to find a model number stamped on them.

Many Thanks,

PM

I have fairy free wheeling hubs on mine and there is a notch feel of resistance just before it is fully engaged or fully disengaged allowing the selector to "click" into place and then not move. I do not know if the AVM hubs have something similar, if so maybe this has become worn allowing the selector to slip over i without any resistance.
On the resistance point if you have recently overhauled the swivels were the hubs removed/cleaned at the same time. Particularly if oil has been leaking though them they may be over lubricated so are free to move with the vehicle vibration. I use a heavy grease inside my selectors which when combined with the grub and mud on the outside of the hub means that the selectors need to be actively moved as there is resistance when they are turned. If yours have been soaked in thin (compared to grease) ep90 oil this may have removed the previous natural resistance.

Many Thanks. That all makes sense. The activation mechanism on the AVM's is similar to that described for the Fairey, where you turn the selector nearly a full rotation and they click into place to lock or unlock. I'm guessing that these detents have become worn as you describe, and it make sense that the oil overfill could enable the selector to slip out of position. That said, I've never had a problem before and have always used EP90 in them, but they have been on the vehicle as long as I've had it (>20yrs), so they could indeed be becoming worn. Once it cools down a bit (it's too darned hot and humid at the moment to go and do battle with the Landy), I will go and pull them, inspect and see if they need repacking with grease. It may be few days before I can do this, as I'm on work travel for the next few weeks.

Many Thanks for the suggestions.

PM

Pictures of one mine stripped down, hopefully you can see the sprung ball and corresponding features it detents into. It may be that the spring behind the ball has failed. The middle bit that you turn also has two o rings, on mine they have taken a bit of a set, I'm sure if they were new they would add some additional turning resistance and vibration isolation.

Not sure if you can see it but the image on the right shows how mine failed, a broken spring allowed the mechanism to cock over and hook up on the splines leaving one hub engaged, as you can imaging the diff didn't tolerate that for long, worth checking as removing the front one is a pain.

Getting the lube right matters, they can be quite sensitive. If they have too much grease (as mine did when i got it) they won't engage, I think they get haydraulic lock, too little and they get stuck.

Thanks All.

That gives me plenty to work on when I get a moment. Thanks for everybody's help.

PM

They should run dry. They don’t need any lubrication. If oil has got in that may be the problem. Mine are similar but one of them has stoped working because the return coil spring will no longer grip on the plunging sprocket. I have never tried to fix it as I never use them. I just leave them in four wheel drive all the time.

Here is Steamwally's view on stripping and fitting FWHs. Not sure it is of any help to you, but it's worth a try!

I've got the same hubs on my 88" and when I rebuilt it I did grease them well inside, had no issues with them at all but they do seem a bit stiff to get them engaged.

My Series 3 has a set of these AVM hubs fitted.

Citizen Kane: Do you have any more photos of them stripped down? I am struggling to see how they work from that photo.

Just an update. Did about 100 miles over the weekend (on some rather bumpy roads), and apart from the time I deliberately locked the hubs ( to splash oil around in the swivels and into the UJ's and kingpin), I had no problems. A little bit of oil has still leaked out between the hub outer and the selector, but nothing much I am thus thinking that the swivel oil over fill must have gotten some oil into the selector locking mechanism, and thus made it easier to rotate. Now that the oil level has dropped again, and the selector mechanism has dried out, things seem to be back to normal. I will still see if I can pull and clean the mechanisms at some point, but I'm feeling a bit more comfortable with them again.

Many Thanks for all your help and replies.

PM

AVM appear very similar to the Warn FWH.

If oil is leaking out dirt can get in. It should run "wet" inside as the locking spline attached to the drive shaft end needs lubrication when the hubs are freewheeling. I suspect you need to at least put in a new set of o rings.

I have a funny feeling thatb they may actually be Warn hubs made under license or AVM purchased the rights to them at some point. CK, that is exactly the kind of exploded diagram I was looking for. Many Thanks.

PM

Thanks for uploading the diagram. I hope that will come in useful.

https://www.ebay.co.uk/itm/Land-Rov...350884?hash=item3fa31a5264:g:qY4AAOSw60NbLnPN

Might be useful just came across this on ebay.

Just to bring this to conclusion, the oil leaks from the hubs have stopped and so has the annoying habbit of the hubs slipping position. So I guess it was due was due to EP90 getting into the mechanism. Which having solved one problem, indicates that I now probably need to replace the axle breathers and / or the seals between the swivels and the axles themselves........

However, now trying to rectify an electrical issue first!

Many Thanks to all for their helpful advice.

PM

Oh, and I'm still awaiting a reply from AVM (Brazil!)!!