Locking hubs

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Originally Posted by pfillery

If running with drive flanges, doesn't this mean the whole front axle from hubs to diff to gearbox is turning and wearing the whole time you are driving? Surely this can't be good .....

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I have always had freewheeling hubs on my Hilux's, and noticed that they provide a significant improvement in fuel consumption. However as a farmer they were engaged/disengaged almost daily.

On the Land Rover, however, I am told that it makes little difference to the fuel economy.

The issue (as has been mentioned above) is that if the front hubs are disengaged for long periods, none of the components forward of the transfer box rotate. So the oil drains off the upper sides of the components, risking damage (rusting, seizing) from lack of lubrication. Additionally the splined joint on the front propshaft, which slides in and out as the suspension moves up and down, wears unevenly because the weight rests on the top and bottom splines. When rotating, the top and bottom constantly change so the wear is spread evenly around the joint, but when disengaged this is not the case.

Whilst I have no experience of the fuel economy issue, I do have a front propshaft that has a flat spot on the splines (10mm or so lateral movement in the joint), and that vehicle does have freewheeling hubs.

And the lack of handbrake worries me.....

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Originally Posted by vnx205

Not everyone has bad experiences with FWHs.
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So while the disadvantages of FWHs may be real, it seems that it is possible to do two or three hundred thousand kilometers without them showing up.

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The SII that I am currently working on has freewheeling hubs, and the owner never had a problem. One hub is cracked, the front propshaft is destroyed (haven't opened the diff yet) but the vehicle still moved and she never noticed ;)

It is, of course, entirely possible to drive forever on FWH's. The question, to me, is whether they offer any significant benefits, and whether those benefits justify the risks.

For hard off-road usage, or high powered motors, they introduce another weak point in the system. If left disengaged for long periods they introduce the risk of uneven wear, lack of lubrication etc. Under certain cirumstance they stop the handbrake from working. On the other hand they may marginally improve fuel economy, though JD says otherwise from his experience, and they allow low range 2WD.

None of my LR's will ever be a daily driver, so fuel economy is not an issue. To me, the negatives outweigh the positives.

Having just this morning started stripping the front axle, and in the process chipping some paint from the hub (resprayed at some point, wheels and all!), I discovered that my "Shute Upton Engineering" hubs are in fact "Power-Lock" made under license. When I posted the link to the Powerlock data above, I thought they looked familiar!

So, some photo's. Note the crack on the hub, I've not tested but I assume there is no drive to the wheel. The peening on the crack is because the case had pushed out to such an extent that neither the wheel nor the brake drum would come off. I had to hammer the crack closed to get the wheel off!

Attachment 41644

Attachment 41645

These are going in the bin, but if anybody wants them for spare parts (the other one is not cracked as far as I know) they can have them for the cost of postage and packing! Can't say I recommend them though!

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Originally Posted by vnx205

Not everyone has bad experiences with FWHs.

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I have to agree - though I know the reasons for not having them and it does make sense but my own experience is that I had no issues.

I have had FWHs on three vehicles - all daily runners and only engaged the hubs when offroad.

The first was AVM hubs on a series 1 that I owned for 8 years and was also a daily runner - I never had an issue and the car was smoother to drive with them unlocked - but the front drive shaft was a bit worn so the hubs prevented a lot of vibration on the highway.

The second was a Suzuki Sierra that I bought new and it had Aisan (s) hubs as standard. I did have some problems after a few water crossings but a cleanup fixed them. I had this for 3 years.

The last was on a series 3 landie - again a daily runner and no issues but more vibration when engaged but more due to a worn front driveshaft. Had this one for 5 years and I know is still on the road 20years later with the same front end.

So - benefits not a lot but can help with less vibration if you have wear in the front end.

Cons - again not a lot - I did not find any of the issues such as brindling of bearings and UJ wear in the swivel hubs.

I think it comes down to personal preference. I think that the downsides and the positives are overstated in both cases.

Garry

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Originally Posted by vnx205

When I bought my Series III at 110,000 km, it had FWHs on it. When I sold it at about 300,000 km, they were still there.

The spline on the front shaft had a bit of wear when I bought it and it still had a bit of wear when I sold it.

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Originally Posted by Warb

The SII that I am currently working on has freewheeling hubs............the front propshaft is destroyed

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Originally Posted by garrycol

The first was AVM hubs on a series 1 that I owned for 8 years and was also a daily runner - I never had an issue and the car was smoother to drive with them unlocked - but the front drive shaft was a bit worn so the hubs prevented a lot of vibration on the highway.

The last was on a series 3 landie - again a daily runner and no issues but more vibration when engaged but more due to a worn front driveshaft.

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I'm a relative newcomer to Land Rovers, so I don't know if front propshaft wear is normal across the board, but here we have four vehicles with freewheeing hubs and propshaft wear to a degree that causes vibration at speed. Did the FWH's contribute to the wear? There is a logical reason why they should cause wear, but that doesn't prove anything. But if four out of four FWH vehicles show appreciable propshaft wear that surely raises questions?

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Originally Posted by Warb

I'm a relative newcomer to Land Rovers, so I don't know if front propshaft wear is normal across the board, but here we have four vehicles with freewheeing hubs and propshaft wear to a degree that causes vibration at speed. Did the FWH's contribute to the wear? There is a logical reason why they should cause wear, but that doesn't prove anything. But if four out of four FWH vehicles show appreciable propshaft wear that surely raises questions?

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We can add a fifth rover to the list - my S3.

One of the front hubs had collapsed inside and the front propellor shaft was so worn on the splines, I had to chuck it. To my delight my spare S3 had no free-wheeling hubs and a perfect front propellor shaft!

In addition the swivels were badly worn, although that could be because someone had filled them with grease.

By contrast my '51 S1 had the splines in perfect condition, even though the uni-joints were cactus and my Disco has done 253 000km and the propellor shaft is fine.

If the best thing about free-wheeling hubs is that they mask a worn propellor shaft, then perhaps the cost of new hubs should be better spent on fixing the shaft.

I have also done exhaustive testing in the SES Landloser, which has FW hubs, by driving it to Albany and back (about 500km return) on the same route with the same driver numerous times and I couldn't detect any difference in fuel consumption,

Cheers Charlie

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Originally Posted by Warb

I'm a relative newcomer to Land Rovers, so I don't know if front propshaft wear is normal across the board, but here we have four vehicles with freewheeing hubs and propshaft wear to a degree that causes vibration at speed. Did the FWH's contribute to the wear? There is a logical reason why they should cause wear, but that doesn't prove anything. But if four out of four FWH vehicles show appreciable propshaft wear that surely raises questions?

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Front driveshaft wear has nothing to do with FWH (the rear driveshafts wear more and there is no FWH there). Being on the front and only used where 4wd is required they tend not to get maintained as much as they should - also when used you are normally offroad and going slowly so an slack is less noticeable - a worn driveshaft turning at speed on the highway with hubs locked chatters away and causes vibration. So not relevant to FWHs but if you have them fitted none of this stuff is turning so no vibration. My Suzuki front driveshaft never showed wear and my FWHs were unlocked all the time.

Garry

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Originally Posted by Warb

.........propshaft wear to a degree that causes vibration at speed. Did the FWH's contribute to the wear?

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I have run a S1, S2, S2a & a 2b FC. over 30 years. Always had FW hubs, never had any problem with any wear! Liked the reduced vibration, even with unworn bits, & reduced steering feedback.

(1) always greased front prop every 500 odd Ks (both ujs & slider)
(2) always used approx 50/50 oil/grease mix in swivels.

Have noticed when driving a bonneted LR without floor that the front prop did actually slowly rotate at speed, although probably not enough to lubricate top swivel cone/railko. The absolute HUGE plus was being able to use 2WD low range on the FC. It generated huge wind up in 4WD on "very steep", for an FC :D, bitumen roads, eg Cooma to Tumut. Also when low speed reversing in confined areas.

Also I have never broken any hub, had SUE powr-lok, selectro & AVM. Seen broken of all, SUE thru not engaging BOTH pins, selectro thru external tree contact & AVM from not fully engaging (rotating) knob. Yes, I have broken axle UJs, but that's not the hubs fault, nor lack of lubrication.

From my experience, I've had about 40 LRs thru my hands, that front prop re-lubrication is usually pretty poor by most owners. I've had very few with FWHs, but nearly every front prop sliding joint was stuffed. Also most had little or no oil in front swivels by the time I got them.

I can't make any claim about fuel economy, my LRs have done what was required at the time, I just kept filling them up. :)

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Originally Posted by Warb

I'm a relative newcomer to Land Rovers, so I don't know if front propshaft wear is normal across the board, but here we have four vehicles with freewheeing hubs and propshaft wear to a degree that causes vibration at speed. Did the FWH's contribute to the wear? There is a logical reason why they should cause wear, but that doesn't prove anything. But if four out of four FWH vehicles show appreciable propshaft wear that surely raises questions?

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I would not have described the wear on my front spline as "appreciable". The slight wear that was there could just as easily have been caused by 110,000 km with negligible maintenance.

Surely a more significant factor is that probably because of the FWHs, there was no necessity to replace it during the next 200,000 km.

So maintenance or lack thereof, regular engagement or lack thereof all play a part. I'm not convinced about the lack of maintenance specific to front propshafts - if the owner or mechanic is underneath with a grease gun I find it hard to believe that he/she would ignore the front shaft because it doesn't get much use......

Nevertheless, having removed the uncracked SUE PowerLock and run it through the parts cleaner, here are more photo's for anyone interested:

(Photo from rear of unit) When disengaged, the hub spins separately to the driveshaft on this nylon bush.
Attachment 41685


The engage/disengage is done by rotating a pair of cams in the deeper lobes of the aluminium hub.
Attachment 41686


The cam itself (one of a pair per hub). The cam is sealed with a O ring to prevent grease exiting through the faceplate (or dirt entering). A spring pushes the cam down in to the hub, where a pair of depressions line up with the two lobes on the base of the cam to help locate the cam in either the engaged or disengaged position (in practice it can be left at any position with nasty consequences). When engaged, the solid side of the cam engages the star gear, and the drive is transmitted to the case only by the two 5mm sections (on the right hand side in this picture).
Attachment 41687

When engaged, the drive is transmitted through two cams to the outer case of the hub which is about 5mm thick at this point. Because the star gear is attempting to push the cam outwards, this is the point of failure where the case gives way and the cam is forced out through the side. This reportedly happens mainly when only one cam is engaged, though some people say they have seen both sides pushed outwards simultaneously.
Attachment 41688

Witness marks on the inside of the hub show where the two 5mm lobes of the cam transmit the drive when the hub is engaged.
Attachment 41689

Although I can't upload a sixth picture in this post, the solid side of the cam and the star gear both have witness marks showing where the drive is transmitted from the star to the lobe on the cam when engaged. Rather than being even wear across the full surface, which would demonstrate a well mated pair of components, both show that contact is made only over a strip about 1.5mm wide. The surface of the cams appears to be breaking down to some extent, and strangely shows several strips of engagement whilst the gear shows only one per lobe - perhaps the hub has been run with the cams not quite aligned correctly?