Rear axle issues.

[Trouble at t'Mill]

Hello.

My 2WD Bongo has some rear axle 'whine' especially at speeds of 50mph+. It isn't dreadful, but is very noticeable & annoying especially as the rest of the car is now running so sweetly!

I know that axles/diffs can go on for many years without failing after developing a noise like this, so I was wondering if anyone on here has ever had success in reducing axle noise with, say, additives or a thicker grade of oil?

I know many products - Molyslip, etc - claim to reduce axle noise, but I believe in practice their effectiveness is limited.

I'm not looking for a miracle cure (and I certainly ain't going to be adding sawdust to it!) but it would be nice to be able to delay the 'inevitable' for a year or so whilst still making the car a pleasant drive.

When I bought the car on behalf of my niece, I noticed the noise pretty much straight away, but it's taken a couple of dreadful months to get anything out of the supplying dealer (and not nearly enough...). My poor niece has been waiting these months to get her hands on her Bongo, so I was looking to not only to save some cash short-term, but to get the car sorted for her asap.

The oil level was low when I checked the axle, and took around a pint to bring it back up. I also noticed that there was a considerable vacuum inside the axle housing when I undid the level plug - quite a prolonged 'hiss' as I removed the bolt! This points to the breather not being able to, er, breath? What I assume is the vent is the little 'protuberance' sitting on the top of the axle housing, and is covered by a loose cap. But I'm guessing that it must be blocked underneath this cap? Does the cap simply pull off?

Many thanks for any suggestions.

[francophile1947]

I've had some small success with things like Molyslip in the back axles of cars I had years ago, but I think you need to check if yours has a limited slip differential. I could be wrong, but I don't think you should use extra-slippery additives in these.
The axle breather often gets blocked when the vehicle is undersealed - try cleaning around it.

[dandywarhol]

Yep, the cap pulls off. I've seen the breather choked with underseal by a careles UK supplier - then the seals pop

No harm in trying an additive to prolong it a bit.

[lizard]

I'm not looking for a miracle cure (and I certainly ain't going to be adding sawdust to it!) but it would be nice to be able to delay the 'inevitable' for a year or so whilst still making the car a pleasant drive.

A pair of tights is better than a load of sawdust.

[Trouble at t'Mill]

Thanks all for your replies.

I doubt it'll be an LSD on this beast, Franco, tho' I'll look again for the yellow tag just in case. Yes, the vent must be blocked, even tho' the cap on top is loose and moves easily - I'll prise it off and clean out the hole - cheers, Dandy. I guess with it being blocked, pressure builds up inside with heat and forces the oil out past the seals? (even tho' there's no signs of leaks). I suspect it was happening over a fair period of time - clearly not a component that was looked at during any recent services!

If I can get the noise level down a tad, then my niece will be able to collect the car very soon and should be happy with this for a year or so. We know that a repair is on the cards, and Bell Hill Garage is earmarked for the job.

Lizard, I've tried the tights - thanks for that tip. The noise is just as loud, my legs are real warm, and the missus is threatening divorce.

Oh, any idea if a more viscous oil might help - I've seen SAE 80-140 oil mentioned on some websites that people have tried for this very reason, tho' I'm struggling to find definitive answers as to whether they work. The car certainly won't be used as a high speed cruiser, most likely pootling along at 60-65mph.

Any other ideas would be welcome! Thanks again.

[Manny]

This is interesting. The last MOT a couple of months ago I got a couple of advisory notes, one of them being a slight leak on the rear axle. It's a 2 wheel drive, and it was undresealed when it came to this country. I wonder if the vent is blocked and that is the problem. I was going to check the oil level to see how bad the leak is as I had a look around the axle and could not see any sign of oil anywhere, but then I dont really know exactly where to look. Help in where to look would be welcomed. I know, I know I could ask the garage to show me, but I would like to find out for myself if possible.

Manny

[Trouble at t'Mill]

Hi Manny.

Checking - and replacing - the rear axle oil is just about one of the easiest jobs you can do! (Wow, how often do you hear that?!)

You don't even need to jack up the car and, in fact, when you come to refill the axle, the car should be as level as possible.

If you look at the rear axle housing (the bulbous bit in the middle of the axle) from the back of the car, you should find a nut located on the curved surface towards the right (offside) and just above half way up (without me running outside to check). This takes - if my memory hasn't failed over the last two weeks - a 24mm socket. This plug hole is used to (a) refill the axle, and (b) guide the level - you stop filling when it begins to trickle back out...

(Don't be tempted to jack up the car rear just to get a bit more oil in there - over-filling can lead to leaks!!!)

Underneath this axle housing, pretty much at the very bottom, you'll find another plug which is removed to drain the oil. I don't know what size this is as I haven't undone my yet.

It's worth checking the oil level first as this can indicate whether there's a leak, or if it's been neglected (like mine was...) for some time. Undo the 24mm nut; if oil trickles out then it's absolutely topped up!. Most likely, you'll need to check the level - I used a clean piece of wire bent so's it would go in through the hole and point downwards, just like a dipstick.

Look at the colour of the oil. If it's black, then it should be replaced (tho' I guess if someone's added Molyslip it'll also look black?!)

Really, really, worth replacing. Choose a very good quality (recognised brand like Millers) fully-synthetic oil. By all means add an additive too, such as Molyslip.

(Oh, of course you need to be certain it isn't an LSD - unlikely it is, but I believe it should have a yellow tag attached near the fill plug if it is. An LSD axle will need special LSD oil - and no 'normal' additive should be used.)

If you are going to drain and refill, I'd warm it up with a short run first, just as you would with engine oil.

Oh, and if the plug 'hisses' at you when you remove it - suggesting there's a vacuum or pressure inside - then check the vent as mentioned in the posts above!)

(If you do have a slight oil leak - visible as stains around the axle input shaft, etc, - then you might get a period of grace by using a thicker oil - such as 140W - instead of the 90. There are also additives which claim to 'rejuvenate' seals, and slow down leaks. Bear in mind these aren't miracle cures, but should help to some extent, so hopefully delaying the repairs a bit. If there's a leak and it's at the wheel ends of the half shafts (ie: the half-shaft seals have gone) then this does need sorting as oil could contaminate the rear brake discs...)

[mikeonb4c]

More excellent sutf from Trouble and Keefy. If its not in a factsheet it wouldn't 'arf be useful in one pop pickers

[al & chris]

Ours is 4WD and the rear diff went on our a few months ago. Got a new one from a breakers for £150 complete , was fitted by our local garage. We had a lot of noise from rear axil and now nothing. We got quotes from some of the internet breakers yards. May have been lucky with what we got dont know?

[missfixit70]

Regarding the LSD & yellow tag, I'm sure we've had people that have had the yellow tag, but it's not LSD, always worth jacking up & checking

[Trouble at t'Mill]

All useful stuff, many thanks.

(Keef - I can't help visualising your scenario - imagine trying to squirt oil up through the drain hole and getting the plug back into place... )

Al & Chris, I've been told that rear axle wear is unusual on these cars. Seems very likely that they'll go on pretty much forever IF CHECKED AND LOOKED AFTER! So very likely your new axle will be completely fine. The fitting garage will have - surely - replaced the oil as well?

I think I mentioned before that Bell Hill Garage has not only an advantage in being Bongo specialists, but will both supply and fit the replacement axle (or, in their case, the internals.) This way, the whole job is warranted. Clearly, this is what I'll be doing in the future. It's just that we've had a dreadful time with the supplying dealer, which has not only been costly, but has wasted months of time - although bought in September, my niece has still to see her new Bongo That's why I'm looking for a quick (and cheap) temporary 'fix' for a year or so. She can then come back down next year for a 'proper' holiday - with a visit to Bath included!)

I've now decided to try the SAE85W-140 oil with an additive. If nothing else, it'll provide useful info for others!



ONE OF THE EASIEST AND CHEAPEST TASKS YOU CAN DO ON YOUR CAR! (Ergo: financially and emotionally rewarding!)

AND VERY COSTLY IF NEGLECTED!! So PLEASE check your AXLES! (Yes, I am shouting )

[al & chris]

Yes oil was changed when fitting. They said they get a good indication of axil condition as to state of the oil that comes out of diff when changing. Said it was clean so should be OK. Changed all other oils as well including auto box just in case!

[Manny]

Thanks for all the useful advice Trouble at t'Mill and others. I had already bought the oil for the AT but have not got round to doing it (weather and man flu! ). I am glad now as all this new information has made me feel a bit more confident to tackle this and the diff for the first time.

Manny

[Trouble at t'Mill]

Very pleased, Manny.

I'd suggest warning your nearest and dearest that you will almost certainly be walking around with a very smug, self-satisfied grin on your face for a few days after doing these jobs...

Oh, the filling plug is a 23mm, not 24 as I mentioned above. Not sure if the draining one is different - I should know in a day or two when I try a thicker oil in my axle!

[teenmal]

Very pleased, Manny.

I'd suggest warning your nearest and dearest that you will almost certainly be walking around with a very smug, self-satisfied grin on your face for a few days after doing these jobs...

Oh, the filling plug is a 23mm, not 24 as I mentioned above. Not sure if the draining one is different - I should know in a day or two when I try a thicker oil in my axle!

Hi,as Kirsty stated,jack the vehicle up and check to see if you have a LSD before filling up with heavier oil.
You could end up knackering the diff altogether.
Or if you have a LSD and want to put in heavier oil you might be able to use a modifier.

Cheers Mal..