Outer Limits 4x4 Board

Hi,

I am having an issue with my Pajero 1994 GLS LWB.

When in unlocked position, I get a chattering/grinding/vibrating sound coming from the axle/tyre/brake area. As soon as I lock the hubs (in 2wd) it goes away. It seems to be coming from the left side only.

It is intermittent and seemingly random when it happens, although it does seem to do it more often when on rougher Tarseal than on Bitumen.

I have completely pulled apart the hub and removed the disc calipers and disc, but can see no evidence of what could be making this sound?

The bearings are fine, there is ample grease inside the housing, I have replaced the brake pads, it has new shocks, new sway bar links and bushes and a new Idler arm. It is a real strange one due to the noise disappearing when I lock the hubs in.

I have AVM Manual Locking Hubs.

Any help much appreciated.

Nik.

Thats really odd as when they are unlocked nothing is turning in the front except the hub and rotor.... Try taking the AVM hub off and go for a drive with out it on.

Hi NJV6,

Thanks for the reply, yeh it sure is a strange one, the noise/rumble comes and goes so randomly! I will try taking the hubs off and see what happens, thanks mate.

Nik.

Tried taking the hubs off, didn't help, I spoke to a guy who mentioned that it might have something to do with the LH drive shaft/axle, perhaps inside the boot where it connects to the diff? He said it might be that the shaft/axle may not be fully out of 4wd or catching somehow? Hence when the hubs are in/and/or in 4wd the noise goes away.

Any other suggestions?

COuld be.....

Try having the hubs unlocked and the vehicle in 2WD (ie making the noise)

Come to a stop, leave vehicle running, climb under and try turning the CV and axle by hand? See if it moves in and out at all? Can you replicate the sound by hand???

Ok will try that, was talking to the guy who did my suspension, he mentioned that there is a brass plate/washer or something in between where the brake rotor is bolted to the 'CV Housing' and apparently this may need greasing? Wish I knew the correct terminology for all this haha!

Ok, have done that NJV6, there is a little bit of play on each side for the CV and axle? Can't seem to replicate the sound though. If I leave the hubs unlocked but engage 4WD the noise goes away as well!?

Probably the washer he is talking about is the one that goes onto the drive shaft before the shaft is slid through the hub assembly.
To best get access to this you'd need to separate your top ball joint. However, you might just have enough space if you jack the wheel off the ground (so the suspension droops). Probably will want to take the wheel off. Then take the circlip off the axle shaft (inside the manual hub), then push/pull the (outer) CV joint towards the centre of the vehicle. A (small) gap should open up between the CV joint and the hub assembly. Might be just big enough to apply some grease through. The brass ring is down inside there around the shaft, quite often stays stuck to the hub side with grease.

Hi pjb,

Yeh I know the one you mean, that is the next step I guess, I have stripped everything down except disconnecting the ball joints. The RHS has plenty of space and I was able to get some grease in there, however, the LHS has less off a gap, I disconnected the Tie Rod which gave me some more room but I am thinking I will have to pretty much take off the whole hub carrier assembly to access that Brass Washer.

In saying that though, that whole 'area', the hub assembly, CV and Half Shaft including the Brass Washer should be completely stationary when in 2WD? I have taken note of the Half Shaft location when in 2WD and it is not rotating at all, only when the hubs are locked or 4WD engaged.

The frustrating thing is that I drove to work today, approx 40kms with nothing, hit the edge of town and the problem appears for split second then stops! It did this when i went from one section of tarseal to another, say smooth to rough.

Thanks very much for your response mate!

Nik.

I guess it could be something to do with relative movement.
With the hubs locked then the drive axles are doing the same speed as the hubs, but with the hubs unlocked, the hubs are spinning at a pretty good speed compared to the stationary drive axles.

I've never really thought about it before, but perhaps the brass washer is acting a thrust bearing between the CV joint and the knucle/hub? In which case, if it was dry of grease, one could imagine a rough bit of road might make it orbit the shaft in a planetary motion? I could be full of shit though of course.

You definitely got circlips on the outer ends of your drive shafts?
With the circlips installed, do you have the right amount of end-play on the drive shaft (not sure what the spec is, probably something like 1 mm). The service manual mentions something about using shim washers to set the end-play (if necessary).

As for getting more space on the LHS, you should only need to pop the top ball joint to gain plenty of access.

Hopefully all will be revealed once i get a look in behind the hub carrier assembly, but that does sound fesible.

Yeh, both circlips are in. There seems to be around 5-7mm end play on both sides?!

Cheers,

Nik.

Hmm, that sounds like way too much end play, but I'm no expert. Anyone else?
I'll have a quick peek in the workshop manual tonight.

Sounds good mate, I will be pulling it all apart again tomorrow, so would be good if I can set that end play correctly.

Thanks for your help!

Nik.

Had a look in the workshop manual - end play spec is 0.2 - 0.5 mm
Brass ring definitely there?

Pulled it apart again and got into the where the Brass Ring is, it is there and there was plenty of grease in the housing and it all looked ok. On second look the play is about 1-1.5 mm. I cleaned and repacked it with grease, BUT, the noise is still occuring! However, it is really only doing it when it hits a rough patch on the road or when it goes from bitumen to tarseal.

Everything looks to be ok in that area, could it be where the half shaft goes into the diff?, I looked in there and there is plenty of grease also.

I'm completely stumped!!!

Thanks again.

Nik.

I'm fresh out of ideas.
The inner CV joint shaft (that goes into the diff) shouldn't be able to slide in/out of the diff. There's probably a little bit of play, but should need a pretty solid yank to pop the snap ring (on the diff end of the shaft) out of the diff. If this is loose, get a new snap ring. Nevertheless, I can't see how this would contribute to the noise you're describing.

Possibly worth checking the front axle disconnect too if you haven't already. With engine running in neutral, have someone alternate between 2H and 4H. Slide back the front axle disconnect actuator shaft boot (concertina boot just above the crossmember behind the front diff) - check the the shaft is moving back and forth.

Also, you said you went for a run with the manual hubs removed. Presume this was just the outer half off? Perhaps there is a problem with the half that bolts to the hub flange? Don't know much about AVM hubs, I got aisin. I guess if you've repacked the bearings, then you would have had this off at some stage and been able to have a good look at it.

Ok, will check that front axle disconnect also.

When I disconnected the top of the tie rod and upper ball joint, I was able to move the inner CV joint shaft in and out a few centimetres without much resistance? Does that seem excessive? It felt as though had I taken off the hub carrier assembly I could have quite easily slid the shaft out of the diff. Can't say I felt the snap ring pop off although I didn't attempt too! I am learning a lot about this as I go, so am unsure as to what amount of movement/travel I can expect from each part.

Yeh, I only took off the outer part of the hubs, have had that whole hub apart three times now and it all looks to be ok, have had a mate who is an engineer look at it also and he didn't notice anything out of place. Can you take off the whole hub and still drive around ok? just to see if the noise occurs that is?

I'm just hoping that this is not developing into something serious, i.e $$$$$$$$!!!

Really appreciate your help with this!

Cheers,

Nik.

The top CV joint is designed to slide in and out as the suspension moves up and down. This movement is part of the joint, and you should have seen the inner CV boot stretching/compressing as you moved it. Should slide something like 40 mm if the outer end of the axle is free (disassembled).

The (usually) green cup (the CV joint housing) that the big end of the boot clamps onto should NOT slide in/out from the diff housing. If this is the case, then the snap ring that retains the shaft in the diff has fallen off, or isn't there. If you pull this shaft completely out of the diff housing, you might want to drain the diff oil first.

Nope - can't drive around with the inner part of the hub off.

Ok, that sounds all good. Will check that CV joint housing when I get it back. Though from memory I think it's ok.

I have just been getting my Fuel Inj Pump overhauled and replaced the Injectors as well, gonna chuck it on the dyno and get a bit of a tune up while it's in there, looking forward to getting it back! Hanging out for a thrash up Thompsons or Whakamarama!

Had a similar problem with my ng. The front hub was partially engaging and disengaging and the gears were rubbing on each other. replaced the springs on the fwhs and re assembled with plenty of grease and make sure they are in the off position when assembling.

Hi Andy,

That sounds like what it is doing, "partially engaging and disengaging" so you replaced the springs inside the FWH? Ok, will see if I can get some replacement springs, I bought a service kit for the hubs, but they only came with replacement bolts and gaskets.

EDIT: I have driven without the front hubs on and it still makes the noise?!

Cheers,

Nik.