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Thread: Rear axles and hub bearings

  1. #1
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    Rear axles and hub bearings

    This may or may not be an issue, but it is something I did not expect. I'm hoping that the VW experts here can confirm what is actually right or wrong!

    Before the car was transported to its present location (several years ago...), the swing axles had been removed, checked, and refitted with new retainer plate gasket shims. The hub bearings, gaskets, O-ring etc were also replaced on re-assembling. The transaxle had been previously drained, and the rubber boots had not been refitted.

    I was slightly concerned that even when the hub nuts had been tightened right up, there seemed to be 'play' in the rear wheels...

    When I say 'play', it was evident when the wheels are on the ground (i.e. not jacked up), and when shaking the top of the wheels or body work side to side, and it could be heard as a 'click', although there was no apparent movement visible in the wheel rim.

    I assumed I must have got something not right on re-assembly, not sure if on the inner assembly or outer bearing assembly, as I had expected the whole axle assembly to be 'solid' and nothing that could make the clicking noise.

    After getting the chassis to Paul's barn, we have disassembled again and re-checked all the inner assembly, re-shimming the inner retainer plate gaskets again etc.

    We also re-fitted new wheel bearings, gaskets, O-ring etc again, and been very careful to ensure correct assembly. And we still get the 'click'.

    I then bought yet another set of parts, and bearings, and did the hub bearing assemblies again, pretty sure the inner ends are correct.

    We still get the 'click'.

    The outer race of the hub bearings are a tight fit in the bearing housing, and the spacer rings with the bevelled edges are the right way round.

    Knowing that the hub bearings are of the ball type, we are wondering if some 'play' is expected as everything else is sandwiched tightly in the assembly by the hub nuts. We have decided that there is no in-out play at all when pushing / pulling on opposite sides of the wheel, but when the wheel is 'wobbled' either when the bottom of the wheel is on the ground and the top of the wheel is pushed and pulled (it has to get a swing on it before it becomes apparent), or if jacked up, wobbling the side to side of the wheels. i.e. it seems to be a lateral play rather than an 'end float' movement.

    The click sound may be accentuated due to the fact that the transmission has no oil in it yet?

    I have bought yet another set of bearings, but pretty sure if we redo it again, we will still be in the same place. (With the new bearing off the car I ought to fit a bar through the inner race and fix the outer race to see if there is any movement possible by rocking the bar which would simulate the assembly on the car - but have not tried that yet; will try next time I go over to Paul's)

    Can any VW experts shed any light as to whether we are trying to solve something which is normal for ball bearing hub assemblies as its driving me mad! (or point at any other possible causes...)

    There are two videos here illustrating the issue, and it is a little deceptive in that it looks like the wheel is moving a lot, but in fact the tyres are deforming as well as the car is rocking side to side with my rocking it all back and forwards.

    Swing Axle Hub Bearing Replacement 01
    https://youtu.be/EfOijmkIe5s

    Swing Axle Hub Bearing Replacement 02

    https://youtu.be/4Rgepm3g-V8

  2. #2
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    Are you sure its not the axle tube on the gear box end the noise sounds very hollow and not like a clunking bearing. Perhaps one too many gaskets under the axle tube cover? have you had someone else wobble the wheel whilst you are under it feeling the tube?

    Dirk

  3. #3
    Hi MartinB. make sure those axle nuts are tightened down to the correct torque setting. 217 ft-lbs as far as i can remember.

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    Quote Originally Posted by Dirk View Post
    Are you sure its not the axle tube on the gear box end the noise sounds very hollow and not like a clunking bearing. Perhaps one too many gaskets under the axle tube cover? have you had someone else wobble the wheel whilst you are under it feeling the tube?

    Dirk
    Hi Dirk, do you mean the gasket shims under the inner axle tube retainer plate? This is what I thought originally and why we re-did them the second time. They have been set such that the axle tube moves smoothly in all directions without stiffness or slackness and without any appreciable shaft end float, as described in the Haynes manual and Autodata repair manual. We also reduced the shims until we could leave the axle tube unsupported and it would not move (too tight) and then added the thinnest shim to bring it back to free movement. I was originally convinced this was the issue, and why I was surprised when it made no difference. The Haynes suggests the clearance to be 0.0-0.2mm, but that it can only be checked by the 'movement' test. I think the thinnest shim is 0.1mm.

    I guess that we could disassemble the whole thing again and make it so it binds, and put back together to see if that alters the 'click', but am hoping not to have to go that far having done the inners twice now! (its the same on both sides as well.) It may come down to that just to see, but then would mean possible having to do it all twice again to get it back if that does not solve it... `¬( ...and in theory would be too tight?

    I will get underneath and feel the tube as you suggest to see if that helps narrow down the area its coming from, but with everything bolted up so tight I'm not sure how easy to identify it would be, but I will try! `¬)

    Quote Originally Posted by Scorpion View Post
    Hi MartinB. make sure those axle nuts are tightened down to the correct torque setting. 217 ft-lbs as far as i can remember.
    Yes, we have done the hub nuts up to 230 ft-lbs; Haynes manual said 217, and the Autodata manual said 253... I'm also assuming that's the 'initial' torque, as you then have to turn the nut a fraction to allow the split pin to be fitted, which increases the torque quite a lot!
    Last edited by MartinB; 09-08-2017 at 12:48 PM.

  5. #5
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    I have also wondered if the 'click' is the sound of the clearance between the inner end of the shaft (the spade) and the side gear and / or the clearance between the fulcrum plates and the shaft end, bearing in mind (oh, did I really type that?) that there is no transmission oil in at the moment.

    The axle shaft itself is really only supported at the outer end by the inner race of the hub bearing, so the slight clearance of the spade end may be what I'm hearing?

    I'm also wondering that if the outer tube is basically only supported by the outer part of the hub bearing, and fixed to the swing arm, and the inner is supported by the axle casing dome on the hemispherical packing piece (as determined by the gasket / shims mentioned), then should it be possible to remove the wheel and drum assembly and trying to move the outer tube by swinging on the swing arm so to speak to see if it is coming from the inner end at the transmission... don't know, just thinking out loud!

    I would be interested to hear if anyone with the same assembly can 'feel' any 'click' if they swing the back wheel back and forward (hard) as per the first vid (wheels on the ground). If its coming from the transmission end, it may not be heard if full of transmission oil, but maybe felt?

    As Dirk says, I don't think its the bearing itself, and looking on the internet, some people are saying there should be no play, and others say a little play is normal due to it being a ball bearing rather than roller bearing - just perhaps not relevant if we don't think it is the bearing in any case...

  6. #6
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    Quote Originally Posted by MartinB View Post
    I have also wondered if the 'click' is the sound of the clearance between the inner end of the shaft (the spade) and the side gear and / or the clearance between the fulcrum plates and the shaft end, bearing in mind (oh, did I really type that?) that there is no transmission oil in at the moment.
    ...
    That would make that sort of hollow noise especially with no oil, but the inner can only move as much as the outer since the outer is bolted to the gearbox and the wheel!? If I get chance over the weekend Ill have a wobble of my wheels but I am sure there isn't any play there. Are all your gearbox mounts OK? I would get under whilst someone wobbles your wheels and have a good look.

    Dirk

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    Hi Dirk; going over today to have a closer look - will get underneath.

    One thing though; the outer isn't bolted to the wheel? the outer end of the sleeve is bolted to the bearing cover sandwiching the brake backplate. (with it being bolted to the swing arm prior to that).

    The wheel is bolted to the outer drum, and the drum is torqued to the inner axle onto the inner race of the bearing. The only connection on the outer end between the axle/drum/wheel to the outer axle casing are the balls in the bearings with the outer part of the bearing being attached to the casing/bearing cover isn't it? (does that make sense - effectively, if the hub bearing was not there, the outer axle casing would not be attached to the drum / wheel) - or is that what you mean? i.e. its bolted together via the bearings and axle castle nut?

    I'll also check the mounts, but think they are pretty solid (urethane) - hopefully getting underneath will let me narrow down the sound source; maybe a rod to the ear! `¬)

    Thank you for your suggestions so far, the more opinions I can get the better! `¬)

  8. #8
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    I was thinking the spade end of the driveshaft might be the cause too. There has to be some clearance between this and the differential, the question is how is the sound being provoked? If your wiggling of the wheel caused some rotational movement, fair enough, but if it was a pure rocking motion I would not necessarily expect a noise. That said, even though the outer bearing is torqued to 200+ ft/lb, that doesn't necessarily mean there is no axial play - it is just very minimal. Maybe over the length of the driveshaft that could translate into discernible movement and an audible click?

    Lauren
    only Pythagoras can save me now!

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    Having now been under the car, as well as lifting the body off again and having a good listen and feel, the axle outer tube is definitely not moving and is solid. The sound is coming from the end of the axle on the wheel end, and from the inner end inside the transmission.

    I think Lauren is correct in that the sound is traveling the length of the driveshaft.

    The outer tube assembly is as below, and as the domed end is pre coated in moly grease I'm 99.9% sure is not the source, and is not moving due to excessive shims fitted.






    The inner domed end was all wrapped in cling film to prevent any muck getting in! `¬)

    I have also checked the bearing part numbers here https://www.thesamba.com/vw/archives...f_t1_kg_t3.php
    and have found out that the 'C3' at the end of the number indicates that the bearings are larger than 'normal' internal clearance. i.e. there will be some movement.

    The first bearing (SKF) we replaced was marked as


    and another new bearing is marked as


    I'm not sure how that fits with it needing to be 'C3'...

    But we have put both bearings onto a bar and it can be seen that there is play in both of them;- (you may need to turn up the sound...)
    https://youtu.be/lvzyhPxDuOU
    https://youtu.be/BN1yeQ72AjA

    https://youtu.be/N3JLGLfnV9g


    As the only source of 'play' is from the ball bearings in the groove of the bearing due to the axle being locked to the inner race by the axle nut at the drum end, Paul and myself are now convinced this is assembled correctly and is expected. The sound being exacerbated by the fact that there is no transmission oil in yet.

    The plan is to fit the boots this weekend and fill with sae90.

    It would be interesting if anyone knows why the hub bearings are required to be 'C3' internal clearance, I suspect it is due to the fact that there is only one bearing at the hub end that allows for movement / alignment of the inner end of the drive shaft?

    I would also be interested in any views, especially from anyone else that has replaced the rear bearings etc! `¬)

    Has anyone given their rear wheel a hard shake to see if you can 'feel' any play?

  10. #10
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    We have now fitted the axle boots; very hard to get them to seal at the ends with the jubilee clips as they seem to need to be 'stretched' around the axle as they do not quite meet to start with!

    There seems to be some debate; instructions say to have the seems horizontal, but on other forums / you tube vids, they say to have the seems at either 2 o'clock or 10 o'clock... we fitted them both to be at 10 o'clock i.e. pointing forward. Not sure what the difference is between having them horizontal or at 2 or at 10, but hopefully someone will reply with a reason or let me know if we've got it wrong! `¬)


    having now filled the transmission with sae90, we no longer have the nasty 'clicks', and we are happy that this is now ok.

    The sound we think is because of the tiny clearance in the bearings (C3), allowing the spades of the axles in the transmission to move in their fit to the internals of the transmission.

    All we have now are squeaks... `¬)

    https://youtu.be/L7--wZIAjbw

    https://youtu.be/IB6kJY1aV54

    ...now need to sort out problems bleeding the rear brakes... the jobs go on!

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