To rebuild or not to rebuild !

Discussion in 'Mech Tech' started by Mickle, Sep 12, 2011.

  1. My '73 bay camper has a whining gerabox. Well they'll keep going like that for ages is the general opinion, but while under him - like you do - I noticed there's about 3mm of side play on the drive output shaft flanges (worst on the nearside). Now that doesn't seem right, and I'm assuming it's the ring gear/diff carrying shaft that's horrendously loose in its bearings. I which case this is a seriously shot box ! So my dilema is should I try to rebuild it myself, or take the easy (and more expensive ?) option of dobbing it in for a recon.
    As a rule I hate paying for somebody to do what I can do myself, I'm an engineer, have access to more kit than most, and previous experience in setting up rear ends on fuel dragsters - so I know about pinion depths, lash, bearing preloads etc.
    Any advice ? If i could get some instructions, settings, depths to reference faces etc. I think I'd be OK, but this seems to be a subject noticeably lacking in "how to's" Or am I a klutz and missed them ?
    This will be a winter project, but I'm planning ahead.
    Any comments/suggestions ?
     
  2. Fix it yourself its the dub way

    Dont forget the pictorial guide whilst you do it
     
  3. davidoft

    davidoft Sponsor

    if you get a bentley manual its all very well detailed in there, i think you need a few special tool, though perhaps you could make them, as there is a ring of bolts to the gearbox behind the driveshaft flange i wonder if its possible to replace the bearing with the box in place. is it a 1600 as they are pretty cheap second hand, probably less than a pair of bearings and seals.
     
  4. Haven't heard of the manual, will lok out for it. Thanks. Certainly with high load racing gears, if they've been run (even just once) with the wrong settings they'll have a wear pattern that's either too deep or too near the top, and almost impossible to set up from then on - so I'm assuming mine can't be adjusted back to a use-able state.

    Haven't seen many used boxes for sale, it would be an option if I found one, anyone got any comments on how to avoid buying one that's not shot as well ?

    Cheers.
     
  5. davidoft

    davidoft Sponsor

    depends on how the box is set up, could be that the input shafts are not rigid to the diff, beetle ones arent and therefore no wear pattern. its been a long time since i rebuilt a gearbox, but it could just be a whining output shaft bearing

    http://www.vwheritage.com/vw_act_shop.product_pID_110478_lang_EN_country_GB.htm

    i have a type 25 manual like the one above and it goes into full detail for the gearbox detail, i assume the bay oen is the same however i have never seen one,
     
  6. the drive cups do move around a little on the splines on a old box thats normal as there only held on by a circlip behind the central oil seal. if it's anything other than the diff bearings which can be checked through the bellhousing hole and replaced without stripping the box if you mark there original position (you should use a special multisided tool but they will tap round with a chisel once the lock tab has been removed), then you will need a pinion bearing locknut tool around £250 and a setting jig £500 to setup the selector forks. I'd say a second hand box would be cheapest and easiest
     
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  8. Hmmmm. Still interested, if this Bentley manual has pics of tools and it's possible to work out how they work, I'm still tempted, can somebody mail me a sample page ? If promising Amazon flog 'em and I'll get one. I have milling & turning capability "in me shed" plus clocks, mikes etc, so "special" tools ought to be do-able. So let's have a vote: Am I about to drop myself in the brown smelly stuff ? Cheers !
     
  9. if your adament on the idea of stripping the box yourself you can strip the box and check it over and swap bearings over if your need too. but you do need a few special tools as mentioned pinion bearing locknut tool to even get inside the box and if you need to remove the pinion bearing from the output shaft you need another special tool to remove the serated sleeve that holds it on etc if the box shifts ok now you can mark the selector shafts so you have marks to refit the selector forks too
     

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