Swirling clouds of metal debris in the gearbox oil 
Bugger!! That not good
- Thread starter Rob Farmer
- Start date
brassmonkey001
I should change this
It's the big chunks of metal you really need to worry about...
Uh oh
Full rebuild coming up
I've got a rebuilt spare ready to go so not that much of a problem.
The butchers bill for this one is:-
Fifth Gear - £99 + Vat
Output shaft - £265 + Vat
Intermediate Helical gear - £128 + Vat
Full set of bearings, seals etc - £132 + VAt
Comes to around £750 so this box is scrap.
Outch
Is it scrap simply because of the costs, or because the shaft/bearing seats will be buggered?
BTW Rob, Is it possible to fit lower ratio first and second gears in these boxes?
Val.
brassmonkey001
I should change this
Is it not worth keeping for any of the bits that aren't knackered, i.e. the casings? You might be able to make a good one out of two perhaps.
Rob - had same prob with my gearbox after Summer trip to Dolomites and Croatia - it was getting a bit noisy and snatching going down steep hills and hairpins on the Giau Pass !
Looked like fine silver paint in the oil around the drain plug.
Turned out to need a full new set of the 5 gearbox bearings ....
Suggested cause of problem was determined as worn swivel bearings on the final drive/ bevel box. The achilles heel of the paralever, according to both Gary Burton, his gearbox rebuild man, and Steve Scriminger.
Mine had only done around 30K since its last gearbox rebuild, but should have replaced the swivel bearings at the same time !!!! Learnt that lesson the hard way.
Looked like fine silver paint in the oil around the drain plug.
Turned out to need a full new set of the 5 gearbox bearings ....
Suggested cause of problem was determined as worn swivel bearings on the final drive/ bevel box. The achilles heel of the paralever, according to both Gary Burton, his gearbox rebuild man, and Steve Scriminger.
Mine had only done around 30K since its last gearbox rebuild, but should have replaced the swivel bearings at the same time !!!! Learnt that lesson the hard way.
Outch
Is it scrap simply because of the costs, or because the shaft/bearing seats will be buggered?
BTW Rob, Is it possible to fit lower ratio first and second gears in these boxes?
Val.
Just the cost of the parts.
Yes you can fit different ratios for first and fifth. a 5% reduction in top gear RPM is common but Richie Moore sells a 10% gear.
I've a big box of knackered/worn gearbox parts where these parts will be thrown.
I've actually dug out a circlip output shaft and a decent 17° fifth gear from my stash, just need a new intermediate gear from Motobins and it should be ok so not too expensive in the end.
I've a few worn output shafts I'm going to take along to get a price on metal spraying and grinding. should be far cheaper than binning and buying new.
My pivot bearings are ok. Is the suggestion that the worn bearings were passing the shock through to the gearbox? I can see this hammering the output shaft bearings but can''t really see how it's going to knock the other about.
I've known for a while that mine were on the way out. If I'd have stripped it straight away It wouldn't have been an issue.
Rob,
As far as I understand it, the problem is that if swivel bearings are
worn, then shaft can turn out of true, and hence oscillate. This places stress
on the rear main, and once this becomes worn, begins to wear other G'box bearings.
Gary Burton showed me all the 5 bearings from my knackered 'box
and I think 3 of them were very worn.
Gary's 'box repair guy has been repairing 'boxes for many years
, so guess he knows his stuff!
Scriminger has similar views on causes too. Scary really
and guess solution is to treat these rather flimsy plasticky
Swivel bearings as a service renewable item @ 25K miles or so.
As far as I understand it, the problem is that if swivel bearings are
worn, then shaft can turn out of true, and hence oscillate. This places stress
on the rear main, and once this becomes worn, begins to wear other G'box bearings.
Gary Burton showed me all the 5 bearings from my knackered 'box
and I think 3 of them were very worn.
Gary's 'box repair guy has been repairing 'boxes for many years
, so guess he knows his stuff!
Scriminger has similar views on causes too. Scary really
and guess solution is to treat these rather flimsy plasticky
Swivel bearings as a service renewable item @ 25K miles or so.
Beemerboff
Registered user
Rob ,Motobins had a stash of non circlip output shafts with a bit surface rust that they were knocking out for 40 quid a few weeks back - I added one to my last order just in case I ever needed one.
They might still have some left if you ask ------.
They might still have some left if you ask ------.
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