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More gearbox issues than I thought
https://www.ausmini.com/forums/viewtopic.php?f=2&t=99607		 Page 1 of 2
Author:  Morbo28 [ Sat Jan 18, 2020 1:26 pm ]
Post subject:  More gearbox issues than I thought
Quick recap included below for the story to date if interested...

Quote:
I had to slip the clutch for a decent distance uphill (my dizzy cap was/came loose, couldn't run under much load, so slipped clutch to get myself to safety to pull over as I was in a dangerous blind uphill corner in a cutting). A few days after I did that, there was a squealing noise from my gearbox/flywheel area as a result.

I found the primary gear bush had scored the crank (likely due heating from slipping clutch) and I figured that was the only issue - everything else seemed in great condition. We concluded I needed to regrind the crank at the primary gear journal to fit a 998cc one. Since the crank was out, I then checked the condition of the main and big end bearings, and most were in great nick, but one conrod big end bearing had some slight marks in it, so since it's apart I now have ACL Duraglide bearings ready to go. It also lead Dr Mini to suggest centre oil pickup.

Thanks for your advice in the other threads:
* Thread on primary gear bush - viewtopic.php?f=2&t=99457
* Thread on crank bearing conditions - viewtopic.php?f=2&t=99598


Now, the story continues...

I decided to go ahead with the centre oil pickup. Lucky I did because when installing it, I found this is the condition of the layshaft

Bearing destroyed:
Image

Shaft:
Image

I wonder how it all happened - maybe the swarf from the primary gear issue cause the layshaft to fail...Maybe they're unrelated issues...Maybe they all happened at the same time... I don't know. But it looks like a gearbox rebuild is on the cards.

If the main shaft is all fine, I might just refit standard stuff. If there is issues throughout, I might refit the box with the Minispares "Evo" stronger gearsets while I'm in there. Does anyone have experience or opinions on these?

http://www.minispares.com/product/Class ... 0to%20shop

Also, I see there are two different layshafts claiming to be high quality. One Aussie made, here it is sold by Minisport Australia
https://minisport.com.au/mini-layshaft- ... rade-steel
Quote:
This is the ultimate in layshafts for all 4 syncromesh gearboxes, this suits all morris cooper S/mini K/rod change gearboxes- (Leyland)

You will also require a Pr of CHM141 and 1x HYL8473 bearings to suit

This is Made in Australia (not the cheap chinesse ones), this is high grade steel and will not fail unlike other cheap ones we have used.

PLEASE we do stress that you do not compromize on the layshaft as it one of the most important parts in your gearbox.


And one from Minispares
http://www.minispares.com/product/Class ... 0to%20shop
Quote:
Minispares were the first company to produce these layshafts for performance engine/gearboxes as the standard type would flex and result in the breakage of the bearings causing seizure. Produced in an upgraded material and heat treated to the correct core depth they are a must in any straight cut gearbox or helical type where the engine has been tuned. The price of these although quite high is far below the standard type from the OE manufacturer. For 4 synchromesh mini Pre A plus gearboxes only. A plus had 3 steps-see C-22A1739


Any advice on the "Evo" gearset, the best layshaft to use or other comments welcome.
(It's a pre-a+ rod change 4 syncho FYI)
Author:  drmini in aust [ Sat Jan 18, 2020 4:24 pm ]
Post subject:  Re: More gearbox issues than I thought
Measure inside diameter of the cluster gear, mine did the same, the 50 year old S cluster had .033" wear. New layshaft was worn .022" in 20,000 miles. And the bearing cage in bits.
This layshaft was an Australian made one from MG Heritage.
I've been told Karcraft ones are currently made in UK by McLaren engineering, and are good. What's in mine now. With a new $500 S cluster gear. More expensive to repair the old one, as it's all hardened.
Author:  Morbo28 [ Sat Jan 18, 2020 4:54 pm ]
Post subject:  Re: More gearbox issues than I thought
I can get my hands on a NOS laygear cluster...maybe I should grab that and the UK made hardened layshaft.

I'm currently trying to decide whether I should tear down the main shaft to make sure it is okay. It feels smooth, turns well. If there are no signs of issues without dismantling should I leave as is? Or should I pull it apart to make sure it is all fine and cleaned out?

I am conscious there is a few hundred bucks worth of bearings to replace if I tear the main shaft down. Is it worth it to check condition and clean out possible swarf? Or should I leave well enough alone do you think?
Author:  FNQ [ Sat Jan 18, 2020 5:25 pm ]
Post subject:  Re: More gearbox issues than I thought
If you don't take it apart and something else happens you will never forgive yourself. Given the size of the little fragments appearing on the bright orange glove, i wouldn't take a risk.- you might get away with reusing the two big box bearings.(the dear ones) - only my opinion
Author:  TK [ Sat Jan 18, 2020 7:09 pm ]
Post subject:  Re: More gearbox issues than I thought
I bought a layshaft from Minispares and it was bent like a banana.
Author:  Morbo28 [ Sat Jan 18, 2020 7:16 pm ]
Post subject:  Re: More gearbox issues than I thought
TK wrote:
I bought a layshaft from Minispares and it was bent like a banana.


Really? Was that their you-beaut hardened shaft?
Tell me more context...
Author:  timmy201 [ Sat Jan 18, 2020 7:35 pm ]
Post subject:  Re: More gearbox issues than I thought
I got the same bent minispares one from a local supplier.
Author:  Morbo28 [ Sat Jan 18, 2020 7:53 pm ]
Post subject:  Re: More gearbox issues than I thought
Maybe the Aussie one is the way to go then. Jeez it's a bloody mine field trying to get good stuff.

Sent from my Pixel 2 XL using Tapatalk
Author:  drmini in aust [ Sat Jan 18, 2020 9:28 pm ]
Post subject:  Re: More gearbox issues than I thought
Morbo28 wrote:
Jeez it's a bloody mine field trying to get good stuff.

Sent from my Pixel 2 XL using Tapatalk

Most of the layshaft needle bearings seem to be coming from China now. The boxes have a UK name, but my googlefu shows them originating from Beijing....
Author:  Bill B [ Sun Jan 19, 2020 8:41 am ]
Post subject:  Re: More gearbox issues than I thought
drmini in aust wrote:
Most of the layshaft needle bearings seem to be coming from China now. The boxes have a UK name, but my googlefu shows them originating from Beijing....


I'm having the same doubts with quality of gearbox and other bearings.
Is there any benefit in taking a sample of the "doubtful" bearing to a bearing supplier and buying a branded bearing based on the bearing dimensions and not the mini part number?

I replaced the unbranded roller bearings in a trailing arm overhaul kit with "Torrington B1316 USA" from a local bearing supplier. Also bought idler bearings and upper control arm bearings in Torrington - with and without cages.

For the layshaft bearings, I came across 2 of the larger bearings in SKF boxes - "K 20X26X17" dated 1986- but no small bearings. Am going to see if the local shop can supply a branded small bearing.
Author:  TK [ Sun Jan 19, 2020 11:25 am ]
Post subject:  Re: More gearbox issues than I thought
Buy NOS.
Author:  TheBoy [ Sun Jan 19, 2020 1:20 pm ]
Post subject:  Re: More gearbox issues than I thought
Definitely pull the box down, inspect and clean everything. Even a tiny bit of that swarf will ruin your day.
Author:  Morbo28 [ Sun Jan 19, 2020 2:39 pm ]
Post subject:  Re: More gearbox issues than I thought
Gearbox now stripped down. Plenty of swarf in the box from the largest bearing.

Removed main shaft, all looks in good nick, can't see swarf but maybe there's traces in there.

The bearings I removed are still intact and could be reused. I'll replace the 1st motion / outrigger bearing (as I damaged it on removal) and the idler bearing (as it had swarf in it from disassembly process).

2 questions:

Should I replace all of the various shaft bearings anyway, just in case there is shavings inside?

How should I clean out the case and the parts prior to reassembly? Petrol, turps? Water? Brush?

Sent from my Pixel 2 XL using Tapatalk
Author:  TK [ Sun Jan 19, 2020 4:38 pm ]
Post subject:  Re: More gearbox issues than I thought
5 Star degreaser for the case and use a old stiff paint brush. Usually about five cans and three rinses should bring it up like new. Only use 5 Start.

For gears and shafts etc use kero.
Author:  winabbey [ Sun Jan 19, 2020 4:51 pm ]
Post subject:  Re: More gearbox issues than I thought
Morbo28 wrote:
How should I clean out the case and the parts prior to reassembly? Petrol, turps? Water? Brush?

I had my case (and other bits) hydroblasted.

Attachment:
Transmission after hydroblasting.jpg
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