It shouldn't be tight at all. The new Fibre Thrush Washers these days are too thick, they are about 0.048" but should be 0.035". This is your problem. If left as is, it is likely that they'll split. I make mine from brass sheet.
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| Diff rebuild https://www.ausmini.com/forums/viewtopic.php?f=2&t=61643 |
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| Author: | Frank Mathews [ Tue Mar 09, 2010 8:01 pm ] |
| Post subject: | Diff rebuild |
Hi everyone. Have just put new copper washers, fibre washers, new small gears and new diff pin into my diff. Question is, how tight should all this feel? Before changing these parts everything felt very loose and easy to turn. Now its almost too hard to turn by hand. Will this tightness soon just wear out in use or should I be a bit more concerned. Cheers. Frank |
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| Author: | GT mowog [ Tue Mar 09, 2010 8:05 pm ] |
| Post subject: | |
It shouldn't be tight at all. The new Fibre Thrush Washers these days are too thick, they are about 0.048" but should be 0.035". This is your problem. If left as is, it is likely that they'll split. I make mine from brass sheet.
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| Author: | Frank Mathews [ Tue Mar 09, 2010 8:11 pm ] |
| Post subject: | |
have still got the old ones so will measure them against each other. Hopefully that all it is. 
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| Author: | drmini in aust [ Tue Mar 09, 2010 8:59 pm ] |
| Post subject: | |
Don't refit those old washers, they break up when old and black. I trial assemble the diff centre with all the new bits and no spacer. Measure the gap between the side gears with a telescopic gauge, then surface grind or linish 2 of the spacer's flats so that you get around .005-.006" clearance. Then put it together. |
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| Author: | doogie [ Wed Mar 10, 2010 3:02 pm ] |
| Post subject: | |
Make sure you have a decent diff pin, most these days are made from chewing gum. Doogie |
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| Author: | drmini in aust [ Wed Mar 10, 2010 3:51 pm ] |
| Post subject: | |
Karcraft's competition ones are good now.
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| Author: | simon k [ Wed Mar 10, 2010 7:27 pm ] |
| Post subject: | |
drmini in aust wrote: Karcraft's competition ones are good now.
define "now".... I bought one in August '08, and by February '09 it was badly pitted, replaced that with an ultra tough EN40B and it lasted from Feb until July I'll never use a standard diff again, cross pin diffs for me. Almost tempted to buy another one to put on the shelf since the exchange rate is so good |
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| Author: | Morris 1100 [ Wed Mar 10, 2010 7:32 pm ] |
| Post subject: | |
simon k wrote: drmini in aust wrote: Karcraft's competition ones are good now. define "now".... I bought one in August '08, and by February '09 it was badly pitted, replaced that with an ultra tough EN40B and it lasted from Feb until July Was it the one that was... Quote: Manufactured from a special steel which undergoes 4 heat treatments and 2 centreless grindings. Then finally has a black tuftrided finish.
(before being being hand packed by virgins) 
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| Author: | drmini in aust [ Wed Mar 10, 2010 7:59 pm ] |
| Post subject: | |
Simon K is a special case, he canes the bejesus out of it in `khanas. 
He NEEDS a 4 pin diff... When I pulled my 1310S motor down (finally) and did the box up, its competition black tufftrided? diff pin had 70,000 of my miles on it, + God knows how many the PO did. Wear?? A mere .0005" (1/2 a thou). It was a good 'un. Nope I dunno who made it. Anyway GR has Rockwell tested the current crop of Karcraft ones, he says they are the best ones about. |
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| Author: | BALLISTIC [ Thu Mar 11, 2010 2:08 am ] |
| Post subject: | |
simon k wrote: I'll never use a standard diff again, cross pin diffs for me.
Sorry doc I have to agree with Simon here, cross pin diffs are the way to go . . . Ive had mine in for 8 or 9 years now, the gearbox has been apart 3 times (i think) and could not fault it when i disassembled it . . . i did replace the brass tabbed washers last time just because they were in my "spare parts" but didnt need too. |
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| Author: | Wombat [ Thu Mar 11, 2010 7:49 am ] |
| Post subject: | |
When I rebuilt my diff the fibre washers were too thick so on the Doc's advice I dug up some original brass washers from an original 850 diff and used those 
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| Author: | drmini in aust [ Thu Mar 11, 2010 8:00 am ] |
| Post subject: | |
Scott, I agree that a crosspin diff is good value- at only around 3x what a diff repair kit (2 gears, comp pin, and the 4 thrust washers) costs now. However... If/when it wears, it won't be a cheap fix. More parts to replace.... Wombat, if I'm doing a diff up that has the brass side washers in (like M1100's did), I leave them in . They don't wear or break up like the fibre ones. |
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| Author: | BALLISTIC [ Thu Mar 11, 2010 9:26 am ] |
| Post subject: | |
No disrespect intended Doc, Im going on the "once bitten, twice shy" theory, if I get as many years out of one of these cross pins as people have out of the original single pin diffs it will be a cheap investment and I will be happy.  Especially because my car is only diven on sundays by an old man in a smallish country town, using standard minitopia engine and gearbox spec components
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| Author: | drmini in aust [ Thu Mar 11, 2010 10:06 am ] |
| Post subject: | |
re the crosspin diffs, I have heard that the Mini Spares ones are fine but the Minisport (UK) ones had problems. May be fixed now, but I've not heard so. |
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| Author: | doogie [ Thu Mar 11, 2010 3:04 pm ] |
| Post subject: | |
Have to agree about the crosspin diffs, as many of your know im extremley gentle on my Cooper S's & there diffs, i have crosspins in both my S's & have found everytime i've checked them they have had no wear what so ever to them. However im seriously cosidering buying a Swftune LSD in the near future.
Doogie |
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