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 Post subject: Downshift problems
PostPosted: Wed Jan 02, 2013 11:22 pm 
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848cc
848cc

Joined: Sat Oct 27, 2012 12:06 am
Posts: 122
Location: Mt Martha, VIC
Well, after having my Mini sat in the driveway for 6 months while I finished the house renovations, I have finally got it up on stands ready to start inspecting the extent of the work needed. One thing that I am all too aware of is the seemingly impossible task of down shifting. When driving, it goes up the box no problem but no combination of downshifting seems to work without some almighty grinding going on. Double-dipping the clutch makes no difference and the only way to make a clean downshift is when the car is completely stopped - any forward motion and a downshift is pretty much out of the question.

Today, I got the front end up on stands to take a look at the source of a couple of oil leaks and while it was up, I fired it up and ran it through the gears and downshifting was perfectly possible, no grinding whatsoever regardless of which gears I went between.

So, given the ease of downshifting while up on stands and the impossibility of downshifting while mobile, what do you think I should start looking at as the most likely cause? It's been over twenty years since I last owned a Mini at which point I'd had in the region of 10-15 of them and never ran into this particular problem so any ideas would be greatly appreciated.


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 Post subject:
PostPosted: Thu Jan 03, 2013 8:06 am 
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1275cc
1275cc
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Joined: Mon Sep 19, 2005 4:57 pm
Posts: 3635
Location: Gulgong
Up on jack stands there is no load on the gearbox and you can change gears easily enough. Probably art times without even using the clutch. But dont try it though !!!!

Assuming that the hydraulics are working and the throw out arm is moving in and out enough to disengage the clutch then the next place to look is the actual clutch adjustment. its done at the big nut on the wok shaped part of the gearbox on the drivers side.

The best way to adjust the clutch is to get the manual and read the clutch adjustment section several times while you are also looking at the assembly. Then get a non mechanical friend, partner or what ever to read it and tell you what they have just read. That way there is no preconcieved ideas. Follow their advice.

Other people say to simply take the nut off and let the clutch adjust itself. I am no so sure that that is the best way.

Just be aware that the flimsy pressure pressure plate can become brittle and snap or the crankshaft itself can have end float problems with wear and both of these will also give you clutch problems

Start with the adjustment though !!!

Mike


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 Post subject:
PostPosted: Thu Jan 03, 2013 12:20 pm 
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998cc
998cc

Joined: Sun Sep 04, 2011 10:46 pm
Posts: 526
Location: S.A
Double clutching on the down shift requires blipping the throttle too, so the revs match the next gear ratio down.


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 Post subject:
PostPosted: Thu Jan 03, 2013 1:55 pm 
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848cc
848cc

Joined: Sat Oct 27, 2012 12:06 am
Posts: 122
Location: Mt Martha, VIC
After having a closer look, I think there are bigger problems than I first anticipated. While wiping a lot of caked on oil and dirt from the sump while tracing a couple of oil leaks, I uncovered a nasty looking crack in the clutch housing and on following it around, it ends with a chunk missing, leaving a jagged hole through which the flywheel can be seen. So given the amount of oil and crap all around the hole there is a high chance the clutch is going to be in something of a sorry state due to contamination etc. Looks like the engine will be coming out as soon as the tempertaures drop enough for me to be able to sit outside for long enough.


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