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Old 12th May 2019, 17:51   #1
Comfortably Numb
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Default Engine harder to turn as I tighten up gearbox bolts.

Having changed the clutch on my CDT, using the clutch alignment method I have always succeeded with, namely, a piece of 15mm copper pipe with electrical tape wrapped around it, and using a threaded bar in the top, rearmost bolt-hole in the engine to 'hang' the gearbox on, and using 2 trolley jacks and a scissor jack to get the gearbox level and onto it, I was able to get the gearbox within 18mm of the engine face on 2 bolts and the stud, with only light spannering. Using a screwdriver through one of the notches in the bottom of the bell-housing, and in gear, I could turn the engine, and see the drive shafts turning. However, with a couple more turns on each of the bolts and stud nut, they became much harder to turn, and so did the engine.When I slackened the bolts (near the bottom of the gearbox) but not the nut at the top, the gearbox started to move away from the engine, and it again became easier to turn the engine. I should add that by now, I had only one jack - supporting the engine. I have used slightly longer bolts to get to this stage, as the proper ones will not yet reach their threaded holes. Nothing is trapped in the gap. What have I done wrong? Is marginal mis-alignment of the clutch causing this difficulty? If the input shaft has made its way through the clutch centre, is it possible that it can't get into the flywheel bearing? If I reconnect the clutch slave, and press the pedal at this stage, will it release the driven plate and allow it to centre itself?
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Old 12th May 2019, 18:11   #2
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I think leaving it in gear will make it difficult to turn as the clutch plate gets connected with the flywheel.
the clutch plate should center itself, if you release the clutch, provided the gear shaft goes through on the splines on the plate!
Turn the gearbox output shaft to make sure it engages the splines.
Is the clutch friction plate the correct one?
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Old 12th May 2019, 18:22   #3
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Quote:
Originally Posted by Comfortably Numb View Post
Having changed the clutch on my CDT, using the clutch alignment method I have always succeeded with, namely, a piece of 15mm copper pipe with electrical tape wrapped around it, and using a threaded bar in the top, rearmost bolt-hole in the engine to 'hang' the gearbox on, and using 2 trolley jacks and a scissor jack to get the gearbox level and onto it, I was able to get the gearbox within 18mm of the engine face on 2 bolts and the stud, with only light spannering. Using a screwdriver through one of the notches in the bottom of the bell-housing, and in gear, I could turn the engine, and see the drive shafts turning. However, with a couple more turns on each of the bolts and stud nut, they became much harder to turn, and so did the engine.When I slackened the bolts (near the bottom of the gearbox) but not the nut at the top, the gearbox started to move away from the engine, and it again became easier to turn the engine. I should add that by now, I had only one jack - supporting the engine. I have used slightly longer bolts to get to this stage, as the proper ones will not yet reach their threaded holes. Nothing is trapped in the gap. What have I done wrong? Is marginal mis-alignment of the clutch causing this difficulty? If the input shaft has made its way through the clutch centre, is it possible that it can't get into the flywheel bearing? If I reconnect the clutch slave, and press the pedal at this stage, will it release the driven plate and allow it to centre itself?
Although there is a spigot bearing fitted to the crankshaft, it does precisely nothing whatsoever.

Your driven plate isn't centralised, so off it comes again I'm afraid.

If you don't have the proper alignment tool, here is a method which works,

Align the clutch driven plate on the cover, measuring from the machined edge of the cover, mark it up, then put a couple of small dots of superglue on the clutch cover and place the driven plate onto the clutch cover, aligning with the marks.

Double check the measurements, then refit the assembly to the flywheel, then it will go back together easily.

A proper(ish) tool can be found HERE however the other method works fine.

When the clutch is pressed for the first time, the bond of the superglue will break.

Under no circumstances press the clutch pedal with the gearbox not in place, or the slave seals will pop

Brian
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Old 12th May 2019, 21:22   #4
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What is the point of the spigot bearing, if not to engage the end of the input shaft? And how can the flywheel and clutch cause the driveshafts to turn if the clutch centre has not engaged on the input shaft splines. I was very careful to only nip the driven plate with the pressure plate bolts before centring the driven plate, then tightening by one turn at a time on each bolt. I have a pretty good eye for this sort of thing; is less than 0.5mm off centre (probably much less) not close enough?
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Old 12th May 2019, 21:24   #5
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PS, I put it into gear having got the gearbox into place to check whether the clutch would drive the drive-shafts, ie had engaged on the input shaft splines.
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Old 12th May 2019, 22:15   #6
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Quote:
Originally Posted by Comfortably Numb View Post
What is the point of the spigot bearing, if not to engage the end of the input shaft?
Probably a fitment for another type of gearbox. In the photo you can see that there isn't a stepped end on the input shaft to locate in the spigot bearing:

[IMG][/IMG]

As to the alignment I'd hazard a guess that it is slightly out - there are two dowels to align the gearbox casing and if the clutch plate isn't in the correct position these won't locate.

If you don't have the correct alignment tool then use the Superglue method that Brian suggested. You can align it on the bench so it is easy to be accurate.

When you get it right the gearbox slides into place by hand, so don't be tempted to draw it in on the bolts.




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Last edited by Mike Noc; 12th May 2019 at 22:18..
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Old 12th May 2019, 22:15   #7
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Is the driven plate in the right way around? (Flywheel side usually marked as such)
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Old 12th May 2019, 22:59   #8
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I'll try removing all bolts and the threaded location stud I put in. That way, even if it is off -centre, the gearbox should slide on until it hits the location dowels (currently can't get within 10mm of them). If it does that, then I'll know the clutch is off-centre. And I checked and double-checked that I had the driven plate the right way round, as stamped into it. Thanks for the pic, Mike - I could have sworn mine had a plain section at the end!
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Old 12th May 2019, 23:24   #9
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If you can't get any joy with it Andrew and have to take it out again, it is worth trying the friction plate on the input shaft splines to make sure it slides on easily.
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Old 13th May 2019, 06:01   #10
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Brian has given the best advice, just remove it and follow his method. One thing I’ll add though, no matter how light your spannering is never ever pull a gearbox in using the bolts, it should slide on albeit a bit tight sometimes. Once you’ve got everything removed check the drive plate as you may have distorted it
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