LT Clutch Adjustment

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31 Oct 2012 18:21 #1 by dandjcr
dandjcr created the topic: LT Clutch Adjustment
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Pete Fox
Member
Posts: 140
Sometimes when working on this Oka I think it is really well designed and other times I just shake my head. The clutch adjustment setup must have been designed by a crazy person.
_ _
There have been a few posts around here about clutch adjustment, and reading those it seems all straight forward, but it isn't.
The manual goes on about getting freeplay at the pedal, but says nothing about the adjusting the pivot bolt (labelled 8 below). It is necessary to adjust this because it controls the engagement of the thrust bearing (4) with the pressure plate. The bearing must not spin IMHO when the clutch pedal is released. Increasing freeplay at the pedal doesn't have any effect on the overall adjustment it just ensurs that hydraulic pressure is not the cause of the thrust bearing riding on the pressure plate.
This bolt threads into the clutch housing (11) and is adjustable from the back via a screwdriver slot in the end of the bolt, until you put the gearbox on that is. The gearbox blocks the hole. WTF!
The thread of the bolt is the only thing available to work on and is only just visible through the opening in the bottom.
In order to hold the weight of the thrust bearing, bearing carrier (5) slides (7) and pivot (6) into alignment, there must be some preload on the thrust bearing otherwise it just won't sit in position while the gearbox is being fitted . This preload needs to be taken out once the gearbox is on, but you can't get at it. Hmmm.



This is almost impossible to do with standard tools, except this one



Its a poor photo, but one side of the vee at each end is serrated and will fit into position and grip the thread without damage if it is not tight and then the same tool can be used to tighten the locknut. Job done.
--
Peter Fox

OKA 266 Multi-cab.

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June 21, 2012 at 4:39 PM Flag Quote & Reply

Tony Lee
Member
Posts: 539
"The bearing must not spin IMHO when the clutch pedal is released. "

Don't get this part. Is an LT different to an XT This means the bearing is always under load. I was appalled to find that mine was maladjusted - no pedal free play and unable to spin the bearing by hand. God knows how many billions of revolutions it had done iunnecessarily - and mine has no grease nipple.
--
Tony

picasaweb.google.com/114611728110254134379

June 24, 2012 at 1:38 PM Flag Quote & Reply

Pete Fox
Member
Posts: 140
Tony
you've read it the wrong way round. what I am saying that when the clutch pedal is released, i.e. foot on floor then the bearing must not be in contact with the clutch fingers, i.e. it is not spinning (but can be spun by hand).
Perhaps I should have worded it better. 10/10 for ambiguity.
--
Peter Fox

OKA 266 Multi-cab.

Photobucket album



June 24, 2012 at 2:31 PM Flag Quote & Reply

Tony Lee
Member
Posts: 539
Yes, I read it from the point of view of my (bad) experiences. Mine WAS spinning - as per your definition - and could not be spun (by hand) as per my definition
--
Tony

picasaweb.google.com/114611728110254134379

June 24, 2012 at 3:52 PM

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15 Sep 2014 18:04 #2 by Chalkie
Chalkie replied the topic: LT Clutch Adjustment
I am about to refit my clutch and bell housing (See Engine Adaptor Plate thread)
The clutch through out leaver has no return spring and no provision for it.
My replacement metal slave cylinder has a fairly strong spring internally forcing the cylinder out
ie into the clutch disengaged position, thus forcing the through out bearing to contact the clutch operating fingers. I do not see how, without a return spring, the bearing can move away from the fingers and stop spinning when foot is off the pedal. If I am missing something please advise.

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16 Sep 2014 06:50 #3 by Tony Lee
Tony Lee replied the topic: LT Clutch Adjustment
Could it be that since you can grease the release bearing, it doesn't matter so much if it is spinning under load all the time.

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16 Sep 2014 11:35 #4 by Chalkie
Chalkie replied the topic: LT Clutch Adjustment
Mmmm,I guess Bearings are made to turn provided they are lubricated. But still poor design I think.
It will see me out anyway.

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16 Sep 2014 18:58 - 17 Sep 2014 06:39 #5 by outyonda
outyonda replied the topic: LT Clutch Adjustment
adjust pivot bolt}no8]

wind the bolt in till you have free play,
if it is left running against the clutch fingers, after the bearing fails, the fingers ware out. quickly!!

if you don't have the fancy adjuster fork, you put b/house on & off 19 times to adjust!!!!
one of the not so clever OKA design featchers"

OKAs 091, 093, 094, 113, 346x6 & 405
Last Edit: 17 Sep 2014 06:39 by outyonda.

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18 Sep 2014 18:55 #6 by Dean and Kaye Howells
Dean and Kaye Howells replied the topic: LT Clutch Adjustment
Not as bad as it might seem Chalkie. Re-install the pivot bolt with two lock nuts screwed all the way on and you're just about right, dunno about 19 on and offs, I reckon Brett is venting a bit of frustration here :) it's not rocket science, if you're that pedantic about being really spot on it's easier to set it all a bit tight and grind the slave cylinder rod length to fit. Forget about the greasable bearing, it's all obsolete now with sealed packed bearings, disconnect the old grease tube and throw it away. Doesn't need a return spring on the lever as long as it's not under tension on the thrust bearing. ie. the rod length and the pivot height must allow the fork to have a little bit of movement so that the thrust bearing is not always under load.

Deano :)

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21 Oct 2016 09:15 - 21 Oct 2016 09:20 #7 by Peter Davis
Peter Davis replied the topic: LT Clutch Adjustment
I have just measured the distance between the top of the pivot ball No.8 and the engine plate.
Old bell housing 165mm, "new" bell housing 158mm. The new appears to have less free play.
Surely Oka had a set distance that they used when assembling vehicles.
My old one seemed to have a lot of free travel so I might play the average game and adjust the new one by 3 to 4 mm.
If others particularly from the dark side, have there old bell housings off could measure and post, it may help others in the future with this crazy set up.
Last Edit: 21 Oct 2016 09:20 by Peter Davis. Reason: added

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25 Oct 2016 12:15 #8 by Peter Davis
Peter Davis replied the topic: LT Clutch Adjustment
I have installed bell housing, clutch but left off gearbox. To hold the carrier I put in the clutch alignment tool and a bit of pipe over the top to match the diameter of the gearbox nose. I can turn thrust bearing but it is in contact with the clutch fingers.
Is the thrust bearing meant to be in constant contact with the fingers or a slight gap?
With the clutch engaged about an inch I can still turn bearing but it is tighter.
Any thoughts would be appreciated.
Peter D

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26 Oct 2016 13:57 - 26 Oct 2016 14:08 #9 by Dean and Kaye Howells
Dean and Kaye Howells replied the topic: LT Clutch Adjustment
Hi Peter,

With the inspection plug removed from the bell housing you should be able to check that the operating rod is not tight. ie. the rod should be loose, say with about 1mm or so free play end to end. This ensures that there is no actuating pressure from the slave cylinder piston onto the actuating rod to the fork to the slippers to the thrust bearing to foul the clutch plate 'fingers' with the clutch dis-engaged.

Moving the pivot point of the fork will set this adjustment as will shortening the actuating rod (if it's too tight). As long as the pivot point is 'about right' it's no big deal to grind the actuating rod for your 'fine adjustment'.

What you need to be check here is that the pivot bolt thread in the housing is good. If the lock nut becomes loose the force of the fork on the pivot point is transferred to the threads in the alloy bell housing and will chop them out (normally the force is transferred to the locknut on the pivot bolt and then onto the inner surface of the bell housing so the thread stays OK). If the thread in the bell housing is badly damaged you can either helicoil it or lock two locknuts together on the pivot bolt and use locktite or some other product to 'glue' the pivot bolt into the bell housing.

When I replaced the slave cylinder in #413 it came with a new actuating rod which was too long so I used the old one as it was OK but I could just as easily ground the new one to fit. On another vehicle I worked on the original actuating rod was bent so we ground the new one to fit, slightly doming the end and finishing with a fine grind so to give the rod and fork a smooth contact surface.

Deano.
Last Edit: 26 Oct 2016 14:08 by Dean and Kaye Howells.

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28 Oct 2016 06:38 #10 by Peter Davis
Peter Davis replied the topic: LT Clutch Adjustment
I think Chalkie is right. The XT has a return spring on the throw out arm so the thrust bearing isn't touch the 3 levers when the clutch pedal is up. I can't see how on an LT that the thrust bearing isn't touching the levers at all times. If a return spring was on the throw out arm then it maybe be possible.
When the slave cylinder is installed the rod is already at full extension. It then pushes into the cylinder as the rod hits the throw out arm which is in contact with the 3 levers. I think Michael Hession's idea of checking if the bearing spins with an inch of clutch pedal deployment is probably the right idea.
The Oka manual says nothing about the pivot ball or the slave cylinder rod length.
Cheers
Peter D

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