990 clutch housing cover

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Mossop
Posts: 21
Joined: Thu Jul 18, 2019 6:36 pm
Location: Perthshire

990 clutch housing cover

Post by Mossop » Sun Feb 16, 2020 8:13 pm

Hi looking for some advice again , currently started work to split selectamatic 990 to change clutch as very hard to get pto engaged, I've taken off starter and taken out bolts for top clutch cover , I took out the three bolts I can see to remove the wedge from between cover and steering box , and although slack can't get wedge out , is there a knack to it or is there a fourth bolt somewhere else that I'm not seeing , the parts book only lists three bolts but by the looks of it the wedge has four holes. Whilst I'm here would anyone have or know someone who would have a top link with the clutch safety cable on it many thanks

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db2d
Posts: 2195
Joined: Fri Feb 24, 2012 10:01 pm
Location: Monmouthshire

Re: 990 clutch housing cover

Post by db2d » Sun Feb 16, 2020 11:31 pm

There are two methods for accessing the clutch assembly.
One is by removing PTO unit, steering box and gearbox covers and clutch cover housing. There are four bolts going through the wedge.This method involves more time.
The second and easiest method is to splitting the tractor. The clutch cover housing and wedge etc does not have to be removed.
If you have a workshop manual both methods should be explained
You are correct in thinking that the transmission plate is worn ( probably almost down to the rivets )
The three adjustment screws in the cover assembly can be re-adjusted to obtain PTO plate clearance but bear in mind that the transmission plate will now continue to wear down through the rivets until it destructs causing severe damage in most cases to the separator and pressure plates ( expensive)
Is the tractor a Selectamatic or Implematic?

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ollek
Posts: 3969
Joined: Tue Apr 10, 2012 1:20 pm
Location: South West Finland

Re: 990 clutch housing cover

Post by ollek » Mon Feb 17, 2020 3:53 am

Please be avare of the following. You must split the tractor if the tractor is a Selectamatic with a 12-speed synchronized gear box. What are you refering to when you wrote: a top link with the clutch safety cable on it. Do you mean the top link and cable for the owerload release? If so, then I would recommend not to use this system as it can be potentially dangerous. Operating the lever from behind the tractor can result in that the tractor runs over the operator. It is most important that you tell us if your tractor is a Implematic or a Selectamatic and if the tractor has a 6-speed or a 12-speed gear box, with or without syncronisation (with syncro only in Selectamatic) before we continue with this discussion.

Mossop
Posts: 21
Joined: Thu Jul 18, 2019 6:36 pm
Location: Perthshire

Re: 990 clutch housing cover

Post by Mossop » Sun Mar 01, 2020 9:45 am

Hi , sorry for the late replies , the tractor is a six speed selectamatic , I have managed to split it , the selector plate was seized in but also both clutch plates at a almost down to rivers , I suppose the plate was seized as it has little use , is there any tips on how to keep it free , I have given it a good wire brush prior to it being refitted, is the selector plate flush on both sides as there is a groove on the pto side but it looks like a machined edge on it or maybe it has been historic damages , person I bought it from continued to try and work the pto even though it was very difficult to engage , as for the top link yes I was meaning the one with the cable to disengage clutch , just trying to keep it original

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db2d
Posts: 2195
Joined: Fri Feb 24, 2012 10:01 pm
Location: Monmouthshire

Re: 990 clutch housing cover

Post by db2d » Sun Mar 01, 2020 10:23 am

The damage on the separator plate is probably historic. Clean it and the flywheel well prior to refitting, do not lubricate.
There are three springs located in the flywheel to push the separator plate away from the PTO plate, I suggest renewing these.
Check the condition of the carden shaft bearing in the flywheel and also the rear engine crank oil seal.
Do you have a workshop manual that explains the procedures required ?
The Selectamatic does not have a clutch release mechanism on the top link.

Mossop
Posts: 21
Joined: Thu Jul 18, 2019 6:36 pm
Location: Perthshire

Re: 990 clutch housing cover

Post by Mossop » Sun Mar 01, 2020 4:29 pm

Hi yeah have workshop manual , bearing condition ok , tractor definitely has the clutch release , has the handle at the side when you knock it cuts the drive by engaging clutch pedal

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ollek
Posts: 3969
Joined: Tue Apr 10, 2012 1:20 pm
Location: South West Finland

Re: 990 clutch housing cover

Post by ollek » Sun Mar 01, 2020 4:58 pm

The clutch release was a optional extra, not a standard equipment, for Implematic and early 880 and 990 Selectamatic tractors and only a few Selectamatic tractors were orderd from the manufacturer with this equipment fitted. This feature can be potentionally dangerous and was therfor discontinued at an early stage after the Selectamatic tractor production started. It was not possible to homologate tractors with this feature after early 1960:s in the country I live, but it was legal in some other countries, but not for long. As I said before, for your own safety, remove the system. This is important, as the systerm can be used against the manufactureres instructions, and some people do.

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