Type 9 - roller release bearing

[moggymaniac]

Hi all,
I currently have my type 9 gearbox out for rebuild. My setup is as follows:

Hybrid clutch plate as supplied by david manners, morris minor pressure plate/cover on morris minor flywheel (drilled out to 6 stud to fit my midget 1275 engine).

Upon inspecting the carbon thrust bearing which has done maybe 5000 miles, It isn't in great shape with cracking across the surface and at the edges. It's also rather noisy when coming into contact with the pressure plate.

I'm wondering if anyone has experience with roller bearings when using the original minor pressure plate? I've only seen people using roller bearings with a finger clutch plate (midget or sierra) and some complain about uneven contact causing premature wear. I'm hoping to overcome this with a front gearbox cover with a bearing tube that the roller release bearing can slide along nicely, aided with a little copper grease.

I'm planning on keeping the minor clutch linkage as I don't want to go hydraulic (I do a lot of miles and it's just another thing to go wrong with going hydraulic. But I am concerned this may make for a heavy clutch pedal.

I know this topic has been covered before but all threads i've found seem inconclusive, so anyone with any experience of the above setup and/or thoughts/advice?

Many thanks

[philthehill]

You can convert your carbon release to one of these:-
https://www.ebay.co.uk/itm/NEW-CLUTCH-S ... gKp8_D_BwE
I would advise that you check with the seller to ensure that the release bearing will fit over the type 9 release bearing carrier tube.
The release bearing and carrier fits over release bearing carrier tube of the type 9 gearbox.
Because the release bearing moves just fore and aft there has to be some jiggle room with the release lever arm as the arm moves in an arc and the two movements are not compatible.
The two incompatibles can be overcome by slotting the pivot of the release arm.
I have a Ford 2000E gearbox fitted and which has the same front end as the type 9 and I have had to allow some jiggle room for it to work.
You can modify the mechanical linkage to decrease the required foot pedal pressure. I have fitted a hydraulic release system using the 1275cc Midget slave cylinder and a separate master cylinder mounted on the cross member.
The carbon thrust is not really suitable for up-rated clutch covers and should be converted to a roller bearing release if you want a good service life.
See the special notes on the release bearing in the link below.
https://frontlinedevelopments.com/wp-co ... remote.pdf

[moggymaniac]

Hi Phil,
Thanks for the info.
I'll check with the seller to see if this bearing will fit over the bearing tube for the type 9.
I think I understand what you mean in terms of incompatible movement as the pivot arm wants to move in an arc but needs to travel straight along the bearing but i'm not entirely sure what you mean about slotting the fork and how exactly to do it...do you have any pictures of this? Or do you mean elongating the hole in the pivot arm bracket to allow the arm to move as necessary to travel up and down the sleeve of the input shaft?

I found this page to be quite useful back when I fitted the kit first time round - the hole in the lever bracket is elongated to allow for bearing travel: http://biker-lofty.co.uk/hobbies/bolton ... midget.htm

I've seen a few different roller bearings. I'll enquire to make sure they'll fit over the input shaft sleeve. Here are the ones I found:

https://www.petermayengineering.com/pro ... aring-kit/

https://www.abingdonmgparts.co.uk/produ ... /seir%2019 (presumably this one will work as it's for the 5 speed ...just expensive!)

I'll stick with the standard linkage for now as I'm retaining the minor pressure plate (non finger) and if I have a heavy clutch I can alter as you suggest. Don't see why it would make for a heavy pedal with a roller bearing unless i was also changing to a fingered clutch pressure plate.

[philthehill]

The release arm pivot bracket hole is elongated (as per the biker-lofty link above) to allow the release arm to follow the correct path.
The link in my post above does actually refer to the elongated hole for the release arm.
Going back to your original post re fitting the flywheel to the MG Midget crankshaft. The Midget crankshaft has 6 bolts and 2 studs plus a register that the flywheel fits over. You do not mention the 2 studs or the register. The register is most important as it does help keep the flywheel in place and the two studs help with the additional rotational forces generated by the 1275cc engine.