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MG Midget and Sprite Technical - Type 9 conversion bell housing and clutch release

Type 9 conversion bell housing and clutch release mechanism

as for the second time I have a serious problem with clutch failure on the equipment made up by, bought from and installed by the ’specialist expert’ outfit I wondered if they’d been kind enough to give me something different to what is supplied to others

if you have a photo of your type 9 conversion showing the release mechanism and mounting could you please post it for me so that I can compare it with this -


Nigel Atkins

Nigel,

What problems are you experiencing? Looking at that installation with the release bearing on the guide tube where is the allowance for the articulation, is the release lever mount slotted or is there enough slop in it to cope.
David Billington

Identical to the item supplied by Morry Minor Centre to me and most others I suspect Nigel

It does A job averagely but no doubt other users of the basic mechanisms have avoided finding the "better way" because it does a job, if only averagely

I can name three of us at least who have gone "concentric" simply because the way derived from the BMC box by MMC doesnt QUITE work



I have added WOT I DUN to this item

You can clearly see the threaded holes that no longer have a function for bracketery and the SAAB release bearing and CSC

Oil courtesy of a badly sealed type 9



Bill1

I see what you say David, Nigel you know that Ford's bearing is spring mounted so it can slip sideways as well as forwards and backwards don't you?

This lets it slide along the guide tube in action

The cheap "fix" involves cutting off the guide tube when using on Spridgets

But then you may get the dreaded "tramping" when changing gear

After too many miles driving like that I decided to go concentric

Then I discovered I was not the only one who had...
Bill1

Similar kit as sold for Minors. As you have found out this is not a very accomplished design. We always fit concentric units which give a much lighter pedal and doesn't rattle around on idle.

J L HEAP

The earlier kits used a simple pivot point for the clutch release arm, and this caused the release bearing to move through an arc as the pedal is depressed. On this early type the advice was to cut the guide tube off the front, allowing the freedom of movement needed by the thrust bearing. The problem was that when the pivot points loosened up a bit the mechanism sagged, allowing the lever arm to drop and the thrust bearing to bounce around and rattle on the rotating input shaft.

I had just that type, and just that problem. I resolved it by fitting a DIY version of the concentric slave system similar to Bill's.

Later lever-arm kits used some form of articulated or sliding pivot point which meant that the guide tube could be retained.

It isn't quite clear from the photo Nigel, but looks as if yours is the sliding type. But if the pivot point is a simple hole through the bracket, then the guide tube should have been cut off. If it is a slotted bracket, then the pivot bolt needs to be loose enough to allow the lever arm to slide radially in the slot. It isn't an adjusting arrangement where one might expect to tighten the bolt until it locks! It should have a Nylock nut so it can be set with a mm or two sliding slack.

HTH,

Guy
Guy

Thanks David, Bill, J L, Guy

please keep all advice and comments coming they are very gratefully received and I’m noting and passing on all your advice

to keep to the point and a long story short I’ve only ever see this part of the conversion in this photo and when I saw it I thought it looked a crude method and not well executed but this was after the box came out 2 years ago

I bought the conversion and paid to have it installed along with other work by what I euphemistically call a ‘specialist expert’ outfit, I’d checked them out and even now imagine that at an earlier time I might have got a much better product and work from them but not at the time I happened along

David,
to answer your question, this time the slave has popped it’s rod and the release arm jammed so this time I am without a working clutch - the previous time the release bearing fell apart and damaged the gear housing cover this was 2 years ago and about 8 months after installation of the conversion kit but I’d had gremlins for a few weeks before
Nigel Atkins

I have done a number of T9 conversions on various engine sizes of Spridgets - about 10 I think.
To mount the clutch yoke there are two types of bracket
a slotted one for use with a roller thrust when the imput shaft sleeve is left in situ.
one with a pivot hole for use with a carbon thrust when the imput shaft sleeve is cut off.
I have fitted both types although I retain carbon thrusts on my own cars. I have had no feed back re problems.
With the slotted bracket it is best to allow some slack. Also ensure that the pivot bolt is free to move along the slot.
There is often a casting lip on the slave cylinder platform on the bellhousings. I usually file this off to ensure that the slave cylinder sits nicely.
Alan Anstead

Nigel,
Although the mechanism in your photo looks crude, it is pretty standard and the parts are normal for that type of conversion. I don't think that there is anything wrong with those parts or that assembly that would directly cause your present problems. Assembly is pretty straightforward.

Possible potential problems:
1. That the pivot bolt is overtightened so that the sliding pivot doesn't slide. But that would have given problems when first installed.
2. The two small allen bolts holding the pivot bracket have worked loose so that the pivot is no longer secure.
3. The pivot bolt itself has either dropped out or worn through, allowing the clutch fork arm to flap about and the pushrod to break free, Freddy Mercury style.

The rod is normally pretty well trapped between the concave end of the slave cylinder piston and the pivot pin in the end of the clutch fork. That end of the clutch fork being pushed forwards towards the slave cylinder by the pressure of the clutch cover springs acting via the thrust release bearing and the leverage of the clutch fork. This should hold it in place and in principle is no different for the Type 9 conversion that you have than the standard Spridget arrangement.

You might be able to get a sight line into the bellhousing through one or other of the two openings and with a good light check if the pivot point is secure and complete as it should be.

Guy
Guy

The clutch cover and roller release bearing that the M.M Centre supplied to me just wouldn't work on my 1098. The release fork jammed on the input shaft tube because it travelled through an arc and even when fully forward with the bellhousing bolted up it didn't depress the cover. After much haggling I sent the complete clutch back to them, they refunded my money and sent me the correct Avenger driven plate which I used with my original clutch cover and carbon thrust. It's been in for about 4,000 miles with no problems.

Bernie.
b higginson

Some T9 conversion kit suppliers advertise that one kit fits all but do not understand the subtle differences in components used on the various engine types. This surprised me when such a supplier contacted me about how to do a 948 T9 conversion.
Alan Anstead

Alan, Guy, Bernie, again thank you for the info and it is noted and will be passed on

the first clutch problem was an engagement issue as the clutch worked but I got a quiet graunching which I might have been able to just feel through the pedal or I might have been fooling myself about that but it was found that the release bearing had fallen apart

this time the pedal went hard then collapsed then offered no resistance, looking under the car the slave has popped with release arm jammed solid

until the box is removed it can't be said with certainty what has happened this time other than something is jammed (another technical term from me)

I don't want to distract from this tread but I can put up another thread with photos of the box when it was out last time if there's interest
Nigel Atkins

Nigel
You get a pretty good picture if you have a look in through the aperture on the nearside of the bellhousing, from under the car.
I think I can see from your pic that you have the correct slotted support for the yolk. I cant see the swivel nut. Is it that an ordinary nut has been used instead of a nylock and it has tightened, with the motion of the yoke, and locked the yoke in one position?
Alan.
Alan Anstead

Alan,
I don't know, I hope not, but I'll have look when I get a chance as the car is always outside and I have to push the car on to wooden blocks to get the jack under the front

IF I can get my old camera to work long enough to take a photo I'll do that too
Nigel Atkins

Just a point there - I have often found when trying to get a view in awkward places it is often easier to hold a camera and take a few shots than get your head into the same confined position. You can then view the photos, zoom in etc and see much more than trying to jam your head into some confined space!

Bernie, the fixed pivot ones must all travel through an arc -basic geometry - and therefore are used with the guide tube cut off. Although the implication of what you say is that the carbon thrust perhaps has more clearance from the guide tube such that it doesn't jam on it. Maybe also, the 1098 clutch cover is deeper?

The kit that I had used the roller bearing type release, and a fixed pivot. I cut the guide tube off and it worked fine, together with my standard 1275 clutch cover and an Avenger plate. The only problem was later, after a few thousand miles when with the weight of the heavy roller release bearing it began to clatter and bounce around on the rotating input shaft. That's when I went concentric!

Clutches using the carbon thrust have a flat thrust "contact washer" attached to the cover plate. If using a roller type bearing with a curved thrust face as in Nigel's photo, then this washer needs to be removed and the bearing acts directly onto the "fingers"
Guy

Nigel as Guy says you need to cut the guide off mine worked fine but after a time the roller bearing began to clatter but still worked ok . Ive now gone back to 4 speed.

b bithell

Guy,
I was thinking of using my camera in that way but it's not so easy to do as its a camera type camera needing to zoom and focus plus it likes to switch itself off just before a shot or just after and I have start all over again

so I do need to get my head under there and to set the focus inside on the pivot nut

then there's my eyes, I've just been trying to do a jod where three different sets of lenses didn't help

sometimes it's case of numbers take enough shots and one might work, you know throwing mud, or other stuff against a wall until some sticks

I've been sent a copy of the fitting instructions now so that helps
Nigel Atkins

which bit is the guide please?
Nigel Atkins

OK, another thought:
If you think about the clutch fork as a simple lever, pivoted in the middle with one end moving forwards to compress the clutch springs whilst the outer end moves rearwards. If the outer end has moved so far back that the slave cylinder piston has either popped out of the cylinder, or has come up against the circlip end stop, allowing the pushrod to pop out, then I would suggest that one of three situations may have occurred.

1. The inner end ( the clutch release bearing) has moved too far forward. Damaged release bearing or damaged clutch cover.

2. The pivot point has broken - Bracket come loose or pivot bolt dropped out / sheared as I suggested earlier.

3. The clutch fork arm has bent. This itself is not an uncommon fault with standard clutch arrangements and standard gearboxes.

Guy

PS, the guide is a tube around the input shaft. It has been cut off in that last photo, but the end of it can be seen in your own photo, concentric with the release bearing. The bearing slides back and forth along the guide tube whist the input shaft rotates within it.
Guy

Guy,
thanks, the machined end, I got confused I was thinking of the arm/bracket but my mind is really on my other thread about wiper motor

how you chaps enjoy any of this mechanical stuff is beyond me even getting a c-clip off was begining to annoy me
Nigel Atkins

Guy,
I was thinking around 2. and 3. as I had 1. last time but it doesn't rule it out
Nigel Atkins

This thread was discussed between 30/05/2012 and 31/05/2012

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