Herald 1200 clutch

[Tom]

Hello, as well as todays diff adventures (those that have been following) And due to my angle gringer blowing up I decided to confirm my suspicions that the juddering clutch I was experiencing just before the old girl went into hibernation was due to either a failed rear crank seal or a leaking gearbox seal. I pulled to box out and to my joy it was bone dry in the bell housing so I can remove seals from my parts list.

Inspection of the clutch has revealed a broken spring in the plate (see pic ) could this have been the source of the judder? Pressure plate springs are fine and flywheel looks good, thrust bearing is a little lumpy so I'm hoping a clutch kit will sort that out.

Also could judder be caused by general wear, slop in the drivetrain itself? I have rebuilt the hubs and uj's already and had the propshaft reconditioned and balanced, also all the rubber bushing and mountings will be new so that will tighten the show up I suppose?

can anyone reccomend a clutch kit and supplier?

[johny]

I think a new clutch will greatly improve things (sorry no recommendations). What's the slight shiny band on the left of the friction plate underneath the screwdriver in your photo?

[Colin Lindsay]

Go for the best you can afford; you want it to perform, and last. If you can find a NOS Borg and Beck online, go for it - modern ones aren't as good. Make sure you get the correct version as some will say they fit all Heralds, others will sell a kit for 1961 - 1965 models, and still others will sell pre and post 1967 versions. I suspect yours is coil spring? You might want to upgrade to diaphragm, same fitting (unless the dowels in the flywheel differ? Anyone remember?) but slightly larger plate and you'll need to replace the slave cylinder too.

 

[Adrian Cooper]

4 minutes ago, Colin Lindsay said:

You might want to upgrade to diaphragm, same fitting (unless the dowels in the flywheel differ? Anyone remember?) but slightly larger plate and you'll need to replace the slave cylinder too.

I'm sure that they are the same fitting onto the flywheel but I think that the release bearing carrier arm is different too.

Adrian

[Pete Lewis]

broken springs  is often the result of a bent rear engine plate 

Pete

clutch diag 1.pdf

[Tom]

Hi Pete, I'll check that. Can I just put a straight edge on it? Would that have potentially been the source of the judder?

[Nigel Clark]

1 hour ago, Pete Lewis said:

broken springs  is often the result of a bent rear engine plate 

Pete

clutch diag 1.pdf

....And that would certainly cause judder. I would suggest removing the flywheel and checking the engine plate with a straight edge.

I fitted a Borg & Beck 3 part clutch to my get last year. Very smooth so far with a light pedal too.

Nigel

[DanMi]

The flywheel is different between the spring and diaphragm clutches that looks like a later diaphragm. The flywheel looks a bit scored and very shiny so maybe worth having it skimmed. plus yes remove and check the backplate

 

[Colin Lindsay]

10 hours ago, DanMi said:

The flywheel is different between the spring and diaphragm clutches that looks like a later diaphragm. The flywheel looks a bit scored and very shiny so maybe worth having it skimmed. plus yes remove and check the backplate

 

I think there are three dowels for the diaphragm and only two for the coil; I've a few spares lying about (too heavy to post!) so just select the corresponding one for the clutch and use that.

Tom - if you're buying a coil spring clutch try to get the nine-spring cover rather than the six, it's not really strong enough for the 1200 although many suppliers do sell them.

 

[Pete Lewis]

engine plates are often gorilla damaged by odd years of gearbox on /off and the likely misaligned attempts to refit 

the plate is fine if left alone from human ingress

a tip i use to refit , when youre close and have engagement and a decent gap get a stick of timber ,poke it in the gap all round and you can easily  judge if the clutch hsg is aligned with the back plate,  where as just looking gives a false sense of its ok when its miles out  then jack engine and waggle g box to get a accurate line up in in she goes 

dont rely on eyes and brain alone   

pete

[Peter Truman]

The current aftermarket option of alloy engine plates has worried me for just that reason.

I relatively spent quite a sum of $ getting the front plate professionally straightened it had obviously been accident damaged/kinked

Peter T

[Tom]

Right chaps. Mine is a 9 spring unit, 2 dowells.

close inspection reveals a potential hot spot on the pressure plare and some hairline cracks (see pic ) I suspect some localised heating has been taking place at this point?

the flywheel looks a bit grotty, but remember it has sat for 8yrs or so, but it is as smooth as a baby's bum almost mirror smooth.

I will remove the flywheel this afternoon to check engine plare.

I have always been a fan of sticking with original parts so my gut is too stick with the spring clutch, also I have enough on at the momant and unless conversion to diaphragm is a straightforward affair I'd rather just stick with original. I won't be doing big miles or hammering it.

 

[Pete Lewis]

i would de graze the ever so shiney  to a bit more dull  use a orbital sander  to bust the shine  

too much shine gives more likely slip 

the heat cracks on the pressure plate are from a long time ago and possibly from a worn disc in the past 

its unlikely normal slip times would crack up the plate   

it can be affected by having a diaphragm disc fitted which is thinner and this gives you a heavy pedal and less clamp load = more slip time  = more heat

 

pete

[Colin Lindsay]

1 hour ago, Tom said:

Right chaps. Mine is a 9 spring unit, 2 dowells.

I've always wondered how feasible it is to recondition these covers? The springs are similar to valve springs, so I'm wondering if you could locate similar springs and refit those, thereby only needing a new clutch plate?

[Pete Lewis]

much of the spec is in the WSM but no detail , you would need a spare flywheel , dial indicator and a press using a load cell so you can measure loads /lift 

for both pressure and release hysteresis  and a dummy disc /or three  0,305" sized buttons 

pressure springs are 3 @ 90/100 lbft   and 6  @ 75/85lbft  doesnt give the the   @ length 

its all a bit complicated to attempt DIY 

and if you reface the pressure plate you need to play with the settings to get the release height correct now its all changed without upsetting the clamp and release loads 

all a bit of a nightmare not a task you can succeed  on a wing and a prayer , unless youre stuck in the middle of the desert and need to get home its best left alone

even under house arrest

Pete

 

[Colin Lindsay]

57 minutes ago, Pete Lewis said:

its best left alone

even under house arrest

Pete

 

Pete, you should know by now... never ever post something like that where I can read it...

But you mean it's not just a case of wheeking new springs in and job done?

[Tom]

Ok, yes that all sounds a bit complicated. 

Flywheel came off no probelm, have a feeling the bolts sound have tab washers, mine didn't.

took the glaze off with some fine..ish emery wrapped eround a V block to keep it flat, worked a treat, there is no scoring.

engine plate has no impact damage and putting a good quality steel rule across it in many directions revealed it to be almost 100% flat, there was a very small amount of 'unflatness' towards the bottom right hole, I could just slip a 3thou feeler gauge where the hole is. I can't imagine that would cause any issues with a big super ridging cast bell housing attaching to it!

I also cleaned the bell housing mating surface as it had some blobs of paint that had run over onto the mating surface.

I think it all looks good, tempted to order the clutch kit and get it bolted together!

[Pete Lewis]

at least you know where you are starting from with known conditions

dont forget to fit the slave pushrod clevis  you wont do it easy if the box is fitted 

new clutch kit sounds a plan 

pete

[Pete Lewis]

4 hours ago, Colin Lindsay said:

Pete, you should know by now... never ever post something like that where I can read it...

But you mean it's not just a case of wheeking new springs in and job done?

Colin save you ponderings for the  TR7  Ha!

I spent many happy hours   testing /rejecting  clutches supposedly remanufactured by unwitting supposed professional  companies that thought shiney and black was all there was  to it....... a right nightmare .

pete

  

 

[Tom]

As you have said Pete the key will be finding a decent kit!

[Tom]

Just a thought, what is the hole on the end of the clutch release arm for arm ? It also has a hole in the bell housing directly behind. 

[Nigel Clark]

The flywheel to crankshaft bolts don't have spring washers or tabs. I always put them back with Loctite and torque as per workshop manual.

Nigel

[Pete Lewis]

the hole in the arm  is surely    for the slave cyl pushrod ,.  and clevis 

Pete

[Colin Lindsay]

15 hours ago, Tom said:

Just a thought, what is the hole on the end of the clutch release arm for arm ? It also has a hole in the bell housing directly behind. 

You mean right out at the end of the arm? Early cars had a lever there for adjustment of the clutch arm from outside the bellhousing, but I think with improved clutch and engine technology it became unnecessary, so the lever went but the hole remained. I still remember older drivers talking about having the clutch 'tightened up'.

[Pete Lewis]

youve got it  Colin.   I couldnt picture a 4cyl slave , . must try harder  !!!!