Coil Spring Clutch nightmare

[Rich997]

Reaching out to Mk1 technical wizards.

My 997 engine and gearbox are fully rebuilt.

No problem selecting gears, but the clutch will not disengage.

First thought was friction plate stuck to flywheel, hence a strip down to check.

Having built everything back up, replaced master cylinder (just in case) and made all efforts to make sure the hydraulics are working, still can't persuade the clutch to disengage.

Has anyone had a similar issue?

Might need to resort to drastic measures if I can't solve the issue ie. Engine out / convert to diaphragm clutch? but really want to preserve the originality.

Any ideas or suggestions would be warmly appreciated.

W

[InimiaD]

Is the hydraulic hose and slave cylinder in good nick / new.?

[Rich997]

All hydraulic components new, not sure how good the slave cylinder is (not genuine Lockheed)

Seem to be getting reasonable travel on the arm, but seeminly not enough.

Having built up the pressure plate, I know there is tremendous force on the friction plate.

I've adjusted everything, bled the system, still no joy

[Andrew1967]

New clutch arm and plunger ?

[woodypup59]

Did you (lightly) grease the splines on the primary gear ?

Was the clutch plate a nice sliding fit on the P G ?

If you dont have enough travel, perhaps the plunger in the bell housing has a worn hole - hence some clutch arms being bent to compensate.

[Rich997]

Clutch arm and plunger original, no obvious signs of wear.

Primary Gear was greased, no problem fitting clutch plate.

How much travel would you expect to see on the push rod?

[Spider]

Primary Gear bushes?

[bpirie1000]

Have you got the right length of starter motor bolts......

Seen this before......may not be the issue but worth checking...

[captain]

I think it's time to bend the arm

[Andrew1967]

If the ball on the end of the arm where it enters the plunger is not perfectly round and the plunger has any wear where the arm ball contacts it then you will lose clutch clearance.

Bending the arm might work but is not a solution to the problem, just a work round to mask the underlying problem.

[ianh1968]

Bend the arm? I know that this is a "technical fix" but it's normally
considered a bit $#!t...

How about just extending the rod, either by welding and re-finishing
the tip, or sawing it in half and re-joining it with a thin-wall sleeve?

If you have access to a lathe, make yourself an extension:
1) Get a 3/8" diameter [stainless]steel bar
2) Bore a hole in the end to allow a snug fit on the original rod's diameter, say 3/8" deep
3) Saw this new extension off to a total length of about 1"
4) Re-create a "ball" shape on the solid end
5) Using trial and error, trim off the original rod until it all goes together satisfactorily
6) Loctite/braize/weld the extension onto the original rod if you want to

... or use/make this:
http://www.minimania.com/part/C-13H396/ ... ve-Pushrod
... Expensive, but nice!

All hydraulic components new,<SNIP>

What about all the clevis pins?
Can you press the pedal with your finger and get an appreciable amount
of movement before anything happens?
Is the "eye" hole in the pedal worn out? (Mine is... New pedal "pending"...)
Is the pivot-hole through the ally "cover" a decent fit?
... As the people at Tesco would say:
"Every little helps..."

I am a bit confused by this, though -

Have you got the right length of starter motor bolts......
Seen this before......may not be the issue but worth checking...

Would you care to elaborate please, or am I just being a bit dense here?
I'd say at this point that my clutch knowledge is limited to the diaphragm type.

Ian

[LarryLebel]

Throw out stop collar on too far? It seems to me the clutch arm stop adjustment also makes a difference.

[Dean]

with my car i found i just did not have enough throw, when i pressed the clutch pedal,the bite point was hard on the floor,with the release bearing adjustment having to be in contact all the time.

tried a few clutch arms, i know there are even new clutch arm that have the incorrect angle and need a womp with a hammer on the small ball on the end to help give more throw.( pad )

the fix i did was to remove the clutch peddle, put a cut almost all the way through near the top of the arm, bending it open and re-welding it back up,now i have a brilliant pedal, my bite point is not on the floor, and the clutch pedal is higher and more inline with the brake pedal.
not saying its a fix for your car, as your having second thought about your spring clutch,etc,
but of me it was throw, and like you everything was new, bending the arm does not work, as the slave is still only going to push as much as what travel you clutch pedal can move!!!!

so giving you clutch pedal more travel, will give your clutch arm more travel,which with allow you to disengage the clutch, it does not bottom out or have any problems of "over throw" there is still more to go!

[Rich997]

Thanks Dean.

That all makes very good sense.

If the hydraulic system and mechanicals are all sound / assembled correctly, more travel seems to be the answer.

Bending the arm doesn't make sense.

I've seen the extendable push rods on certain interweaving sites, which might be a plausible 'fix'

Thanks very much for the advice

[Dean]

yes that is another answer to getting more travel, buy lengthening the master cylinder push rod

its so much nicer to drive when you don't feel like you have to have your clutch pedal hard down on the floor to just about get the clutch to disengage, and hope it won't crunch the gears.

one of the best things i have done to mine,

i have even tried using a late 80's mini clutch pedal, like the similar thing you can do with the brake pedal, but they are the same angle, ( mine is a 62 as well)

[JohnA]

Lengthening the push rod or bending the end of the long part of the arm will not usually cure the problem. Arms that appear to be in good condition may be bent between the ball and the hole where the clevis pin fits, this changes the angle that it operates. This can be checked by placing it alongside a new one with both clevis pins fitted and observing the height of the ball. If the clutch pedal has been pressed with the stop nuts screwed to far it will bend the arm and open the angle. It seems that new arms don't appear to be manufactured correctly and don't always cure the problem
If you have a press place the arm v facing upwards supporting it under the ball and equal distance the opposite side of clevis pin hole and apply pressure where the clevis pin fits increasing the angle in the arm. Only minimal movement is required try about 20thou first you may need to do in more than once.
I have done this a few times over many years quite often with a lump hammer at the side of the road
Pads clutch had been built with all new parts and wouldn't clear at Blyton the clutch arm seemed to be the problem. Don't trust a new arm.

[pad4]

3 new arms now and Jims had a couple - there not cast / machined right and need a good whallop with a big hammer but its got to be done at the ball end

utter shite

pad

[pad4]

Oh and be wary of the return spring - minispares ones are way to strong and will also stop your clutch from working

pad

[Andrew1967]

From what has been said above, like most things it seems like new old stock arms are the only way to go to be pretty sure of getting it right.

From experience, I know that the ball on the end of the arm wears a flat spot and only a small amount of wear can make a big difference to the clearance (simple physics if you think about it). The plunger hole also wears where the arm ball contacts it.

I dont know if they are different on coil spring clutches but have you got the correct thrust bearing fitted to the correct plunger ?

If you can't get a new old stock arm and have to use an old and probably worn arm, you can add some weld to the ball on the arm and then file it round until its a nice fit in the plunger. Best bet is to replace both with genuine old stock parts though.

As I said before, all of the extending arms and rods and bending arms methods are OK and may well do the job, but they are not cures for the actual problem. Having said that sometimes desperate measures do have to be taken.

[Rich997]

Thanks for the comments about angle of the clutch arm.

Mine has the original arm and cover, so could be worn.

I'll have a look at the angle at the plunger end to verify.

Haven't seen a NOS arm on eBay but will look out for one.

Would anyone have an idea on what the correct angle should be?

Appreciate the suggestions on how to modify mine, be that with a degree of precision, or the more pragmatic approach ie. Wallop with a big hammer.

Presume yours was fine (Pad) after the therapy?

Cheers