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Super Minx clutch losing pressure
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Jaguar



Joined: 24 Jan 2013
Posts: 19
Location: The Netherlands

PostPosted: Tue Aug 29, 2017 7:13 am    Post subject: Reply with quote

Hear, hear to Farmer John! That's why I wrote : "if your measurements are correct"
And indeed changing the thrust washers isn't that difficult and it can be done with the engine in situ. But whatever the cause is you really need to get your hands dirty either in measuring end float/taking the sump pan off and/or taking out the gearbox and check all the clutch parts.
Good luck!

Peter R.
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MVPeters



Joined: 28 Aug 2008
Posts: 822
Location: Northern MA, USA

PostPosted: Tue Aug 29, 2017 4:42 pm    Post subject: Reply with quote

I came across this US web site - perhaps you've already found it.
In the Clutch section there is a reference to the brake & clutch master cylinders being 'identical', but the brake master contains a non-return valve which, when used as a clutch master, it doesn't.
I can't quite work out what effect residual pressure in the clutch system might have if the inappropriate cylinder was installed.
It also refers to correct bleeding procedures & ends with "This will cure all your clutch problems" !

http://www.whatsahillman.com/parts.html#clutch

Edited to add: slight misquote - "should fix", not "will cure"!
Note that this refers to Series III cars, later cars may or may not be the same.
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peter scott



Joined: 18 Dec 2007
Posts: 7113
Location: Edinburgh

PostPosted: Tue Aug 29, 2017 6:59 pm    Post subject: Reply with quote

MVPeters wrote:

I can't quite work out what effect residual pressure in the clutch system might have if the inappropriate cylinder was installed.


Sounds like a recipe for a clutch that slips when you don't want it to but a bit difficult to connect this with a problem that is only apparent when the engine is running.

Peter
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Peter_L



Joined: 10 Apr 2008
Posts: 2680
Location: New Brunswick. Canada.

PostPosted: Tue Aug 29, 2017 7:44 pm    Post subject: Reply with quote

Question for the knowledgeable ones..

Assuming that the thrust washer absent/worn, whatever and the crankshaft is capable of lateral movement,

Does a crankshaft at rest require less force to slide than a crankshaft that is rotating. ?

Look back at previous posts....... there is 5" difference in movement of the slave piston between a running engine and one that is not.
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alastairq



Joined: 14 Oct 2016
Posts: 1950
Location: East Yorkshire

PostPosted: Tue Aug 29, 2017 8:09 pm    Post subject: Reply with quote

I still reckon the thrust bearing has become dislodged or mis-placed.

Or, the wrong master cylinder is fitted?
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alastairq



Joined: 14 Oct 2016
Posts: 1950
Location: East Yorkshire

PostPosted: Tue Aug 29, 2017 8:09 pm    Post subject: Reply with quote

I still reckon the thrust bearing has become dislodged or mis-placed.

Or, the wrong master cylinder is fitted?
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Peter_L



Joined: 10 Apr 2008
Posts: 2680
Location: New Brunswick. Canada.

PostPosted: Tue Aug 29, 2017 8:59 pm    Post subject: Reply with quote

Hi Alastair. Previous posts from Tricia indicate that there is excessive end float on the crankshaft.

But why ?

Were they left out after the last engine build or not fitted correctly and dropped out ?

Or was the wrong clutch and / or thrust bearing fitted and the crankshaft was under constant end pressure from the clutch.

In a recent post by Tricia, and others back in Nov 2016, this car was sold with numerous problems. It hasn't had much use since Tricia and her partner purchased it, who knows what other issues there may be.

Tricia got upset after one of my recent posts. Just let me say this... a lot of OCC members, including myself, have put considerable time, effort and thought into the problem. Why ? because we have sympathy for them, we are trying to help, we are trawling the depths of our combined knowledge in an attempt to find an answer but in the end there is no "magic fix".

Many of us have the experience. tools and facilities that would have enabled us to have the car in the air, the gearbox off, the clutch examined and the excessive crank float sorted.

I have been on OCC for close to 10 years and in all that time I don't recall any one issue that received so much interest, comment, suggestions and goodwill.
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MVPeters



Joined: 28 Aug 2008
Posts: 822
Location: Northern MA, USA

PostPosted: Tue Aug 29, 2017 9:04 pm    Post subject: Reply with quote

peterwpg wrote:
Question for the knowledgeable ones..

Assuming that the thrust washer absent/worn, whatever and the crankshaft is capable of lateral movement,

Does a crankshaft at rest require less force to slide than a crankshaft that is rotating. ?

Look back at previous posts....... there is 5" difference in movement of the slave piston between a running engine and one that is not.


This is certainly a mystery & becoming an International debate!

I struggled with some of the movements quoted.
The master & slave cylinders are, what, 3 inches long?
A clutch releases in, what, 1/4" - 1/2"?
A thrust washer is maybe 100thou +/- quite a lot of thousandths.
So I can't see where the 5" or 7" comes in.

I'd still like to get it up on a lift.
(Dad liked Hillmans - he learned to drive one on a Canadian airfield & then we had a '53, a '56 & a '57. ).
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Peter_L



Joined: 10 Apr 2008
Posts: 2680
Location: New Brunswick. Canada.

PostPosted: Tue Aug 29, 2017 9:09 pm    Post subject: Reply with quote

MVPeters wrote:
peterwpg wrote:
Question for the knowledgeable ones..

Assuming that the thrust washer absent/worn, whatever and the crankshaft is capable of lateral movement,

Does a crankshaft at rest require less force to slide than a crankshaft that is rotating. ?

Look back at previous posts....... there is 5" difference in movement of the slave piston between a running engine and one that is not.


This is certainly a mystery & becoming an International debate!

I struggled with some of the movements quoted.
The master & slave cylinders are, what, 3 inches long?
A clutch releases in, what, 1/4" - 1/2"?
A thrust washer is maybe 100thou +/- quite a lot of thousandths.
So I can't see where the 5" or 7" comes in.

I'd still like to get it up on a lift.
(Dad liked Hillmans - he learned to drive one on a Canadian airfield & then we had a '53, a '56 & a '57. ).



I struggled with some of the movements quoted.
The master & slave cylinders are, what, 3 inches long?
A clutch releases in, what, 1/4" - 1/2"?
A thrust washer is maybe 100thou +/- quite a lot of thousandths.
So I can't see where the 5" or 7" comes in.


I guess we can only work with the info provided.....
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TriciaS



Joined: 17 Nov 2016
Posts: 63

PostPosted: Thu Aug 31, 2017 7:09 pm    Post subject: Reply with quote

I am very grateful for all the interest shown and possible answers, I will when my partner is up to it do the crank washers although cannot buy any till old ones come out to measure if thicker ones have already been fitted or as suggested none fitted on rebuild although I would have thought the problem would have shown up on test drive so can only assume that they have fallen out or disintegrated since getting it here. I have seen some for sale on eBay at +5 and +10 I was going to buy both, I have also considered buying a dial gauge but am having some difficulty understanding how to use one so more reading needed on my part.
I also was very confused as to why I was asked to do all the measurements of the slave push rod and shock horror a good 4-inch difference between engine on or off but then no real follow up on what the difference should be or what anyone else's measurements are to know why I did these measurements because for all I know it could be normal, she is due her m.o.t in 6 weeks and I have found a garage near me who seems to have a lot of old cars always outside so presume they know more about old cars so latest question is should I risk driving it to the garage (3 miles) or am I likely to cause more damage if it is the thrust washers or should I sort the thrust washers first before m.o.t'ing
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Peter_L



Joined: 10 Apr 2008
Posts: 2680
Location: New Brunswick. Canada.

PostPosted: Thu Aug 31, 2017 7:38 pm    Post subject: Reply with quote

Hello Tricia. Trust your partner is cheering up a bit.

I am copying this because it seems there are a few of us who can't relate to these measurements.

If the slave cylinder is only ? 3 inches long ? how can the push rod move 5 or 7 inches, it would fall out of the cylinder.

Quote:

I struggled with some of the movements quoted.
The master & slave cylinders are, what, 3 inches long?
A clutch releases in, what, 1/4" - 1/2"?
A thrust washer is maybe 100thou +/- quite a lot of thousandths.
So I can't see where the 5" or 7" comes in.

Un Quote
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MVPeters



Joined: 28 Aug 2008
Posts: 822
Location: Northern MA, USA

PostPosted: Thu Aug 31, 2017 7:58 pm    Post subject: Reply with quote

TriciaS wrote:
............ and I have found a garage near me who seems to have a lot of old cars always outside so presume they know more about old cars..........


Tricia
I really think this is your best bet.
As long as it can be safely driven, I doubt if any further damage could occur.
Get a MOT while you're there! (Does it actually need one?),
& please let us know the outcome!
All the best.
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2002 MINI Cooper 'S'
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TriciaS



Joined: 17 Nov 2016
Posts: 63

PostPosted: Thu Aug 31, 2017 8:05 pm    Post subject: Reply with quote

peterwpg wrote:
Hello Tricia. Trust your partner is cheering up a bit.

I am copying this because it seems there are a few of us who can't relate to these measurements.

If the slave cylinder is only ? 3 inches long ? how can the push rod move 5 or 7 inches, it would fall out of the cylinder.

Quote:

I struggled with some of the movements quoted.
The master & slave cylinders are, what, 3 inches long?
A clutch releases in, what, 1/4" - 1/2"?
A thrust washer is maybe 100thou +/- quite a lot of thousandths.
So I can't see where the 5" or 7" comes in.

Un Quote

I said originally that the new slave was longer than the old one and I have not said how long new or old is, when we put the slave on and it was on the side the old came from the piston nearly did come out which was why my partner moved it to the other side of the bell housing lip as we thought where the rod came out so far it would be sucking in air and causing our bleeding problems and at one point he put the old slave back on and it too nearly pulled the piston right out
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Peter_L



Joined: 10 Apr 2008
Posts: 2680
Location: New Brunswick. Canada.

PostPosted: Thu Aug 31, 2017 8:22 pm    Post subject: Reply with quote

Reply to Tricia's last post.

On any correctly working clutch, (hydraulics), the design of the master/slave/pedal travel/ Clutch lever - Bearing - Plate, Cover, Flywheel, Gearbox-bellhousing are such that the clutch pedal can go to 100% travel without the clutch cover mechanism being pushed too far (throw out). Excess throwout can/will damage the clutch and put unwanted lateral pressure on the crankshaft.

If any one of these items is the wrong one, then the "ideal" configuration of the various items may be impossible and or damaging.

P.S Tricia. on a very early post, you described the vehicle as having "overdrive".... is that correct ?
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Rick
Site Admin


Joined: 27 Apr 2005
Posts: 22429
Location: UK

PostPosted: Thu Aug 31, 2017 8:47 pm    Post subject: Reply with quote

MVPeters wrote:
TriciaS wrote:
............ and I have found a garage near me who seems to have a lot of old cars always outside so presume they know more about old cars..........


Tricia
I really think this is your best bet.
As long as it can be safely driven, I doubt if any further damage could occur.
Get a MOT while you're there! (Does it actually need one?),
& please let us know the outcome!
All the best.


Seconded, I think getting it looked at would be a wise decision, even if only to confirm where the problem is, and cross other possible reasons from the list. I'd also be checking any local clubs in the area, to see whether someone with a similar car might also be willing to cast an eye over things for you.

Just my 2p worth.

RJ
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