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Super Minx clutch losing pressure
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TriciaS



Joined: 17 Nov 2016
Posts: 63

PostPosted: Sun Aug 06, 2017 3:33 pm    Post subject: Super Minx clutch losing pressure Reply with quote

I find searching this site impossible so apologise if this subject is already covered, I have a Hillman Super Minx MKIV and it had a new clutch fitted shortly before I purchased it but the slave needed doing so I have replaced with a new slave cylinder, now a new problem I bleed all the air out and it seems fine but then I start engine and the pedal goes halfway down before getting firm, I have tried bleeding again and again but still the same problem, I did notice the new slave was slightly longer than the old one so do not know if this might make a difference and am in the process of removing the spacer to see if it makes it any better but I just can't see what the engine running has to do with it, I bleed it till it is nice and firm and then start engine and it is suddenly gone. I have read about the warm engine makes the air expand or something but this is not getting warm it is as soon as you turn the engine on so any ideas please as getting annoyed with it now and can't even try it out properly until I can put the wheel back on.
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Bitumen Boy



Joined: 26 Jan 2012
Posts: 1733
Location: Above the snow line in old Monmouthshire

PostPosted: Sun Aug 06, 2017 4:55 pm    Post subject: Reply with quote

That's an odd one. Sounds almost as if it has a remote servo fitted for the clutch. You are sure it hasn't had one fitted by a PO that found the clutch a mite heavy? Photos would be handy.

Definitely check the new slave as the relative bore sizes of the cylinders can be very important for things to work correctly, some cars are more sensitive to this than others.
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TriciaS



Joined: 17 Nov 2016
Posts: 63

PostPosted: Sun Aug 06, 2017 5:23 pm    Post subject: clutch Reply with quote

I have just refitted the old slave after cleaning it but now that one is leaking so my problem is still the same, I now suspect it might be the master, I will look into getting a new one or a seal kit but just can't understand the reason it seems on until I turn on the engine, I can't see a servo anywhere and the master is o course in awkward place above pedal so I will find a replacement before I take old one out, I was wondering if the push rod needs to be shorter as the new slave is a little longer, I know older models had adjustable rods but I cannot find one yet, I am making a list of things to get from speedy spares to save on postage
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peter scott



Joined: 18 Dec 2007
Posts: 7113
Location: Edinburgh

PostPosted: Sun Aug 06, 2017 6:16 pm    Post subject: Reply with quote

Hi Tricia,

If by pumping the pedal it becomes firm and you are sure the slave cylinder is good then I would suspect the master cylinder but before replacing that do check that all the hydraulic connections are properly tight and not damp.

Peter
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1939 SS Jaguar 2 1/2 litre saloon
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TriciaS



Joined: 17 Nov 2016
Posts: 63

PostPosted: Sun Aug 06, 2017 6:43 pm    Post subject: Reply with quote

peter scott wrote:
Hi Tricia,

If by pumping the pedal it becomes firm and you are sure the slave cylinder is good then I would suspect the master cylinder but before replacing that do check that all the hydraulic connections are properly tight and not damp.

Peter

Hi Peter,
This is what I am finding so confusing when the engine is off after bleeding it is firm then I start the engine and nothing there and pumping does not help but when I turn engine off and pump pressure comes back, all connections seem dry except now the old slave connection so I will put the new slave back on tomorrow, I saw on eBay a hose for the clutch saying, super minx, mine has metal pipes so presume over the years been changed, I was going to buy the hose but noticed it has one end female and my metal pipes are both male so would like to know if it was originally female at master as I don't want to buy a new master and find my pipes don't fit and I need the hose and don't want to buy the hose and not be able to get a connector to change it to male as cannot see any in a 7/16
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peter scott



Joined: 18 Dec 2007
Posts: 7113
Location: Edinburgh

PostPosted: Sun Aug 06, 2017 7:45 pm    Post subject: Reply with quote

Hi Tricia,

I wouldn't expect the starting or stopping of the engine to have any influence on the clutch hydraulics. Perhaps it would be an idea to check the plumbing and make sure there isn't some confusion of brake and clutch pipework.

Peter
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1939 SS Jaguar 2 1/2 litre saloon
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TriciaS



Joined: 17 Nov 2016
Posts: 63

PostPosted: Sun Aug 06, 2017 8:00 pm    Post subject: Reply with quote

peter scott wrote:
Hi Tricia,

I wouldn't expect the starting or stopping of the engine to have any influence on the clutch hydraulics. Perhaps it would be an idea to check the plumbing and make sure there isn't some confusion of brake and clutch pipework.

Peter

it is definitely making a difference between engine off and on, pedal travel goes from firm to half way nothing when engine on and pumping makes no difference yet turn engine off and you can then pump the pedal back to normal, I will see if I can find a master cylinder to fit as don't like just doing seals.
I do hope someone has experienced the same problem as I have no confusion between clutch and brake, and definitely no servo fitted to either, it is just the same as when pushing the clutch the revs drop you would not think that is normal yet it is very common.
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alastairq



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

PostPosted: Sun Aug 06, 2017 10:43 pm    Post subject: Reply with quote

Could the problem be the actual clutch itself?

Could the fingers be sticking?

Or maybe there is an issue with the clutch release bearing? (Thrust bearing?)

Is it possible the arm,or bearing, have become displaced?

I'd be inclined to drop the gearbox, to see what's going on?
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Bitumen Boy



Joined: 26 Jan 2012
Posts: 1733
Location: Above the snow line in old Monmouthshire

PostPosted: Mon Aug 07, 2017 10:39 am    Post subject: Reply with quote

I wonder if the crankshaft could be moving when the clutch is operated? Probably wouldn't happen with the engine off, but running and lubricated it may be much more free to shift. Can you get an assistant to watch the crank pulley while you operate the clutch, see if there's any fore and aft movement? Also try prying the crank pulley with the engine off. I don't know these Rootes engines at all but on a Triumph with similar symptoms I would suspect dropped crankshaft thrust washers as a possible cause.
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TriciaS



Joined: 17 Nov 2016
Posts: 63

PostPosted: Mon Aug 07, 2017 5:48 pm    Post subject: Reply with quote

Thanks for replies, I will check the clutch tomorrow, I do doubt it will be the crankshaft as was working ok before replacing slave and the car hasn't moved for months so I hope just a bit of rust on the clutch plate or fingers. I will update once I have checked.
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Rallymantony



Joined: 20 Apr 2017
Posts: 18

PostPosted: Wed Aug 09, 2017 4:40 pm    Post subject: Reply with quote

alastairq wrote:
Could the problem be the actual clutch itself?

Could the fingers be sticking?

Or maybe there is an issue with the clutch release bearing? (Thrust bearing?)

Is it possible the arm,or bearing, have become displaced?

I'd be inclined to drop the gearbox, to see what's going on?


I was about to say the exact same thing. I had it once where the clutch would be fine when the engine was off, it would hold the car on a hill in gear but as soon as you started the engine it was like you had no clutch what so ever! Turned out that the rod was slightly off place.
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TriciaS



Joined: 17 Nov 2016
Posts: 63

PostPosted: Thu Aug 10, 2017 4:33 pm    Post subject: Reply with quote

I was about to say the exact same thing. I had it once where the clutch would be fine when the engine was off, it would hold the car on a hill in gear but as soon as you started the engine it was like you had no clutch what so ever! Turned out that the rod was slightly off place.[/quote]

Hi,
Do you mean the push rod, I have been looking to buy a new one as mine is really rusty and pulls the rubber cover off the slave every push but I cannot find one yet, I suppose I will add it to the list of thing to ask speedy spares if they have, I have checked the crankshaft (perfect) and put the new slave back on, still looking to buy a new master as can't find one of them either yet, I will look at the push rod again tomorrow
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alastairq



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

PostPosted: Fri Aug 11, 2017 1:10 pm    Post subject: Reply with quote

The arm the push rod acts on [clutch lever] might also be displaced.
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Peter_L



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

PostPosted: Fri Aug 11, 2017 1:35 pm    Post subject: Reply with quote

Perhaps look at the clutch lever travel.

Under the vehicle,

#1 Engine off. 1 push, Measure the furthest travel point on the lever with engine off. Keep pedal down for 30sec to 1 minute, does the lever move back ?

#2 Engine off multiple pushes, stop with pedal down , measure as in #1.

#3. Same routine but with engine running.

With hard data it may be possible to recognise the problem and then solve it.

If the clutch lever is moving the same distance under all conditions then, the problem is other than the hydraulics.
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TriciaS



Joined: 17 Nov 2016
Posts: 63

PostPosted: Fri Aug 11, 2017 6:05 pm    Post subject: Reply with quote

peterwpg wrote:
Perhaps look at the clutch lever travel.

Under the vehicle,

#1 Engine off. 1 push, Measure the furthest travel point on the lever with engine off. Keep pedal down for 30sec to 1 minute, does the lever move back ?

#2 Engine off multiple pushes, stop with pedal down , measure as in #1.

#3. Same routine but with engine running.

With hard data it may be possible to recognise the problem and then solve it.

If the clutch lever is moving the same distance under all conditions then, the problem is other than the hydraulics.



ok, done tests today.
1. Engine off measures 6 inches
2. push pedal measures 7 inches
3. hold for 1 minute still 7 inches
4. 8 pumps measures 7 inches
5. hold for 1 minute still 7 inches

6. Engine on measures 2 1/4 inches
7. push pedal measures 2 1/2 inches
8. hold for 1 minute still 2 1/2 inches
9. 8 pumps measures 2 1/2 inches
10. hold for 1 minute still 2 1/2 inches
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