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roger's-spit

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hi alll, I have had a problem with my clutch not engaging and not being able to select any gears. After reading some articles in books and on the forum, I put it down to the friction plate sticking to the fly wheel because of lack of use. I tried the usual methods of freeing it off but in the end I took the gear box out. When I did so the friction plate was free and no signs of sticking. I put it all back together and still nothing. It is anew clutch,release bearing and slave cylinder. On pressing the clutch the pivot arm appears to be moving ok. Has anyone got any ideas what could be the problem. thanks, Roger

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How are your thrust washers? These keep the crank from moving back and forth in the block - if they wear out (or drop out) then you are left with a space into which the crank can move - as you put your foot on the clutch you are pushing against the crank and if the thrusts are knackered or missing then all you do is push the crank forward - result is no clutch movement. There are lots of other things it could be but if you have had the lot out and looked it over you may well be down to only the expensive options.

Are you 100% sure you have the right components in there in the first place?

There's a good check list here http://www.canleyclassics.com/?xhtml=xhtml/infodatabase/clutch.html&xsl=infodatabase.xsl including how to check for what I describe above - I hope it's not "thrusted" otherwise it's probably new engine time :-(

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2907 wrote:
hi alll, I have had a problem with my clutch not engaging ..... On pressing the clutch the pivot arm appears to be moving ok. Has anyone got any ideas what could be the problem. thanks, Roger


Are you sure the push rod is going far enough in to operate the clutch?
It may be moving ...but not enough
There have been many posts about this problem
A worn slave cylinder or need of adjustment is quite common
The slave is attached to bell housing with a pinch bolt mechanism
Remove tunnel, undo the pinch bolt holding the slave and see if the slave will move forward and then re nip
Best undoing the bleed screw first and lit a little fluid be pushed out when taking up the excess movement.
If the slave will not move forward ..but will pull back...then remove he slave, and grind a little off the location `trough` to allow the pinch bolt to slide along more
There is plenty of meat on the slave to do this so dont worry
I`ve ground approx 3/4" away before now to allow the clutch to operate the gears
  

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Good news, ( I think ) there is no movement at the crank pulley so hopefully not 'thrusted'. adjusted the slave cylinder in a bit and got it in gear but not very smoothly so its progress but not right. got quite a lot of play on the rod coming out of the master cylinder but no signs of clutch fluid. Could the master cylinder be not good enough to push the slave cylinder without showing any leaks?

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1684 wrote:
Check where the lever connects to the master under the rubber boot. The hole wears oval. This makes a big difference to the travel at the slave


...hence adjusting the slave to compensate
If there has been improvement by moving the slave forward ,but it won`t move any further ,as I said, take out the slave and grind a little off the rear face of the retaining grove to allow it to move further forward......and it should work

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Hello Andy,

"How old is the fluid if it been in there a long time it can take up water and become more compress able hence not activating the slave enough"

Not very likely in a clutch, it is relevant for brakes, which can get quite hot, as the boiling point of water is much lower means it can boil and steam is like having air in the system, i.e it compresses.

Alec

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Hi all, thanks for the advice, I have ground the side of a spare pinch bolt away just enough to ease the slave cylinder in to try and find out where it needs to be before I grind the body of the slave cylinder. I have had to move it in about 20mm so far which is why I am questioning the sloppy arm on the master. Car is at work so I can't check the possibly elongated hole under the gator until Tuesday morning.

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2907 wrote:
Hi all, thanks for the advice, I have ground the side of a spare pinch bolt away just enough


...no ....not the bolt ..the slave, retaining slot.
If you take the slave out you will see the recess in the body of the slave,with tapered ends. What you have to do is elongate that recess in the body of the slave.That allows the body to slide in more when the bolt is in place .

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Hi, by grinding the bolt I thought I could adjust the slave in as far as I need and mark it before I start grinding my groove in the slave body. The picture is interesting in that it seems quite a distance that you have adjusted it in. As I said I have gone in a further 20mm and thought that was a lot so thought the problem might be elsewhere. I will give it another go on Tuesday, thanks for the pics.

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Hi Roger,

My car came to me as a non runner, I can't believe it ever ran like it was. It was also fitted with a Dolomite engine so it had probably been messed with.

I seem to remember a lot of discussion about the pushrod length somewhere, anyway maybe it was a Dolomite part or something.

I later upgraded to an overdrive box which was fully rebuilt by Mike Papworth, the slave cylinder then fitted exactly as it left the factory.  :)

Same clutch fitted with both, but different release lever I might add.

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Sorry to say this but I think grinding the slave cylinder is a bodge. If there's wear in the system, it needs to be sorted by replacement parts.

Last week I took out the gearbox as the clutch bite was starting to get nearer to the floor, and had difficult engaging first like yourself. I found all manner of horrors inside the bellhousing. The pushrod had an elongated hole where it is in the release arm, and the excess slack there had in turn worn down the pivot pin going through it. The end of the pushrod was slightly shorter than an original one too. The release bearing carrier bushes were sticking, the release bearing was completely trashed, and the release arm was also missing a bushing that went inside the bellhousing to hold the pivot pin for it.

I replaced all the relevant parts with originals from Mick Dolphin, and renewed the seals on the slave and master. The result is a clutch pedal that feels like it's from a brand new car, and a lovely takeup of drive. A lot of stiffness I (incorrectly) associated with the gearbox is totally gone. Furthermore, I know that this will last well for years to come, and not accelerate wear in other components.

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Thanks bainzy, good advice, I removed the gear box and changed the release bearing bushes,push rod and checked it all, all looked good. So I went to manners and got a clutch kit put it all back together and I now have a perfectly workin clutc. Problem was that I bought a clutch kit from the stonliegh show a couple of years ago which was labeled up as a1500 1980 spitfire. Don't know what is really for but is different to the one I got yesterday. Anyway, all sorted now and thanks to all who responded.

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1381 wrote:
Sorry to say this but I think grinding the slave cylinder is a bodge.


Don`t do bodges...I did an article in the club mag ,beginning of the year, showing how to replace all the worn parts to make an effective repair
Doing the grinding of the slave cylinder is common ,to make the finite adjustment as most parts like these now come from India and are not 100%

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  • 1 month later...

It still sounds to me that the clutch is not sufficiently bled. In a Spitfire the engine slopes upwards slightly towards the front, since the slave is in line with the engine a bubble gets trapped at the front end. Unclamp the slave, point it sightly toward the ground and bleed it again (suggest pressure bleed at 10 psi). Gently feel the clutch pedal - should be solid. gently bend the slave back up and re-clamp. An alternative of course is to sgnificantly jack up the back of the car.

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