Clutch slave insert

[doublegarage]

While I'm waiting for parts for the starter clutch...I'm struggling with the clutch slave.

I rebuilt it with the repair kit from Wolfgang. It looks like this in case anybody hasn't see these - the top part is a drill guide that screws into the slave hose thread - then you drill an enlarged hole through the clutch-cover and into the 'top-hat' insert. Then you take out the drill guide and screw in the bottom fitting, its 'snout' sticks into the new hole (loctited too) and fluid gets pumped into the insert, not the cover-bore.



First attempt didn't go great - I haven't had time to talk to Wolfgang about this yet, but after assembly, trying to bleed it, the bleed screw didn't seal any more when screwed down (it used to). Looking down the bleeder-bore, the seat looks fine so i don't know what happened. The drill maybe opened a crack in the threads - don't see why because it's close, but not that close. I made a plug with a bleed screw shaped taper and screwed that in and it sealed. So..bled it with the bleed-screw, then quickly swapped in the plug while my beautiful assistant maintained slight pressure on the lever. Fluid all over the place but the clutch worked and no (visible) leaks. I win!

Or do I. A week later, it's no longer disengaging (haven't ridden it, no starter...just sitting in the garage), AND when working the lever I can see the outside of the cover flexing, directly outside the piston. It looks horrible on a cast part, bound to crack soon.

So I took the whole thing off again - inside looks like this:

dismantled it more and looking closely at the insert in the cover, especially at the newly opened hole and the bleeder hole...it dawns on me that my "top-hat" insert doesn't have a top. Therefore the pressure behind the piston acts on the cover, no wonder it's flexing. And the fluid will still get pumped in between the insert and the bore. Not an easy thing to get a picture of, but here are two tries.


This shows how the newly enlarged hole just clips the lower skirt of the insert, and as far as I can see, the 'cup' (in this shot) of the insert has no bottom.


another view. I measured the thickness/distance of the bottom of the bore to the outside of the cover and it's about 5mm. Pretty sure that's the inside of the cover I'm looking at.

So..calling all people who have seen the inside of their clutch slave - does my insert look like yours? Or what am I missing? I've searched the entire forum for a picture but can't find one, thanks.

-Richard
P.S. I know i could maybe solve all problems by shifting to a cable-clutch (yes I've read all the clutch threads on the forum ) but I have to get this working before I decide whether to modify it.

 

[sfcpiet]

Looks like your "top hat" has been moved outwards through the pressurized clutch fluid. A side-on view would confirm. I've never seen a gap at the bottom of the piston bore.

You will need to press the insert back home and repeat the drilling routine to enable the hose fitting to seal against the sleeve part. Or remove it completely and make yourself a new one, with a top/bottom, this would relieve the casting completely.

piet

 

[Sir Sidney Ruffdiamond]

I used Wolfgang’s kit about 3 years ago I will have a look tomorrow- I did take some pics - my previous cover had cracked and I still have it - bleeding was a barstewsrd but a £5 Halfords bleed kit did it in 2 mins - something clearly wrong if the casting is flexing as per Piet above

 

[doublegarage]

Looks like your "top hat" has been moved outwards through the pressurized clutch fluid. A side-on view would confirm. I've never seen a gap at the bottom of the piston bore.

Thanks Piet - i don't think it's moved outwards - here's the side view that shows it pressed home.

pretty sure it's just missing its bottom.

I know I saw a picture on the forum somewhere of an insert removed - Red talking about them falling out when he tried to weld up cracks - but now I just cannot find it.

-Richard

 

[tom3c75]

Interested in this thread, as I'll soon need to do the same on a TS clutch cover, also using Wolf's insert.
Is that top hat insert then a topless top hat, i.e. only a sleeve?
Surely that sleeve needs to be bucket shaped, i.e. closed at the inner end?
Otherwise won't the hydraulic pressure eventually cause the outer side of the cover to crack?
Perhaps in this case the pressure has indeed forced part of cover outwards, resulting in the gap?

Another question: I can't see from the images, but is there also a bleed hole in the sleeve?

Tom

 

[doublegarage]

Interested in this thread, as I'll soon need to do the same on a TS clutch cover, also using Wolf's insert.
Is that top hat insert then a topless top hat, i.e. only a sleeve?
Surely that sleeve needs to be bucket shaped, i.e. closed at the inner end?
Otherwise won't the hydraulic pressure eventually cause the outer side of the cover to crack?
Perhaps in this case the pressure has indeed forced part of cover outwards, resulting in the gap?

Another question: I can't see from the images, but is there also a bleed hole in the sleeve?

Tom

well, mine seems to only be a sleeve - no bottom in the bucket. No it hasn't been forced outwards, see latest picture, it's fully pressed in and the lower edge of the sleeve's 'skirt' just doesn't reach the bottom of the bore. Can't be right.

yes there's a bleed hole in the cover, but not in the sleeve, because the sleeve/insert doesn't reach down as far as the bleeder hole. Another reason it can't be right.

Wolfgang's kit makes total sense for a bucket-shaped/closed insert - not so much for one like mine.

 

[Sir Sidney Ruffdiamond]

some pics during the procedure the last one - shows similar to yours

 

[CLEMTOG]

se below

 

[CLEMTOG]

and some more

 

[CLEMTOG]

my repair removes the insert completely, machines straight through the cover, a boss is made externally for a bleed nipple ( which is a little vulnerable) or blanking plug (narrower) and an extended hose fitting is installed through the case into the new sleeve, maintaining 10mm thread through out and using whatever hose arrangement is existing. This system recovers previously welded cracks, removes the fluid path from the bleed nipple and with the extended hose adapter seals direct into the new sleeve with a Loctite product that becomes plastic on contact with metal, removable but why would you? you have a new 10mm female thread a few mm's higher for the hose disconnection.
price varies according to condition of cover, and previous repairs. delivery varies according to how much moonlighting three contacts are doing at that time (yes their employers know they do this) alloy welder, machinist, polisher.
Please do not try to remove the piston.
I will say again, please do not try to remove the piston, there are no new ones available, unless someone knows differently.
included are two gaskets, inner and outer, new seal and a spare, new dust boot, and the hydraulic extended adapter, send me your cover and the hose, and it comes back to you ready to fit, a part exchange is possible for certain types of cable type covers, if yours has the blank part for the (not used with cable) bleed nipple, then you laughing
CLEM

 

[redax5]

Please do not try to remove the piston.
I will say again, please do not try to remove the piston, there are no new ones available, unless someone knows differently.
CLEM

we have been making and supplying a couple of dealers with both the 30mm and 31mm pistons for years

 

[CLEMTOG]

Brill, great news was about to get some made.
CLEM

 

[CLEMTOG]

picture

 

[Dellortoman]

Interested in this thread, as I'll soon need to do the same on a TS clutch cover, also using Wolf's insert.
Is that top hat insert then a topless top hat, i.e. only a sleeve?
Surely that sleeve needs to be bucket shaped, i.e. closed at the inner end?
Otherwise won't the hydraulic pressure eventually cause the outer side of the cover to crack?
Perhaps in this case the pressure has indeed forced part of cover outwards, resulting in the gap?

I presume a bucket-shaped insert would require some machining work to the cover to make it fit.

 

[1200ts]

Is the problem with the clutch slave cracking the cover and needing Wolfgang's repair kit, apply to all triples with the hydraulic clutch or just early ones? Three of my triple have the hydraulic clutch and have never had any problems. Or will this eventually happen and I am just lucky so far?

 

[doublegarage]

Thanks for all the replies.
Sir Sidney's pictures look very similar to mine, so maybe mine isn't abnormal - not easy to tell.
Clem, your repair looks great and the way to go when all else fails i.e. if/when the cover cracks.

What I still don't get is...if my insert fell out, would it be bucket-shaped with a bottom? or would it be a cylinder open each end, with a collar at top?

Mine looks like an open cylinder, but if I'm wrong and it's the bucket shape, then fluid is definitely getting between the insert and the cover, despite the modification that's supposed to avoid that.

-Richard

 

[Dellortoman]

Aside from Red's complete new CNC machined hydraulic cover, Keith Nairn also does a fix for the crappy original hydraulic slave cylinder. His version uses an old cover modified to accept a bolt-on slave cylinder. He does an exchange deal on the cover. I don't reckon it would matter whether your trade-in cover is hydraulic or cable because he replaces the guts in it anyway. That would be a good way to go if you want to retain the original look of the outer cover.

Pictures here (scroll down): http://www.laverdascozia.co.uk/services/tuning.html

 

[Sir Sidney Ruffdiamond]

Keith does need a cover without a crack which is where my plan fell down - luckily I managed to source a used cover in good nick

 

[CLEMTOG]

120 type covers do not seem to crack, its the 180 type that this happens to.

My repair does show, but that doesn't bother me if it brings back in a cracked cover or badly repaired cover, I have been changing the HT leads on Nippon Denso coils for ages and I always fit red leads, this show it has been done, same with the repair to the covers, it shows it has been done, but I am not a purist, no original C or D type Jags exist, they have all had repairs etc etc, my own one doesn't even have a nipple, and the hose is on a banjo on the outside, as stock, fluid can get between the sleeve through two routes, the hose adapter and the nipple, and I am not even sure that is the cause of the cracking as once opened, they are always very dry (well so far) it could be flexing of a tiny airspace on the very thin cover, . The ones that I have seen are always a bucket sleeve with a big lip at the open end, which is supported on a flange and gussets, might add more gussets on the next one.

Recently discovered that the last cable type covers (120's excepting Jota 120 could not have cable type) have a blank for the (not needed) nipple, the machining inside of what is (essentially) a hydraulic cover removes huge amounts of metal and hence strength, they don't seem to fracture though.

CLEM

 

[doublegarage]

Thanks Clem, I think I've just misunderstood the shape at the bottom of the bucket-sleeve - i get it now, it has a bottom. good.

But the cover was seen flexing so fluid is definitely getting pumped between insert and cover - today i was getting ready to hook up MasterCylinder + Hose + Slave on the bench (piston clamped into place) to see if I could understand where the leak was - but thought I'd have a last good look at the cover. Finally spotted this:


That triangular shadow at the base of the threads is a hole through into the open area behind the insert. I'd been assuming that the modification to drill through into the insert and use the Wolfgang hose-adapter had caused the leak - but now I think this hole was always there, sealed up by the old hose screwed in with some sort of sealant - then when I replaced that with the hose fitting, it didn't seal any more - so instant leak.

Need to find a way to seal that hole (it's pretty big) with the threads of the hose adapter? Some sort of loctite? PTFE tape? Different thread sealant of some sort. The cover could definitely be just toast, so we shall see. I might need a proper fix Like Clem's or Keith's.