Clutch Master Cylinder - Reservoir Extender Mod
Discussion
A while back there was some chat on the forum about this, so I thought I'd share my experiences and feedback.
Basically the Girling type clutch master cylinder used by TVR on the Chimaera and countless other British car makers in the 60's & 70's has a very small fluid reservoir, this tiny egg cup of fluid is just about acceptable when you mount the cylinder on the horizontal as the Girling designers intended.... but TVR chose to ignore this and mounted the thing at an angle
Obviously TVRs angled installation means the reservoir now holds even less fluid, on full stroke fluid fills the slave cylinder so the level in a Chimaera clutch master cylinder reservoir can fall dangerously low. If the fluid level is anything other than absolutely on the edge brim full from the outset you run the very real risk of drawing air into the system should the port become exposed.
As this master cylinder is used so extensively in many different applications that include kit cars and single seater race cars where access to topping up can be tricky, some bright spark came up with the idea of a reservoir extender.
While hardly essential, fitting such an extender would clearly be helpful on our cars, but the Chimaera application does present an additional challenge in the form of ensuring the new taller reservoir will fit under the cover on the inner wing, here's how it looks with the cover off.
And here's my adapted cover that goes over it.
Ok ok, I know it looks a bit like a boil so get your gags in now folks
And I'm not suggesting for a minute this is in anyway an essential mod as quite clearly the standard angled cylinder setup does it's job most of the time. But I'm sure as others have found when they've suffered the common problem of a mildly weeping slave or master cylinder, a very low or empty reservoir will soon follow. Eventually when you get around to removing that cover on the inner wing to have a look the level can be critical.
I'd also suggest the cover itself adds to the problem as the inconvenience of removing it can mean clutch fluid level checks become less frequent than they should be on our cars. The extender just gives that extra capacity and so time to top up before the cylinder starts sucking air, it also makes bleeding the system less off a pain as you've got more than just one stroke of fluid available before you need to top it up again.
The extender has been on my car for the last few weeks and has given no trouble, it does not leak at all which is something I'd feared so I think it will stay. More importantly I also discovered the threaded clutch pedal adjuster rod on my Leven pedal set was stopping the cylinder from fully stroking, this had clearly been an issue that went unnoticed for years and before the car came into my possession as it was the previous owner who fitted the pedal set.
After trimming a full 2" off the threaded Leven pedal rod I found my clutch suddenly felt way nicer with a much more progressive arc of travel and bite point, the issue also meant a full bleed could never have been achieved so that's the next job on my list.
I hope all this helps someone?
Dave.
Basically the Girling type clutch master cylinder used by TVR on the Chimaera and countless other British car makers in the 60's & 70's has a very small fluid reservoir, this tiny egg cup of fluid is just about acceptable when you mount the cylinder on the horizontal as the Girling designers intended.... but TVR chose to ignore this and mounted the thing at an angle
Obviously TVRs angled installation means the reservoir now holds even less fluid, on full stroke fluid fills the slave cylinder so the level in a Chimaera clutch master cylinder reservoir can fall dangerously low. If the fluid level is anything other than absolutely on the edge brim full from the outset you run the very real risk of drawing air into the system should the port become exposed.
As this master cylinder is used so extensively in many different applications that include kit cars and single seater race cars where access to topping up can be tricky, some bright spark came up with the idea of a reservoir extender.
While hardly essential, fitting such an extender would clearly be helpful on our cars, but the Chimaera application does present an additional challenge in the form of ensuring the new taller reservoir will fit under the cover on the inner wing, here's how it looks with the cover off.
And here's my adapted cover that goes over it.
Ok ok, I know it looks a bit like a boil so get your gags in now folks
And I'm not suggesting for a minute this is in anyway an essential mod as quite clearly the standard angled cylinder setup does it's job most of the time. But I'm sure as others have found when they've suffered the common problem of a mildly weeping slave or master cylinder, a very low or empty reservoir will soon follow. Eventually when you get around to removing that cover on the inner wing to have a look the level can be critical.
I'd also suggest the cover itself adds to the problem as the inconvenience of removing it can mean clutch fluid level checks become less frequent than they should be on our cars. The extender just gives that extra capacity and so time to top up before the cylinder starts sucking air, it also makes bleeding the system less off a pain as you've got more than just one stroke of fluid available before you need to top it up again.
The extender has been on my car for the last few weeks and has given no trouble, it does not leak at all which is something I'd feared so I think it will stay. More importantly I also discovered the threaded clutch pedal adjuster rod on my Leven pedal set was stopping the cylinder from fully stroking, this had clearly been an issue that went unnoticed for years and before the car came into my possession as it was the previous owner who fitted the pedal set.
After trimming a full 2" off the threaded Leven pedal rod I found my clutch suddenly felt way nicer with a much more progressive arc of travel and bite point, the issue also meant a full bleed could never have been achieved so that's the next job on my list.
I hope all this helps someone?
Dave.
I saw this subject mentioned before or perhaps on a different forum. Unfortunately I can't find it again. Reason for looking is that it featured an all alloy version of the extender with a nice billet cap. The result was that the extender could be fitted with the cap protruding through a cover which was perfectly acceptable due to is good looks.
Anybody got any pointers?
Steve
Anybody got any pointers?
Steve
Steve_D said:
I saw this subject mentioned before or perhaps on a different forum. Unfortunately I can't find it again. Reason for looking is that it featured an all alloy version of the extender with a nice billet cap. The result was that the extender could be fitted with the cap protruding through a cover which was perfectly acceptable due to is good looks.
Anybody got any pointers?
Steve
Hi Steve, that was my original braided clutch hose post where this all started, I searched and searched for that nice ally one, sadly without luck.... so I ended up with what you see above.Anybody got any pointers?
Steve
https://www.pistonheads.com/gassing/topic.asp?h=0&...
phillpot (Mike Phillips) presented us with the ally version here:
https://www.pistonheads.com/gassing/topic.asp?h=0&...
But it seems to be Unicorn Smoke as I'm beggered if I can find it
TBH I'm happy enough with what I've ended up with as the standard angled master cylinder arrangement TVR gave us really wasn't very clever of them, I'd assumed air in the system was the source of my odd clutch feel issue that has followed me across three different clutches, and in a way I was right.
But I now believe the air came from the fact the master cylinder could never be fully stroked when being bled, the biggest victory in all this was discovering the Leven pedal issue. That threaded Leven pedal rod that protruded too far the bulkhead side of the pedal arm was actually touching the bulkhead before the cylinder could be fully stroked, this was the real reason the three different clutches I've tried all never felt quite right to me in a very similar way.
A quick slice with my stainless cutting disc to remove two inches of protruding Leven clutch pedal thread and correct service was instantly resumed, sometimes the best solutions are the simplest ones. I studied my clutch setup a number of times to work out why it felt wrong, others including TVR Specialists have been there too, none of us spotted the real problem which was blindingly obvious once I'd worked it out.
I still say the Helix clutch was horrible but I.m certain it would have felt a lot better if I or others had just sussed the real issue out a little sooner. To replace the admittedly excessively heavy Helix, my friends at Lloyds fitted an AP unit which was definitely way better. But it wasn't until last week when I trimmed the Leven threaded clutch pedal rod that it felt truly correct to my mind. I'm left with no regrets, just the pleasant feeling of victory I eventually sussed the problem out once and for all, and I'd found it myself.
And the cost of this highly effective clutch repair?????.... Just £3.45 for a stainless cutting disc from Tool Station
I'm still keeping the master cylinder reservoir extender though as its definitely an massive improvement over TVR's original half an egg cup of fluid balls up
Thanks for your constructive comments Alun .
The issue TVR hard wired into every TVR when they fitted the clutch master cylinder at an angle is a real one, the reservoir on a Girling master cylinder is already painfully small, but it's capacity is sufficient if the unit is mounted horizontally, I've fitted many in the past on mostly on Triumphs and the like.
But TVR's choice to mount the cylinder at an angle reduces the already tiny fluid capacity by a third which puts the whole setup right on the edge of adequate and introduces the very real possibility of air entering the system, it also makes bleeding tiresome. The extender I found, fitted, tested and presented to the forum for the benefit of my fellow TVR enthusiasts solves the problem in a stroke (no punn intended).
If you need to see the potential problem and how marginal the fluid situation is for yourself, just remove your cover and master cylinder cap and get a friend to fully depress the clutch pedal, peer down into the reservoir and you'll soon understand why my doubling on the fluid capacity is actually a very good idea.
The Leven pedal issue was super slight so very easy to miss, we are only talking a one maybe two mm of travel at the cylinder itself, to be fair because both clutches worked acceptably it was never forensically investigated. But not being able to fully stroke the master cylinder the last few mm is multiplied over the length of the pedal arm, the hydraulic ratio between the master & slave, plus the length of the release arm of course......... suddenly those last few mm become a driven plate clearance issue, but only when the clutch system becomes heat soaked and everything is subject to expansion.
The original owner who fitted the pedal set missed it, his TVR specialist missed it, Stra8ght Six missed it, my local clutch specialist who I had fit the Helix missed it, LSD missed it when they fitted the far superior AP clutch..... and right up until last week I'd missed it too.
The purpose of posting all this is to help others, others who have the same Leven pedal set and long legs like me, if this is you its well worth checking how far the threaded rod protrudes the bulkhead side of your pedal arm. Obviously the issue here is seeing if the threaded rod is meeting the bulkhead when you fully depress the clutch before the master cylinder is fully stroked..... and that's far easier said than done which is another reason why it was missed for so long by so many.
The Leven pedal problem is of course a completely different subject to clutch master cylinder fluid reservoir capacity issue so apologies for mixing the two, I should have created a separate post for each but I still hope my findings on both points remain useful information to others?
Dave.
.The issue TVR hard wired into every TVR when they fitted the clutch master cylinder at an angle is a real one, the reservoir on a Girling master cylinder is already painfully small, but it's capacity is sufficient if the unit is mounted horizontally, I've fitted many in the past on mostly on Triumphs and the like.
But TVR's choice to mount the cylinder at an angle reduces the already tiny fluid capacity by a third which puts the whole setup right on the edge of adequate and introduces the very real possibility of air entering the system, it also makes bleeding tiresome. The extender I found, fitted, tested and presented to the forum for the benefit of my fellow TVR enthusiasts solves the problem in a stroke (no punn intended).
If you need to see the potential problem and how marginal the fluid situation is for yourself, just remove your cover and master cylinder cap and get a friend to fully depress the clutch pedal, peer down into the reservoir and you'll soon understand why my doubling on the fluid capacity is actually a very good idea.
The Leven pedal issue was super slight so very easy to miss, we are only talking a one maybe two mm of travel at the cylinder itself, to be fair because both clutches worked acceptably it was never forensically investigated. But not being able to fully stroke the master cylinder the last few mm is multiplied over the length of the pedal arm, the hydraulic ratio between the master & slave, plus the length of the release arm of course......... suddenly those last few mm become a driven plate clearance issue, but only when the clutch system becomes heat soaked and everything is subject to expansion.
The original owner who fitted the pedal set missed it, his TVR specialist missed it, Stra8ght Six missed it, my local clutch specialist who I had fit the Helix missed it, LSD missed it when they fitted the far superior AP clutch..... and right up until last week I'd missed it too.
The purpose of posting all this is to help others, others who have the same Leven pedal set and long legs like me, if this is you its well worth checking how far the threaded rod protrudes the bulkhead side of your pedal arm. Obviously the issue here is seeing if the threaded rod is meeting the bulkhead when you fully depress the clutch before the master cylinder is fully stroked..... and that's far easier said than done which is another reason why it was missed for so long by so many.
The Leven pedal problem is of course a completely different subject to clutch master cylinder fluid reservoir capacity issue so apologies for mixing the two, I should have created a separate post for each but I still hope my findings on both points remain useful information to others?
Dave.
ChimpOnGas said:
phillpot (Mike Phillips) presented us with the ally version here:
https://www.pistonheads.com/gassing/topic.asp?h=0&...
At the risk of being ridiculed for my lack of talent with a mastic gun here it is............. https://www.pistonheads.com/gassing/topic.asp?h=0&...
Looks great Mike 
Clearly the aluminum one is taller than my plastic version which literally just fouls the cover, hence my boil arrangement, it also means I could never hope to get the cap off with the cover on even with the hole cut in it, again hence the boil
.
Clearly the taller aluminum version is a better thing altogether with an even greater capacity, but the problem of availability remains, can you remember where it came from because all my searches have drawn a blank, saying that they both do the same job and are both a significant improvement over the standard 'half an egg cup of fluid' arrangement TVR gave us.
Regards, Dave.
Clearly the aluminum one is taller than my plastic version which literally just fouls the cover, hence my boil arrangement, it also means I could never hope to get the cap off with the cover on even with the hole cut in it, again hence the boil
.Clearly the taller aluminum version is a better thing altogether with an even greater capacity, but the problem of availability remains, can you remember where it came from because all my searches have drawn a blank, saying that they both do the same job and are both a significant improvement over the standard 'half an egg cup of fluid' arrangement TVR gave us.
Regards, Dave.
pb450]hillpot said:
At the risk of being ridiculed for my lack of talent with a mastic gun here it is.............
That’s a really good idea for maintenance purposes.
Looks lovely that, the photo also demonstrates perfectly the effect of TVR mounting the master cylinder at an an angle, obviously this also means there's a diminishing benefit the taller you make the reservoir, the spirit level principle of fluid always finding true horizontal takes care of that.That’s a really good idea for maintenance purposes.
Giving the extender a cranked body would therefore be preferable to return the upper portion of the reservoir vertical and so putting it's cap/brim in the horizontal, this cranked arrangement would add complication to the fabrication but on the other hand it would also maximize fluid the capacity and give the neatest appearance.
Deleted my post.
I thought it was funny but just comes across rather aggressive and nasty.
Long long day!
Anyway it still looks a bit naff if you ask me.
Having been around the track boys in the past I’ve never heard or seen a problem with clutch fluid.
Philpot has made a nice job of it. Ive done close to 40,000 miles in my Tvr, never had the problem you say exists.
That’s my problem with this sort of thing,,,
I do think it’s time you COG STOPPED using every opportunity to have a go at Tvr engineering just to try and support your hair brained ideas.
It comes across as you actually dislike the cars and or the company as it’s a consistent line you use.
We all own these cars because we’re half mad that’s pretty obvious and in many cases you might be correct but I don’t know of a car that does’nt have a few faults or design that could be improved especially something designed close to 30 years ago now.
Just think if they’d never bothered making them.
I personally applaud the workforce for getting these cars to market as the Place looked like it was managed by apes.
The workforce being under skilled is not the fault of the workforce and all the sales leaches that creamed off the top and all the people who made fortunes out of these cars are to blame for Tvr failures.
The cars are remarkably robust and reliable given all this.
Happy Tivvin
I thought it was funny but just comes across rather aggressive and nasty.
Long long day!
Anyway it still looks a bit naff if you ask me.
Having been around the track boys in the past I’ve never heard or seen a problem with clutch fluid.
Philpot has made a nice job of it. Ive done close to 40,000 miles in my Tvr, never had the problem you say exists.
That’s my problem with this sort of thing,,,
I do think it’s time you COG STOPPED using every opportunity to have a go at Tvr engineering just to try and support your hair brained ideas.
It comes across as you actually dislike the cars and or the company as it’s a consistent line you use.
We all own these cars because we’re half mad that’s pretty obvious and in many cases you might be correct but I don’t know of a car that does’nt have a few faults or design that could be improved especially something designed close to 30 years ago now.
Just think if they’d never bothered making them.
I personally applaud the workforce for getting these cars to market as the Place looked like it was managed by apes.
The workforce being under skilled is not the fault of the workforce and all the sales leaches that creamed off the top and all the people who made fortunes out of these cars are to blame for Tvr failures.
The cars are remarkably robust and reliable given all this.
Happy Tivvin
TVR's are (imho) wonderful cars but do have their quirky points, to put it politely!
I started with, and still have, an S series. As I understand it these were built to a tight budget so they'd actually make money rather than loose money as I believe every Wedge did? For this reason I could forgive a few shortfalls in design that made simple jobs a right pig or one or two things looking a bit "Heath Robinson"!
Bought a Chimaera next, soon realised nothing had changed despite the Company presumably now solvent and a bit more time/money to spend on development?
All that space and they couldn't even fit a glove box in!
Now have a Griffith, what a "lash up" the heating system is and bits of carpet just spray glued over everything, no thought of ever needing access to anything and the jewel in the crown, a sealed cover over the clutch fluid reservoir.... genius!
While I much prefer a hydraulic clutch operation to cable, slave cylinders do "take some stick" in that location which leads to them leaking. the only way you're going pick this up before a complete failure is by regularly checking the fluid level, obviously helps if the cap is readily accessible.
Sods law says if there's going to be a leak it's going to happen a long way from home! A decent sized reservoir will greatly reduce the number of stops to top up and hopefully be able to drive home rather than use recovery.
Finally............ needed a larger bore master cylinder when I converted my Taimar to hydraulic, to get sufficient movement at the slave cylinder, came with a sensible sized reservoir
I started with, and still have, an S series. As I understand it these were built to a tight budget so they'd actually make money rather than loose money as I believe every Wedge did? For this reason I could forgive a few shortfalls in design that made simple jobs a right pig or one or two things looking a bit "Heath Robinson"!
Bought a Chimaera next, soon realised nothing had changed despite the Company presumably now solvent and a bit more time/money to spend on development?
All that space and they couldn't even fit a glove box in!
Now have a Griffith, what a "lash up" the heating system is and bits of carpet just spray glued over everything, no thought of ever needing access to anything and the jewel in the crown, a sealed cover over the clutch fluid reservoir.... genius!
While I much prefer a hydraulic clutch operation to cable, slave cylinders do "take some stick" in that location which leads to them leaking. the only way you're going pick this up before a complete failure is by regularly checking the fluid level, obviously helps if the cap is readily accessible.
Sods law says if there's going to be a leak it's going to happen a long way from home! A decent sized reservoir will greatly reduce the number of stops to top up and hopefully be able to drive home rather than use recovery.
Finally............ needed a larger bore master cylinder when I converted my Taimar to hydraulic, to get sufficient movement at the slave cylinder, came with a sensible sized reservoir
Perfectly summarised there by Phillpot, and no one is suggesting the standard arrangement doesn't work acceptably as I have been very careful to point out.... but mostly in anticipation of all the clever beggers who like to preach from 'the bible of the blindingly obvious'.
Acceptable and good design are of course often worlds apart, in my humble opinion the woefully tiny amount of fluid held by the master cylinder reservoir is marginal at best, the problem as I've been clear to point out is this situation only really exists because TVR mounted the master cylinder at an angle when the Girling designers intended it to be mounted horizontally.
I do hope people don't think I'm presenting the reservoir extender as some amazing miracle must do modification, all it does is give some extra fluid capacity which in turn provides some margin of safety to avoid air entering the system when the level falls should either cylinder start leaking or even weep slightly....... which with my extensive experience of Girling hydraulics is really rather common.
It amused and disappoints me in equal measure that some seek to ridicule the aesthetics on my simple solution, my TVR is for driving not polishing, personally I would never dream of casting judgment over a fellow enthusiast who chooses to spend hours of his life shinning up their engine bay...... if that sort of thing floats your boat then hey who am I to judge.
No doubt if what we are now reducing this technical discussion to is some sort of beauty contest, Philpot wins hands down, which is why I've shared my praise and as you'll see from my first comments when I started this post I even ridiculed my own handwork, this should tell you I neither take myself seriously or that I am in the slightest bit bothered about under bonnet aesthetics.
In my opinion there's and underlying competitiveness and posturing on this forum which detracts from what it's here for, this is a technical discussion about something TVR clearly could have done better and really should remain as such. The most revealing part of all of this for me is both Philpot and I have completely independently identified and tackled the same issue in parallel, this just indicates to me logical thought from Phillpot and merely supports of my own reasoning.
Funnily enough I was discussing the issue of limited clutch fluid and TVR's angled cylinder installation with Jason Clegg of Str8Six only a few weeks ago at the London Classic Car Show, I don't think there's anyone more skilled and passionate about TVRS than Jason who is always keen to defend the brand in the face of the typical criticism it receives from the general public. Despite this as fundamentally Jason is a very experienced and talented engineer he will always balance his passion for TVR's with a healthy serving of pragmatism.
As such when discussing the issue of limited clutch fluid and TVR's angled cylinder installation with Jason his response was to smirk, we discussed the fluid capacity thing a little further and it was clear his opinion was perfectly in line with mine and that of Phillpot. As I have been meticulously clear to point out time and time again no one is suggesting the standard arrangement doesn't work acceptably when the reservoir is brim full and each of the two cylinders are completely fluid tight, but that doesn't mean it cant be improved upon because quite clearly and unarguably the standard arrangement is marginal at best.
Now all the boring technical debate is out of the way lets all get back to the way more important 'my engine is more shinny than your engine' beauty contest, because as we all know from years of being on this forum.... "making your TVR pretty, is way more important than how it works"
Love you all, Dave.
Acceptable and good design are of course often worlds apart, in my humble opinion the woefully tiny amount of fluid held by the master cylinder reservoir is marginal at best, the problem as I've been clear to point out is this situation only really exists because TVR mounted the master cylinder at an angle when the Girling designers intended it to be mounted horizontally.
I do hope people don't think I'm presenting the reservoir extender as some amazing miracle must do modification, all it does is give some extra fluid capacity which in turn provides some margin of safety to avoid air entering the system when the level falls should either cylinder start leaking or even weep slightly....... which with my extensive experience of Girling hydraulics is really rather common.
It amused and disappoints me in equal measure that some seek to ridicule the aesthetics on my simple solution, my TVR is for driving not polishing, personally I would never dream of casting judgment over a fellow enthusiast who chooses to spend hours of his life shinning up their engine bay...... if that sort of thing floats your boat then hey who am I to judge.
No doubt if what we are now reducing this technical discussion to is some sort of beauty contest, Philpot wins hands down, which is why I've shared my praise and as you'll see from my first comments when I started this post I even ridiculed my own handwork, this should tell you I neither take myself seriously or that I am in the slightest bit bothered about under bonnet aesthetics.
In my opinion there's and underlying competitiveness and posturing on this forum which detracts from what it's here for, this is a technical discussion about something TVR clearly could have done better and really should remain as such. The most revealing part of all of this for me is both Philpot and I have completely independently identified and tackled the same issue in parallel, this just indicates to me logical thought from Phillpot and merely supports of my own reasoning.
Funnily enough I was discussing the issue of limited clutch fluid and TVR's angled cylinder installation with Jason Clegg of Str8Six only a few weeks ago at the London Classic Car Show, I don't think there's anyone more skilled and passionate about TVRS than Jason who is always keen to defend the brand in the face of the typical criticism it receives from the general public. Despite this as fundamentally Jason is a very experienced and talented engineer he will always balance his passion for TVR's with a healthy serving of pragmatism.
As such when discussing the issue of limited clutch fluid and TVR's angled cylinder installation with Jason his response was to smirk
, we discussed the fluid capacity thing a little further and it was clear his opinion was perfectly in line with mine and that of Phillpot. As I have been meticulously clear to point out time and time again no one is suggesting the standard arrangement doesn't work acceptably when the reservoir is brim full and each of the two cylinders are completely fluid tight, but that doesn't mean it cant be improved upon because quite clearly and unarguably the standard arrangement is marginal at best.Now all the boring technical debate is out of the way lets all get back to the way more important 'my engine is more shinny than your engine' beauty contest, because as we all know from years of being on this forum.... "making your TVR pretty, is way more important than how it works"
Love you all, Dave.
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