Clutch Peddle failure rectification
Discussion
Alot of people seem to be posting about issues with the clutch peddle going limp during heavy use. And there's alot of discussion about sucking out the master and filling with new then pumping the system 30 times and repeating the process.
Basically the round donut type release bearing we have provides a large surface contact area. That combined with the materials used allow for alot of the heat produced by the clutch plates to be transfered into the release bearing (slave) which boils any degraded fluid. Note that hydraulic fluids are hydroscopic and as such they will obsorb moisture over time and this reduces the boiling point of our hydraulic fluid.
To get over the problem you need to bleed the system properly via the slave cylinder, normally this would not be a problem but the uterly ridiculas setup we have means its a PITA to get to. Tuners can do this for you as they have ramps and small sockets to get to the assembly but Id imagine even they dont find it easy. The real way to solve the problem is to fit a S/Steel flexible hose in place of the stock bleed tube and to route the other end to somewhere easily accesable. On this end will be a standard bleed nipple so you can bleed the whole system whenever you feel your fluid is getting tired or before you get any peddle issues. This is easier said than done however as the gearbox needs to be split from the block to gain access so if your having clutch work done then make sure you purchase one of these kits. I don't have any links as at work now but they are searchable on Google or such like. IL post a link if I get time tonight.
PS: It would be sensible if Rapid and MF offered this as part of any clutch change or upgrade work, for the insignifigant additional cost I think everyone would have it done!
I'm going to do this with mine soon so I will post picture of the process.
Basically the round donut type release bearing we have provides a large surface contact area. That combined with the materials used allow for alot of the heat produced by the clutch plates to be transfered into the release bearing (slave) which boils any degraded fluid. Note that hydraulic fluids are hydroscopic and as such they will obsorb moisture over time and this reduces the boiling point of our hydraulic fluid.
To get over the problem you need to bleed the system properly via the slave cylinder, normally this would not be a problem but the uterly ridiculas setup we have means its a PITA to get to. Tuners can do this for you as they have ramps and small sockets to get to the assembly but Id imagine even they dont find it easy. The real way to solve the problem is to fit a S/Steel flexible hose in place of the stock bleed tube and to route the other end to somewhere easily accesable. On this end will be a standard bleed nipple so you can bleed the whole system whenever you feel your fluid is getting tired or before you get any peddle issues. This is easier said than done however as the gearbox needs to be split from the block to gain access so if your having clutch work done then make sure you purchase one of these kits. I don't have any links as at work now but they are searchable on Google or such like. IL post a link if I get time tonight.
PS: It would be sensible if Rapid and MF offered this as part of any clutch change or upgrade work, for the insignifigant additional cost I think everyone would have it done!
I'm going to do this with mine soon so I will post picture of the process.
You have to split engine/box to install a remote bleed line.
Although on my car, Ive only ever experienced a problem once that has led me to bleed again. And even then, not sure Im convinced it was the actual problem.
But that was on a scorching hot day, in the middle of racing all day.
Ive never experienced a problem any other time, even when racing back to back runs.
Why...that I dont know. Although looking at the Monaro's hyrdaulic lines, the long routes of steel piping, I'm sure dont help matters.
Although on my car, Ive only ever experienced a problem once that has led me to bleed again. And even then, not sure Im convinced it was the actual problem.
But that was on a scorching hot day, in the middle of racing all day.
Ive never experienced a problem any other time, even when racing back to back runs.
Why...that I dont know. Although looking at the Monaro's hyrdaulic lines, the long routes of steel piping, I'm sure dont help matters.
another good idea would be to use a lot bigger resovior bottle to hold more fluid,as when you work the clutch it constantly uses and returns fluid to the bottle,draining and putting in fresh does help as it goes bad fast.bleeding is good but it all helps.there are people who think its the master cylinder thats the problem but there are a few things that make it worse. and use the best fuild you can get your hands on happy shopper dot4 is no good.any proper fluid will have a boiling point on it,(the higher the better) but it does all absorb water so change it often !!
Not sure the last post (fitting a larger master cylinder) makes a lot of sense, the principals of a master cylinder and slave cylinder setup don’t really allow fluid to return back to the master cylinder from the slave (of course a little does) but not sure heat in the master cylinder is the issue here. This about heat build up in the fluid in the slave cylinder and connected steel pipes, so unless the fluid is changed completely by flushing out and replacing (a process known as bleeding) you won’t fix the problem.
I would say its the small diameter steel lines thats the biggest issue.
As I say...Ive virtually never had a problem. I run a -4 braided line from master to slave, routed so in no real close path of direct heat from manifolds etc. Although obviously it gets close where it enters the slave.
Im now using Millers brake/clutch fluid, although had been Castrol before that.
As I say...Ive virtually never had a problem. I run a -4 braided line from master to slave, routed so in no real close path of direct heat from manifolds etc. Although obviously it gets close where it enters the slave.
Im now using Millers brake/clutch fluid, although had been Castrol before that.
06:41 quote
Not sure the last post (fitting a larger master cylinder) makes a lot of sense, the principals of a master cylinder and slave cylinder setup don’t really allow fluid to return back to the master cylinder from the slave (of course a little does) but not sure heat in the master cylinder is the issue here. This about heat build up in the fluid in the slave cylinder and connected steel pipes, so unless the fluid is changed completely by flushing out and replacing (a process known as bleeding) you won’t fix the problem
if you read my post it says resovior not master cylinder !, and the fluid does return to the resovior thats what its there for when you derpess the clutch it flows fluid to the slave and when you release it it goes back into the resovior, if you take the lid off and watch the fluid level , get some one to work the clutch and you will see the level go up and down. bleeding is the best way but changing the fluid will keep it better . i would swap it after every drag day !!
Not sure the last post (fitting a larger master cylinder) makes a lot of sense, the principals of a master cylinder and slave cylinder setup don’t really allow fluid to return back to the master cylinder from the slave (of course a little does) but not sure heat in the master cylinder is the issue here. This about heat build up in the fluid in the slave cylinder and connected steel pipes, so unless the fluid is changed completely by flushing out and replacing (a process known as bleeding) you won’t fix the problem
if you read my post it says resovior not master cylinder !, and the fluid does return to the resovior thats what its there for when you derpess the clutch it flows fluid to the slave and when you release it it goes back into the resovior, if you take the lid off and watch the fluid level , get some one to work the clutch and you will see the level go up and down. bleeding is the best way but changing the fluid will keep it better . i would swap it after every drag day !!
tinker-27 said:
06:41 quote
Not sure the last post (fitting a larger master cylinder) makes a lot of sense, the principals of a master cylinder and slave cylinder setup don’t really allow fluid to return back to the master cylinder from the slave (of course a little does) but not sure heat in the master cylinder is the issue here. This about heat build up in the fluid in the slave cylinder and connected steel pipes, so unless the fluid is changed completely by flushing out and replacing (a process known as bleeding) you won’t fix the problem
if you read my post it says resovior not master cylinder !, and the fluid does return to the resovior thats what its there for when you derpess the clutch it flows fluid to the slave and when you release it it goes back into the resovior, if you take the lid off and watch the fluid level , get some one to work the clutch and you will see the level go up and down. bleeding is the best way but changing the fluid will keep it better . i would swap it after every drag day !!
OK I take issue with this now. I also am a qualified engineer with quite a few years experiance behind me so when I say the fluid does not cycle It does not - full stop. The movement you see in the header tank is the small master piston moving back and forward as you press the peddle and this in turn increases and decreases the space behind the master piston slightly. The fluid between the master and slave is sealed there because as soon as you move the master piston it seals off the link to the slave and the fluid acts as a solid rod to push against the slave piston (or ring in our case). As such no fluid moves between the section between the master and slave cylinders and the header tank or at least next to fNot sure the last post (fitting a larger master cylinder) makes a lot of sense, the principals of a master cylinder and slave cylinder setup don’t really allow fluid to return back to the master cylinder from the slave (of course a little does) but not sure heat in the master cylinder is the issue here. This about heat build up in the fluid in the slave cylinder and connected steel pipes, so unless the fluid is changed completely by flushing out and replacing (a process known as bleeding) you won’t fix the problem
if you read my post it says resovior not master cylinder !, and the fluid does return to the resovior thats what its there for when you derpess the clutch it flows fluid to the slave and when you release it it goes back into the resovior, if you take the lid off and watch the fluid level , get some one to work the clutch and you will see the level go up and down. bleeding is the best way but changing the fluid will keep it better . i would swap it after every drag day !!
k all! The reason we get so much crap fluid is the heat transfer rate between the slave ring cyclinder and the release plate is very high as by the nature of the design the slave is very close to the action and has a larger than normal contact area. Its simple mechanics and I dont want people not as mechanically minded being miss led! 
fluid does not circulate a lot, but there is some degree of circulation when the clutch is not depressed.
Otherwise the dirt couldnt work its way back up into the reservoir.
But it is absolutely minimal. In essence, once the master is full, and slave full etc.....the fluid stays stagnant, just moving back and forward as the clutch is operated, with perhaps some swapping about within that closed system.
There are systems out there that will allow the fluid to actually circulate, although they would need adapted to our setup.
That said, until I experience this problem, I'm happy to leave it as is.
Otherwise the dirt couldnt work its way back up into the reservoir.
But it is absolutely minimal. In essence, once the master is full, and slave full etc.....the fluid stays stagnant, just moving back and forward as the clutch is operated, with perhaps some swapping about within that closed system.
There are systems out there that will allow the fluid to actually circulate, although they would need adapted to our setup.
That said, until I experience this problem, I'm happy to leave it as is.
The slave cylinder might be in better thermal contact compared to a cylinder outside the bell housing on a release arm but the heat still has a tortuous path. The cylinder is well heat sinked to the front of the gearbox, all aluminium, this conducts heat 3 times better than steel. The heat has to soak into the pressure plate, bell view washer, release fingers and the release bearing. Spending most of its time in the unreleased state the contact force is low.
I think many starts in quick succession would be needed to build up the level of heat needed. Perhaps it is more of a gearbox heat issue, but you don't hear of manual gearboxes needing oil coolers etc and it is not covered in fins.
I've had my clutch slip once which I think was a runaway condition where the friction surfaces burning evolves gas keeping the surfaces apart against the full engaged pressure. Pedal operation during and after the incident was normal.
I wouldn't totally dismiss fluid issues. My clutch effort does vary, seems to get heaver on long journeys and lighter if the car is unused for a few days.
Gas or liquid, the master and slave cylinder pressures must still be equal. So if the pedal goes hard due to high pressure, this pressure must disengage the clutch also, which is not reported.
I think many starts in quick succession would be needed to build up the level of heat needed. Perhaps it is more of a gearbox heat issue, but you don't hear of manual gearboxes needing oil coolers etc and it is not covered in fins.
I've had my clutch slip once which I think was a runaway condition where the friction surfaces burning evolves gas keeping the surfaces apart against the full engaged pressure. Pedal operation during and after the incident was normal.
I wouldn't totally dismiss fluid issues. My clutch effort does vary, seems to get heaver on long journeys and lighter if the car is unused for a few days.
Gas or liquid, the master and slave cylinder pressures must still be equal. So if the pedal goes hard due to high pressure, this pressure must disengage the clutch also, which is not reported.
i think we will beg to differ on this one, im not saying it swaps much fluid each time but it does return to the resovior or as stevie says how does the old crap stuff itno the res ? also when the system gets hot it heeds space for the fluid to go somewhere or it would hold the clutch on (the same as over filling a brake resovoir and causing the brakes to lock on).if any of you have black dirty fluid in your resoviors suck it out and re fill with fresh and then work the clutch 20 30 times or drive for a day and i bet the fluid goes dirty again (not as bad but it will mix with whats in the system .bleeding is the best way,but keeping it fresh in the res will help,
S600VXR said:
Alot of people seem to be posting about issues with the clutch peddle going limp during heavy use. And there's alot of discussion about sucking out the master and filling with new then pumping the system 30 times and repeating the process.
Basically the round donut type release bearing we have provides a large surface contact area. That combined with the materials used allow for alot of the heat produced by the clutch plates to be transfered into the release bearing (slave) which boils any degraded fluid. Note that hydraulic fluids are hydroscopic and as such they will obsorb moisture over time and this reduces the boiling point of our hydraulic fluid.
To get over the problem you need to bleed the system properly via the slave cylinder, normally this would not be a problem but the uterly ridiculas setup we have means its a PITA to get to. Tuners can do this for you as they have ramps and small sockets to get to the assembly but Id imagine even they dont find it easy. The real way to solve the problem is to fit a S/Steel flexible hose in place of the stock bleed tube and to route the other end to somewhere easily accesable. On this end will be a standard bleed nipple so you can bleed the whole system whenever you feel your fluid is getting tired or before you get any peddle issues. This is easier said than done however as the gearbox needs to be split from the block to gain access so if your having clutch work done then make sure you purchase one of these kits. I don't have any links as at work now but they are searchable on Google or such like. IL post a link if I get time tonight.
PS: It would be sensible if Rapid and MF offered this as part of any clutch change or upgrade work, for the insignifigant additional cost I think everyone would have it done!
I'm going to do this with mine soon so I will post picture of the process.
Roger have you done this mod yet? I lost my clutch several times at Shakespeare even though I'd done the "clutch fluid change by pumping and syphoning" two dozen times the night before (i.e. waste of time since the fluid just cycles back and forth up and down the pipe as you've pointed out).Basically the round donut type release bearing we have provides a large surface contact area. That combined with the materials used allow for alot of the heat produced by the clutch plates to be transfered into the release bearing (slave) which boils any degraded fluid. Note that hydraulic fluids are hydroscopic and as such they will obsorb moisture over time and this reduces the boiling point of our hydraulic fluid.
To get over the problem you need to bleed the system properly via the slave cylinder, normally this would not be a problem but the uterly ridiculas setup we have means its a PITA to get to. Tuners can do this for you as they have ramps and small sockets to get to the assembly but Id imagine even they dont find it easy. The real way to solve the problem is to fit a S/Steel flexible hose in place of the stock bleed tube and to route the other end to somewhere easily accesable. On this end will be a standard bleed nipple so you can bleed the whole system whenever you feel your fluid is getting tired or before you get any peddle issues. This is easier said than done however as the gearbox needs to be split from the block to gain access so if your having clutch work done then make sure you purchase one of these kits. I don't have any links as at work now but they are searchable on Google or such like. IL post a link if I get time tonight.
PS: It would be sensible if Rapid and MF offered this as part of any clutch change or upgrade work, for the insignifigant additional cost I think everyone would have it done!
I'm going to do this with mine soon so I will post picture of the process.
Since I've now fixed my blown valve stem seals
and stopped it smoking, I'm keen for anyone to post links to these remote kits and recommendations for fluid so I can sort my clutch...iacs_hsv said:
S600VXR said:
Alot of people seem to be posting about issues with the clutch peddle going limp during heavy use. And there's alot of discussion about sucking out the master and filling with new then pumping the system 30 times and repeating the process.
Basically the round donut type release bearing we have provides a large surface contact area. That combined with the materials used allow for alot of the heat produced by the clutch plates to be transfered into the release bearing (slave) which boils any degraded fluid. Note that hydraulic fluids are hydroscopic and as such they will obsorb moisture over time and this reduces the boiling point of our hydraulic fluid.
To get over the problem you need to bleed the system properly via the slave cylinder, normally this would not be a problem but the uterly ridiculas setup we have means its a PITA to get to. Tuners can do this for you as they have ramps and small sockets to get to the assembly but Id imagine even they dont find it easy. The real way to solve the problem is to fit a S/Steel flexible hose in place of the stock bleed tube and to route the other end to somewhere easily accesable. On this end will be a standard bleed nipple so you can bleed the whole system whenever you feel your fluid is getting tired or before you get any peddle issues. This is easier said than done however as the gearbox needs to be split from the block to gain access so if your having clutch work done then make sure you purchase one of these kits. I don't have any links as at work now but they are searchable on Google or such like. IL post a link if I get time tonight.
PS: It would be sensible if Rapid and MF offered this as part of any clutch change or upgrade work, for the insignifigant additional cost I think everyone would have it done!
I'm going to do this with mine soon so I will post picture of the process.
Basically the round donut type release bearing we have provides a large surface contact area. That combined with the materials used allow for alot of the heat produced by the clutch plates to be transfered into the release bearing (slave) which boils any degraded fluid. Note that hydraulic fluids are hydroscopic and as such they will obsorb moisture over time and this reduces the boiling point of our hydraulic fluid.
To get over the problem you need to bleed the system properly via the slave cylinder, normally this would not be a problem but the uterly ridiculas setup we have means its a PITA to get to. Tuners can do this for you as they have ramps and small sockets to get to the assembly but Id imagine even they dont find it easy. The real way to solve the problem is to fit a S/Steel flexible hose in place of the stock bleed tube and to route the other end to somewhere easily accesable. On this end will be a standard bleed nipple so you can bleed the whole system whenever you feel your fluid is getting tired or before you get any peddle issues. This is easier said than done however as the gearbox needs to be split from the block to gain access so if your having clutch work done then make sure you purchase one of these kits. I don't have any links as at work now but they are searchable on Google or such like. IL post a link if I get time tonight.
PS: It would be sensible if Rapid and MF offered this as part of any clutch change or upgrade work, for the insignifigant additional cost I think everyone would have it done!
I'm going to do this with mine soon so I will post picture of the process.
Roger have you done this mod yet? I lost my clutch several times at Shakespeare even though I'd done the "clutch fluid change by pumping and syphoning" two dozen times the night before (i.e. waste of time since the fluid just cycles back and forth up and down the pipe as you've pointed out).
Since I've now fixed my blown valve stem seals
and stopped it smoking, I'm keen for anyone to post links to these remote kits and recommendations for fluid so I can sort my clutch...You need a clutch!!
I got mine from here: http://www.ls1tech.com/forums/manual-transmission/...
monkfish1 said:
iacs_hsv said:
S600VXR said:
Alot of people seem to be posting about issues with the clutch peddle going limp during heavy use. And there's alot of discussion about sucking out the master and filling with new then pumping the system 30 times and repeating the process.
Basically the round donut type release bearing we have provides a large surface contact area. That combined with the materials used allow for alot of the heat produced by the clutch plates to be transfered into the release bearing (slave) which boils any degraded fluid. Note that hydraulic fluids are hydroscopic and as such they will obsorb moisture over time and this reduces the boiling point of our hydraulic fluid.
To get over the problem you need to bleed the system properly via the slave cylinder, normally this would not be a problem but the uterly ridiculas setup we have means its a PITA to get to. Tuners can do this for you as they have ramps and small sockets to get to the assembly but Id imagine even they dont find it easy. The real way to solve the problem is to fit a S/Steel flexible hose in place of the stock bleed tube and to route the other end to somewhere easily accesable. On this end will be a standard bleed nipple so you can bleed the whole system whenever you feel your fluid is getting tired or before you get any peddle issues. This is easier said than done however as the gearbox needs to be split from the block to gain access so if your having clutch work done then make sure you purchase one of these kits. I don't have any links as at work now but they are searchable on Google or such like. IL post a link if I get time tonight.
PS: It would be sensible if Rapid and MF offered this as part of any clutch change or upgrade work, for the insignifigant additional cost I think everyone would have it done!
I'm going to do this with mine soon so I will post picture of the process.
Roger have you done this mod yet? I lost my clutch several times at Shakespeare even though I'd done the "clutch fluid change by pumping and syphoning" two dozen times the night before (i.e. waste of time since the fluid just cycles back and forth up and down the pipe as you've pointed out).Basically the round donut type release bearing we have provides a large surface contact area. That combined with the materials used allow for alot of the heat produced by the clutch plates to be transfered into the release bearing (slave) which boils any degraded fluid. Note that hydraulic fluids are hydroscopic and as such they will obsorb moisture over time and this reduces the boiling point of our hydraulic fluid.
To get over the problem you need to bleed the system properly via the slave cylinder, normally this would not be a problem but the uterly ridiculas setup we have means its a PITA to get to. Tuners can do this for you as they have ramps and small sockets to get to the assembly but Id imagine even they dont find it easy. The real way to solve the problem is to fit a S/Steel flexible hose in place of the stock bleed tube and to route the other end to somewhere easily accesable. On this end will be a standard bleed nipple so you can bleed the whole system whenever you feel your fluid is getting tired or before you get any peddle issues. This is easier said than done however as the gearbox needs to be split from the block to gain access so if your having clutch work done then make sure you purchase one of these kits. I don't have any links as at work now but they are searchable on Google or such like. IL post a link if I get time tonight.
PS: It would be sensible if Rapid and MF offered this as part of any clutch change or upgrade work, for the insignifigant additional cost I think everyone would have it done!
I'm going to do this with mine soon so I will post picture of the process.
Since I've now fixed my blown valve stem seals
and stopped it smoking, I'm keen for anyone to post links to these remote kits and recommendations for fluid so I can sort my clutch...iacs_hsv said:
monkfish1 said:
iacs_hsv said:
S600VXR said:
Alot of people seem to be posting about issues with the clutch peddle going limp during heavy use. And there's alot of discussion about sucking out the master and filling with new then pumping the system 30 times and repeating the process.
Basically the round donut type release bearing we have provides a large surface contact area. That combined with the materials used allow for alot of the heat produced by the clutch plates to be transfered into the release bearing (slave) which boils any degraded fluid. Note that hydraulic fluids are hydroscopic and as such they will obsorb moisture over time and this reduces the boiling point of our hydraulic fluid.
To get over the problem you need to bleed the system properly via the slave cylinder, normally this would not be a problem but the uterly ridiculas setup we have means its a PITA to get to. Tuners can do this for you as they have ramps and small sockets to get to the assembly but Id imagine even they dont find it easy. The real way to solve the problem is to fit a S/Steel flexible hose in place of the stock bleed tube and to route the other end to somewhere easily accesable. On this end will be a standard bleed nipple so you can bleed the whole system whenever you feel your fluid is getting tired or before you get any peddle issues. This is easier said than done however as the gearbox needs to be split from the block to gain access so if your having clutch work done then make sure you purchase one of these kits. I don't have any links as at work now but they are searchable on Google or such like. IL post a link if I get time tonight.
PS: It would be sensible if Rapid and MF offered this as part of any clutch change or upgrade work, for the insignifigant additional cost I think everyone would have it done!
I'm going to do this with mine soon so I will post picture of the process.
Basically the round donut type release bearing we have provides a large surface contact area. That combined with the materials used allow for alot of the heat produced by the clutch plates to be transfered into the release bearing (slave) which boils any degraded fluid. Note that hydraulic fluids are hydroscopic and as such they will obsorb moisture over time and this reduces the boiling point of our hydraulic fluid.
To get over the problem you need to bleed the system properly via the slave cylinder, normally this would not be a problem but the uterly ridiculas setup we have means its a PITA to get to. Tuners can do this for you as they have ramps and small sockets to get to the assembly but Id imagine even they dont find it easy. The real way to solve the problem is to fit a S/Steel flexible hose in place of the stock bleed tube and to route the other end to somewhere easily accesable. On this end will be a standard bleed nipple so you can bleed the whole system whenever you feel your fluid is getting tired or before you get any peddle issues. This is easier said than done however as the gearbox needs to be split from the block to gain access so if your having clutch work done then make sure you purchase one of these kits. I don't have any links as at work now but they are searchable on Google or such like. IL post a link if I get time tonight.
PS: It would be sensible if Rapid and MF offered this as part of any clutch change or upgrade work, for the insignifigant additional cost I think everyone would have it done!
I'm going to do this with mine soon so I will post picture of the process.
Roger have you done this mod yet? I lost my clutch several times at Shakespeare even though I'd done the "clutch fluid change by pumping and syphoning" two dozen times the night before (i.e. waste of time since the fluid just cycles back and forth up and down the pipe as you've pointed out).
Since I've now fixed my blown valve stem seals
and stopped it smoking, I'm keen for anyone to post links to these remote kits and recommendations for fluid so I can sort my clutch...You need a clutch!!
Rog - problem was disengaging it, not slip! (...apologies for tardy response)
Indeed. Previous comment applies
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