Clutch travel issues - PICS & VIDEO
08-12-2011, 12:21 AM
#31
Burning Brakes
Clutch slaves are 69 quid at Design911, mates 
http://www.design911.co.uk/fu/pt251_...lave-Cylinder/
I reckon what's happened is that the slave seals are probably a bit ropey, and now that you have got a fresh pressure plate and the fixed rollpin (and so it's getting a full pedal stroke for the first time in a while)...the slave now has to work harder than before.
There's a bit of a trick to refitting the slave though. You can really only reach it with one hand, and you have to push it onto its locating studs against the spring loading of the slave piston. Once it's pushed onto the studs, **** it at a slight angle, and it should jam in place against the threads of the studs...at least long enough for you to hastily spin on one of the nut/washer.
http://www.design911.co.uk/fu/pt251_...lave-Cylinder/
I reckon what's happened is that the slave seals are probably a bit ropey, and now that you have got a fresh pressure plate and the fixed rollpin (and so it's getting a full pedal stroke for the first time in a while)...the slave now has to work harder than before.
There's a bit of a trick to refitting the slave though. You can really only reach it with one hand, and you have to push it onto its locating studs against the spring loading of the slave piston. Once it's pushed onto the studs, **** it at a slight angle, and it should jam in place against the threads of the studs...at least long enough for you to hastily spin on one of the nut/washer.
08-12-2011, 02:43 PM
#32
Three Wheelin'
Thats a handy tip on refitting the slave, thanks Babalouie.
Was it easy to crack open the union betwen the hard pipe and the soft hose or is like the brake pipes where at this age its best not to try to turn the fitting on the metal pipe and instead just counter hold the hard pipe fitting and rotate the hose end?
Was it easy to crack open the union betwen the hard pipe and the soft hose or is like the brake pipes where at this age its best not to try to turn the fitting on the metal pipe and instead just counter hold the hard pipe fitting and rotate the hose end?
08-12-2011, 08:56 PM
#33
Burning Brakes
Thats a handy tip on refitting the slave, thanks Babalouie.
Was it easy to crack open the union betwen the hard pipe and the soft hose or is like the brake pipes where at this age its best not to try to turn the fitting on the metal pipe and instead just counter hold the hard pipe fitting and rotate the hose end?
Was it easy to crack open the union betwen the hard pipe and the soft hose or is like the brake pipes where at this age its best not to try to turn the fitting on the metal pipe and instead just counter hold the hard pipe fitting and rotate the hose end?
Mine was on pretty tight, and it is a bit of a faff to get off, so your proposed method sounds like a good idea.
Also remember that the rod in the new slave has go to fit into the cup in the clutch fork
And leave the union at the hardline loose until you have got the new slave buttoned up, otherwise the softline can be a bit twisted.
08-13-2011, 09:13 AM
#34
Drifting
Thread Starter
Thats a handy tip on refitting the slave, thanks Babalouie.
Was it easy to crack open the union betwen the hard pipe and the soft hose or is like the brake pipes where at this age its best not to try to turn the fitting on the metal pipe and instead just counter hold the hard pipe fitting and rotate the hose end?
Was it easy to crack open the union betwen the hard pipe and the soft hose or is like the brake pipes where at this age its best not to try to turn the fitting on the metal pipe and instead just counter hold the hard pipe fitting and rotate the hose end?
Yes, the hardpipe end is not supported by a bracket nearby, so you certainly have to be careful. The hardpipe is a bigger diameter than the typical brake hardpipe tho, so it is less fragile.
Mine was on pretty tight, and it is a bit of a faff to get off, so your proposed method sounds like a good idea.
Also remember that the rod in the new slave has go to fit into the cup in the clutch fork And leave the union at the hardline loose until you have got the new slave buttoned up, otherwise the softline can be a bit twisted.
Mine was on pretty tight, and it is a bit of a faff to get off, so your proposed method sounds like a good idea.
Also remember that the rod in the new slave has go to fit into the cup in the clutch fork
And leave the union at the hardline loose until you have got the new slave buttoned up, otherwise the softline can be a bit twisted.
08-13-2011, 09:46 AM
#35
Burning Brakes
So you're going to have a go?
I reckon there's nothing too tricky about it if you take your time, the only gnarly bit I would say is the bleeding. Something like that Gunson Ezebleed thing looks like it'll do the job.
I reckon there's nothing too tricky about it if you take your time, the only gnarly bit I would say is the bleeding. Something like that Gunson Ezebleed thing looks like it'll do the job.
08-13-2011, 02:55 PM
#36
Three Wheelin'
Re bleeding, i used the ezi bleed to bleed my clutch, brakes and pdas and it seemed to work, though its always a bit of a pain when you have a completely dry cylinder to start with.
Interestingly the ezi bleed doesnt work so well on the skyline as a i couldnt a tight fit on the reservoir lid.
08-14-2011, 06:30 AM
#37
There are three separate systems using brake fluid on the C4
1) Brakes
2) Hydraulic clutch
3) Center and rear diff locks on the tranny.
In your case, you need to focus on the hydraulic clutch. If you have already bled the clutch then the next step is to replace the clutch slave and associated hose. If that doesn't solve the problem then replace the clutch master. By doing it in this order, you are going in order of likelihood of the problem and also going from least expensive to most.
1) Brakes
2) Hydraulic clutch
3) Center and rear diff locks on the tranny.
In your case, you need to focus on the hydraulic clutch. If you have already bled the clutch then the next step is to replace the clutch slave and associated hose. If that doesn't solve the problem then replace the clutch master. By doing it in this order, you are going in order of likelihood of the problem and also going from least expensive to most.
08-18-2011, 09:31 AM
#38
Rennlist Member
Join Date: Jun 2010
Location: Detroit (Rock City); 1990 C4
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My '90 C4 has had balky and inconsistent shifting since I bought it in June.
I bled the clutch slave first; fluid looked like ****e but it made no difference.
I then checked the roll-pin. Perfectly straight; could see right through it.
Ordered a slave and softline from Pelican on Friday, they arrived and I installed them yesterday; really not that bad of a job. I shot the hardline/softline junction with penetrating oil a couple days before and once I verified that I could break all the connections free (hardline/softline and the two slave mounting nuts) I just cut the old softline to make removal simpler.
To prevent continuous dripping from the hardline I capped the end of the new softline and then installed it alone; finger-tight was plenty to prevent dripping. Note well that if you go this way a) you have to put the new slave on the new softline prior to slave installation, and b) don't forget to tighten this joint down!
I did not need to remove the heater pipe; was concerned that removal would destroy it.
I found that the old slave had lost the mushroom-headed protective cap where it meets the throwout lever; the pushrod underneath was badly mushroomed (explains why I had to get the clutch *all* the way to the floor!).
With the slave out it was easy to verify that the throwout lever moved freely; there's ~20mm of freeplay there.
I also used an inspection mirror to both determine where the recess in the throwout lever sat in relation to the hole and to verify that I had the slave pushrod seated in the recess prior to fastening it down. A headlamp is crucial here; I use the previous version of this and like it very much (own a couple, in fact): Petzl Tikka
Finally, I did find eventually that I could get two hands in there to hold the slave in position long enough to install the upper mounting nut. There was only one orientation which allowed this, and that was lying under the car* with my legs on either side of the passenger rear wheel and the trans above my chest. Not comfortable, but doable.
*Car on jackstands ~20" off the ground, me on a creeper.
Unsurprisingly, replacing the slave made for a substantial improvement in shift quality.
I bled the clutch slave first; fluid looked like ****e but it made no difference.
I then checked the roll-pin. Perfectly straight; could see right through it.
Ordered a slave and softline from Pelican on Friday, they arrived and I installed them yesterday; really not that bad of a job. I shot the hardline/softline junction with penetrating oil a couple days before and once I verified that I could break all the connections free (hardline/softline and the two slave mounting nuts) I just cut the old softline to make removal simpler.
To prevent continuous dripping from the hardline I capped the end of the new softline and then installed it alone; finger-tight was plenty to prevent dripping. Note well that if you go this way a) you have to put the new slave on the new softline prior to slave installation, and b) don't forget to tighten this joint down!
I did not need to remove the heater pipe; was concerned that removal would destroy it.
I found that the old slave had lost the mushroom-headed protective cap where it meets the throwout lever; the pushrod underneath was badly mushroomed (explains why I had to get the clutch *all* the way to the floor!).
With the slave out it was easy to verify that the throwout lever moved freely; there's ~20mm of freeplay there.
I also used an inspection mirror to both determine where the recess in the throwout lever sat in relation to the hole and to verify that I had the slave pushrod seated in the recess prior to fastening it down. A headlamp is crucial here; I use the previous version of this and like it very much (own a couple, in fact): Petzl Tikka
Finally, I did find eventually that I could get two hands in there to hold the slave in position long enough to install the upper mounting nut. There was only one orientation which allowed this, and that was lying under the car* with my legs on either side of the passenger rear wheel and the trans above my chest. Not comfortable, but doable.
*Car on jackstands ~20" off the ground, me on a creeper.
Unsurprisingly, replacing the slave made for a substantial improvement in shift quality.
08-27-2011, 04:48 PM
#39
6th Gear
Join Date: Jan 2010
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clutch slave cylinder
I ftted one of these the other day
http://www.ebay.co.uk/itm/Kupplungsn...item19c8206a5a
........nice reduced pedal pressure. They're not cheap although I got mine for a snip at £53!!!!! + post.
http://www.ebay.co.uk/itm/Kupplungsn...item19c8206a5a
........nice reduced pedal pressure. They're not cheap although I got mine for a snip at £53!!!!! + post.
08-28-2011, 12:32 AM
#40
Did you change the pedal cluster plastic bushes while you were in there. As these parts are only pennies but well worth changing out and adding some White grease as well. Because rust and small crud accumulates in the pedal assembly and causes poor travel and sticking pedal issues ?
08-28-2011, 12:42 PM
#41
08-28-2011, 04:42 PM
#42
Drifting
Thread Starter
Thanks for all the feedback gentlemen.
Alex and I gave a crack at it today. No success. Having just drove home from Alex's, no improvement at all in the end
So to update: New clutch, new roll pin, new slave, system bled.
It seems that the clutch pedal when pulled fully out ward is not at level with the brake pedal. Looking at Alex's pedals his clutch and brake pedal are in line.... I'm starting to think it could be that the pedal has been mounted too far away - is it possible to detach the pedal and mount it closer? Is it possible the pedal has bent over time?
Also the master cylinder rubber boot is broken and it seems that some of it's travel has no effect. Is the next step to replace the master?
I'm starting to get to my wits end with this issue, it's been like this since the beginning of my ownership!
Anyway a huge thank you to Alex who was great today and his Mrs who allowed me to steal him for effectively most of Sunday!
Cheers mate!
Alex and I gave a crack at it today. No success. Having just drove home from Alex's, no improvement at all in the end
So to update: New clutch, new roll pin, new slave, system bled.
It seems that the clutch pedal when pulled fully out ward is not at level with the brake pedal. Looking at Alex's pedals his clutch and brake pedal are in line.... I'm starting to think it could be that the pedal has been mounted too far away - is it possible to detach the pedal and mount it closer? Is it possible the pedal has bent over time?
Also the master cylinder rubber boot is broken and it seems that some of it's travel has no effect. Is the next step to replace the master?
I'm starting to get to my wits end with this issue, it's been like this since the beginning of my ownership!
Anyway a huge thank you to Alex who was great today and his Mrs who allowed me to steal him for effectively most of Sunday!
Cheers mate!
08-28-2011, 05:04 PM
#43
Three Wheelin'
Yeah a fun day in the garage but not much forward progress sadly.
So do you think the pedal board is restricting the full throw of the pedal?
It seemed like the pedal action was mcuh longer and more like mine with the board out.
We tried adjusting the stopper on the board but no real effect.
I cant help thinking there is something odd, possibly bent, with the clutch pedal. It just seem you would never get the full throw with the board in.
Would be good to get some thoughts from the forum.
The factory spec is 14cm pedal throw, we were just getting this, with the board out. Reduced by 30 to40% with the board in place even with the stopper in place.
Frank, did it get worse again on the way home?
So do you think the pedal board is restricting the full throw of the pedal?
It seemed like the pedal action was mcuh longer and more like mine with the board out.
We tried adjusting the stopper on the board but no real effect.
I cant help thinking there is something odd, possibly bent, with the clutch pedal. It just seem you would never get the full throw with the board in.
Would be good to get some thoughts from the forum.
The factory spec is 14cm pedal throw, we were just getting this, with the board out. Reduced by 30 to40% with the board in place even with the stopper in place.
Frank, did it get worse again on the way home?
08-28-2011, 05:32 PM
#45
Drifting
Thread Starter
Yeah a fun day in the garage but not much forward progress sadly.
So do you think the pedal board is restricting the full throw of the pedal?
It seemed like the pedal action was mcuh longer and more like mine with the board out.
We tried adjusting the stopper on the board but no real effect.
I cant help thinking there is something odd, possibly bent, with the clutch pedal. It just seem you would never get the full throw with the board in.
Would be good to get some thoughts from the forum.
The factory spec is 14cm pedal throw, we were just getting this, with the board out. Reduced by 30 to40% with the board in place even with the stopper in place.
Frank, did it get worse again on the way home?
So do you think the pedal board is restricting the full throw of the pedal?
It seemed like the pedal action was mcuh longer and more like mine with the board out.
We tried adjusting the stopper on the board but no real effect.
I cant help thinking there is something odd, possibly bent, with the clutch pedal. It just seem you would never get the full throw with the board in.
Would be good to get some thoughts from the forum.
The factory spec is 14cm pedal throw, we were just getting this, with the board out. Reduced by 30 to40% with the board in place even with the stopper in place.
Frank, did it get worse again on the way home?
+1 Insight from the board would be greatly appreciated!