Clutch pedal feel question
04-21-2020, 10:14 PM
#16
RL Community Team
Rennlist Member
Rennlist Member
The motive should have a rubber seal inside the cap that prevents fluid from leaking out the top where the cap is screwed on. Also, once you pressurize the Motive it should hold pressure. If the needle is dropping you have a leak somewhere.
04-22-2020, 08:27 PM
#17
Rennlist Member
Thread Starter
Stan,
Thanks for the step-by-step...exactly what I needed. I do have a question...I've read numerous threads about this, and there was one group cutting a hole in the inner fender well to access the master, and then there was a method with a string and pulling the thing through from one side or the other, that was supposed to be easier than everyone though...where does all that come into play here? Because the steps below seem relatively straightforward?
Thanks for the step-by-step...exactly what I needed. I do have a question...I've read numerous threads about this, and there was one group cutting a hole in the inner fender well to access the master, and then there was a method with a string and pulling the thing through from one side or the other, that was supposed to be easier than everyone though...where does all that come into play here? Because the steps below seem relatively straightforward?
If you follow these suggestions your clutch will work forever till its time to replace the hydraulics again say in 20 years?
NOTE If the brake MC has rusty collars around the tank feed grommets buy
a new ATE brake master cylinder,
and 4 new SS brake lines.
If your booster has ever seemed suspect buy
a new ATE booster,
1 liter of Gold ATE brake fluid.
Buy a
new clutch Master cylinder
new slave cylinder,
new blue hose/black now,
new Greg Brown flex line from the sway bar to slave,
new release arm bushing.
Remove the tank then the brake MC then the booster.
NOTE to remove the booster make a cover for the where the MC sits so you dont scratch the surface ,
I like to use an old coolant bottle as a cover for the booster,
then clamp the pushrod while the pedal is being pushed full down
NOTE this must be done as this will make the booster threaded rod easy to remove past the fender and cam cover otherwise it will get stuck.
NOTE unscrew the threaded clevis off the booster input shaft before removal.
Once the booster is out of the way then you will have clear access to the clutch M/C
NOTE if you have a dual disc then the piston tip of the new clutch MC should be cut down about 4.5MM and 2 winds off the spring at the base.
The new M/C pistons are 80MM so your looking for 75mm or a hair more.
bleeding the slave is as easy as opening the slave bleeder with a rag under the bleeder ,
and waiting for solid fluid to come out.
once this is done then remove the slave from the bell housing.
let the slave dangle,
while holding the bleeder so it at its highest point while dangling the slave,
open the bleeder again to expel any more air.
Close the bleeder,
then hold the slave with the line port facing up,
and with a folded rag over the pushrod,
push the rod slowly into the slave all the way.
Hold this position for about 30 seconds, then release the pushrod. it will extend . wait for about 30 seconds then repeat .
do this procedure 3 times then install the slave into the bell housing.
NOTE put some grease on the pushrod and release arm.
NOTE If the brake MC has rusty collars around the tank feed grommets buy
a new ATE brake master cylinder,
and 4 new SS brake lines.
If your booster has ever seemed suspect buy
a new ATE booster,
1 liter of Gold ATE brake fluid.
Buy a
new clutch Master cylinder
new slave cylinder,
new blue hose/black now,
new Greg Brown flex line from the sway bar to slave,
new release arm bushing.
Remove the tank then the brake MC then the booster.
NOTE to remove the booster make a cover for the where the MC sits so you dont scratch the surface ,
I like to use an old coolant bottle as a cover for the booster,
then clamp the pushrod while the pedal is being pushed full down
NOTE this must be done as this will make the booster threaded rod easy to remove past the fender and cam cover otherwise it will get stuck.
NOTE unscrew the threaded clevis off the booster input shaft before removal.
Once the booster is out of the way then you will have clear access to the clutch M/C
NOTE if you have a dual disc then the piston tip of the new clutch MC should be cut down about 4.5MM and 2 winds off the spring at the base.
The new M/C pistons are 80MM so your looking for 75mm or a hair more.
bleeding the slave is as easy as opening the slave bleeder with a rag under the bleeder ,
and waiting for solid fluid to come out.
once this is done then remove the slave from the bell housing.
let the slave dangle,
while holding the bleeder so it at its highest point while dangling the slave,
open the bleeder again to expel any more air.
Close the bleeder,
then hold the slave with the line port facing up,
and with a folded rag over the pushrod,
push the rod slowly into the slave all the way.
Hold this position for about 30 seconds, then release the pushrod. it will extend . wait for about 30 seconds then repeat .
do this procedure 3 times then install the slave into the bell housing.
NOTE put some grease on the pushrod and release arm.
04-22-2020, 08:29 PM
#18
Rennlist Member
Thread Starter
I do have that rubber seal. Not sure what was going wrong, tbh. It was holding pressure, too. So that really doesn't make much sense now that I think about it.
The clutch pedal doesn't need to be held in while pressurizing the reservoir does it?
The clutch pedal doesn't need to be held in while pressurizing the reservoir does it?
04-22-2020, 10:48 PM
#19
Team Owner
once the brake booster is out of the way the clutch master cylinder is easily removed and installed
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bureau13 (04-24-2020)
04-23-2020, 11:38 AM
#20
Nordschleife Master
Maybe a bit on the 'Captain Obvious' side, but don't forget that the brake master is also the reservoir for the clutch system. So when you pressurized the clutch system, that pressure pushed fluid up the blue hose into the brake master...
And out the top of the cap.
And out the top of the cap.
04-23-2020, 09:09 PM
#21
Rennlist Member
Thread Starter
My bleeder actually connects where the cap to the reservoir so it was pushing down through the slave.
Maybe a bit on the 'Captain Obvious' side, but don't forget that the brake master is also the reservoir for the clutch system. So when you pressurized the clutch system, that pressure pushed fluid up the blue hose into the brake master...
And out the top of the cap.
And out the top of the cap.
04-23-2020, 09:41 PM
#22
Nordschleife Master
05-03-2020, 04:15 PM
#23
Rennlist Member
Thread Starter
I decided to do the easy stuff first, in case I got lucky and that fixed it. Unfortunately there's easy, and then there's "easy for me."
I got a new slave cylinder from Roger. Unfortunately Greg's flex line is back-ordered and I wanted to see if I could get the car going, so I hooked up the Motive again. Got quite a bit of fluid out of the slave, it seemed bubble-free, although I'm still getting fluid leaking from the cap. I don't know what's up with that, maybe I have a defective aluminum Motive cap. It does make it impossible to tell if I'm getting any other leaks though. After, I noticed I was getting some pedal pressure at the bottom end of the clutch pedal travel. Initially, not enough to put the car in gear, but after pushing it in and out a bunch and starting the car (not sure why that would matter, or if it actually did) I was able to get enough pressure to change gears. It's still not enough to overcome the spring on the pedal, so it doesn't come back up like it should, but it's progress, and it didn't seem to lose that pressure overnight.
This morning, I decided to try to get it better, so I hooked everything up again and continued, only this time I ran dry of fluid in the Motive...oops. However, the reservoir is still full to the top...however I now have lost all pedal pressure. I put another liter of brake fluid in the Motive (otherwise known as "down the drain") but almost nothing is coming out of the slave bleeder, just more from the cap. I took the Motive off, replaced the cap, and had my kid push the clutch pedal back and forth would see small trickles of fluid out of the slave when he did that, but that's it.
I don't want to go through the pain of changing out the master cylinder until I know if the slave has fixed anything, but I'm not sure how to tell that. Presumably I have not bled anything correctly because it got better, but now is worse, and I have no idea to just flush more brake fluid down the drain until I get a better plan than this stupid Motive. I'm also not overly happy to just wait for Greg's flex line, since my car luck is terrible right now and the only functional vehicle is my daughter's car. Does it buy me anything to remove the slave and manipulate that rod manually without Greg's hose? And for possible future reference...when pushing that slave rod in and out, should the reservoir cap be off to let the air bubbles escape?
I got a new slave cylinder from Roger. Unfortunately Greg's flex line is back-ordered and I wanted to see if I could get the car going, so I hooked up the Motive again. Got quite a bit of fluid out of the slave, it seemed bubble-free, although I'm still getting fluid leaking from the cap. I don't know what's up with that, maybe I have a defective aluminum Motive cap. It does make it impossible to tell if I'm getting any other leaks though. After, I noticed I was getting some pedal pressure at the bottom end of the clutch pedal travel. Initially, not enough to put the car in gear, but after pushing it in and out a bunch and starting the car (not sure why that would matter, or if it actually did) I was able to get enough pressure to change gears. It's still not enough to overcome the spring on the pedal, so it doesn't come back up like it should, but it's progress, and it didn't seem to lose that pressure overnight.
This morning, I decided to try to get it better, so I hooked everything up again and continued, only this time I ran dry of fluid in the Motive...oops. However, the reservoir is still full to the top...however I now have lost all pedal pressure. I put another liter of brake fluid in the Motive (otherwise known as "down the drain") but almost nothing is coming out of the slave bleeder, just more from the cap. I took the Motive off, replaced the cap, and had my kid push the clutch pedal back and forth would see small trickles of fluid out of the slave when he did that, but that's it.
I don't want to go through the pain of changing out the master cylinder until I know if the slave has fixed anything, but I'm not sure how to tell that. Presumably I have not bled anything correctly because it got better, but now is worse, and I have no idea to just flush more brake fluid down the drain until I get a better plan than this stupid Motive. I'm also not overly happy to just wait for Greg's flex line, since my car luck is terrible right now and the only functional vehicle is my daughter's car. Does it buy me anything to remove the slave and manipulate that rod manually without Greg's hose? And for possible future reference...when pushing that slave rod in and out, should the reservoir cap be off to let the air bubbles escape?
05-03-2020, 05:54 PM
#24
Rennlist Member
Thread Starter
Well because I had nothing better to do I went out and backed out the slave cylinder bolts almost all the way then compressed and held it for 20 sec, repeated x5, with the cap off. I'm now back to pedal pressure sufficient to change gears, but not sufficient to push up past the spring. But maybe I just need to do that more, or perhaps take the slave cylinder all the way out and do it, etc? I guess it can't hurt.
I wish I could tell if the slave cylinder were the actual problem by looking at the old part. I had this problem (but not as drastic) sort of off and on, until it sank to the floor and couldn't get in gear. I guess if I can get the pedal right, I can drive it around a little and see if anything happens while awaiting the new flex line. If it has problems again, time to get a master cylinder as well I guess.
I wish I could tell if the slave cylinder were the actual problem by looking at the old part. I had this problem (but not as drastic) sort of off and on, until it sank to the floor and couldn't get in gear. I guess if I can get the pedal right, I can drive it around a little and see if anything happens while awaiting the new flex line. If it has problems again, time to get a master cylinder as well I guess.
05-03-2020, 10:59 PM
#25
RL Community Team
Rennlist Member
Rennlist Member
If only the motive ran dry but not the reservoir then that shouldn't have done any harm. If the reservoir also ran dry you forced air back into the system and are starting over.
Yes, removing the slave and pushing the rod in and out as a bleeding technique will help. You may also be able to feel any issues in the rod motion that would point to a problem in the slave. The rod should be firm, but move able with steady force. When reinstalling the slave, you should be able to push it in just enough to get the bolts started then draw it in the rest of the way using the bolts. If it's easier than that, I think it's bad, at least that's been my experience.
Yes, removing the slave and pushing the rod in and out as a bleeding technique will help. You may also be able to feel any issues in the rod motion that would point to a problem in the slave. The rod should be firm, but move able with steady force. When reinstalling the slave, you should be able to push it in just enough to get the bolts started then draw it in the rest of the way using the bolts. If it's easier than that, I think it's bad, at least that's been my experience.
05-04-2020, 01:11 AM
#26
Rennlist Member
Thread Starter
Your description of the slave matches what I'm seeing, but I'm not surprised, it's brand new. It also matches my recollection of the old one, at least before...I should mess around with it some more to see if I can feel any differences.
If only the motive ran dry but not the reservoir then that shouldn't have done any harm. If the reservoir also ran dry you forced air back into the system and are starting over.
Yes, removing the slave and pushing the rod in and out as a bleeding technique will help. You may also be able to feel any issues in the rod motion that would point to a problem in the slave. The rod should be firm, but move able with steady force. When reinstalling the slave, you should be able to push it in just enough to get the bolts started then draw it in the rest of the way using the bolts. If it's easier than that, I think it's bad, at least that's been my experience.
Yes, removing the slave and pushing the rod in and out as a bleeding technique will help. You may also be able to feel any issues in the rod motion that would point to a problem in the slave. The rod should be firm, but move able with steady force. When reinstalling the slave, you should be able to push it in just enough to get the bolts started then draw it in the rest of the way using the bolts. If it's easier than that, I think it's bad, at least that's been my experience.
05-06-2020, 07:46 PM
#27
Rennlist Member
Thread Starter
For what it's worth, after pulling out the slave and trying to work any additional air bubbles out that might be in there, the pedal regularly springs back all the way. I still feel a bit of a hitch or a pause before it returns all the way up. I may be paranoid however. I haven't taken it for a test drive yet as I'm afraid I'll lose clutch pedal action somewhere and I'm out of AAA tows until mid June 
(only one of those was this car). But I'm going to just go for it here soon. It does seem like everything needed to be bled. Now, why it needed that after NEVER having an issue until just recently, I don't know. Something was compromised. I'm hopeful it was the slave cylinder, but it's entirely possible it was not. When it started failing it was not consistent. If you look back over this thread it was initially just a pedal feel thing that came and went. So it might come back, and if it does I replace the rest of the clutch hydraulics, and following Stan's advice, take a close and careful look at the brake master cylinder and booster as well, since it seems they'll all be coming out. For now though, it looks like I have a functioning vehicle once again.
(only one of those was this car). But I'm going to just go for it here soon. It does seem like everything needed to be bled. Now, why it needed that after NEVER having an issue until just recently, I don't know. Something was compromised. I'm hopeful it was the slave cylinder, but it's entirely possible it was not. When it started failing it was not consistent. If you look back over this thread it was initially just a pedal feel thing that came and went. So it might come back, and if it does I replace the rest of the clutch hydraulics, and following Stan's advice, take a close and careful look at the brake master cylinder and booster as well, since it seems they'll all be coming out. For now though, it looks like I have a functioning vehicle once again.
05-06-2020, 08:36 PM
#28
RL Community Team
Rennlist Member
Rennlist Member
The little hitch you feel could also be a small burr or imperfection on the splined shaft that the clutch moves on when you push the pedal.
05-06-2020, 11:59 PM
#29
Rennlist Member
Thread Starter
I suppose it's possible. I can only sense it on pedal rebound, however. And I went over the shaft pretty carefully when I had it out. I couldn't feel or see anything like that, nor feel it when sliding the shaft in and out of the clutch assembly. Not saying it's impossible, but this paralleled the issues I was having on-and-off before I lost all pedal pressure as well.
05-21-2020, 12:20 AM
#30
Rennlist Member
Thread Starter
After the "final" bleed and working the pedal a bunch, it seemed to be fine. I drove it a couple times...perfect. Then today, it started getting that hitch where it hesitates before it pops all the way up. Then it started NOT coming all the way up, although it was enough action to use the clutch. I parked it, got my groceries and when I came back out it was fine.
So this makes me nervous. Either the system is fine, but I just have a few air bubbles left in there, or something (presumably the master cylinder/reservoir/blue hose/clutch line part of the system, as I've replaced the slave cylinder) is occasionally letting air in. Does that make sense? What is the most likely culprit here? Master cylinder? Is there a good way to prove it that doesn't involve disassembling the entire car?
I'm still a little bothered that I kept getting fluid leaking from the reservoir lid when using my power bleeder. Yes, it has the gasket/seal thing in the bleeder cap, yes it was threaded on properly and tightly, etc. In fact, I then used it to bleed the clutch on my 931 and it worked perfectly with zero leaks.But even if there is a problem with the reservoir lid,that really shouldn't have any impact on whether air gets into the system or not, should it? As long as the fluid doesn't drop below a certain point, it shouldn't matter, and I don't see leaks from normal operation. Also, the brakes seem fine.
So this makes me nervous. Either the system is fine, but I just have a few air bubbles left in there, or something (presumably the master cylinder/reservoir/blue hose/clutch line part of the system, as I've replaced the slave cylinder) is occasionally letting air in. Does that make sense? What is the most likely culprit here? Master cylinder? Is there a good way to prove it that doesn't involve disassembling the entire car?
I'm still a little bothered that I kept getting fluid leaking from the reservoir lid when using my power bleeder. Yes, it has the gasket/seal thing in the bleeder cap, yes it was threaded on properly and tightly, etc. In fact, I then used it to bleed the clutch on my 931 and it worked perfectly with zero leaks.But even if there is a problem with the reservoir lid,that really shouldn't have any impact on whether air gets into the system or not, should it? As long as the fluid doesn't drop below a certain point, it shouldn't matter, and I don't see leaks from normal operation. Also, the brakes seem fine.