Bad master or slave or....?
10-25-2015, 10:39 PM
#1
Bad master or slave or....? alright guys trying to figure out an issue im having with my ls1 t56 rx7 im swapping. ive done several swaps but never had an issue like this. i cant get the clutch to disengage when pedal is pressed. i originally had a weird clutch setup so i thought that was it, pulled trans and swapped to a brand new ls7 clutch kit. but still having the same issue.
parts im using:
new ls7 flywheel
new ls7 clutch disc
new ls7 pressure plate
new 7/8 wilwood modified adjustable master
new stock slave/ TOB
new pilot bushing
freshly rebuilt trans with 0 miles
i have bled the system several times by bleeding the master, bleeding the slave, vacuum bleeding with a mityvac and all that stuff. when i had the trans off i measured to see if it might need a shim but the measurements were dead on. (used Ticks method to measure). my buddy suggested to put the car on the ground to see if that would do anything so i did. with it on the ground and clutch pedal pressed i cant push it into gear. the car starts to lurch as its goin in. ive tried adjusted the rod on the master but no difference. pedal feels like it should but not disengaging. i even got a mirror and flashlight and looked into the hole where the slave bleeder is, then had my bro slowly press the pedal and it seems to be moving fine and a complete travel. well at least from what i can tell.
i found this on another forum and thought i might try it:
In order to figure out what is going on, do the following test. You will need two people for this. Jack up the car and get under it. All this is to be done with the engine off, obviously. Put the transmission in 4th gear and then grab hold of the driveshaft and put rotating force on it. As you do that, have your helper start to press down on the clutch pedal. At some point you will be able to start turning the driveshaft by hand. Note the position of the pedal when that happens. If the pedal is all the way down then the bearing is not releasing the clutch fully. If, however, the pedal is only half way down, then you can have the helper press the pedal more and you will feel the driveshaft is getting hard to turn again, or you might not be able to at all. This indicates that the bearing is over extending and the clutch is engaging again. This obviously cases shifting problems and it's also not good for the thrust bearing.
ive been reading all sorts of posts and stuff but either they never say what they did to fix it or they just replaced everything. i dont wanna start throwing parts at it nor do i wanna keep pulling it in & out of the car to test different things.
any help is greatly appreciated. and if this should be in the "conversions" area please move it.
parts im using:
new ls7 flywheel
new ls7 clutch disc
new ls7 pressure plate
new 7/8 wilwood modified adjustable master
new stock slave/ TOB
new pilot bushing
freshly rebuilt trans with 0 miles
i have bled the system several times by bleeding the master, bleeding the slave, vacuum bleeding with a mityvac and all that stuff. when i had the trans off i measured to see if it might need a shim but the measurements were dead on. (used Ticks method to measure). my buddy suggested to put the car on the ground to see if that would do anything so i did. with it on the ground and clutch pedal pressed i cant push it into gear. the car starts to lurch as its goin in. ive tried adjusted the rod on the master but no difference. pedal feels like it should but not disengaging. i even got a mirror and flashlight and looked into the hole where the slave bleeder is, then had my bro slowly press the pedal and it seems to be moving fine and a complete travel. well at least from what i can tell.
i found this on another forum and thought i might try it:
In order to figure out what is going on, do the following test. You will need two people for this. Jack up the car and get under it. All this is to be done with the engine off, obviously. Put the transmission in 4th gear and then grab hold of the driveshaft and put rotating force on it. As you do that, have your helper start to press down on the clutch pedal. At some point you will be able to start turning the driveshaft by hand. Note the position of the pedal when that happens. If the pedal is all the way down then the bearing is not releasing the clutch fully. If, however, the pedal is only half way down, then you can have the helper press the pedal more and you will feel the driveshaft is getting hard to turn again, or you might not be able to at all. This indicates that the bearing is over extending and the clutch is engaging again. This obviously cases shifting problems and it's also not good for the thrust bearing.
ive been reading all sorts of posts and stuff but either they never say what they did to fix it or they just replaced everything. i dont wanna start throwing parts at it nor do i wanna keep pulling it in & out of the car to test different things.
any help is greatly appreciated. and if this should be in the "conversions" area please move it.
Last edited by Swapper; 10-25-2015 at 11:25 PM.
10-26-2015, 12:25 AM
#2
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How long have you gone on the adjustable master?
10-26-2015, 09:02 AM
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So, if you have a turnbuckle on your master cylinder, crank it to raise the clutch pedal. Do it a turn at a time until you can shift easily into all gears with the engine off. Then, start the motor and adjust it a half turn at a time until it shifts easily. Then road test. It might need another half turn or full turn. Then, tighten the lock nuts.
10-26-2015, 12:45 PM
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So you've been adjusting it out and still can't get it to disengage no matter how high you adjust the pedal?
The last guy that happened to was "Midnight02". His pedal ended up really high and still wouldn't disengage properly, and it turned out the friction disc was bad. There was another similar thread a while back, and the friction disc was in backwards. And there was a third thread that the flywheel bolts were sticking out too far and not letting the disc move.
Sort of grabbing at straws, but with a 7/8" master, you should be able to adjust it out enough to disengage unless something is wrong underneath - or unless there is a ton of air still in there, but you described quite a lot of bleeding already.
The last guy that happened to was "Midnight02". His pedal ended up really high and still wouldn't disengage properly, and it turned out the friction disc was bad. There was another similar thread a while back, and the friction disc was in backwards. And there was a third thread that the flywheel bolts were sticking out too far and not letting the disc move.
Sort of grabbing at straws, but with a 7/8" master, you should be able to adjust it out enough to disengage unless something is wrong underneath - or unless there is a ton of air still in there, but you described quite a lot of bleeding already.
10-26-2015, 01:24 PM
#7
I had this same problem after i did my swap and switching to a TICK adjustable master was what fixed it for me. It was the third master i tried after bleeding the others for hours thinking i just wasn't getting the air out, and as soon as it was on it all worked.
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10-26-2015, 08:15 PM
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A typical adjustable master has a turnbuckle on it to raise or lower the pedal. Lots of people seem to think it's there so you can pick where your clutch shifts. What it is actually for is to set your pedal height so that you get enough travel to disengage the clutch without blowing out the slave seal.
So, if you have a turnbuckle on your master cylinder, crank it to raise the clutch pedal. Do it a turn at a time until you can shift easily into all gears with the engine off. Then, start the motor and adjust it a half turn at a time until it shifts easily. Then road test. It might need another half turn or full turn. Then, tighten the lock nuts.
So, if you have a turnbuckle on your master cylinder, crank it to raise the clutch pedal. Do it a turn at a time until you can shift easily into all gears with the engine off. Then, start the motor and adjust it a half turn at a time until it shifts easily. Then road test. It might need another half turn or full turn. Then, tighten the lock nuts.
10-26-2015, 08:54 PM
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You are correct except for the bolded part. Tick's instructions state that you want the car to be able to go into 1st with the engine off without forcing it into gear. Doesn't necessarily need to go into every gear smoothly with the engine off. I thought this the first time around and could never get it to go into every gear with the motor turned off and i kept adjusting the rod length all the way out until it was even with the brake pedal, which was way further out than it needed to be.
10-31-2015, 06:04 PM
#12
read somewhere that someone had the same issue so they shortened the modified rod about half an inch to allow more adjustment. so i shortened mine and re-installed it. bled the system several times, tried adjusting the rod in different positions and still clutch wont disengage. again i can look into the hole where the slave bleeder is and can see the slave moving the pressure plate. i ordered up a new master but it hasnt come yet.
think it could be a bad slave? maybe not pressing clutch in hard enough?
think it could be a bad slave? maybe not pressing clutch in hard enough?
11-01-2015, 08:24 PM
#13
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read somewhere that someone had the same issue so they shortened the modified rod about half an inch to allow more adjustment. so i shortened mine and re-installed it. bled the system several times, tried adjusting the rod in different positions and still clutch wont disengage. again i can look into the hole where the slave bleeder is and can see the slave moving the pressure plate. i ordered up a new master but it hasnt come yet.
think it could be a bad slave? maybe not pressing clutch in hard enough?
think it could be a bad slave? maybe not pressing clutch in hard enough?
I have built 2 FCs in the past and never had any issues. I used a 3/4" bore MC. With the 7/8" bore you may be over-traveling the clutch spring. If you do that, the clutch can start to engage again giving a false "clutch not disengaging" symptom, hence the need to do the test that I outlined.
Andrew
11-03-2015, 06:23 PM
#14
On The Tree
I have a ls1 swapped FC rx7 also...t56 also, 7/8 wildwood, also...LOL
I would bet that the rod on the master needs to be adjusted longer. I've never had a proble with over travel of slave with it, but you never know.
I would bet that the rod on the master needs to be adjusted longer. I've never had a proble with over travel of slave with it, but you never know.
11-03-2015, 06:25 PM
#15
On The Tree
Did you do the test that you outlined in the first post? I wrote that...
I have built 2 FCs in the past and never had any issues. I used a 3/4" bore MC. With the 7/8" bore you may be over-traveling the clutch spring. If you do that, the clutch can start to engage again giving a false "clutch not disengaging" symptom, hence the need to do the test that I outlined.
Andrew
I have built 2 FCs in the past and never had any issues. I used a 3/4" bore MC. With the 7/8" bore you may be over-traveling the clutch spring. If you do that, the clutch can start to engage again giving a false "clutch not disengaging" symptom, hence the need to do the test that I outlined.
Andrew
11-04-2015, 05:24 AM
#16
You are correct except for the bolded part. Tick's instructions state that you want the car to be able to go into 1st with the engine off without forcing it into gear. Doesn't necessarily need to go into every gear smoothly with the engine off. I thought this the first time around and could never get it to go into every gear with the motor turned off and i kept adjusting the rod length all the way out until it was even with the brake pedal, which was way further out than it needed to be.
Putting it in gear with the car off will usually go in 1st even if the clutch doesnt fully disengage because the motor isn't spinning the clutch at all so it can still slip a little on the flywheel and allow the trans internals to align.
11-05-2015, 09:45 AM
#17
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I'm sor5ry but that's wrong. I'm just corrrecting this in case someone else sees it. I've installed a few ticks and know those directions backwards and forwards. They state to install the master, get a base adjustment the START the car and attempt to put it in gear.
Putting it in gear with the car off will usually go in 1st even if the clutch doesnt fully disengage because the motor isn't spinning the clutch at all so it can still slip a little on the flywheel and allow the trans internals to align.
Putting it in gear with the car off will usually go in 1st even if the clutch doesnt fully disengage because the motor isn't spinning the clutch at all so it can still slip a little on the flywheel and allow the trans internals to align.
11-05-2015, 09:32 PM
#18
Guys, you should test for clutch disengagement with the engine running.... If the engine isn't running the transmission might slip into a gear or two without even using the clutch just because nothing is turning and that particular gear is lined up with the syncro/slider. It won't necessarily go into every gear smoothly when the engine isn't running even if the clutch is disengaged because things aren't spinning freely to line themselves up. This is why it might be hard to get a certain gear to go in if the engine is off.....but if you do get it in then it will slip in very easily over and and over if you pull the shifter back out, until you engage another gear that might move the internals a bit.
A 7/8 bore master isn't going to over extend an LS7 pressure plate most likely either. The LS7 pressure plate was designed to be used in cars which came with a 3/4 bore cylinder.....but that cylinder also had 1.5" of stroke. So technically, the 7/8 bore and 1.1" stroke Tilton or Wilwood cylinder doesn't offer a huge difference from the oem master that came in a c6 vette. If you adjust the aftermarket master to achieve full 1.1" stroke it won't hurt the pressure plate, but it might hurt the slave if shimming wasn't properly measured for.
If the pedal feels normal and you have room to raise the pedal higher by adjusting the rod that is what I would try. You should measure how much the rod is moving the piston inside of the master..... This don't have to be real precise but full throw is 1.1" as mentioned. If your rod is attached too high on the pedal the ratio won't be right and even though the pedal itself is moving a whole lot, the piston in the master may not be moving that much, or enough.
A bent/warped clutch disk can cause disengagement issues as well as a faulty pressure plate. If the pilot bearing is trying to 'seize' up on the tip of the input you can have a disengagement issue as well.
A 7/8 bore master isn't going to over extend an LS7 pressure plate most likely either. The LS7 pressure plate was designed to be used in cars which came with a 3/4 bore cylinder.....but that cylinder also had 1.5" of stroke. So technically, the 7/8 bore and 1.1" stroke Tilton or Wilwood cylinder doesn't offer a huge difference from the oem master that came in a c6 vette. If you adjust the aftermarket master to achieve full 1.1" stroke it won't hurt the pressure plate, but it might hurt the slave if shimming wasn't properly measured for.
If the pedal feels normal and you have room to raise the pedal higher by adjusting the rod that is what I would try. You should measure how much the rod is moving the piston inside of the master..... This don't have to be real precise but full throw is 1.1" as mentioned. If your rod is attached too high on the pedal the ratio won't be right and even though the pedal itself is moving a whole lot, the piston in the master may not be moving that much, or enough.
A bent/warped clutch disk can cause disengagement issues as well as a faulty pressure plate. If the pilot bearing is trying to 'seize' up on the tip of the input you can have a disengagement issue as well.
11-05-2015, 10:46 PM
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Guess I was wrong. Thanks for the information! You guys might want to update your instructions and make it clear that the car should be running when you try to engage first gear for the future.
11-09-2015, 12:32 AM
#20
havent messed with it in the past couple days. was pissing me off to the point i was about to part evertything out. decided to step away and focus on other parts of the car.
although i did try that test and didnt get any free play spot. i tried doing small increments of adjusting the rod in/out and nothing. tried slowly pressing in the clutch while doing those adjsutments each time but nothing.
i did buy a new master but havent put it in yet. i might buy a new slave too caus ei ended up buying a remote bleeder to install.
i doubt the clutch disc is warped. its brand new and looked flat from what i can tell.
although i did try that test and didnt get any free play spot. i tried doing small increments of adjusting the rod in/out and nothing. tried slowly pressing in the clutch while doing those adjsutments each time but nothing.
i did buy a new master but havent put it in yet. i might buy a new slave too caus ei ended up buying a remote bleeder to install.
i doubt the clutch disc is warped. its brand new and looked flat from what i can tell.
