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Clutch works... but only on the floor

866 Views 25 Replies 8 Participants Last post by  WalksInThunder
Hi all first post here. I'm the dad of a teen who just bought himself a high mileage (177k) 2005 GT 5-speed. Yes, I'm envious. I drove a 4-door Pontiac Sunfire in high school haha.

We're just now getting familiar with the car and trying to get it safe and road worthy. Aside from tires, brakes, tie rod ends, ball joints, and a few leaks, the main problem (IMO) is the clutch.

As the title says, it must be pressed all the way to the floor to change gears (any gear), and it feels like I'm leaning pretty hard on the synchros even then. The seller said it was normal/fine (of course), but I've been driving standards all my life and it does not feel normal to me.

My first surprise was learning that the slave cylinder is around the input shaft. I've worked on a lot of cars and have never seen that design before! Shame, because I assumed it would be a matter of swapping an external component, perhaps even one with a bleeder screw!

I've also observed the clutch through the little peep hole on the bottom of the bellhousing while my son pushed the pedal. To my surprise, I can actually see the throwout bearing moving the diaphragm springs even at the very beginning of a clutch push (it's already in contact even with no pedal pressure) and all the way until the pedal bottoms out. My "laser calibrated" eye says it's moving about 1/2" to 5/8" along the input shaft, which according to other posts I've read, seems to be normal/enough?

Of course I've looked around and it seems the slave cylinder is a common issue, but it appears to me this one is doing its job? I'd expect if there was air in the system I wouldn't see movement from the beginning. Also, I'd expect a leak, of which I don't see evidence.

So, I turn to you all for help...

Should we:

A) Stop crying and move the seat forward - this is just how Mustang 5-speeds are
B) Perform more tests and report back? If so, what tests are recommended?
C) Try the "tilt the car 8 inches and bleed" routine?
D) Suck it up and buy the vacuum bleeder and do it right according to the service manual?
E) Shim the slave cylinder?
F) Replace the slave cylinder?
G) Replace the diaphragm/pressure plate?
H) Replace it all?
I) Something else I haven't thought of because we're noobs?

Any opinions or experiences with this issue are much appreciated!
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It does indeed sound like you have an issue with the clutch hydraulic system. The first thing I suggest you do is try to bleed the clutch. If that doesn't help, it's quite likely the last person who replaced the clutch didn't shim the slave cylinder.
100% Agree on this. And a strong chance it will over-extend the hydraulic TOB and ruin it, if not corrected quickly. In fact, I’d replace it anyway at this point if pulling the trans.
it's quite likely the last person who replaced the clutch didn't shim the slave cylinder.
Thanks for the reply! For bleeding do you suggest the "lean the car over" method? Or the vacuum method?
Regarding shimming, can you point me to a resource on how to approach it? Or is it just trial and error? I can't seem to find any "official" Ford shims - it seems like people just find washers etc and stick them in?

It does indeed sound like you have an issue with the clutch hydraulic system. The first thing I suggest you do is try to bleed the clutch. If that doesn't help, it's quite likely the last person who replaced the clutch didn't shim the slave cylinder.
100% Agree on this. And a strong chance it will over-extend the hydraulic TOB and ruin it, if not corrected quickly. In fact, I’d replace it anyway at this point if pulling the trans.
We basically have zero history on this car... so I have no idea when the clutch was last touched. The seller's friend is a dealer who bought it at auction and sold it to him 6 months ago, and the seller barely drove it since it needed work. I think when the P0345 code popped up and he decided it was cam phasers (I have doubts), he just got overwhelmed and wanted his money back.
Given that, I'd assume if the slave was going to be overextended it's already happened. If that's the case, are there symptoms to look for? It's not leaking at all.
I'd really love to know whether there's a specification somewhere on how to choose shims or how set up the clutch, or if it's all just unofficial at this point?
I can't help you with your clutch issue however that P0345 code that you mentioned is a possible significant concern on your 3V engine. The 3V is known for several design deficiencies with the VCT variable camshaft timing system. Your engine is right about at the mileage where factory timing parts usually tend to give up and if they haven't been replaced before with the reengineered and upgraded Ford/Motorcraft brand parts then you should immediately take action before engine damage occurs. Being that you have a cam circuit code is a red flag that your timing parts might be original.
The chain tensioners, plastic chain guides, and cam phasers are all problematic. The factory oil pump is also not really quite up to the task. The original tensioners are the major problem that leads to oil starvation and/or timing chain failure. Another problem is the cam followers(rockers). They've also been redesigned but the originals can lead to significant cam and/or head damage on higher mileage engines.
Ford 5.4L 3v Engine Noises You Shouldn’t Ignore: How To Tell When a Timing Job is Really Needed - YouTube
If you're lucky then you might just have a driver side sensor or wiring/connector issue. It could also be the crank sensor or wiring since the crank circuit is connected into the cam circuits.
the seller barely drove it since it needed work. I think when the P0345 code popped up and he decided it was cam phasers (I have doubts), he just got overwhelmed and wanted his money back.
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The only thing you're going to find is that the clutch friction plate will wear out rapidly. You'll also wear out the synchros and gear teeth from grinding the gears because the clutch friction plate isn't completely disengaging from the flywheel. Shimming the slave cylinder will fix it.
As for the P0345 cam position code, I'm willing to bet that at 177k miles, the timing chains are stretched and the tensioners are failing. Replacing the camshaft drive kit alone is only a bandaid solution because you'll also need good oil pressure to prevent a recurrence. A new HV oil pump might get the job done but I suggest you also pull the oil pan and inspect the rod bearings 'cause if they're worn, the oil pressure will still be low at hot idle. These engines need at least 25psi to maintain adequate pressure feeding of the timing chain tensioners and cam phasers.
As @Cobrajet67 suggested, you should also replace the cam followers/lash adjusters with the updated versions, and I'd strongly recommend you replace the valve stem oil seals.
All of the above components, apart from the rod bearings, should be replaced by 150k miles or sooner if the engine shows symptoms of wear. All things considered, that's damn good and it shows just how durable these engines are when well maintained and not abused.
Given that, I'd assume if the slave was going to be overextended it's already happened. If that's the case, are there symptoms to look for?
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Understood - is there any procedure you know of (even "unofficial" is fine) that will help? I've found this shim diagram on another forum that shows how to fabricate a 3/8 inch spacer, and others have seemed to have good luck with it. Do you agree this more or less the way to go? I don't get a strong feeling there is any definitive way to know ahead of time what will work... it's more of a "try it and see if it helps" kind of thing? I'm perfectly okay doing that, but I'd love a specific thing or things to measure if known so we don't have to practice removing the transmission any more than necessary haha :)

Shimming the slave cylinder will fix it.
As for the P0345 cam position code, I'm willing to bet that at 177k miles, the timing chains are stretched and the tensioners are failing. Replacing the camshaft drive kit alone is only a bandaid solution because you'll also need good oil pressure to prevent a recurrence. A new HV oil pump might get the job done but I suggest you also pull the oil pan and inspect the rod bearings 'cause if they're worn, the oil pressure will still be low at hot idle. These engines need at least 25psi to maintain adequate pressure feeding of the timing chain tensioners and cam phasers.
As @Cobrajet67 suggested, you should also replace the cam followers/lash adjusters with the updated versions, and I'd strongly recommend you replace the valve stem oil seals.
All of the above components, apart from the rod bearings, should be replaced by 150k miles or sooner if the engine shows symptoms of wear. All things considered, that's damn good and it shows just how durable these engines are when well maintained and not abused.
Perhaps this is worthy of another post or side discussion, but I think it will come down to the philosophy my son wants to follow. I agree that at 177k, every single wearing part on the car could probably benefit from replacement. But this is a teenager with a limited budget driving a $3,000 car that is NOT show quality - not even close. I've already twisted his arm to spend $500 on new tires and another $500 on a huge order from rockauto (control arms, tie rod ends, brakes, etc), which we'll be installing over the coming weeks. I would be thrilled to completely tear the thing apart and make it like new, but he (very understandably) wants to DRIVE it haha. The cam phaser issue is intermittent, and I'm (currently) of the opinion that it's a failing VVT solenoid. We actually haven't even been able to reproduce it - we only know about it from the seller. Further, my hunch is that as soon as we get it driving we're going to find other problems... I'm guessing the differential clutch packs may need replaced, so there will be plenty to keep us busy :)
All that said, I really appreciate your point about the oil pressure. It's generally a great way to keep tabs on the overall health of the engine. I (wrongly, as it turns out) assumed the gauge on the dash would help him monitor it, but alas, from my limited research it seems it's a "dummy gauge" that only shows 6psi or 'not 6psi' - is that correct? If so, I'm wondering if, at an absolute minimum, it would make good sense to install a sending unit with a 20psi or 25pis cutoff? That way, at least we'll know when it's time for a rebuild. Is a higher-limit sending unit something people do?

PS - Completely unrelated to this post, but I thought I'd share something you might find interesting relating to oil pressure.... My son ALSO has a 2006 V6 auto mustang he's been driving since he was 16. I bought it from auction with 185k on it, and it had LOADS of problems, not the least of which was very rattle-y and noisy timing chains on startup. It makes a terrible racket for about 3-5 seconds then becomes perfectly quiet. As I'm sure you well know, the problem is with the springs failing in the hydraulic chain tensioners. As I'm sure you also know, it's a nightmare to replace the timing on the 4.0. So, again for limited budget reasons, we decided to see if there were any alternatives to yanking the engine out. One suggestion online was to install a Motorcraft oil filter with a flapper which will reduce the amount of "back draining" of oil. This DEFINITELY helped with hot/warm starts. But if the car sits for more than a couple hours, it still gets the rattle. So, the other thing we learned was that when doing a cold start, you can mash the gas pedal all the way to the floor and the engine will just crank without starting, building oil pressure. If you do that, you can crank until the oil pressure light goes out (just a few seconds) and then release the gas pedal... and voila! No chain rattle! He's been driving it this way for 2 1/2 years now and put on about 25,000 miles with no other signs of trouble. Yes, yes, it's a completely ******* solution, but it works :) I honestly never expected that car to last more than a year without massive problems.
You will have to gravity bleed the clutch, can't pump it like old days type.
As I explained above, if it has the original timing parts in it then they will fail very soon. Low oil pressure is what destroys these 3V engines.
The cam phaser issue is intermittent, and I'm (currently) of the opinion that it's a failing VVT solenoid. We actually haven't even been able to reproduce it - we only know about it from the seller.
I (wrongly, as it turns out) assumed the gauge on the dash would help him monitor it, but alas, from my limited research it seems it's a "dummy gauge" that only shows 6psi or 'not 6psi' - is that correct? If so, I'm wondering if, at an absolute minimum, it would make good sense to install a sending unit with a 20psi or 25pis cutoff? That way, at least we'll know when it's time for a rebuild. Is a higher-limit sending unit something people do?
I believe that the oil gauge signal goes thru the PCM. If so, that's not going to be possible with the factory gauge.
My son ALSO has a 2006 V6 auto mustang he's been driving since he was 16. I bought it from auction with 185k on it, and it had LOADS of problems, not the least of which was very rattle-y and noisy timing chains on startup. It makes a terrible racket for about 3-5 seconds then becomes perfectly quiet. As I'm sure you well know, the problem is with the springs failing in the hydraulic chain tensioners. As I'm sure you also know, it's a nightmare to replace the timing on the 4.0. So, again for limited budget reasons, we decided to see if there were any alternatives to yanking the engine out. One suggestion online was to install a Motorcraft oil filter with a flapper which will reduce the amount of "back draining" of oil. This DEFINITELY helped with hot/warm starts. But if the car sits for more than a couple hours, it still gets the rattle. So, the other thing we learned was that when doing a cold start, you can mash the gas pedal all the way to the floor and the engine will just crank without starting, building oil pressure. If you do that, you can crank until the oil pressure light goes out (just a few seconds) and then release the gas pedal... and voila! No chain rattle! He's been driving it this way for 2 1/2 years now and put on about 25,000 miles with no other signs of trouble. Yes, yes, it's a completely *** solution, but it works :) I honestly never expected that car to last more than a year without massive problems.
If you already have chain rattle then the chains have already started eating away at the guides. You could just do the front chain cassettes and see if that stops the rattle. If not, then the on the 4.0 v6 that means the rear chain is the problem and requires engine removal to get at it. That's where it becomes expensive or laborious.
Sometimes pumping the clutch removes will entrapped air in the slave cylinder. Not all the time by itself. The most efficient method is buy a hand vaccuum pump at harbor freight with adapters and put a vacuum on the system for about a minute and then pump the clutch a dozen or more times after releasing the vacuum. And repeat one or two more times.

Why this hyd clutch system rarely gets air in it is an oddity to me especially if there has not been any work performed that cavetated the fluid reservoir or clutch replacement.
You will have to gravity bleed the clutch, can't pump it like old days type.
Of course, you should check that the cylinder is properly bled, but the fingers in the pressure plates in certain brands of replacement clutch kits are not as tall. This shortens the total throw of the cylinder because part of the throw is already used up to get to the fingers. From the factory there is no shim plate behind the hydraulic cylinder, but it is required for several of the aftermarket clutches. There are sources to buy the shim plates. RAM Clutches makes shims for this and I am sure there are others. A shim plate would not be hard to fabricate...

Unfortunately, by finding it this way there is no way to tell how long this has been going on. The synchros have been strained and will have at least some damage/shortened life. The transmission does have to come out to install the shim.
Pumping the clutch pedal does Not work on these systems to remove air, it has to be gravity fed or a vacuum system.
Sometimes pumping the clutch removes will entrapped air in the slave cylinder. Not all the time by itself. The most efficient method is buy a hand vaccuum pump at harbor freight with adapters and put a vacuum on the system for about a minute and then pump the clutch a dozen or more times after releasing the vacuum. And repeat one or two more times.

Why this hyd clutch system rarely gets air in it is an oddity to me especially if there has not been any work performed that cavetated the fluid reservoir or clutch replacement.
You're communicating with someone who did bleed a hyd slave cylinder after installing an Exedy clutch kit in my 06. I primed the slave cylinder before installing it best I could but it still had air entrapped in the system and removed it by painstakingly pumping the clutch. It is neither fast or as effective as a vacuum.

I'm not disputing gravity bleed or vacuum bleeding as the best methods. I make that clear in my post. But I am disputing the claim it can not be bleed pumping the clutch. It is just very painstaking and does not always work as I mentioned. Hence the recommendation to use a vacuum method in my post. Or as you added gravity bleeding,
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Thank you, yes this seems to be the consensus. I'm headed to harbor freight in a few hours for a MityVac and then to Lowe's for a 1 3/8 drain stopper. Fingers crossed that does it and we don't have to pull the trans! :)

Sometimes pumping the clutch removes will entrapped air in the slave cylinder. Not all the time by itself. The most efficient method is buy a hand vaccuum pump at harbor freight with adapters and put a vacuum on the system for about a minute and then pump the clutch a dozen or more times after releasing the vacuum. And repeat one or two more times.

Why this hyd clutch system rarely gets air in it is an oddity to me especially if there has not been any work performed that cavetated the fluid reservoir or clutch replacement.
Of course, you should check that the cylinder is properly bled, but the fingers in the pressure plates in certain brands of replacement clutch kits are not as tall. This shortens the total throw of the cylinder because part of the throw is already used up to get to the fingers. From the factory there is no shim plate behind the hydraulic cylinder, but it is required for several of the aftermarket clutches. There are sources to buy the shim plates. RAM Clutches makes shims for this and I am sure there are others. A shim plate would not be hard to fabricate...

Unfortunately, by finding it this way there is no way to tell how long this has been going on. The synchros have been strained and will have at least some damage/shortened life. The transmission does have to come out to install the shim.
This all makes perfect sense, thank you! And yes, I agree with everything, which is why I have 'forbidden' my son to drive it as-is (not really, but strongly discouraged). We're going to try the vacuum bleed today and hope for the best, but if that doesn't work I guess it's time for a shim at the absolute minimum - we may end up replacing the clutch altogether.

One problem I have is I STILL don't understand how we're supposed to know what's right... I've seen on another forum that 24mm of "preload" on the slave is what we should be shooting for, but that's just me parsing random comments as best I can. As far as you know, is there a specific guide (even "unofficial") for measuring and setting up a clutch and knowing whether and how much to shim? Or is it literally 'put it all together and try it, and if it doesn't feel right, take it apart and try again'?

Regardless, I'll report the results we get here :)

I believe that the oil gauge signal goes thru the PCM. If so, that's not going to be possible with the factory gauge.
Again, probably "different post worthy", but my impression was that the oil pressure sender is a simple on/off switch that closes at 6psi. The PCM may well control the gauge and the light, but if it's a simple pressure switch, wouldn't swapping it for a higher pressure switch serve our purpose? I may very well pull the sending unit and test it on a rig to confirm/deny this, and then maybe even experiment with a different sending unit to see if we can get something more useful than 6psi. If I do it, I'll post the results in another thread!

(Note: I already sort of started researching this, and the tough part for me is, assuming I understand how these work, figuring out the pressure at which the sending units close... If we look at this list of Motorcraft pressure switches on rockauto, we can see there are many choices, but none describe how they actually work. I'm not willing to spend hundreds on testing, but perhaps a trip to the junkyard could yield some interesting results)
The OEM oil pressure switch simply tells you if you have oil pressure or not, and is wired up to a dummy gauge. If you want a real oil pressure gauge, you'll need to install an Autometer version with its own sending unit. If you want to keep both, you'll need to screw a T fitting (1/4" NPT I think) into the oil filter adapter where the OEM pressure switch currently sits.
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Had the same problem recently. I replaced the whole clutch with a kit. If you're gonna change the throw-out bearing you might as well replace the whole thing. We had approx. 100,000 miles on the clutch and the clutch wouldn't release even when jammed to the floor. Well worth it as I can now shift with ease. I used an Exidy kit but you can choose whatever's in your budget.
Hi all first post here. I'm the dad of a teen who just bought himself a high mileage (177k) 2005 GT 5-speed. Yes, I'm envious. I drove a 4-door Pontiac Sunfire in high school haha.

We're just now getting familiar with the car and trying to get it safe and road worthy. Aside from tires, brakes, tie rod ends, ball joints, and a few leaks, the main problem (IMO) is the clutch.

As the title says, it must be pressed all the way to the floor to change gears (any gear), and it feels like I'm leaning pretty hard on the synchros even then. The seller said it was normal/fine (of course), but I've been driving standards all my life and it does not feel normal to me.

My first surprise was learning that the slave cylinder is around the input shaft. I've worked on a lot of cars and have never seen that design before! Shame, because I assumed it would be a matter of swapping an external component, perhaps even one with a bleeder screw!

I've also observed the clutch through the little peep hole on the bottom of the bellhousing while my son pushed the pedal. To my surprise, I can actually see the throwout bearing moving the diaphragm springs even at the very beginning of a clutch push (it's already in contact even with no pedal pressure) and all the way until the pedal bottoms out. My "laser calibrated" eye says it's moving about 1/2" to 5/8" along the input shaft, which according to other posts I've read, seems to be normal/enough?

Of course I've looked around and it seems the slave cylinder is a common issue, but it appears to me this one is doing its job? I'd expect if there was air in the system I wouldn't see movement from the beginning. Also, I'd expect a leak, of which I don't see evidence.

So, I turn to you all for help...

Should we:

A) Stop crying and move the seat forward - this is just how Mustang 5-speeds are
B) Perform more tests and report back? If so, what tests are recommended?
C) Try the "tilt the car 8 inches and bleed" routine?
D) Suck it up and buy the vacuum bleeder and do it right according to the service manual?
E) Shim the slave cylinder?
F) Replace the slave cylinder?
G) Replace the diaphragm/pressure plate?
H) Replace it all?
I) Something else I haven't thought of because we're noobs?

Any opinions or experiences with this issue are much appreciated!
Why are you trying to change the setting at which the oil light comes on at/gauge drops off to 0? It's just there to let you know that you have a dangerous lack of pressure.
A real gauge is what you should add if you want to monitor the pressure for the overall timing system and passenger side head health(this head gets oil very last from the rest of the engine).
There are A-pillar gauge pods, triple dash gauge pods if you don't mind drilling into your dash, and single vent gauge pods(may not be available for the 2005-09 models).
Again, probably "different post worthy", but my impression was that the oil pressure sender is a simple on/off switch that closes at 6psi. The PCM may well control the gauge and the light, but if it's a simple pressure switch, wouldn't swapping it for a higher pressure switch serve our purpose? I may very well pull the sending unit and test it on a rig to confirm/deny this, and then maybe even experiment with a different sending unit to see if we can get something more useful than 6psi. If I do it, I'll post the results in another thread!

(Note: I already sort of started researching this, and the tough part for me is, assuming I understand how these work, figuring out the pressure at which the sending units close... If we look at this list of Motorcraft pressure switches on rockauto, we can see there are many choices, but none describe how they actually work. I'm not willing to spend hundreds on testing, but perhaps a trip to the junkyard could yield some interesting results)
Since you don't mention shimming, I'm guessing you didn't need one, even with the Exedy kit. That by itself is good information to have - so thank you!

At this point I'm beginning to wonder if the whole slave cylinder shimming thing is a red herring... it comes up a lot, but every time I ask specific questions about it, like how to know whether it's needed and how to know how much to shim, it's crickets haha. And thinking about it more, I'd be surprised if any company made and sold aftermarket clutch parts that would need to be shimmed, without including shims and instructions for using them.

A bit more info/updates for any future readers of this thread: Before researching bleeding the clutch, I was eager to get my eyes on the actual clutch master cylinder reservoir to see if it was maybe just low, and I admit I felt pretty stupid when I wasn't able to find it. On most cars, it's right next to the brake reservoir, directly in front of the clutch pedal, but apparently on the S197 it's somewhere else...? I crawled under the car, looked under the dash next to the pedal, but I was stumped... It was only after reading up on it that I learned the reservoir (and fluid) is SHARED with the brakes. Interesting!

This discovery led me to tell my son we should do the brakes before we even look at the clutch. Here's why: As mentioned in the initial post, part of the process this "new" car is going through is getting new brakes - specifically new pads for the front and new pads and rotors for the rear. While the front rotors are "acceptable", the pads are nearly down to the metal, and the rear rotors are worn almost completely through. Worse, the pad wear indicators had been removed from all the pads. Scary!

So here's my thinking: The mustang has a "Brake" dash warning indicator light that comes on when the brake fluid is low or when the parking brake is on. Therefore, it's conceivable to me that with the brakes so badly worn, the previous owner saw the light come on and dutifully added brake fluid - perhaps several times, considering the extreme wear on the brakes. With the fluid level low, and since the clutch shares the same reservoir, it seems very possible air was introduced into the clutch at some point.

So, if we go adding fluid, bleed the clutch, and THEN change the brakes, we're just going to end up spilling brake fluid everywhere.

Therefore, on Saturday we changed the outer tie rod ends and control arms as planned (the $10 pickle fork from Harbor Freight came in huge for us), and yesterday my son put new pads on just ONE wheel - the front left, and after pressing the caliper pistons back in, he remarked that the reservoir had nearly overflowed! This is sign number one that my theory MAY have some merit.

From here forward, the plan is to finish replacing all of the brakes FIRST, and THEN bleed the clutch using the service manual procedure (we already have the MityVac and the rubber stopper from Lowe's which fits perfectly - it's the Hillman 1 5/8" black neoprene hole plug, which is 1 5/8" at the widest and 1 5/16" at the narrowest).

Currently I'm about 26.3% confident that the clutch is actually fine and just has air in it because of the brake wear, but of course I'll report back here with the results!
Had the same problem recently. I replaced the whole clutch with a kit. If you're gonna change the throw-out bearing you might as well replace the whole thing. We had approx. 100,000 miles on the clutch and the clutch wouldn't release even when jammed to the floor. Well worth it as I can now shift with ease. I used an Exidy kit but you can choose whatever's in your budget.
No, it’s not a red herring …

At this point I'm beginning to wonder if the whole slave cylinder shimming thing is a red herring... it comes up a lot, but every time I ask specific questions about it, like how to know whether it's needed and how to know how much to shim, it's crickets haha. And thinking about it more, I'd be surprised if any company made and sold aftermarket clutch parts that would need to be shimmed, without including shims and instructions for using them.
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