Another Clutch Bleeding Question

[RacerX1166]

Hello All,

Long story short, due to being new with the car (and floor attached pedals) I drove my 89 coupe for two days with the floor mat partially depressing the clutch. Now, I'm getting variable results when depressing the pedal but mostly the pedal doesn't return to where it's supposed to; it stops short but is slack and can be easily pulled the rest of the way.

I realize there are a few possible issues here, ranging from air in the system to a fried master or slave cylinder, to the need for a new clutch. However, being forever optimistic (and not wanting to spend $3k if I don't have to), I'm hoping that I only introduced air into the system. I just procured a pressure bleeder and accessories from our host and will be using it this weekend but have a few questions not covered under previous posts.

I'll preface by saying that my car is under a cover in my rather tight garage so I haven't done any exploratory work.

The Bentley book says nothing about bleeding the master cylinder, just the slave. Should I do both?

If I should bleed both, which one should I do first?

I know the slave is at the transmission but where do I need to be to get at it? Under the car or can it be seen from the engine bay?

I'm pretty mechanically inclined but new to working on my Carrera since I've not had it very long.

Thanks for your guidance.

[KTL]

I can't really envision how your floor mat could slightly depress the clutch. It takes quite a bit of effort to depress!!! How far short does the pedal fall from it's proper restiing position? There is supposed to be a slight amount of freeplay- this is mentioned in your Bentley.

There's no way you "fried" the master or slave. One or the other could possibly need replacement just due to age alone- the slave is sometimes recommended to be replaced when a clutch is done.

I think you should first bleed it and see what the result is. I'm confident in saying it very likely could use new fluid anyway. You can't bleed the master. Only the slave can be bled and that's fine because the slave is downstream of the master, so the master gets bled in the process of doing the bleeding at the slave!

The slave is at the top of the transmission, just forward of where the trans. connects to the engine. You can't miss it because it's the only thing on top of the trans. The only way to see it is under the car. It is a tough reach to get to the bleed nipple on the slave, so I HIGHLY recommend when you bleed it, you unbolt the slave from the trans. and drop it down so you can get at it very easily. I have bled my slave while still connected to the trans and it always was a struggle- because of access and mess. The mess occurs because the nipple lets fluid out of the slave with only a slight turn of the nipple. Turn it too much and you let fluid past the threads, which then drips all over the top of the trans.

I would hope you don't need a new clutch. Although it's not as expensive or hard to do as you think- $3K is way to expensive. You can do it yourself for less than $1K. But let's not think about that yet. How does the clutch feel? Sticky? Soft? Stiff? Is the feel consistent throughout the entire range of motion? Bleed the clutch first and see how it feels. It costs you nothing more than some brake fluid and time. I know from experience that if the clutch hydraulics were not bled properly (pressure or vaccuum bleeding is the only way to reliably flush the system of air & old fluid) by pumping the pedal, you'll have a crappy pedal that doesn't want to return- i've done it myself.

Give bleeding a try and post your results.

[RacerX1166]

First, thanks, Kevin for your thorough explanation. It made things a lot clearer for me.

Bleeding is definitely my first plan of attack since I may have sucked up more brake fluid than I had in the reservoir while driving with the floormat issue. And bleeding is a lot cheaper than throwing a new clutch in right off the bat. But, driving it like that certainly didn't do the clutch any good so I'm prepared for the worst. 65k miles and original clutch so the extra wear may have done it in.

To answer your questions:
There were two floor mats in the car when I purchased it (OEM carpet and a Lloyds). The top mat walked its way forward and pushed on the clutch pedal. I've since removed the OEM piece of carpet from the driver's side to prevent this situation from happening again, as well as remaining constantly vigilant of the situation.

The clutch pedal, when it doesn't return, is probaby 1-1.5 inches off of where it should rest. I'm working from memory so don't hold me to that. Lately, depending on its mood and temperature, it will come back the whole way from time to time.

Feel depends upon when I use it. Last time I drove it, it was soft and dropped to the floor but came back after a few pumps (on start up). Also, last time I drove it, shifting seemed to be a bit on the notchy side, which is why she's in the garage until I can complete the bleeding process.

Keep in mind that I've only driven the car 4 times since it came out of winter hibernation, so my observations are based upon a limited sample size.

I'll get underneath the car this weekend and post the results of the bleeding exercise. Thanks again!

[KTL]

Having to pump it up definitely sounds like air in the system. Just know that regardless of how you operate/ride the clutch pedal, you're not going to overheat the clutch hydraulics (clutch disc or pressure plate can easily be overheated by improper use). Clutch hyd. system is not like brakes where the brakes are exposed to high heat that easily can migrate into the fluid and boil it.

If you reservoir is low, it is not hard to introduce air into the system. The feed line for the clutch is rather high in the reservoir, so it can get in there. But you'd have to draw a good bit of fluid through the supply line to get it to reach the master way down in the pedal assembly.

Keep us posted after you bleed it. If it's something else, we'll figure it out. The clutch system as a whole is quite simple & straightforward once you know all the components' involvement in the process!

[burgermeister]

If you decide to bleed the slave while attached to the tranny, keep in mind the orientation of the cylinder (fore-aft) and the bleeder screw (on the front).

If you jack the back of the car up and take the tire off for easier access, you can (if you go high enough) create an air pocket in the slave that will make it impossible to bleed (the bleeder scre won't be the highest point). If you jack the front up too, the problem will go away. Cost me almost a quart of brake fluid to figure this one out ...

[RacerX1166]

Thanks for the reminder on the orientation. I've seen this mentioned in other threads and have already made a mental note to keep this in mind when doing the job.

At this point, I've only got two jack stands, so I'll have to wait until I get under the car to figure out how to make sure I don't make this mistake. Thinking that I can jack the rear up, install jack stands, then, during the bleeding, jack the front up while making sure I'm not in harm's way should the front decide to return to earth.

[88911coupe]

Had the same thing happen to me and it would slowly get worse. I first replaced the master cylinder since it was, allegedly, easier to get to. No help, so I replaced the slave cylinder which solved the problem. Don't waste time trying to replace the slave cyl. w/out doing a partial engine drop. I wasted HOURS trying to avoid ding a partial drop.
Good Luck

[rnln]

do you see any wet on the bottom of the tranny? Before my slave gone, I see wet on the bottom seam of the tranny. It's the fluid leaked out of the slave inside the bell housing and come out to the bottom.
If you suspect your fluid leak, I would suggest you to check the slave. It is on top of the tranny. You can access to it on the left side from underneath, very tough. There are 2 bolts holding it to the tranny case. Pulling it out, on your hands, you can see if it's leaking. If so, you need to replace the slave and bleed fluid.

[KTL]

I would disagree with the slave requiring a partial engine drop (and I have long arms and big hands...... ). If you move some things like heater hose, heater cable and throttle rod, you can get at it easier. It's when you try to get at it by removing nothing else that is frustrating. Been there done that.

I actually think the slave is easier to get to. The master is a real pain because of the obvious under dash accessibility and also I love how when you're trying to remove it (and there's no fluid in the system to keep the pedal up, because you've removed the pressure side line) the pedal will fall to the floor and hose hyd. fluid all over the footwell area......... Word to the wise? Right after removing the pressure line, put some paper towels around the master and depress the pedal a few times to pump out the fluid. Otherwise you and your car can get hosed with fluid REAL EASILY. Then leave the pedal down, if possible, while you work on removing the master

Brake fluid is bad news for paint! Take it from a guy who's also had his pressure bleeder hose split open on him- while pressurized and quite full!!! I spent SEVERAL hours flushing my trunk of brake fluid..........

[RacerX1166]

Well, that was a total disaster.....

Remembered to clamp off the overflow hose but didn't do it hard enough - puddle #1

Opened the bleed screw with the pressure on and nothing happened. Opened it a LOT and nothing happened. Went up and reread the Bentley book, came back down and depressed the clutch pedal and a WHOLE LOT happened.....fluid rushing into my catch can so quickly that I couldn't get the bleeder shut off or another can in place before the whole thing erupted. Hose came off and the bleeder is just spewing air.....

Down to my last few ounces of Super Blue and it wouldn't do the trick. I'm not getting any air out of the bleeder at the moment but I'm out of fluid so I'm done for the night. Oh, and the clutch pedal won't come off the floor.....

The worst part is my stupid garage, while a two car, is so shallow that, even angled, I had the nose of the car outside so I had to take it off the stands and push it inside until I can get more fluid.

I'm hoping another round over the weekend will bring my clutch back but, with the week I'm having, I wouldn't be surprised if that didn't do it.....

Looks like I'll need to order a front caliper rebuild kit also since I've found my front right one is dragging a bit.

[krd]

I'm having a similiar problem. Can air in the system actually pull the pedal to the floor occasionally? I can pull it up by hand and it will work fine, then it will eventually pull to the floor again. I recently bled the slave cylinder, I didn't notice any leaks. the master cylinder boot was ripped but no leaks.

[KTL]

Overflow hose.......... meh, don't sweat it. Consider it initiation to the 911 club- everybody does it and sometimes I still do it!

Air in the system will definitely make the pedal fall to the floor. It's my understanding the master cyl. is relatively small, so it does not push a lot of fluid when you operate it. So if you replace that small amount of fluid it is supposed to push with a sizeable amount of air, the clutch pedal falls.

That's odd that you couldn't get fluid to flow without pushing the clutch pedal. I suspect the pedal wasn't fully returned and wouldn't allow the fluid to push thru the system freely. See the picture of how a typical master cylinder works, to understand how this condition could occur.

http://auto.howstuffworks.com/auto-parts/brakes/brake-types/master-brake.htm

If you're in a pinch, you don't necessarily have to use Super Blue. Get some Valvoline SynPower fluid. It'll be perfectly fine for the clutch system. When you do get the clutch fully bled (which you of course WILL successfully complete ) and you're going to tackle the brakes, you can remove the Valvoline in the reservoir with a turkey baster. When you bleed the brakes the Super Blue will flush the Valvoline through and you'll be fine. You actually can use whatever fluid you can get locally for cheap and it'll all get flushed when you do the brake rebuild.

The clutch pedal stuck on the floor could simply be that the pedal is jammed against the stopper in the floorboard. Be sure to check that pedal stop is there and adjusted to a good position. And as long as you're up to your eyeballs in clutch hydraulic diagnosis, it's really not a bad idea to take a look behind the floorboard and see the condition of the master cylinder in the pedal cluster. Plus you'll find all kinds of little goodies in the pedal area- dirt, rocks, maybe some random nuts, some spare change...

A ripped master boot is not a good thing. The dirt that builds up on the master pushrod/shaft can contaminate the seals and cause slow leakage. That's why the accordion boot is on there- to keep the shaft as clean as possible. It's not a immediate CODE RED DEFCON 5 national security alert, but it shouldn't be ignored. I'd try to put some silicone sealant on the boot to repair it. Because like I said replacing the master cylinder sucks- especially for only a damaged dust boot. I had good luck putting blue RTV on a torn parking brake boot on my old Mitsu Eclipse and it lasted for a long time (much to my surprise!).

[RacerX1166]

I wasn't terribly upset about the overflow hose; I'd rather do it slightly wrong than remember that I forgot to close it off. I did pick up some Valvoline Synpower just as you noted for exactly the reasons you noted. Finding Super Blue locally was a bust....

About to head to the garage and make another run at it. I'm remaining confident and optimistic that all will be well at the end of the day. At least I know where everything is this time so the time spent 'feeling everything out' will not be a factor. I already know I need to elevate the car just a bit higher than I did last time so I can get under it a bit more easily. It's a pain but I am of the belief (after spending 3 hours underneath it already) that it can be done quite well without dropping the slave. I believe having a game plan versus the time spent pulling the slave off is a zero sum situation.

So, I'll pump the pedal a few times, making sure it's returned properly and see what I get.

[old man neri]

How exactly are you bleeding this? It essentially a two person job, at least it was for me.

I used a motive power bleeder. This is what I did:

1) Hook up the pressure bleeder correctly and pressurize the system
2) Put a small hose on the slave cylinder bleeder screw and then crack it open.
3) While I am under the car the second person has to slowly press the clutch down a few times.
4) The important part that I forgot the first time. The second person has to press and hold the pedal all the way to the ground while I closed the bleeder valve.

This worked for me. I just hope you weren't missing step 4.

-matt

[burgermeister]

I just did steps 1 & 2, and it worked fine for me.

[RacerX1166]

I'll preface by saying I have to test drive it but I'm pleased to announce:
I HAVE CLUTCH PEDAL and it's the firmest it's been since I've owned the car. Granted, it's been pumped a few times but, apples to apples (i.e. pumping prior to bleeding) it's the best to date.

Matt, since I didn't have any pedal subsequent to my work today, I used the following method:
1) hook the hose to the bleeder screw
2) pressurize the system
3) pump the clutch a few times
4) open bleeder screw
5) curse because nothing was coming out
6) close screw and pump again
7) open bleeder screw
8) talk to the slave like a baby, telling it to get rid of that nasty air for daddy
9) enjoy the gurgling noises as the air escapes
10) repeat 6-9

Need to go out and test drive the car before it rains. I'll report again upon my return. While I'm pleased with the results, I realize I may have to go through the process again after driving it a few times considering I ran the entire system dry during the last bleeding. At least I've gotten to where i can do the job in an hour (if all my stuff is out) as opposed to 3 and a half last time.....

Thanks for all the support and advice from the forum! It's made my life a lot easier.

[old man neri]

Originally Posted by burgermeister

I just did steps 1 & 2, and it worked fine for me.

Really?

When I only did 1 and 2 I all of a sudden got an 1" of free play at the top of the pedal. It's only then did I re-read my bentley and see where I went wrong.

[RacerX1166]

Well, the results are in and they're mixed.

The clutch was the best it's ever been for the first two runs through the gears. After that, it went back to slightly better than it was prior to the bleeding effort. A little less play at the top (an inch or a bit less) and a bit more consistent feel.

While I don't know a whole lot about these cars yet, the logic (and optimist) side of me says that there might still be air in the system that needs to get out. Looking for opinions on that one. I'd bleed it again today but the engine will be hot for quite awhile....maybe tonight after it cools.

The other issue that I've found during this whole 'pinched clutch pedal' saga is that I have symptoms (according to Pete Z's book) of transmission bearings going bad. When all is quiet, and I release the clutch, I get the whirring noises in the tunnel between the seats. I know this wasn't there when I bought the car; it started after the aforementioned floormat issue. I played ostrich hoping the clutch bleed would resolve it. My memory was incorrect as I thought recalled reading that sound was related to the throwout bearing.

Now I'm wondering if I need a trans rebuild as well as a clutch....

[rcaradimos]

slave cylinder bleeding how to help.. please

[burgermeister]

My G50 makes rattely sounds when it's warm and idling in neutral. Based on reading posts on Pelican, seems like many / most of them do it, though some don't.

More gear oil will quiet it down some. I jacked my car up on one side to purposely overfill the tranny a little bit (maybe by 1.5 pints), and it helped somewhat. Also the only way I got even close to the recommended fill quantity (3.5 qts?) - with a level car, 2.8 qts is all she took.