Last Lemming

I've got another thread about removing and replacing my master cylinder and booster but this bleeding of the clutch problem is buried deep in it that thread and I need a response to before I get my shotgun and put about 15 hand size holes to this car! I'm hoping someone can help!

I have used three methods thus far:

1: a motive bleeder
2: a vacuum pump
3: a oil canoil with a hose that I can feed fluid up through the slave cylinder

When I use the motive bleeder the pedal will go down about a third way and just stay there and then I have to pull it back up. From the third way point down I can keep pressing and I do feel line pressure at that point, but I never get a consistent nine pressure from the top of the pedal all the way down.

This is also true when I use the vacuum pump the pedal will just go down 1/3 the way and will not come back up unless I pull it up.

When I use the oil can and pump the fluid up through the slave cylinder all the way up to the master cylinder the pedal goes down about 1 inch with no feel of line pressure. If I keep pushing I do feel line pressure all the way to the floor and then it pops back up on its own, this is the best I can get it at this point

Just for information purposes the bleeding of the clutch came about because I just installed a new master cylinder and a new brake booster. I did bench bleed the master cylinder. Also the back end of my car is up at least 20 inches higher than the front.

One question I have is what is the clutch pedal supposed to feel like as you engage it.

odonnell

Try putting the rear of the car as high up as you can. That way, air doesn't get caught at the front of the master. And the slave bleeder is the high point on the slave. Motive is the ticket once that's done.

Edit: missed the part where you said it was already jacked up. If you're getting a solid stream with the Motive, I'd be looking at parts being bad.

Last Lemming

The clutch felt fine before I changed the master cylinder just a couple days ago. However I can't remember how it felt exactly. The slave cylinder is new (replaced by the PO) and the clutch master cylinder is of unknown condition but like I said it worked fine before I started this work. Can the clutch master cylinder have air trapped in it? How would you get the air out if it did have air trapped inside?

How does your clutch feel? Does it feel like it has constant pressure right when you engage the clutch pedal all the way to the floor or is there a difference in pressure the first inch or so then it "tightens" up?

951and944S

So other than the brake master and brake booster, the only work you did related to the clutch system was removing the clutch master fluid supply hose from the brake fluid reservoir...?

Get under the car on the driver's side behind the front wheel with a large flat screwdriver or small prybar. Looking around the lower portion of the bell housing on driver's side, find a hole in the bell housing where you see the clutch slave extension rod where it enters the divot of the clutch fork.
Insert the flat blade of your tool behind the fork into the rear of the hole in the bell housing. Using the aluminum to lever your tool, push the fork forward. This will push the extension rod of the slave and force the piston inside the slave forward, pushing all fluid and air all the way through the clutch master into the brake fluid reservoir. Sweep this motion several times, keeping a little pressure on your lever tool to limit the speed that the slave piston returns each time after you have pushed forward as far as you can.

Make sure reservoir is as full as you can get it.

Now open driver's door. Kneeling outside the car where your right hand can reach clutch pedal. Put your palm on pedal and grip the pedal with your four fingers for pulling it back up. Push pedal to floor and raise it back only an inch or two over and over in a pumping motion. After 10 pumps or so, raise the pedal all the way to the top on the 11th pump and repeat the 2 inch travel 10 pumps again, going all the way to the top for one pump after 10 short pumps.
Now pump full strokes 5-10 times.
Check your fluid.
Sit in seat and access pedal feel.

T

Last Lemming

This is correct. When I pulled off the blue line I immediately capped it with the end of a sharpie pen until I had to reinstall it. I checked it for leaking - it wasn't and the blue hose looked plyable so just reinstalled it.

A little clarity on your directions. Is it your intent for me to push against the slave extention ow with it when I press on the fork?

MAGK944

It seems like while bleeding with the Motive the fluid in the reservoir might have got below the blue hose nipple and you would have introduced air into only the clutch system. This could happen even if the brakes bleed fine as the clutch nipple is much higher. Another thing that could have happened is that when you connected the blue pipe to the new master, and then topped up the fluid, you trapped some air in the blue pipe and the Motive pushed it further into the system.

Did you run the Motive wet or dry?

There is obviously more risk of this happening if you run it dry and are not vigilant about topping up the reservoir, but it can also happen wet if you let the Motive get too low.

Either way, somehow you introduced air into the clutch hydraulic system. I'm surprised though that reverse bleeding it hasn't pushed the air out. I've had good results pumping air up through the slave and out the reservoir. Are you using a clear tube between the pump and slave to ensure no air bubbles are being reintroduced as you reverse pump?

Last Lemming

I'm not sure exactly what wet vs dry means but I'll assume it's with brake fluid vs without. I always used with fluid.

As for using clear tubing, I do use clear tubing, but what I find is at first there are all sorts of bubbles so I pump those out and bring the fluid just to where it's about to spill out and then slip it on the nipple, but no matter how fast I work the fluid drops down to be tube a 1/4" or so before I have a chance to open up the nipple and pump the fluid in. So it would seem I'm introducing some air in. I'm assuming that the air gets pumped up and out but since I'm by myself I have no way of knowing if it's making it up and out to the reservoir.

MAGK944

It's impractical doing this method on your own, you really need someone to look for air breaking the surface of the fluid in the reservoir. When no further air is coming out the fluid will simply rise in the reservoir, you cannot see all that alone. Ive been through this and feel your pain. Get some assistance and persevere, you are doing all the right things, it's just those air bubbles are stubborn sob's.

odonnell

I had very similar issues, also right after installing my new booster. So at least you aren't having 1-off issues

https://rennlist.com/forums/924-931-...-weigh-in.html


User Otto Mechanic helped me with determining normal clutch pedal action:

https://rennlist.com/forums/924-931-...owing-air.html

(posts about his pedal feel vs mine are somewhere in there)

thomasmryan

it took me a few days to get it.


first fail... flex line was compromised where it had rubbed on the brake booster.

second fail... the $3 oil can created more bubbles in the line unless topped off. the solution was to keep the cat topped off and run a high loop in the clear line above the slave and pump slowly.

third fail... to get a firm pedal (build pressure) I had shoved a worthless-never-going-to-use-it 18mm deep well in the inspection port to block movement of the slave push pin at the fork.

Last Lemming

Thank you for this! It seems to have done the trick. As I pushed the fork I could hear what seems like turbulent fluid emanating from the slave cylinder. 7 - 8 pumps of that then the sound went away. I pumped pedal as indicated and it feels good now. I won't be able to tell for sure until I drive the car. Unfortunately that can't happen until I get the master cylinder bolted down and the intake manifold back on.

951and944S

Of course it did...., and it would have worked for all of these other guys too.

I stated in another thread where somebody was having the same trouble that I have never bled a clutch in the way described in any of the threads.

This method works with all makes/models except types with slaves inside a bell housing as part of the throw out bearing, simply because you lose access once the transmission is bolted up.

Just realized you are in Lafayette too.

Just give a shout of you ever need something,

T

Last Lemming

Hey, awesome! Just hoping this Harvey Hurricane doesn't flood me out. I'm leaving the car jacked up just in case. Last year at this time we had rain for 3 days in a row and my house came within 1" of flooding. Most of my neghbors weren't so lucky - now that she this!

951and944S

LOL, you quoted me before I could edit and add the smiley after the first line.

Not that I didn't mean it, it just read as though I'm an a$$hole, but everybody that knows me for real already knows that I am......

I am on the other side of the river from Baton Rouge proper.

The only thing that saved us from the same fate Baton Rouge was dealt last year during their flood is the Mississippi River levee system.

We received the same amount of rain and have great drainage and a bayou that empties into the Intercoastal Canal but if we would have been land connected to Baton Rouge....., well...,

T

Otto Mechanic

FWIW, I'll repeat them here. I observed no "play" in my clutch pedal prior to bleeding it. After bleeding, it did exactly as you and Michael observe; it went to the floor and stayed.

I had a failure of my Motive feed line that pumped high pressure brake fluid all over the car and shop when I left it pressurized overnight, complicating my life unexpectedly. It may have been the cause of introducing air into the lines.

As a result, I started over completely, bleeding each brake caliper from the left rear, right rear, right front and left front twice until I'd removed all bubbles from the brake system. I then bled the clutch from the clutch slave nipple until I had no bubbles present.

After that procedure, my clutch worked as expected with no play at all; the clutch engaged immediately with no "looseness".

Hope this helps,