Series 3 Clutch Question

[jac04]

Is the throwout bearing on the Series 3 clutch arrangement supposed to contact the pressure plate fingers at all times (even with the clutch fully engaged)? If so, how is the preload of the TO bearing against the pressure plate fingers controlled?

If there is supposed to be a gap between the TO bearing and the pressure plate, how is it adjusted? It seems that there is no adjustment, and there is a spring internal to the slave cylinder that is always trying to push the TO bearing against the pressure plate.

I'm trouble-shooting a faint chirping noise that occurs with the clutch fully engaged. As soon as I move the clutch pedal enough to put a tiny preload on the TO bearing, the noise immediately goes away.

This may be covered in the factory manual, but I haven't had a chance to check yet.

[msggunny]

Im just going to throw this out as i didnt check the manual either.

it happened to me and i just changed the thing out and did a new clutch at the same time, no more bird in the tranny.

[jac04]

Well, everything is basically new.
TO bearing
Clutch
Resurfaced flywheel
master & slave cylinders & slave pushrod

I don't think it's a 'bad' TO bearing. It makes no noise with the pedal depressed.

[jac04]

I checked the manual, and there is no info on TO bearing adjustment. You just put everything together, then adjust free play at the master cylinder.

Maybe I do have a bad TO bearing, and it only makes noise when lightly loaded. It was a Genuine bearing purchased from RN, and I only have about 60 miles on it. The noise started at about 45 miles.

I just got through putting this vehicle back together. I hate to have to take it apart for a chirping TO bearing. Maybe I'll just keep driving it and see if the noise goes away. Wishful thinking.

[LaneRover]

I just got through putting this vehicle back together. I hate to have to take it apart for a chirping TO bearing. Maybe I'll just keep driving it and see if the noise goes away. Wishful thinking.

Just turn the radio up!

or is this not an ffr?

[kevin-ct]

The t-bearing should not be tight to the pressure plate. you can adjust the master cyl rod to give it some free play.

[jac04]

^^OK, but there is a spring inside the slave cylinder that is always trying to push the slave piston out. This will always try to push the TO bearings against the pressure plate.

I confirmed in the green manual that the slave should have this internal spring.

The more I think about it, the more I think that I actually have an unhappy TO bearing that chirps when lightly loaded.

I may pull the slave & the starter to see if I can look in and see any problems. Otherwise, I may be shifting the trans back just far enough to get in there.

Unfortuanately, on the Lightweight, you need to pull the heater to get the trans tunnel cover off. To pull the heater you need to pull the instrument panel to gain access to the motor wire connections. :mad:

[jac04]

Well, I re-set the clutch per factory specs with the correct free play at the pedal. Drove around the block, and the chirping started. Drove in the garage, blocked the wheels, still chirping. Loosened the bolts holding the slave in place, and the chirping stopped. Pushed the slave back in by hand and it chirped. Hmm.

Now, here is where it gets interesting. With the slave bolts loose & no chirping, I stepped on the clutch and released it. The chirping was back. Loosned the bolts some more - chirping went away. Pushed & released the clutch and the chirping was back. More head scratching.

Completely unbolted the slave, leaving the line attached. I could grab the pushrod & move the clutch fork & TO bearing through its range of motion (at least until the TO bearing was aginst the pressure plate fingers).

I could only get the TO bearing to make the chirping noise by just barely letting it touch the fingers of the Pressure plate. If I pulled it away, the noise would stop. If I pushed on the pushrod with my finger (very light pressure) there was no noise.

So, I determined it was lack of preload on the TO bearing, but why?

I turned my attention to the new slave cylinder. I tried to push the piston back up into the bore, and it was VERY difficult to move. When I pushed the piston in, it would not try to move back out on its own as it should. The spring behind the piston should apply enough pressure to the piston to keep a very slight load on the TO bearing. Mine was sticking, so it was just allowing the TO bearing to barely touch the pressure plate fingers, causing the chirping. As a matter of fact, once I pushed the piston in, I had to press on the clutch pedal to get the piston to move back out. Once it got near the end of its stroke, I could feel the spring pushing a little. Using castrol GTLMA fluid by the way, so it shouldn't be a seal swelling issue.

On my old slave cylinder, the piston would push back out once it was pushed in. I now wish I had saved it! Oh well, I'll contact RN on Monday to warranty this slave.

[jac04]

Well, I still have this problem. RN sent me another slave, but that one suffered from a sticking piston as well. Les confirmed that the slaves they have on the shelf also stick, and that the bores are tapered slightly. This causes the piston seal to become tighter in the bore as it is pushed in.
I guess I could try to hone the cylinder bore to free up the piston seal, but I have no way to measure to bore to see if I have gone too far (and end up with a leaky slave cylinder).
Maybe I'll try another Girling slave from another source. Could be a bad batch from Girling.

[SafeAirOne]

Well, I still have this problem. RN sent me another slave, but that one suffered from a sticking piston as well. Les confirmed that the slaves they have on the shelf also stick, and that the bores are tapered slightly. This causes the piston seal to become tighter in the bore as it is pushed in.

Unusual. I've received defective parts from other suppliers before but never RN.

[jac04]

Update:

I tried installing a stiffer spring inside the slave cylinder, but the chirping noise came right back as soon as the vehicle warmed up. So I pulled the slave with the vehicle still warm, and the piston was stuck in place. The spring could not move the piston back out, even though the spring I installed was significantly stiffer than the original.

The piston seems to stick worse when things are warmed up. This may be due to the difference in thermal expansion between the steel piston and the cast iron body. The steel piston expands at a greater rate than the cast iron body. If the bore is a little on the small side, then this could cause additional binding (maybe, just reaching for some type of explanation).

To get a second opinion, I talked to Trevor at the 'Farm this morning. When I told him about the piston sticking in the slave, he immediately stated that this should not be happening. He pulled an Allmakes slave off the shelf (alloy body). He pushed the piston in with his finger and it came right back to its original position. Hmmm. He didn't have a Girling cylinder to compare it to.

So, I have decided to install an Allmakes slave cylinder and see if that takes care of the problem. I try to use OEM parts whenever possible, so I'm a bit leary of using an aftermarket slave cylinder. Trevor told me that he has been using & supplying these for quite some time with no complaints, so hopefully they are good quality. I guess we'll see.

[Jim-ME]

Trevor stands behind his merchandise. You don't have to be concerned about his stuff. I've had one well known shop owner tell me that 50% of the bits he buys are junk. I'm not 100% sure that in this day in age that genuine bits are all they are cracked up to be unless they are NOS. I feel that this is one price we pay for driving old iron.
Jim

[SafeAirOne]

Trevor stands behind his merchandise. You don't have to be concerned about his stuff.

Agreed wholeheartedly.

[jac04]

Yeah, I know he'll stand behind it, I just want to be sure that he doesn't have to. I also want to avoid having to replace the slave cylinder 2-3 years from now because of quality. That being said, Trevor was very up front with me about the country of origin of the part (which actually doesn't mean too much these days). He advised that quality appeares excellent and he has had nothing but good results with them.

I'll report back later.

[alaskajosh]

It was hydraulic cylinders and their seals that taught me that the whole "Genuine Parts" thing wasn't all it was made out to be. Ill fitting and problematic, in my experience.

On many parts Trevor has a range of aftermarket options.. everything from cheap, up to very nice (and probably gobs better than "Genuine"), with a few choices in the middle. I've never been anything but impressed by the quality, though I seldom select his cheapest option. He'll get them all out, while on the phone with you, and tell you which looks good (machined vs. cast, overall impression of quality, etc) or if one seems identical for less money.

Good luck sorting your issue!

[TJR]

Are you sure you are looking at this right? I think your parts are fine.

Here's a few pics of my new Lucas slave cyclinder. It behaves the same way you descirbe. i.e the piston doesn't return 100% when pushed in. The spring is pretty light weight and I assume it's there to keep "slack" out of the system. i.e. to keep the rod from falling out of center. The hydraulic pedal pressure will move it back when it needs to.

By adding a heavier sping . it's mimicking the actual clutching motion. You will ensure the T.O. brg is in contact with enough force to load the races. Chirping gone.. but would you want the T.O brg spinning all the time? (see my poor sketch below)

Take your spring out and see what happens.

Also using your original parts and given enough run in time, the chirp may lap itself in and go away...

http://i895.photobucket.com/albums/ac151/88seriesiii/EB_LR/ClutchSlave/20100601001.jpg
http://i895.photobucket.com/albums/ac151/88seriesiii/EB_LR/ClutchSlave/20100601003.jpg
http://i895.photobucket.com/albums/ac151/88seriesiii/EB_LR/ClutchSlave/20100601004.jpg
http://i895.photobucket.com/albums/ac151/88seriesiii/EB_LR/ClutchSlave/20100601005.jpg
http://i895.photobucket.com/albums/ac151/88seriesiii/EB_LR/ClutchSlave/20100601006.jpg
http://i895.photobucket.com/albums/ac151/88seriesiii/EB_LR/ClutchSlave/Clutch2.jpg
http://i895.photobucket.com/albums/ac151/88seriesiii/EB_LR/ClutchSlave/clutch1.jpg

..Talbot

[jac04]

By adding a heavier sping . it's mimicking the actual clutching motion. You will ensure the T.O. brg is in contact with enough force to load the races. Chirping gone.. but would you want the T.O brg spinning all the time? (see my poor sketch below)

Take your spring out and see what happens.

Also using your original parts and given enough run in time, the chirp may lap itself in and go away...

On a S3, the TO bearing is supposed to contact the pressure plate fingers all the time with enough force to keep the bearing spinning at the same speed as the fingers. This is by design, and is much better from a bearing life standpoint than shock loading the TO bearing every time the clutch pedal is pressed. It also helps keep the lubricant distributed within the bearing. The internal spring does keep the 'slack' out of the system, but should also preload the TO bearing enough to keep it spinning with the fingers.

Problem is, on my Girling slave cylinder it is very difficult to push the piston in, and it stays in whatever position I push it to. It will never attempt to return to the outermost position. From your picture, it looks like yours will return almost all the way when pressed in, correct? Is it fairly easy to push in with your finger? If that's the case, then the slave cylinder is operating correctly (want to sell it?).

You definitely do not want the TO bearing to try to 'lap' into the PP fingers. That is what it is doing now, and this is causing the chirping noise. In my situation, it will actually never go away due to 'lapping in', because the TO bearing always returns to a spot where it is just barely touching the PP fingers. It will continue to wear the PP fingers until they fail.

Now, if I take the spring out of the slave, the TO bearing may well be pushed away from the PP fingers between shifts, eliminating the chirping noise. However, this will introduce slack into the system and could lead to a condition where the clutch will not fully disengage on the first pedal stroke. It will also shock load the TO bearing at every shift. Also, the piston is so sticky in the bore that I doubt the TO bearing will ever be pushed away from the PP fingers.

I believe that if I get a properly functioning slave cylinder in there the problem will be solved.

[TJR]

On a S3, the TO bearing is supposed to contact the pressure plate fingers all the time with enough force to keep the bearing spinning at the same speed as the fingers.

On the Slv.Cyl. I have, the piston move easily with finger pressure and does return most of the way. A slight firm tap and it moves on its own a bit further.

As for the T.O brg designed to always be in contact ?? I never looked at it from your point of view. I gues I'm thinking back to my early bronco mechanical clutch linkage which has a large external extention spring that pulls on the clutch fork to release the TO brg and return the pedal to the set height. There's an adjustable rod to set free play. lengthen the rod and the pedal is "topped out" and the TO will make contact, shorten the rod to set the free play.

How do you ever get "free play" on the LR to ensure the clutch isn't held partially open. At the pedal box I guess. I have to assume the Clutch M/C relives pressure back to the resevoir when the M/C piston is returned to the "home" position ?

interestingly...when we used to drive the S3 I'm rebuilding as a family car many years back, my Dad was always telling my Mom to stop resting her foot on the clutch pedal.. , maybe she knew more than we gave her credit for..??

Interesting thread ..

[jac04]

How do you ever get "free play" on the LR to ensure the clutch isn't held partially open. At the pedal box I guess. I have to assume the Clutch M/C relives pressure back to the resevoir when the M/C piston is returned to the "home" position ?

Exactly. Yes, you set the free play at the MC to ensure that the MC always returns "home" & relieves pressure. That way the only pressure on the TO bearing is due to the spring in the slave, which doesn't exert too much pressure at all.

It took me a while to grasp this concept since my old IIA had external linkage at the slave that was used to adjust free play at the TO bearing and my 68 Camaro is mechanical linkage with an adjustable rod & return spring to adjust TO bearing free play.

So, interested in selling me that good Girling slave?:)

[TJR]

So, interested in selling me that good Girling slave?:)

It's the only one I have for my rig.. based on this thread figure I should keep it.. If you were closer I'd let you "try" it to see if it solved your problem. It's a few weeks before I go back to CT (my home state) for a visit.

Also , the s.cyl this girling cyl. is replaceing was a cast aluminum housing slave and it worked fine.. though later it totally corroded after sitting unused for so long.

...Talbot

[jac04]

.. the s.cyl this girling cyl. is replaceing was a cast aluminum housing slave and it worked fine..
You know, IIRC every old slave cylinder I have seen has been aluminum. I wonder if the originals were aluminum and they were changed to cast iron later on as a cost savings.

[jac04]

Received the Allmakes slave. Pushed the piston in easily with my finger, and it popped right back out to the original position. Not even a hint of any binding. Hopefully installing it will fix my problem.

However, I'm tempted to try to find out exactly why the existing practically new Girling slave cylinder is binding. Is it a bad bore or a bad piston seal? I might just install the piston/seal assembly from the new Allmakes slave into the Existing Girling slave since they are both 7/8" bore. If that fixes it, then it is definitely a bad seal. If not, then the bore must be out of spec.

For now, I'm off to buy another case of Castrol GTLMA fluid!!

[TJR]

Good Luck.. Would like to hear the results of the component swap..

[jac04]

I finally had a chance to mess around with the new slave cylinder. I thought that the piston/seal from the Girling slave might have been oversized, so I took the piston/seal out of the Allmakes and tried to install it in the Girling. It started into the bore just fine, but would only go in about 1/2" then bind. So, I took apart both cylinders to compare them. I measured both pistons at .873" diameter. The bore in the Girling cylinder measured a hair over .873", while the Allmakes bore measured .876". So, I think that the Girling cylinder is just made incorrectly.

Anyhow, I installed the Allmakes slave cylinder and bled the system. I haven't had a chance to drive it yet, but the clutch pedal feels a little 'lighter' now (although maybe I'm just imagining it).

[jac04]

Update:
Been driving around for a little bit now with the Allmakes slave cylinder & everything is working properly. No chirping noises and the clutch definately has a lighter feel to it now.