Clutch throw-out fork-, UPDATE - throw out bearing bad? Guide Tube worn? Options

[sfrenck]

Is the clutch throw-out arm getting close to touching the transmission case a symptom of the clutch going bad?

My clutch works perfectly if I adjust it such that the arm barely touches the case when the clutch pedal is depressed (no reverse gear grinding).

Trying to figure out if I just need to shim the throw-out fork ball with a washer(s), if it's time to replace the clutch or both.

-Thanks-

Update with Tranny out of the car below.

[toolguy]

Just went through this. . it's usually from the flywheel being resurfaced multiple times. . If
you leave it so it touches the trans, then if you depress the pedal fully, you are actually stretching the cable. . and it will snap sooner or later. .
I added a 3/16 washer under the ball and got about 1/2 inch more travel. .
be sure and use thread sealer on the ball threads or you'll get a leak
can be caused from a worn clutch disk. . If it were me, I'd
pull the clutch pack off while the trans is out and inspect..
I got a Sachs OE clutch, pressure plate and throwout bearing setup off ebay
for $300. . looks around for a good price on the right parts. .

[sfrenck]

Transmission is out. There seems to be a huge amount of clearance between the throw out bearing and the guide tube. Bad bearing? Do the guide tubes wear out? Replace both?

The throw out arm was jiggling all over the place (never noticed when it was under the tension of the clutch cable). I was hoping that the problem was the fork bushing - but it seems to be OK and sit pretty well on the ball.

[toolguy]

Don't quite understand what you mean. . the bearing rides over the center guide tube which is over the
the trans input shaft. . Yep. . there is a bunch of 'wiggle room'. . . when the engine is running, the throwout bearing spinning will naturally 'find' the center and stay there.
If the bearing spins with no noise and it didn't make noise before, it's probably OK. .

Remove the arm from the ball. . look at the nylon bushing in the arm. . grease lightly.
pull the ball out, and add the washer and put the trans back and check if the arm. . .
Is now at least in the middle of the hole with the trans all the way in? If not you need another washer or the clutch disk may be worn too much, or flywheel resurfaced too much. .

Here's a link to EBay Sachs clutch package for $288..
http://www.ebay.com/itm/Clutch-Kit-SACHS-K...54f&vxp=mtr

[sfrenck]

Don't quite understand what you mean. . the bearing rides over the center guide tube which is over the
the trans input shaft. . Yep. . there is a bunch of 'wiggle room'. . . when the engine is running, the throwout bearing spinning will naturally 'find' the center and stay there.
If the bearing spins with no noise and it didn't make noise before, it's probably OK. .

Remove the arm from the ball. . look at the nylon bushing in the arm. . grease lightly.
pull the ball out, and add the washer and put the trans back and check if the arm. . .
Is now at least in the middle of the hole with the trans all the way in? If not you need another washer or the clutch disk may be worn too much, or flywheel resurfaced too much. .

Here's a link to EBay Sachs clutch package for $288..
http://www.ebay.com/itm/Clutch-Kit-SACHS-K...54f&vxp=mtr

The bearing isn't touching the guide tube. The arm wobbling isn't due to the ball bushing, rather the bearing itself isn't touching the guide tube. Not sure if I need to replace the bearing, guide tube, or both. Bearing seems to be in good condition.

[toolguy]

sounds normal. . the guide is just that- a guide, the bearing touching the pressure plate is what centers the bearing causing it to run true to actual center. . . . post a picture. . Dr Evil will chime in and let you know if there is and issue. .

[Dr Evil]

Sounds like you are missing the little plastic blocks that go on the arms of the TOB between the fork and the bearing. You get a lot of slop if those are missing. There is some clearance with the TOB and the guide tube. Not sure what you have without a pic. Also, there is a bushing that goes in the fork that is what rides on the ball stud. All of these are common issues. Cheap to fix, too.

[sfrenck]

Sounds like you are missing the little plastic blocks that go on the arms of the TOB between the fork and the bearing. You get a lot of slop if those are missing. There is some clearance with the TOB and the guide tube. Not sure what you have without a pic. Also, there is a bushing that goes in the fork that is what rides on the ball stud. All of these are common issues. Cheap to fix, too.

Have both plastic blocks and the bushing that sits on the ball. The slop is between the bearing and the guide tube. Red arrow below pointing to about 1/16" gap between the bearing and the tube when other side (blue arrow) is touching. Twisting the arm will switch the 1/16" to the blue arrow side (the twisting indicates to me that either the bearing or the tube is tapered?).

Is the bearing supposed to slide closely on the tube? How much, if any, twist should be in the throw out bearing / arm?

[Dr Evil]

That is normal, shim the ball with another washer and put Teflon on the threads.

[sfrenck]

Averting

That is normal, shim the ball with another washer and put Teflon on the threads.

So the arm can twist +/-10 degrees as it moves along the guide tube?

[Dave_Darling]

Yes.

[Jon B]

The slop is between the bearing and the guide tube. Red arrow below pointing to about 1/16" gap between the bearing and the tube when other side (blue arrow) is touching... Is the bearing supposed to slide closely on the tube? How much, if any, twist should be in the throw out bearing / arm?

Just noticed I had a new Sachs release bearing on shelf, so measured bore and also old guide tube across unworn base area.
The difference is only 0.010"...

New Sachs release bearing: 1.146"
Guide tube, unworn base area: 1.136"

A difference of 1/16" (0.0625") is obviously much greater (x6), although not sure if that was a guess or actual measurement.



Jon B.
Vista, CA

[sfrenck]

Plot thickens... or the ball socket bushing does. I replaced the bushing and added washers behind the ball. After putting the tranny back in twice (two added washers first, take out one washer second time) I have to pull it a third time to take out the last added washer and go back to the original washer only.

Guessing the original bushing was worn and/or the new one is thicker - not getting the required 1/2" of free play with the fork now and subsequently my clutch cable isn't long enough (IMG:style_emoticons/default/headbang.gif)

Also, a good deal of the slop in the fork is gone with the new bushing.

At least I'm getting good at balancing the transmission on my floor jack.

To be continued....

[toolguy]

Clutch cable too short puzzles me. . . iThe 1/2 inch of play is at the pedal, not the trans. .this isn't a conventional American clutch setup. . remember the pedal is spring loaded to pull down making the throwout bearing ride on the pressure plate all the time. . . . the free play is measured pulling the pedal up. . anyway, that's how I do it. . for 40 years

[sfrenck]

From the Pelican Clutch Change Tech Article:

"Once the transmission is all of the way in, check the play on the clutch arm. This is a very important step. Ideally, there should be about a half inch of free play in the arm. In other words, when the arm is resting on the transmission case (throw-out bearing all the way back towards the rear of the car), it should travel about half an inch before it hits the pressure plate. "

[sfrenck]

Today's lesson - walk away from the 914 when things that should make sense don't. Clutch cable was fine - just needed the clutch pedal to be in the "clutch out" position to get the end of the cable where it needed to be.

Tip for those adjusting the cable on their own - a baseball placed between the bottom arm of the clutch pedal and the floorboard holds the pedal nicely in the correct place to attach the cable at the fork.

[cwpeden]

Today's lesson - walk away from the 914 when things that should make sense don't. Clutch cable was fine - just needed the clutch pedal to be in the "clutch out" position to get the end of the cable where it needed to be.

Tip for those adjusting the cable on their own - a baseball placed between the bottom arm of the clutch pedal and the floorboard holds the pedal nicely in the correct place to attach the cable at the fork.

(IMG:style_emoticons/default/lol-2.gif) When I first started with 914's I had the whole pedal cluster out trying to figure that exact thing out. Then i realized there was a spring pulling it down, not holding it up. (IMG:style_emoticons/default/slap.gif) Uhh, its not that funny now, I had to ride the 52 seat limo for a week.

[toolguy]

"Once the transmission is all of the way in, check the play on the clutch arm. This is a very important step. Ideally, there should be about a half inch of free play in the arm. In other words, when the arm is resting on the transmission case (throw-out bearing all the way back towards the rear of the car), it should travel about half an inch before it hits the pressure plate. "

As I read the whole Pelican article, it appears this portion of the article is not about adjusting the cable at all. .
This refers to where the pedal should be at rest to be sure the fork ball is in the proper place in height after you are placing shim washers under the ball. . this is to insure an adequate range of motion needed to fully release the clutch disk under the pressure plate. . .

The cable is adjusted with 1/2 inch freeplay pulling up at the top of the pedal. Sort of apples and oranges but both need to be followed.