Pressure Plate Finger Grooves, caused by the throwout bearing Options

[McMark]

Hey guys, check my logic here. I see this type of grooving all the time, on nearly every pressure plate I see - regardless of engine type, horsepower, etc. I hadn't given it too much thought other than, "I don't like it, but it happens every time." But I was just talking with someone and it occurred to me that this might be wear caused by a bad throwout bearing. If the grease is sticky, or if dirt has infiltrated the bearing, it may not be able to rotate/spin correctly and would slip causing wear.

The point of the throwout bearing should be to stop exactly this type of wear, right?
Doest this mean bad throwout bearings are super common?
Or is this a symptom of a loose clutch cable, not holding the throwout bearing tight to the fingers and that lets them slip?

[altitude411]

How many miles are on that PP? What type of driving? Mine is in the same (worse)shape and I was also wondering this same question... (IMG:style_emoticons/default/popcorn[1].gif)

[aircooledboy]

The point of the throwout bearing should be to stop exactly this type of wear, right?
Doest this mean bad throwout bearings are super common?
Or is this a symptom of a loose clutch cable, not holding the throwout bearing tight to the fingers and that lets them slip?

I always understood this was the opposite of a loose cable. I thought ideally your throw out should hover just out of contact with the pressure plate fingers to avoid premature wear to both the bearing and the pressure plate springs, but since many cars have their clutch cable too tight, you get this. (IMG:style_emoticons/default/confused24.gif)

[Bartlett 914]

Hey guys, check my logic here. I see this type of grooving all the time, on nearly every pressure plate I see - regardless of engine type, horsepower, etc. I hadn't given it too much thought other than, "I don't like it, but it happens every time." But I was just talking with someone and it occurred to me that this might be wear caused by a bad throwout bearing. If the grease is sticky, or if dirt has infiltrated the bearing, it may not be able to rotate/spin correctly and would slip causing wear.

The point of the throwout bearing should be to stop exactly this type of wear, right?
Doest this mean bad throwout bearings are super common?
Or is this a symptom of a loose clutch cable, not holding the throwout bearing tight to the fingers and that lets them slip?

That looks pretty bad

I see two forces happening here. One is rotational. If the bearing is stiff (or frozen) then there will be some slippage maybe only at first contact. The worse the bearing the worse the amount of slipping. The other force is the bearing being pressed toward the engine. Even with the throwout bearing operating properly there will be some sliding of the bearing moving in and out on the fingers. This will cause some wear. I don't think there is any getting around that.

[roblav1]

Looks like a real lot shifting, a too tight cable, or a bad release bearing. Not sure what any manual says, but I've always put a very light coat of grease on those fingers.

[Valy]

It happens to all pressure plates, regardless of car make or year.
The sun should outlive the plate itself. No point in investing efforts here.

[Elliot Cannon]

This is one reason I have been taught in the past (I'm talkin' long ago) that the only time you should dis-engage the clutch is when sifting gears. When I come to a stop light etc. I shift the trans into neutral rather than sitting with the engine idling with the clutch dis-engaged. I used to have a 1960 VW bug (I'm talkin' long ago) and instead of a throw out bearing it used a block of graphite that rubbed against the PP to dis-engage the clutch. When the graphite wore down, the metal cup it was housed in would grind a groove in the pressure plate. The less time you held the clutch pedal down, the longer the graphite block would last.

[wndsnd]

I have learned this as well. Always go into neutral, never hold the clutch down at a stop. Probably easier on the clutch cable tube as well. But wouldn't a properly adjusted clutch just narrowly disengage the throwout bearing in neutral. So when the clutch is depressed every time, the bearing has to make contact with those fingers which are rotating and the bearing is not. Friction would occur at every gear change.

John

[McMark]

356 Pressure Plate of unknown age.


914 Pressure Plate of unknown age.

[scruz914]

Do you have photos of the throwout bearing?
What does the bearing surface look like?

[r_towle]

This is one reason I have been taught in the past (I'm talkin' long ago) that the only time you should dis-engage the clutch is when sifting gears. When I come to a stop light etc. I shift the trans into neutral rather than sitting with the engine idling with the clutch dis-engaged. I used to have a 1960 VW bug (I'm talkin' long ago) and instead of a throw out bearing it used a block of graphite that rubbed against the PP to dis-engage the clutch. When the graphite wore down, the metal cup it was housed in would grind a groove in the pressure plate. The less time you held the clutch pedal down, the longer the graphite block would last.

I have been reading quite a bit about this lately because the Mini needs all of this replaced and the PP looks worse than the first one you posted.

It's interesting, but it seems to be a more modern car issues because I never had any issues with big old american iron.

The resurgence of the blame being shifted to the driver is a poor excuse for building an inferior product, the throw out bearing or release bearing.

The crappy manufacturing has taken out a pressure plate, throw out bearing and left the clutch with less than 30 k miles on it....

This is just cheap parts in cheap cars nowadays.

Rich

[Dave_Darling]

I thought ideally your throw out should hover just out of contact with the pressure plate fingers ...

Not on a 914, at the very least! Remember, the 914 has a spring on the pedal cluster that pulls the pedal down in the "press the pedal" direction. That means there is always pressure on the throwout bearing--though not a lot.

This kind of wear is exceedingly common--maybe universal? I don't know why, because it seems to me that the T/O bearing should be there to prevent that. Especially if the bearing is always in contact with the fingers on the plate, so it should not have a chance to slip.

Maybe it would be worse without a real bearing in place?

Do you have photos of the throwout bearing?
What does the bearing surface look like?

The top of the bearing has a rounded surface. Basically it's just the inverse of the wear that you see in the pressure plate fingers in the pics above.

Here's a pic:
(IMG:http://www.914world.com/bbs2/uploads_offsite/www.pelicanparts.com-121-1418175958.1.jpg)


--DD

[scruz914]

..... there is always pressure on the throwout bearing--though not a lot.

Slight contact between the throwout bearing and pressure plate with not a lot of pressure would allow the pressure plate to turn faster than the bearing at times which would cause the wear. Like at a stop light in neutral punching the gas pedal - zoom zoom. Also as the bearing wears it would be less responsive to quick starts, again causing the wear on the PP.

I understand that the pedal is pulled down by a spring which would cause the throwout bearing to always have some kind of contact. I was under the impression that you do not want the throwout bearing to always be spinning which would cause it to wear out faster. Isn't that why we are told to not rest our foot on the clutch pedal while in neutral?

[JStroud]

So my question, the PP picture in the first post, is it usable?
I ask because I'm the one that sent it to McMark wondering if I should use it for my 3.2 or buy a new one. It's a kep stage II.

[tdgray]

I just changed my fifty plus year old original pressure plate in my MGA...the fingers were worn but not grooved. My guess is bad TO bearing.

The bearing in the A was definitely worn but spun freely...the face was worn in a matching pattern. The bearing should ride gently against the surface as pressure dictates...nothing more.

[larryM]

here is a good start for further investigation: see pages 4 & 5

clutch diagnosis

[SirAndy]

I ask because I'm the one that sent it to McMark wondering if I should use it for my 3.2 or buy a new one. It's a kep stage II.

Aha!

Now i'm curious as well, but i see a clear pattern here.
Since my transmission always has had trouble getting into gear when at a standstill, i *always* keep it in gear and my foot on the clutch when stopped.

Interestingly enough, i never noticed any grinding noises ...
(IMG:style_emoticons/default/idea.gif)

[Cap'n Krusty]

I ask because I'm the one that sent it to McMark wondering if I should use it for my 3.2 or buy a new one. It's a kep stage II.

Aha!

Now i'm curious as well, but i see a clear pattern here.
Since my transmission always has had trouble getting into gear when at a standstill, i *always* keep it in gear and my foot on the clutch when stopped.

Interestingly enough, i never noticed any grinding noises ...
(IMG:style_emoticons/default/idea.gif)

Doing as you do, Andy, is a guaranteed way to shorten the life of the thrust bearing in the crankcase. T1s and T4s are known for this (takes out the case, too), as are 4 cylinder VW watercooled engines. I've also seen it in Toyotas, Hondas, and even Hyundais. It CAN happen to you ...

The Cap'n

[r_towle]

I ask because I'm the one that sent it to McMark wondering if I should use it for my 3.2 or buy a new one. It's a kep stage II.

Aha!

Now i'm curious as well, but i see a clear pattern here.
Since my transmission always has had trouble getting into gear when at a standstill, i *always* keep it in gear and my foot on the clutch when stopped.

Interestingly enough, i never noticed any grinding noises ...
(IMG:style_emoticons/default/idea.gif)

From what I could tell once it started to get loud, it was challenging to get into gear, but not everytime.
There was more than enough push to free up the clutch, most of the time.
Mine, on the mini, was worn down more than hallways through the spring teeth.

The issue we had was noise and hard shifting...never any clutch slippage.
To the OP , considering how hard it is to replace, you may want to do it now.....or just run it until it won't shift...then do it.

[SirAndy]

From what I could tell once it started to get loud, it was challenging to get into gear, but not everytime.
There was more than enough push to free up the clutch, most of the time.

No, i guess i should have been more clear.


- The pressure plate in question is from my car, it's my old KEP Stage 2.

- Not being able to get in gear is a problem with my transmission internals and has nothing to do with the clutch setup. I've had this transmission for 12 years and it's always been like that.

- I simply commented above that i never heard any grinding noise when stopped. Judging from the amount of wear, you'd think there would have been some noise.

- Now i wonder what my current PP looks like. I went with a KEP Stage 3 setup a while ago.

(IMG:style_emoticons/default/popcorn[1].gif)