failing throw out bearing?

what is the signs of one going out? is it gradual or all of a sudden?

my 62 has a manual 4 speed and sometimes while sitting at a light with the clutch all the way down i get what sounds to be a loud rub/squel sound from the transmission area. pop it into netural and let off the clutch it goes away. it probaly does it once every 100 uses of the clutch. if the car has sat for a while can the bearing just be dry?

 

Sounds like it is on the way out. It could be dry, but once the damage is done, no amount of grease will undo it.

It is not worth taking it all apart to do a repair that might not work. I'd drive it until you can't stand it, and then replace the whole clutch set.

 

Maybe, yes, yes

Could be the pilot bushing too

 

what exactly is a piolt bushing and what does it do?

 

It is a bushing, or sometimes a bearing, in the back of the crankshaft, into which the tip of the transmissions input shaft slides into. It supports the end of the input shaft, so it does not snap off when you dump the clutch.

 

how difficult is it to replace each of these? does it require removal of the entire transmission and clutch ***embly?

 

Yes, you need to remove the transmission to replace the throw out bearing. You need to remove the clutch as well to replace the pilot bushing. while you're in there, you'll probably decide you want to replace the clutch, and get the flywheel resurfaced.

 

It all, or almost all has to come out. It is all hand-tool work, except for maybe removing the pilot bushing (and machining the flywheel, for a fresh clutch). Most auto parts stores rent a tool for removing that. It is pressed into a blind hole in the end of the crank shaft.

There is a "grease and bolt" removal method, too, but the tool is easier.

 

if it was failing wouldnt it make a constant noise?

 

I'd reckon a throwout bearing. Like others have said, leave till you can't take it anymore then replace it

 

Not necessarily in the early stages. If it goes constant, park the car and fix it.

 

Unless I'm staging, I always put it in neutral - clutch out at a light. Saves wear & tear on your throw-out bearing...............

 

For what it is worth you have recieved good information from everyone on this thread.

 

...and your knee.

 

The pilot bearing would turn with crank/trans till you put in the clutch.

 

It is bad practice to hold a clutch in for an extended period.

 

I once had too grind a little off the fork on the round area between the "fingers", right in the middle, because it was interferring with the back of the thowout bearing when engauged.

I had the trans & bellhousing out & mocked up the trans/bellhousing/fork/t/o bearing then operated it by hand & saw the interference.

 

Not only saves the thrust bearing but it also saves the thrust faces on the crank. They do wear out and can generate excessive end float of the crank. That can mean ditching the crank come rebuild time.

 

While I've never had a sudden failure. When the pedal is depressed, the ones I've seen sound hollow (like the old steel roller skates)

 

Throwout bearings are typically a sealed unit that's lubricated at the time of manufacture. When the lubrication dries out and it starts getting noisy, it can be rejuvenated by drilling a small hole in the side and giving it two squirts of a grease gun with a pointy tip. Screw in the smallest self tapping screw and secure it with a dab of JBWeld. It will last as long as it did originally, and then you do it again. I've done this several times over the decades.... works just fine.

Yeah, yeah... I'm a cheap-****d *******, but I hate throwing things away that basically have nothing wrong with them.

 

Ok, as an old mechanic and old shop teacher this is one of those things where if you have already asked the questions you have in your previous posts it is fairly obvious that the repair may just be beyond your skill level. not saying that Squirrel or I or one of the others can't write out a set of step by step instructions but it just may be better if you bit the bullet and took it to a shop and had the work done.

In a nutshell the work involves.

Jacking the car up and making sure it held up solidly so that it is safe to get under.
Removing the driveshaft
Removing the transmission
removing the throw out bearing
removing the pressure plate and disk
removing and replacing the pilot bushing/bearing
reinstalling the clutch disk and pressure plate after making sure that they are in good condition. And using an alignment tool to get the disk centered.
Install the new throwout bearing
install the transmission back in the car.
install the driveshaft. Check the U joints before reinstalling it to make sure that they are good.
Adjust clutch
let the car down on the ground and test drive.
It is almost all unbolt and then bolt the stuff back in with aligning the clutch being the only thing that might be a challenge except for the weight of the transmission when you are laying under the car on your back.

If it is a truck the first step is to pull the floor mat and unbolt the trans hump and take it out. That trans weighs over 100 lbs and it is best to have a jack to move it with. My back still hurts from wrestling with one when I was 16 years old.

 

thanks everyone for the input. mr 48 just to let you know, i may ask a lot of questions but im not completly inexperianced with transmission work, granted all of my work has been on 50's mopar fluid drives, I was hoping standard chevies parts were easier to replace than messing with fluid filled torque drive and clutches. Last time i used the grease and nut method to replace the piolt bushing, when i had it all apart. I replaced it and the throwout at the same time not because they were bad or making noise but because i thought i should since i had it open. I am asking now what the signs of failure area so i can learn.

 

on my 53 plymouth you can change the throwout bearing with out removing the clutch or pressure plates, do the chevy beelhousing not have large enough access holes to allow this?

 

It's called a "throwout bearing" because you're supposed to take the old one, throw it out, and replace it when you do a clutch job. They are too cheap to justify reusing one. I have seen a throwout bearing seize up and ruin a pressure plate by taking the ends of the clutch fingers off. It's the same amount of labor to put in a new one as it is to put the old one back in.

 

Yup, and it is even more labor to try to "save" an old one.

I don't know about all y'all, but my time ain't free.

 

So did you get it fixed?
They can let go and damage the fingers, on the pressure plate.

 

not yet its only been one day....

 

Hi, I have a 59 corvette that is totally restored. Well to make a long story short after hearing that noise on and off for some time, I decided to change the throwout bearing and low and behold it wasn't it. I found the pilot bearing (bronze) DRIED OUT and squealing some time. Install a ball bearing while at it.

 

Thanks jim, that may be a similar story to me. The car was fully restored 3 years ago and has only had 150 miles on it since then. It was a trailer queen untill i got a hold of it. The previous owner nearly had a heart attack when i told him i plan to use it as a daily driver. It may be the piolt bearing

 

They get skipped sometimes, due to the not being the most simple thing to remove.