Clutch Screeching

nellis003

nellis003

Senior Member
Hi all,

I just put a brand new clutch, pressure plate, TO bearing, and pilot bearing in my '39 ford (it has a 49 flathead so I used the truck clutch). Started the engine up and pressed in the clutch pedal, and there's a really bad screech coming from the trans. I pulled the plate off to look, and actually saw a spark flash when I pressed down on the pedal again. I didn't see clearly enough where it came from and don't want to keep doing it to find out.

My gut tells me it's a bad throwout bearing, but I've also read online that it could be a pilot bearing. If I go though the process of pulling out the whole rear end again to pull the trans, I'll replace both again, but before I do that I wanted to pick brains here to see if there's anything I can try with the trans in place. These are all brand new parts.

Any suggestions?

Thanks,
Nick
 
I had a similar problem with my 49. It ended being my new chines throw out bearing I reinstalled the original to. and all is good again. Jack
 
Have had a few throw bearings for both flatheads and chevy's being noisey right out of the box. All were from NAPA. Just another sad fact of good parts are hard to find.
 
i just put a Mexican throughout bearing in my 36 pickup, you can hear a hiss when i step on the clutch
 
all ways pack the throw out bearing when you install it, even if its new, use your wheel bearing packer, see if you can get a mirrow in there to see if you can see if the bearing is hitting the pressure plate some where, do that with the engine off turn engine by hand till you have looked all the way around the pressure plate, look for shinny grinding marks
 
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Thanks for the input so far. The TO bearing was greased when I got it, once and I pulled the pin out of the linkage arm to let the bearing fall back a bit I can turn the bearing by hand but it's pretty stiff. Should it spin pretty easily?
 
It has to spin up to match the engine RPM almost instantly, so it has to be loose enough for that. And, all that is bringing it up to speed is the friction of the pressure plate arms.
 
The late "Rumbleseat", aka Paul Garrigan wrote a list of things that he did over the years with and to his flatheads. He re-greased his throw out bearings. I've done this a couple of times and it works well. Here is Paul's write up on how he lubed his throw out bearings:

THROW-OUT BEARING LUBRICATION: These used to come packed with a relatively​
heavy high-temp quality grease. Then manufacturers went to a cheap thin grease​
and not much of it. Consequently, bearings no longer last. The cheap grease​
thins from the high temperatures generated in the clutch area and is soon slung​
out of the throw-out bearing. This not only causes the bearing to run relatively​
dry, it can also cause grease to get on the clutch and flywheel engagement​
surfaces which promotes clutch chatter and erratic engagement. One of the added​
benefits(?) is you get to listen to the throw-out bearing let out a blood​
curdling howl on cold days and in front of your buddies. Neat! While rotating​
the bearing slowly you can feel any bearing roughness. New throw-out bearings​
are lucky to last 15,000 to 20,000 miles before they start their howling act.​
​
A cure I use is to grease them myself .... new and used! These can be greased​
without much effort. I wash the new or used bearing in solvent until I’m certain​
all of the cheap grease used by the manufacturer is gone. Dry it without​
spinning it (low heat or compressed air). Drill a single 1/8" hole on the outer​
edge of the bearing (not in the engagement surface nor in the outer bearing​
race). This is pretty hard and a good bit is needed. Then I use a needle type​
U-joint grease zerk adapter and give it TWO shots of high temp grease. Rotate​
the bearing half way around and give it TWO more shots of grease. That’s all​
the grease it’ll need for well past 50,000 miles. Rotate the bearing several​
times to disperse the grease. I plug the 1/8" hole with a tiny sheet metal screw​
and some red Loctite or solder it shut. Either works. In my Ranchero, I’ve got​
over 200,000 miles on the same throw-out bearing using this method.... and this​
is after it first howled.
 
When we restored our 38 conv. coupe.we put a new napa th bearing in it, it has always a noise when clutch is depressed,can't bear the thought of replacing it..runner till she quits
 
rumbleseat has it right, grease all t/o bearings before installing, use long fiber grease, as the grease gets thrown out to the outer race, the ball bearings in the t/o bearing picks it up again because the bearing is sealed
 
I ended up pulling the trans (always fun on these cars, with having to drop the whole rear end), and I'm going to get another TO bearing and make sure to grease it before I install. I also think I may have damaged the bearing by tapping it on instead of using a press, so I'll do that right next time.

Thanks for all the advice.

Nick
 
Here's what I have in my notes for late motor with early trans:

10” Pressure Plate PN# 19a-7563 ’46 -’48 car or ’46 -’52 pickup
10” Clutch Disk PN# 51a-7550 ’46 -’48 car or ’46 -’52 pickup
Throw-out Bearing PN# 78-7580

Lonnie
 
Well, you say truck clutch, is it the 11 inch clutch? is the 3in. bell housing that fits the 8ba to the 39 trans steel or cast iron? I believe the 11 in. will hit the steel bell housing, is the pressure plate the long style or B@B style? Some of those later PP take a smaller dia. thro out bearing. Walt
 
If you have a 11" clutch if Mercury steel bell housing could be hitting, while back someone had a bad noisy they put the throw-out bearing on backwards.
 
When you install any bearing, there should be a way to press or tap it on whereby there is no force on the balls/rollers. Pressing on the working surfaces of the bearing will shorten its life, sometimes by a lot.

The idea would be to use the inner sleeve of the throwout bearing to press on.

Karl
 
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