Rumbling when releasing clutch from start

[wareagle]

Bogging down, hesitating, stumbling from a dead stop and when accelerating at speed are indications that the accelerator pump and its check valve are defective.

But I doubt these parts (and the pilot bearing) are causing the problem.

Oil on the flywheel/pressure plate/clutch disc caused by a rear main seal leak, greasy hand prints on the clutch disc, worn clutch disc/pressure plate, warped flywheel will all cause "clutch chatter" the usual term for your problem.

Once a flywheel is warped, turning it down will not solve anything, because once it's warped, it's warped forever.

All turning it down will do...is remove the blue heat spots, but these will re-appear within a short time.

I doubt the power valve has anything to do with your problem. It's clutch disc/pressure plate flywheel related.

Hey Bill,

The clutch disc, pressure plate and rear main seal were all replaced with my tranny rebuild. They did have the flywheel resurfaced and drive shaft balanced. As far as greasy hand prints, I cannot tell you for sure except for the flywheel.

Really, the only time I notice the issue is from a dead stop. Once the clutch is completely released it stops doing it.

Steven

 

[BKW]

Mebbe you are causing the problem, by letting the clutch out without applying enough "gas."

You said yourself that you are unfamiliar with driving a stick shift.

 

[m78]

Hey Bill,

.

Really, the only time I notice the issue is from a dead stop. Once the clutch is completely released it stops doing it.

Steven

Thats the only time your really using the clutch. you should be able to slip it into 2nd and 3rd with ut using the clutch.

 

[wareagle]

Mebbe you are causing the problem, by letting the clutch out without applying enough "gas."

You said yourself that you are unfamiliar with driving a stick shift.

Never said I was unfamiliar with driving a stick. Matter of fact all the vehicles I have ever owned have been a stick.

 

[wareagle]

Thats the only time your really using the clutch. you should be able to slip it into 2nd and 3rd with ut using the clutch.

But when I use the clutch for 2nd and 3rd I have no issues.

 

[m78]

But when I use the clutch for 2nd and 3rd I have no issues.

Exactly, The clutch and gears in the transmission are already turning near the speed of the engine so its doing close to nothing.

 

[wareagle]

Exactly, The clutch and gears in the transmission are already turning near the speed of the engine so its doing close to nothing.

Gotcha!!!!!!!!

 

[Alvin in AZ]

Never said I was unfamiliar with driving a stick.
Matter of fact all the vehicles I have ever owned have been a stick.

"just because I'd used manuals all my life don't mean I use the
clutch -right-, maybe it's my fault?" -Alvin ...before he got a '91
Bronco that has a -really- smooth operating clutch! A kid drove
it a while back and the 91's clutch worked great for him too.

It's easy to blame the operator without proof the alignment is
bad. I'll post the 75's dial indicator readings good, bad or ugly.

BTW, all else is equal between the two clutches. I put 'em both
together myself. And even had the flywheels resurfaced at the
same machine shop.

One difference now that I think of it tho, all the essential parts
on the '75 F150 are factory-originals and those-parts on the '91
Bronco were swapped over from a ratty parts truck.

Alvin in AZ
ps- Diaphragm pressure plate is another difference!
I remember on the VW's the diaphragm pressure plates were
always the smoother acting. Might turn out that's all there is
to it? LOL

RhinoPac 07057 = '91 Bronco
RhinoPac 07027A = new clutch for the '75

 

[kiwi f150]

Hey Bill,

The clutch disc, pressure plate and rear main seal were all replaced with my tranny rebuild. They did have the flywheel resurfaced and drive shaft balanced. As far as greasy hand prints, I cannot tell you for sure except for the flywheel.

Really, the only time I notice the issue is from a dead stop. Once the clutch is completely released it stops doing it.

Steven

If once you have it rolling in first gear you give it a boot full of gas does the "shudder" appear or is it still smooth ?
As far as greasy hand prints go they will burn off with a bit of work but if the rear main seal was damaged when it was fitted it could be leaking causing problems.

Best thing in my opinion to do is get a couple of mates over one weekend (some beer too) and tear it down to have a look -why not share the newly learned cussing and skinned knuckles

 

[wareagle]

If once you have it rolling in first gear you give it a boot full of gas does the "shudder" appear or is it still smooth ?
As far as greasy hand prints go they will burn off with a bit of work but if the rear main seal was damaged when it was fitted it could be leaking causing problems.

Best thing in my opinion to do is get a couple of mates over one weekend (some beer too) and tear it down to have a look -why not share the newly learned cussing and skinned knuckles

The shudder does not appear if in first gear, clutch fully released, and I put my size 11 all the way to the floor...

Can you check for a rear main seal leak with all parts intact.

 

[kiwi f150]

The shudder does not appear if in first gear, clutch fully released, and I put my size 11 all the way to the floor...

Can you check for a rear main seal leak with all parts intact.

If you slide under the truck with your feet facing the diff and your head at the rear of the sump you will be looking at the bottom of the bell housing front - most stuff i've worked on has a tin plate secured with a couple of bolts - remove that and see if there is much oil on the back of the flywheel.

I'm not sure of your history of the truck but did you have the clutch kit replaced and if so did this problem exist before?
The reason i ask is that in my experience (not vast by any means) clutch shudder can be caused by a myriad of problems and i think you will have to follow a process of elimination frrom the flywheel back - even worn rear suspension bushings can play a part in this.
If the clutch kit was fitted not long ago by a garage then maybe you could take it back for them to have a look at if you're not too keen to do it yourself.

Cheers Mark

 

[Alvin in AZ]

Cool description of how to find the inspection cover etc, Mark.

...and see if there is much oil on the back of the flywheel.
Cheers Mark

Yeah!

It's on the -back- of the flywheel.

I've seen "leaky rear main seals" listed everywhere as a cause for
all sorts of problems with clutches but maybe I'm just too stupid
to see it but I don't see it. LOL The rear main is -behind- the
flywheel and somehow that oil has to make it onto the face, in
between the clutch disk and pressure plate with them doing their
level best to sling the oil out of there.

Grease and oil from the pilot bearing can't stream down the face
of the flywheel either unless it's a bunch really quick and overloads
the drain holes and/or the circular "sink cut".

Same with the rear main seal, wouldn't the leak have to be so bad
that oil would be draining out the inspection cover drain hole and
making a mess before it'd drain down off the teeth of the ring gear
and get on the clutch disc??

Maybe it just takes a misting of oil in the air?
What's the mechanism?

{shrug}

-------------------

The clutch in my '75 hardly leaked a drop out the rear main seal after
the rebuild and yet I'd replaced a badly wallered oil-lite pilot bearing
at least twice during that period. Like every 15 to 22k miles. At 22k
it was hardly drivable, the pilot bearing would be so wallered out!

Alvin in AZ

 

[kiwi f150]

Cool description of how to find the inspection cover etc, Mark.


Yeah!

It's on the -back- of the flywheel.

I've seen "leaky rear main seals" listed everywhere as a cause for
all sorts of problems with clutches but maybe I'm just too stupid
to see it but I don't see it. LOL The rear main is -behind- the
flywheel and somehow that oil has to make it onto the face, in
between the clutch disk and pressure plate with them doing their
level best to sling the oil out of there.

Grease and oil from the pilot bearing can't stream down the face
of the flywheel either unless it's a bunch really quick and overloads
the drain holes and/or the circular "sink cut".

Same with the rear main seal, wouldn't the leak have to be so bad
that oil would be draining out the inspection cover drain hole and
making a mess before it'd drain down off the teeth of the ring gear
and get on the clutch disc??

Maybe it just takes a misting of oil in the air?
What's the mechanism?

{shrug}

-------------------

The clutch in my '75 hardly leaked a drop out the rear main seal after
the rebuild and yet I'd replaced a badly wallered oil-lite pilot bearing
at least twice during that period. Like every 15 to 22k miles. At 22k
it was hardly drivable, the pilot bearing would be so wallered out!

Alvin in AZ

I've often wondered that myself Alvin as when i was working in the workshop in Waimate we would get a few light trucks in for clutches (mainly nissan and izuzu) and it became a habit to replace the rear main seal just cause you are already there - i only ever saw a couple of clutch packs that were oiled up causing a problem but the rear main seals were completely shagged in those and oil was everywhere - the only guess i can take is that because the flywheel would have thrown the oil onto the bellhousing via centrifugal force maybe some dripped down into the clutch plate and cover.
I suggested to Steven that he remove the protection plate and look at the back of the flywheel because i would imagine that he would have enogh natural oil leaks congregating around the back of the sump to disguise any oil leaking between the bellhousing and protection plate.

I reckon we need to know if this was a pre existing condition before he can start the process of elimination.


Cheers Mark

 

[BKW]

Cool description of how to find the inspection cover etc, Mark.

The OP shouldn't have any trouble finding the inspection plate (C3AZ-6366-A-bell housing shield)...cuz it was missing when he acquired the truck, then asked for one in a thread that went several pages.

I assume by now he found one and installed it.

 

[Alvin in AZ]

I reckon we need to know if this was a pre existing condition
before he can start the process of elimination.
Cheers Mark

Yeah. We need more feedback but either way he'll find it and get it back
together and have a good working clutch no matter what he finds because
we won't let 'im put it back together without checking the bell housing and
a few other things and find out what the cause was.

Alvin in AZ

 

[BKW]

Old used car dealers trick to eliminate clutch chatter (for a short time). Apply "Fullers Earth" to the clutch disc.

Now all ya gotta do is find some Fullers Earth. It was available at pharmacies, dunno if it is today...or not.

 

[wareagle]

This clutch chattering was occurring before I took it to have the tranny rebuilt and a full clutch kit installed.

Yes, I do have a flywheel inspection cover. Cannot remember who I bought it from, but got a really great deal on it. I remember when I got the truck I thought it was kinda odd that I could look under the truck and see the flywheel.

 

[wareagle]

Checked my motor mounts tonight and the bolts were tight.

 

[Alvin in AZ]

Old used car dealers trick to eliminate clutch chatter (for a short time).
Apply "Fullers Earth" to the clutch disc.

Now all ya gotta do is find some Fullers Earth.
It was available at pharmacies, dunno if it is today...or not.

What about sawdust? What was that put in "to quite things down"?

I'm just old enough to have heard the stories, never seen it done.

Alvin in AZ

 

[wareagle]

What about sawdust? What was that put in "to quite things down"?

I'm just old enough to have heard the stories, never seen it done.

Alvin in AZ

Heard the same thing Alvin.