Throwout bearing chirps on pressure plate fingers

SpetsACDC

Active Member
I bought and installed a maximum motorsports firewall clutch adjuster:
Clutch Cable, Quadrant, and Firewall Adjuster Package

Now, I get a squeaking sound when the clutch pedal is not pressed down. I recorded the sound here:
It sounds like a high-pitched bird chirping. The speed of the "chirps" matches the engine RPMs, and I can hear it when I'm driving.

The maximum motorsports support said the chirping is likely from the PP fingers sliding and gripping on the forward face of the throwout bearing. They said I should tighten the clutch cable so that the bearing is preloaded on the PP. I've tightened it a lot, and it does help with the sound. However, the clutch cable is really tight, has a very high engagement point. Plus the sound starts back at about 2k rpms.

They said maybe my PP fingers have uneven heights (I replaced the clutch and t/o bearing about 8 years / 45k miles ago). Prior to installing this kit, I would have a rattle when not pressing on the clutch pedal. However, the cable wasn't this tight and I didn't have squeaks.

Any ideas? I'd like to avoid pulling the tranny.

Thanks
 

douglass

Active Member
Do you have any play in the clutch pedal? It should take about 5-8 lbs of force before the pedal moves. I installed a MM cable/quadrant, & firewall adjuster kit, and drove the car a few times making adjustments along the way. You should not have much feedback if any when lightly applying the clutch pedal, and it should not feel like it engages after you press the clutch pedal in. It should just have a constant pressure if that makes sense. What was the reason for the replacement?

My problem was the Clutch would not automatically adjust when lifting the clutch pedal upwards. After removing all the parts, I'm pretty sure my cable was the problem. The OEM quadrant, pad, and springs where in good shape.
 

SpetsACDC

Active Member
Do you have any play in the clutch pedal? It should take about 5-8 lbs of force before the pedal moves. I installed a MM cable/quadrant, & firewall adjuster kit, and drove the car a few times making adjustments along the way. You should not have much feedback if any when lightly applying the clutch pedal, and it should not feel like it engages after you press the clutch pedal in. It should just have a constant pressure if that makes sense. What was the reason for the replacement?

My problem was the Clutch would not automatically adjust when lifting the clutch pedal upwards. After removing all the parts, I'm pretty sure my cable was the problem. The OEM quadrant, pad, and springs where in good shape.

I installed it with 5-8lbs of force, then tightened it more per advice from MM. I replaced it because my stock clutch seemed to adjust itself strangely. Some of the teeth on the plastic gear looked a little worn when I took it out. I'm not 100% sure they were worn enough to cause the adjustment to mess up though.

Below is a full email convo I had with MM that might be helpful. Tightening the cable past 5-8lbs still results in squeaking when I drive at about 2k RPMs. So, I'm inclined to try and loosen the cable to allow a gap between the T/O bearing and PP.

-----Original Message-----
Hi,
Background info:
I have a 99 V6 mustang with 125k miles. It's a daily driver. I replaced the clutch, throwout bearing, pilot bearing about 8 years
ago at around 90k miles. For the last few years, when in neutral without the clutch pedal pressed, I would hear a rattle. Earlier
this year, there were about 2 or 3 times where the clutch pedal would automatically adjust very loose (without me pulling up on the
clutch pedal). When it became loose, I would pull the clutch pedal up, hear a ratchet sound, and then the clutch would be very tight
and the engagement point would be very high (I would barely have to push the clutch pedal down). So things were weird, and I read
good things about your adjustment system. So I bought and installed this:
Clutch Cable, Quadrant, and Firewall Adjuster Package

I think the installation went well. I had to put the extra widget on the end of the clutch cable because it had a lot of extra
slack. The only problem is that now I get a squeaking sound when the clutch pedal is not pressed down.
I recorded the sound here:
It sounds like a high-pitched bird chirping. The speed of the "chirps"
matches the engine RPMs, and I can hear it when I'm driving. If I press the clutch pedal down about 1-2 inches, it stops the sound.
I think the cable adjustment is already pretty tight. It's hard to measure 5-7lbs of force exactly, but I've tightened it quite a bit, and I try to estimate the force with a scale. The engagement point is pretty high (when the clutch pedal is let up past half
way).

Any tips? Thanks!

-----Reply from MM-----

I think that you done everything properly in this case.

The chirping is from the PP fingers sliding and gripping on the forward face of the throwout bearing. With an OEM clutch it is
normally very easy to adjust the clutch cable tension to eliminate this noise. This is because the height of all of the PP fingers
is the same. Since the quality of aftermarket clutches varies, the height of the PP fingers does also. In some cases, the throwout
bearing will ride on the tips of the five or six tallest fingers. Since there is little contact area, it slips and grips. More cable
tension is needed to compress these fingers down so that more fingers are touching the throwout bearing face. When this is done, the
chirping stops.

In your case, you are going to need to find a happy medium between cable tension and noise. The only real solution would be to use a higher quality PP.

There is a chance that the throwout bearing is dying. This could cause the noise also, but it is usually more of a constant squeal
sound, than your sound.

-----My Reply-----

Thanks for the fast response. I'll try to find that happy medium!

Correct me if I'm wrong, but it seems like a bad idea to live with the chirping. I'd worry that the bearing's face or PP fingers
could get messed up from continuous sliding.
Also, I've read conflicting things online about whether the throwout bearing should always be engaged with the PP. It sounds like
the preload is necessary, and it's ok for the bearing to be preloaded, is that correct?

One last thought...any idea on why this noise only occurred after installing the kit? Perhaps how the OEM adjuster worked, the
throwout bearing wasn't close to the fingers?

-----Reply from MM-----

Yes, the PP fingers could get damaged from excessive sliding.

The throwout bearing in your car is an angular contact design. It is designed to be in constant contact with the PP fingers.

Angular contact ball bearings

This type of ball bearing is designed to allow a relatively high thrust load on it. Other types of throwout bearings, particularly
ones from for hydraulic setups, are a nonangular contact type of bearing and are not designed to take high thrust loads. Hydraulic
clutch setups have the throwout bearing barely resting against the PP fingers as a result. The only force involved is from the seal
rollback in the hydraulics.

My assumption about the noise happening after installing the MM kit is this. The OEM quadrant must have been applying more cable
preload. This would keep the noise from happening.
 

douglass

Active Member
How much clutch pedal travel does it take until the chirping noise stops? It might be worth tightening the cable in small increments until the noise stops. In theory I would think you could get the throw out bearing to make contact with all the teeth before it disengages the clutch. This would be the easier approach. If this does not work, then it might be a good idea to pull the tranny to take a look.

Assuming the fingers are the problem that might have been a result to your clutch not adjusting properly, and falling out of adjustment.
 

douglass

Active Member
Another thought is you might be able to remove the clutch cable cover, and disengage the clutch cable from the fork. You might be able to move the bearing out of the way enough to see the condition of the fingers.
 
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