New noise after bleeding clutch
 

Last weekend I was a good car owner and replaced my break fluid and clutch fluid. Things went pretty well, a little bit of spillage. I also took the opportunity to replace the clutch line with a MTECH Stainless Steel one. Hoping it would further improve the clutch feel.

After what appeared to be a successful replacement of both fluid and line for the clutch. Bleeding appropriately etc. I now have a noise somewhere in-between a chirp and a shhh. I think it varies with engine speed, not road speed or gear ratio. It isn't very loud but it is annoying.

The noise is only apparent when the clutch pedal is fully out driving down the street. It is constant when the pedal is out. As soon as I put even a little bit of pressure on the pedal the noise goes away. I mean even before the clutch starts to disengage.

This definitely started right after the replacement of the line and fluid, however I have previously removed the "helper" spring from the pedal mechanism a few months ago.

None of the other clutch noise threads seem to be about this specific issue. It is like a backwards version of a throw-out bearing problem where the noise goes away when you push the pedal.

Anybody have any ideas? Thank you.

Hello _KK and welcome to our helpful forum ....... :clap:

Well, like they in the old country, the sound you are hearing most likely has something to do with the last thing you messed with on the car.....;)

The first thing I would check is make sure the fittings on the new clutch line are tight and not ..... sucking air.

Next, I would re-bleed the clutch system just to make sure you have all the air out.

If that doesn't make the sound go away ...... I would ring up ol @Ultramaroon (I'll do it for you) for his insight. He has younger ears than mine and can better isolate sounds like that .....:thumbsup:


humfrz

Classic symptom of impending TOB failure. Self-adjusting mechanism means it's always in contact with the pressure plate, just no force on it.

When it's starting to seize up, it'll screech when you're not touching it because it's not spinning with the pressure plate. Then when you start laying into it, the force on the face of the bearing overcomes the stiffness of the seizing components and it stops screeching.

You can bring it by my pad this weekend if you want me to listen to it in person.

Thank you for the welcome and your thoughts. I thought I would get a chance to mess with it this weekend but that didn't happen. I am planning on trying to adjust the clutch push-rod a bit next weekend and see if that helps.

Would a TOB fail after only 20K miles? I have only owned the car since 17K miles so not sure how it was treated before that but it seems early for a TOB to fail.

Well, yes, 20,000 miles would be a bit premature for a TOB to start failing ..... however, if the previous owner sat at a lot of lights holding the clutch down for long periods of time, it is possible it's warn.

Whether it's a going bad TOB or air in the master or brake lines ...... the car probably won't grenade on you before next weekend.

When you bled the clutch, did you submerge the bleeder hose in a jar of fluid ... ??


humfrz

I did submerge the bleeder hose in a bottle of fluid. I felt pretty good about the bleeding operation. It went well and I am pretty sure that I didn't introduce air.

I think I may have figured out what the issue was and I think it is going to make me sound crazy.:drool:

There is a retainer clip and some kind of interface piece of metal in the end of the clutch master cylinder. This piece of metal is what the push-rod, from the clutch pedal assembly, pushes up against on the end of the piston. The clip is what holds all of the internal parts in the cylinder. I think something may be out of spec or missing some damper washer or lube, because I think the sound I was hearing was them rattling around. (Ya, I probable need to find something better to do then listen to my car.) I was able to temporarily fix it by cramming some grease in the end of the master cylinder, around the push-rod end.

My theory is that there was air in the system before I did the bleed and the air bubble would expand after each clutch press and take up the slack in the push-rod/piston interface.

When I put the grease in it went away but it has come back a bit after a few days. I think I need to work out something better then grease to dampen the vibration, or stop abscessing over the sounds my car makes.

Thanks everyone for the thoughts and ideas!

You may consider investing in a new clutch master cylinder ........ unless you want to be prepared to do a lot of double clutching, rev matching and general Jake shifting all the way home some time ....... :iono:


humfrz