Subaru clutch issue

Number_35

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If you can push on the fork with the engine running and in neutral and hear a grinding noise that sounds like a damaged throw out bearing and/or pressure plate. Another thing you can do to verify the problem is remove the slave cylinder then remove the rubber boot around the fork and look down into the bellhousing and see if anything looks damaged. The way you described it, it sounds like you need a clutch. The reason for your hydraulic problems is because the slave cylinder has to travel too far for the fork and throw out bearing to apply the pressure plate. Hope this helps.
Very good explanation, thank you!
 
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Here's a photo of the clutch slave cylinder and the top of the fork:

View attachment 91836

I forgot to ask - I think around 200K km (125K miles).

My friend bought it just a few months ago, so it's hard to know how it had been treated previously.
Looking at how far out the slave cylinder rod is the issue must be inside the bell housing regardless of if it’s the clutch fork or the clutch so the gearbox needs to come out.
 

Number_35

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Just tried something else - not my idea, saw it online. Anyway, compressed the rubber hose between the clutch master cylinder and the clutch slave cylinder. The clutch pedal was firm, and didn't go down when pressed. Rats! If it had sunk, that would have indicated that the master cylinder was leaking internally, and it would have been easy to replace.

Not sure if I can check the slave cylinder in any way, but I'm fearing, as so many here have suggested, that the tranny has to come out regardless.
 

Number_35

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Guys, help me out here - I can be a bit dense at times - If the problem is NOT in the clutch's hydraulic system, I still don't understand why the clutch pedal stays down. I get that there may be an internal clutch failure (bent or broken fork, throw-out bearing, and/or pressure plate), but don't see how that would affect the clutch pedal itself. If the hydraulic system was good, I would expect the pedal to operate normally, with the rod or piston coming out of the clutch slave cylinder to push on the top of the fork, and the problem to lie somewhere downstream of that.

The fact that the clutch pedal does not return on its own makes me think the problem may be an internal leak in the clutch slave cylinder. (I say internal leak because there's no external fluid leakage.)

But I understand that I don't know enough about this to be sure. Per #24 above, I think I've ensured that the clutch master cylinder is good, so if the problem is in the hydraulic system, it must be in the hose downstream of where I clamped it (unlikely, because there's no leakage) or in the slave cylinder itself.

Thanks!
 
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Push the slave piston back in and see what happens (the pedal comes back up). Now the slave piston is pushed out and it seems there is no pressure on the fork to push it back.
 
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It's an external slave right? My Subaru was an external slave and my friend's 05 Impreza is external slave.

If the slave cylinder was leaking , you'd be losing fluid in the reservoir.

Have you verified that the clutch fork is actually doing something? Subarus are known for the throwout bearing failing. Is it possible the throwout bearing has failed and it's jamming the pressure plate or something?
 

Number_35

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Push the slave piston back in and see what happens (the pedal comes back up). Now the slave piston is pushed out and it seems there is no pressure on the fork to push it back.
Thanks Trav, I'm going to go over to my friend's (half a block away) and try that!

I was thinking that if the hydraulic system were independent, that is just sitting on a bench or without the fork installed, the pedal would come back anyway due to the spring on the pedal.

But you're saying that the fork would normally be pushing back on the slave cylinder's piston, and that would drive the rod that enters the master cylinder back, in turn raising the clutch pedal back to its ambient (up) position, correct?
 

Number_35

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It's an external slave right? My Subaru was an external slave and my friend's 05 Impreza is external slave.

If the slave cylinder was leaking , you'd be losing fluid in the reservoir.

Have you verified that the clutch fork is actually doing something? Subarus are known for the throwout bearing failing. Is it possible the throwout bearing has failed and it's jamming the pressure plate or something?
It is external, and nicely accessible on top of the bell housing. I'd thought the slave cylinder might have failed internally, so no fluid loss.
 

Number_35

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I can't push the slave cylinder piston back in by hand to drive the clutch pedal up (poor access to get good leverage, and/or I'm old and decrepit) but do understand now.

I can move the top of the fork (where the slave cylinder meets it) about 3/4" quite easily. That can't be normal! That leads to me believe that the problem is not the hydraulic system, but the fork or the clutch ***'y itself, so within the bell housing.

OK, I've finally accepted that the tranny has to come out. Got an estimate from a trusted tranny shop - ouch! Will watch a few YouTube videos and see if I want to take this on myself.

Thanks all, for your feedback - I really appreciate it!
 
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Thanks Trav, I'm going to go over to my friend's (half a block away) and try that!

I was thinking that if the hydraulic system were independent, that is just sitting on a bench or without the fork installed, the pedal would come back anyway due to the spring on the pedal.

But you're saying that the fork would normally be pushing back on the slave cylinder's piston, and that would drive the rod that enters the master cylinder back, in turn raising the clutch pedal back to its ambient (up) position, correct?
Yes that is correct, the pressure plate pushes the slave back in and the fluid pushes the master but there is also an assist spring that keeps the pedal up, check it and see if its broken. #36036F in this diagram.



This Part: https://parts.subaru.com/p/Subaru_2...-Pedal-Return-Spring/49247427/36037FC030.html

Or this one, put the VIN in to get the correct one.


There is a good chance this broken but it alone would not return the slave.
 

Number_35

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Photos from this afternoon -

I can pull the top of the fork forward this far - the slave cylinder piston is pretty much fully retracted:
20220314_123315_HDR.jpg


I can pull the top of the fork back this far, likely beyond where the piston would normally push it to:
20220314_123328_HDR.jpg


That can't be good! Surely that much play is not normal. I'm thinking fork ...
 
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That was my original thought and still is but I think the assist spring may be broken also. that much play is not normal, slight movement sure where the fork is on the throw out but not like that.
 

Number_35

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Yes that is correct, the pressure plate pushes the slave back in and the fluid pushes the master but there is also an assist spring that keeps the pedal up, check it and see if its broken. #36036F in this diagram.



This Part: https://parts.subaru.com/p/Subaru_2...-Pedal-Return-Spring/49247427/36037FC030.html

Or this one, put the VIN in to get the correct one.


There is a good chance this broken but it alone would not return the slave.
Thanks Trav, good information! I think the spring is OK; when I pull the clutch up about halfway, it comes up the rest of the way by itself (i.e. by spring power).
 
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Also, if you have or have access to an endoscope you could have a look inside the box if you push it in past the clutch fork rubber boot.
 

Number_35

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We're still having winter weather here, so I was not able do the work on my friend's car. The fellow who sold it to him did the repair. I'm not sure how much it cost.

As @Trav had predicted, the fork had broken. The clutch was also on its last legs, and the RMS was leaking.

IMG_20220424_141929.jpg

IMG_20220424_141941.jpg
 
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