Clutch issue: Cold weather affected?

[HeX]

I'm having an issue with my clutch engaging properly in my 1997 Civic HX. I noticed the issue began a few days ago when it dropped to to the mid teens in temperature. The clutch engages at a much lower and short point than usual. Last night it wouldnt engage at all and I noticed the clutch fluid reservoir was almost empty so I filled it up with DOT3 fluid, pumped the clutch a bit then it was engaging. Its still engaging too low & short. I came across THIS THREAD which sounds like my same issue. Being that the thread is 6 years old, I want to get more recent opinions and suggestions on what else to inspect.

FYI, the fluid was very dark, which indicates it need to be flushed and air-bleeded, but I'm uncertain of the proper methods to do so and havent yet come across a clear explanation of the process. Please bare in mind Im savvy enough to defend myself automotively but Im not expert.

I also wondered if the cold couldve caused an old hose to partially break and leak, Its rainy today so I cant really inspect it much right now, hence Im doing my "homework" first until the weather clears up.

 

[commandergambit]

I'm having an issue with my clutch engaging properly in my 1997 Civic HX. I noticed the issue began a few days ago when it dropped to to the mid teens in temperature. The clutch engages at a much lower and short point than usual. Last night it wouldnt engage at all and I noticed the clutch fluid reservoir was almost empty so I filled it up with DOT3 fluid, pumped the clutch a bit then it was engaging. Its still engaging too low & short. I came across THIS THREAD which sounds like my same issue. Being that the thread is 6 years old, I want to get more recent opinions and suggestions on what else to inspect.

FYI, the fluid was very dark, which indicates it need to be flushed and air-bleeded, but I'm uncertain of the proper methods to do so and havent yet come across a clear explanation of the process. Please bare in mind Im savvy enough to defend myself automotively but Im not expert.

I also wondered if the cold couldve caused an old hose to partially break and leak, Its rainy today so I cant really inspect it much right now, hence Im doing my "homework" first until the weather clears up.

sounds like the hose is split and or possible clutch wear i had the same problem here when we hit -2 when i pulled the plates they were really worn so i replaced and it fixed it, but im like u im no expert but its what seems to make sence

 

[HeX]

sounds like the hose is split and or possible clutch wear i had the same problem here when we hit -2 when i pulled the plates they were really worn so i replaced and it fixed it, but im like u im no expert but its what seems to make sence

I doubt its the clutch as it was replaced about 4-5 years ago and I dont drive like a ticked off teenager. I briefly inspected the clutch reservoir hose that goes to the clutch master cylinder and I didnt see an obvious leak but it is stiff enough to indicate it may need replacement soon. I did notice slight remnants of a possible leak underneath the clutch master cylinder. Nothing drastic or obvious but I wil try to clean up that area and check it regularly to confirm if it is leaking.

 

[Osiris19]

You leaked the fluid, you pressed the clutch, you got air in the lines. Fill it up, bleed the lines, and find your leak.

 

[HeX]

You leaked the fluid, you pressed the clutch, you got air in the lines. Fill it up, bleed the lines, and find your leak.

There is no help in this reply whatsoever.

... it need to be flushed and air-bleeded, but I'm uncertain of the proper methods to do so and havent yet come across a clear explanation of the process. Please bare in mind Im savvy enough to defend myself automotively but Im not expert...

 

[Osiris19]

The reason you're having issues with clutch engagement is because you have air in the lines. Your reservoir was almost dry, indicating a leak.

Fill the reservoir, and have someone sit in the driver's seat. Have then pump the clutch a few times and hold it. Crack the bleeder screw on the slave cylinder loose and fluid should rush out. Tighten it, and have your helper pump the clutch again. Keep repeating this process until you have full pedal feel. Make sure the reservoir stays filled so you don't trap more air.

Inspect all the metal and rubber clutch lines for wear and wetness to see if you can identify the source of the leak.

 

[HeX]

I flushed out the clutch line using the bleeder screw on the clutch slave cylinder and there was air in the line. It seems to feel fine now. I inspected what I could without lifting the car, because its too cold for my taste, and didnt notice any leaks. I wonder if the slave cylinder could be leaking. Ill have to check it when the weather is more tolerable but will keep an eye on the clutch fluids.

I didnt flush the system completely in part because I didnt see the point of changing all the fluid when I may still have a leak. When I decide to flush the entire system should I just pump it all out from the bleeder screw while adding fresh fluid into the reservoir (and keep it closed) until it all comes out clean, then air-bleed it? Perhaps I should use this technique?

 

[Osiris19]

You can take a turkey baster and suck out the dirty fluid from the reservoir and then do the bleed process to push clean fluid through the lines until its clear coming out of the bleeder screw. If the slave is leaking, you usually notice it around the boot where the plunger is.

 

[HeX]

You can take a turkey baster and suck out the dirty fluid from the reservoir and then do the bleed process to push clean fluid through the lines until its clear coming out of the bleeder screw. If the slave is leaking, you usually notice it around the boot where the plunger is.

Thanks for the info. I bought a fluid hand-pump today to do it since it was only $6. I figured itll also help on the day I decide to flush the tranny fluid. I saw no fluid around the slave cylinder from the top angle, and I tried to feel below it only to feel thick dirt, which could have accumulated from however long the leak may have existed. It didnt feel freshly moist but it wasnt very dry either. I just have to get under the car when its not so cold.

 

[HeX]

The local temperature finally rose into the low twenties, up from 2 degrees, so I inspected the Clutch master cylinder and it is not leaking by the clutch pedal. I may not be able to see a leak but all signs seem to point to the Slave cylinder being the issue. I already ordered it for $14, made by Exedy. At that price, its worth changing out anyways.

For those that may be interested...
How the Clutch Master cylinder and Slave cylinder work together:
Pressing the clutch creates hydraulic pressure in the master cylinder. That fluid pressure goes through the clutch fluid line into the slave cylinder, which leads to engaging the clutch in the tranny. Thus, if the slave doesnt function properly then it impedes proper clutch engagement.

 

[HeX]

The Clutch Slave Cylinder

Here's a picture of the new part with the boot off. This is where the leak should be occurring. Its been a rainy/cloudy day, so Im aiming to install it tomorrow.

FYI, Exedy now owns Daikin Clutch. Ill update over time on how it holds up.

 

[Osiris19]

The local temperature finally rose into the low twenties, up from 2 degrees, so I inspected the Clutch master cylinder and it is not leaking by the clutch pedal. I may not be able to see a leak but all signs seem to point to the Slave cylinder being the issue. I already ordered it for $14, made by Exedy. At that price, its worth changing out anyways.

For those that may be interested...
How the Clutch Master cylinder and Slave cylinder work together:
Pressing the clutch creates hydraulic pressure in the master cylinder. That fluid pressure goes through the clutch fluid line into the slave cylinder, which pushes the slave inner shaft into the tranny to push the shift fork to allow for gear engagement. Thus, if that shaft doesnt fully engage then neither does the shift fork, which causes either no gear engagement or rough engagement.

A little bit of misinformation here, not trying to bag on you. The slave plunger doesn't actually go into the trans, at all. Neither does the fork. The plunger pushes on the fork which is on a pivot ball and is also attached to the throwout bearing that's on the input shaft. When the plunger moves the fork, the fork slides the throwout bearing against the pressure plate fingers, applying the clutch disc to the flywheel. This happens inside the transmission bell housing.

 

[HeX]

A little bit of misinformation here, not trying to bag on you.

I appreciate the clarification. I only intended to give a loose general understanding of the slave cylinders function. I'll think of a better way to word it and edit the post. Thanks for the input.

 

[HeX]

Wording, improved.

How the Clutch Master cylinder and Slave cylinder work together:
Pressing the clutch creates hydraulic pressure in the master cylinder. That fluid pressure goes through the clutch fluid line into the slave cylinder, which leads to engaging the clutch in the tranny. Thus, if the slave doesnt function properly then it impedes proper clutch engagement.


Also, I finally installed the new Slave cylinder. It wasnt difficult but was much easier with the air filter box removed and the clutch line bracket removed. I inspected the old slave cylinder and the inner plunger doesnt seem to slide as freely as the new one, so I assume the inner seal is leading to the impeded movement. It was definitely the original slave cylinder because the bolts were covered in years of thick dry dirt.

 

[JohnS.]

Yeah, those slave cylinders do go bad after a while. Mine crapped the bed and I replaced mine at around 230k. I also bled my clutch line by myself with a good ole 2x4 lol. And on a side note, when I replaced my clutch/flywheel, I originally thought it was the clutch/flywheel when it turned out to be the shift fork. I wore the ball it pivots on clean through. Never heard of that one until then lol. I do A LOT of rev matching/downshifting/engine braking.