2004 5 speed

246k miles. Slave cylinder previously replaced 6 years ago at 176k miles by independent shop. The clutch motion and shifting works perfectly at this time. No spongy feeling, etc.

Note I have researched every post I could find on this website, re low clutch fluid levels, etc, but I could use some additional help/advice.

Bought recently from a trustworthy person. After driving the vehicle home I opened the clutch fluid reservoir and it was empty. It had appeared full due to a very dark thin scum cover on the inside of the reservoir. I filled the reservoir to the max level and drove it about a mile. Checked the reservoir again and it was halfway between the max and min mark. Figured there may have been some air in the hose and it worked its way out. Drove and additional 20 miles and the level is now approx 25% above the min mark.

I carefully checked the firewall on the inside and outside of the vehicle near the clutch master cylinder, then looked at the master cylinder and followed the metal/rubber line to the slave cylinder, checking for leaks. Everything was bone dry, including the slave cylinder. I pressed the rubber "accordion" boot on the slave cylinder to see if there was any fluid inside the seal and it was also completely dry.

Questions:

1. Is it possible that, over the past six years, there was a decrease in the the fluid level due to clutch plate wear over time? (similar to brake pad wear causing a drop in the brake fluid level). If so, the fluid level should stabilize, once the air is out of the line. However, if the fluid is leaking into the bell housing (see question 2) I want to avoid introducing additional fluid into the housing as the fluid could contaminate the clutch plate material. I'm used to manual transmission cars with a combined brake fluid/clutch reservoir, so low clutch fluid level has never been an issue.

2. Could the slave cylinder be leaking into the bell housing area?

3. In this generation, is it the master or slave cylinder that most often fails?

Any recommendation on how to troubleshoot would be greatly appreciated.

thanks!

 

With that much fluid loss, you must have a leak. The system is pretty simple, the master and the slave are connected by a hydraulic hose and one of those items has to be leaking.

I'd clean the outside of the master cylinder and follow the hydraulic line all the way to the slave cylinder cleaning along the way. Take some athletes foot spray powder and coat the entire hydraulic system. Fill the reservoir and look for signs of staining.

 

thank you, will do

 

Do these clutch hoses fail? If they rarely fail I'll leave well enough alone. (Part 17 in the attached diagram). Thanks

 

I haven't seen any posts on here that they have failed. Hoses can fail due to corrosion or if something is rubbing against them from engine vibration over an extended period of time. I'd only replace an item when you verify a leak.

 

I decided replace the master and slave cylinder (only want to do this once). Plan to remove the whole clutch hydraulic system as shown by the lady mechanic in the video below (it's Honda Element, but same K24 engine and clutch system), see minute 2:30-2:55 of the video. She removed the system from the vehicle without removing the clutch fluid. One reason I for removal as a system is to better flush out the contamination in the lines so the the seals on the new cylinders don't get contaminated, leading to early failure. I'll flush the lines with a can of brake cleaner (with the tiny "straw" attached) and afterwards flush out the remaining brake fluid from the lines with compressed air, making sure the lines are dry before proceeding and flushing with new brake fluid.

Question: Is there any reason not to bench bleed the master cylinder and fill the entire clutch hydraulic system with brake fluid before reinstalling it in the vehicle? Seems it would be much easier to purge all the air out of the system by "hanging" the system in more or less vertically while filling with brake fluid. I'm considering reverse bleeding from the bottom, using the slave cylinder bleeder valve and a new oil can with a clear tube attached to pump the fluid from the bottom to the top (several videos on this on Youtube)....unless there's a reason not use this method. Thanks for any advice. By the way, Nissin and Adler were the suppliers to Honda for these slave and master cylinders, so those aftermarket companies make quality cylinders.

You Tube

 

I think bench bleeding the master cylinder then assembling/bleeding the lines outside of the car is a good idea.

 

Thanks I value your input. Parts are on order and I'll be reporting back after work is complete.

 

Researched it and apparently best to use the honda urea grease UM264 to the ball end of the push rod of the slave cylinder, as it lasts the longest.

 

Ordered the parts. Plan on reverse bleeding similar to the method in the link below, using a new 20 ounce oil can in order to avoid contaminating the new brake fluid.