Ravenwoods Posted July 27, 2023 Share Posted July 27, 2023 We have a Forester S with 323,000 miles on it, and looks like it too. But the engine is still strong, doesn't seem to burn oil, but of course leaks oil. New clutch put in about 150,000-160,000 Miles ago. So the clutch is still strong. In past summers when we had lots of temps in the mid 80s or higher the clutch pedal would act strange. You could push it down but then need to pull it up again with your foot. So this only happens in hot weather and after the car has been driven a awhile and all the parts in the clutch system are thoroughly hot. So yesterday was one of those days but this time it was worse. Almost impossible to get it into any gear when the car is stationary. Once you get moving then you can manage. And of course today when the car has cooled down the clutch is back to normal. So there must be some need to make a clutch adjustment. When you have to pull the pedal back up, you can feel that a spring somewhere gives resistance about half way up the pedal stroke, then decreases after that point. It is almost like you have exceeded the springs correct depression. Any suggestions on what to do? Quote Link to comment Share on other sites More sharing options...
forester2002s Posted July 27, 2023 Share Posted July 27, 2023 I'm not familiar with a 1998. But if it has a hydraulic-actuated clutch, then the slave-cylinder may need replacing (located at the top-rear of the engine-block). If it's cable-actuated, maybe the cable is sticking. Quote Link to comment Share on other sites More sharing options...
Ravenwoods Posted July 27, 2023 Author Share Posted July 27, 2023 13 minutes ago, forester2002s said: I'm not familiar with a 1998. But if it has a hydraulic-actuated clutch, then the slave-cylinder may need replacing (located at the top-rear of the engine-block). If it's cable-actuated, maybe the cable is sticking. It does have the hydraulic clutch with brake fluid in it. Quote Link to comment Share on other sites More sharing options...
lmdew Posted July 28, 2023 Share Posted July 28, 2023 New hose and brake fluid. Bleed it wall after the hose change. Quote Link to comment Share on other sites More sharing options...
Ravenwoods Posted July 28, 2023 Author Share Posted July 28, 2023 10 hours ago, lmdew said: New hose and brake fluid. Bleed it wall after the hose change. I'll give it a try. Quote Link to comment Share on other sites More sharing options...
nvu Posted July 28, 2023 Share Posted July 28, 2023 Be careful adjusting the hydraulic clutch pedal. The master cylinder rod needs to fully release when the clutch is all the way up. There's a tiny hole in the master piston that releases pressure when it's all the way released. This is to account for temperature changes and expansion. When the clutch pedal is fully up, there should be some play in the pin connecting the pedal to the master cyl rod. There's a spring in the slave cylinder that takes up the slack. There's no pretensioning to adjust over time like cable clutches, the spring in the slave cyl self adjusts after every press and release. It sounds like either there's air in the system from a bad slave seal or the hose is rotting out. Also could be cracked clutch fork. Quote Link to comment Share on other sites More sharing options...
Ravenwoods Posted July 29, 2023 Author Share Posted July 29, 2023 7 hours ago, Ravenwoods said: I'll give it a try. The "hose" is a steel hydraulic line, not a hose. Do steel lines go bad? Quote Link to comment Share on other sites More sharing options...
Ravenwoods Posted July 29, 2023 Author Share Posted July 29, 2023 1 hour ago, nvu said: Be careful adjusting the hydraulic clutch pedal. The master cylinder rod needs to fully release when the clutch is all the way up. There's a tiny hole in the master piston that releases pressure when it's all the way released. This is to account for temperature changes and expansion. When the clutch pedal is fully up, there should be some play in the pin connecting the pedal to the master cyl rod. There's a spring in the slave cylinder that takes up the slack. There's no pretensioning to adjust over time like cable clutches, the spring in the slave cyl self adjusts after every press and release. It sounds like either there's air in the system from a bad slave seal or the hose is rotting out. Also could be cracked clutch fork. My wife drove it today with no issues, and it was a bit cooler today, only about 80. Yesterday I did vacuum out the old fluid in the reservoir and put in fresh. Do steel hydraulic lines rot out? We are in a low rust area so corrosion is generally not significant here. Wouldn't air in the system cause a problem even in cold weather? Wouldn't a bad slave seal allow fluid to leak out? And one would notice a drop in the fluid level? Before I vacuumed it out the fluid was still on the full line. No signs of leaks. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted July 29, 2023 Share Posted July 29, 2023 (edited) The slave cylinders from that year range have a Subaru service bulletin about weak internal piston return springs. It causes the fluid to be displaced in the system - the pedal will not return to it's upright position and the slave piston will not retain pressure against the fork which causes insufficient throw of the fork and failure of the clutch to fully release. Also the rubber hoses always leak. Get a new NABCO slave cylinder and a new hose. Look harder - it has a steel line AND a hose. GD Edited July 29, 2023 by GeneralDisorder Quote Link to comment Share on other sites More sharing options...
idosubaru Posted July 30, 2023 Share Posted July 30, 2023 (edited) What he said. Replace slave cylinder and hose and prepare to bleed and bleed and bleed. Very common. Or convert that unreliable maintenance required hydro clutch garbage to a maintenance free cable clutch and never think about it again. Granted I’ve never had a repeat hydro failure after I’ve replaced the slave and hose, but the fluid flushing and failure rates of the hydro components are trash on principle for no net gain. been so long I’m forgetting if the fork and ball are the same between the two or the cable swaps right in Edited July 30, 2023 by idosubaru Quote Link to comment Share on other sites More sharing options...
el_freddo Posted July 30, 2023 Share Posted July 30, 2023 Clutch fork and the pivot point need to be changed if swapping from hydro to cable clutch or vice versa. Plus you need the clutch cable mount bracket on the gearbox, mods to the pedal box and a suitable hole in the firewall for the cable to pass through. Much easier to just maintain/replace components on the hydraulic setup as needed. And I’d argue that clutch cables require just as much maintenance as the hydraulic setup. Cheers Bennie 1 Quote Link to comment Share on other sites More sharing options...
Ravenwoods Posted August 1, 2023 Author Share Posted August 1, 2023 Problem has gone away with cooler weather. It only happened that one hot evening. With 323, 000 miles on it maybe the car will die soon! But the engine still seems so strong. Quote Link to comment Share on other sites More sharing options...
Ravenwoods Posted July 25 Author Share Posted July 25 It's been a year since I first posted this about the clutch problems in hot weather. I didn't do anything to maintenance the clutch since then and it has performed well in the last year and the car has 7000 more miles on it (330,000 miles now). So today we have hot weather again and I was out driving and it repeated the same problem as last year when we had temperatures up in the mid 80s here in Fairbanks, Alaska. To refresh the topic, the clutch pedal gets stuck in the down position in hot weather if you drive the car around much and the engine and clutch get hot. You have to pull it up with your foot. And it gets difficult to shift gears. So this only happens in hot weather in the mid 80s or hotter. After the engine cools down, the clutch will be normal again, based on previous experience. Just like last year I don't plan on doing anything to remedy the problem. This is a problem that happens maybe once a year. I just avoid driving it when hot. It definitely would not be a good car in the lower 48, but up here with our cold winters it seems happy. Quote Link to comment Share on other sites More sharing options...
lmdew Posted July 25 Share Posted July 25 Clutch hose replaced? System air free? Quote Link to comment Share on other sites More sharing options...
el_freddo Posted July 25 Share Posted July 25 I can’t be bothered working out what 80°f is in Celsius, anyway, what type of brake fluid are you using in the clutch system and when was the last time it was flushed? Also a good time to put a new flexible hose to the slave cylinder. Cheers Bennie Quote Link to comment Share on other sites More sharing options...
Ravenwoods Posted July 25 Author Share Posted July 25 11 hours ago, lmdew said: Clutch hose replaced? System air free? No maintenance at all. No hose replacement. A year ago I did suck out the brake fluid in the Clutch reservoir and put in new brake fluid. The clutch works normally when its not hot. It feels more like a mechanical problem like a spring or something. When you pull the clutch pedal up it goes through some resistance halfway up and then pops up all the way nicely. Quote Link to comment Share on other sites More sharing options...
Ravenwoods Posted July 25 Author Share Posted July 25 7 hours ago, el_freddo said: I can’t be bothered working out what 80°f is in Celsius, anyway, what type of brake fluid are you using in the clutch system and when was the last time it was flushed? Also a good time to put a new flexible hose to the slave cylinder. Cheers Bennie 85 F. is about 30 C. I'm using DOT 3 brake fluid and I sucked out the fluid in the reservoir and put in new a year ago. I didn't flush the whole system. I suspect the problem is more mechanical. When I pull the clutch up it goes through some resistance, just like you do when you push the clutch pedal down. Halfway up it then pops the clutch all the way up. Its as though a spring or something gives resistance. The car has some bad rust around the right rear fender and rear door frame. So I'm not too interested in the car's longevity. 1 Quote Link to comment Share on other sites More sharing options...
nvu Posted July 25 Share Posted July 25 The pedal is has a bistable helper spring mechanism. The first half of travel the spring wants to push it back up, when you pass halfway, the spring wants to pull the pedal down. Think of an old school light switch. Could you try pressing the clutch all the way down, then keeping it held down with a 2x4 or something. Check if the slave cyl is holding the fork down after an hour. Quote Link to comment Share on other sites More sharing options...
Ravenwoods Posted July 25 Author Share Posted July 25 1 hour ago, nvu said: The pedal is has a bistable helper spring mechanism. The first half of travel the spring wants to push it back up, when you pass halfway, the spring wants to pull the pedal down. Think of an old school light switch. Could you try pressing the clutch all the way down, then keeping it held down with a 2x4 or something. Check if the slave cyl is holding the fork down after an hour. This sounds like the most likely explanation. So is this spring in the passenger compartment? The temperature with air conditioning doesn't get that hot. So I'm assuming it is located at the clutch itself or in the engine compartment. You have to drive the car around for a few miles so that the engine and engine compartment get thoroughly hot. I'm not actually too interested in making a repair since We don't have too many really hot days here. The rest of the year it works normally. I did notice something interesting this morning when I got in the car and tested the clutch. The very first time I pushed it to the floor it did stay down even though the engine is cold. But after I pulled it up it worked normally again. Quote Link to comment Share on other sites More sharing options...
nvu Posted July 26 Share Posted July 26 It's a coil spring on the base of the pedal. You can see it if you're on your back and shine a light up where the pedal pivot is. They never break. Actually while you're under there, check the entire brake/clutch bracket for any cracks from corrosion. It really sounds like something wrong with the hydraulics, to the point where it can't overcome the pedal assist spring. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted July 31 Share Posted July 31 Sounds like the clutch hose is internally collapsing and not allowing fluid to flow freely for nominal operations. Free it up - fine - stick - free it up - fine - stick…. Unsure how to confirm that or diagnose it for sure but often collapsed hydraulic hoses allow fluid to flow one way - the way with leveraged pressure, but not a way with less, or non-leveraged, pressure like a spring, gravity, light incidental contact, etc replace the hose and have a list of favorite cuss words handy to bleed it. Lol Quote Link to comment Share on other sites More sharing options...
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