About how much pre travel is normal? I’ve had the car for about 2 months and bled/replaced the clutch fluid last night, but when I started the car the next morning and went to drive it was very soft. I rebled/ topped up the fluid again today and the clutch feels like it did before when the car is off, but when it is on it feels very light. When I got the car it had a very stiff clutch. Is this normal or something that needs fixed? Any help is appreciated.
Clutch pre travel distance
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Pre travel? Do you mean free play? If so, there are a ton of threads here that can be searched... for simplicity sake, you can watch the old video from Jack's or more recent one from Chris here:
No specifics mentioned about your car, but the usual suspects to check include booster/check valve, vacuum assist, master, slave/throw travel, pedal, etc.
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No specifics mentioned about your car, but the usual suspects to check include booster/check valve, vacuum assist, master, slave/throw travel, pedal, etc.
-sent from my Galaxy S22 Ultra
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142 Posts
Need to know model, year, turbo or NA, DOHC or SOHC, as there are differences in systems....different settings and vacuum asst etc. ?
Clutch pedal free play - Standard value:
<FWD> 6-13 mm (0.24-0.51 in.)
<AWD> 12-20 mm (0.49-0.79g in.)
Did the reservoir level drop overnight?
After you bleed it again, replace fluid and cap, set pedal free play, start it up,,,,,where is the clutch grabbing point as you release clutch to pull out in 1st?
The car is a 91 vr4, it was in a shop a few weeks ago for a timing change and they’d said that the clutch was within spec, but the behavior of the clutch has been strange. When the car is off, the clutch feels heavy, like it did before I bled it. After I bled it, and the car is running, it feels very soft, but engages around the same point, and I get hardly any feedback through the pedal. I image this could be a clutch booster going out. Could I just remove the vacuum lines to the booster to see if that’s the culprit? I wouldn’t think that it would be the master or slave, since it feels fine when the car isn’t running, but I wouldn’t be shocked.
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Unless I'm missing something, it sounds like you are expecting the clutch pedal resistance to be stiff as it was before, and it shouldn't change to a lighter resistance once the car is running ----because that's how it was before your clutch fluid job. If so, you have actually fixed a previous problem and have it working properly now. You have a clutch booster that receives a vacuum supply ONLY WHEN THE ENGINE IS RUNNING which purposely reduces the clutch pedal resistance force by desired design. That's exactly what you now have happening as is expected. The fact that there was no change before...running/not running...implies the vacuum assisted booster was not functioning properly. It's no different than loosing hydraulic assist power brakes and power steering when the engine isn't running.
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What did the old fluid look like when you flushed it out? Was it fairly clear or all black and sludgy?
If it was sludge it could be as Mothsmoths said, getting the muck out got things working again.
Be aware though black muddy fluid is a sign that the rubber parts of the system are deteriorating.
That could mean the seals in either (or both) the master or slave cylinder, as well as the often overlooked rubber hose on the firewall.
With the car running have someone work the pedal while you check the hose for any swelling, bulging, or leaking.
Any of those could make the pedal feel spongy, and flushing the fluid could have made it more noticeable..
Be sure to check the whole hose carefully, a quick look isn't enough.
If it was sludge it could be as Mothsmoths said, getting the muck out got things working again.
Be aware though black muddy fluid is a sign that the rubber parts of the system are deteriorating.
That could mean the seals in either (or both) the master or slave cylinder, as well as the often overlooked rubber hose on the firewall.
With the car running have someone work the pedal while you check the hose for any swelling, bulging, or leaking.
Any of those could make the pedal feel spongy, and flushing the fluid could have made it more noticeable..
Be sure to check the whole hose carefully, a quick look isn't enough.
Yes I realized this after I adjusted the pedal boat loads, as it was engaging 1/2 in from the floor. and it doesn’t help that I’ve not very experienced with manual cars so I’m not super familiar with the weight of a clutch.
I’ll be sure to check the hose, but the fluid wasn’t black at all, but it was pretty brown. Also didn’t seem like there was much sludge.
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Pardon me for butting in but doesn't the system hold vacuum after the engine is shut off much like a brake booster does? It seems like it works that way in my 92 at any rate. Brake pedal ain't stiff and neither is the clutch when I'm starting the car and neither changes when running. My clutch engages about 1/2 way up BTW.
Unless I'm mis-reading the thread which is very possible.
Unless I'm mis-reading the thread which is very possible.
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That is only valid for cars that have retained the clutch vacuum assist (reservoir); it is attached to the right-side crossmember with a hardline running adjacent to battery.
Old and useless "system" with safety switch disabled (save thrust bearings) and booster/check valve intact.
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What do you mean by clutch safety switch disabled? And would doing that extend the life of the thrust bearing? I assume your talking about the clutch booster?
I think it needs to be repaired.
I think it will be extended.
Very novel idea, I think it makes sense.
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The thrust bearings or washers are part of the engine, on the end of the crank, and are meant to limit the back and forth movement of the crank.
The theory is that stepping on the clutch pushes against the crank (and thus the thrust bearings) and that starting the car this way increases wear on them.
Proponents say disconnecting the safety switch to allow you to start the engine without using the clutch (in neutral of course!) saves the bearings....
I'm not an engine re-builder and can't speak on whether there's anything to this theory...
If you're using a heavy duty or racing clutch with heavier springs you might want to look into it but with a stock clutch I'd guess there's a greater risk of your girlfriend/wife driving the car through the garage door with the safety disconnected than ever having problems with your thrust bearings. But that's just a guess, I'm no expert.....
The theory is that stepping on the clutch pushes against the crank (and thus the thrust bearings) and that starting the car this way increases wear on them.
Proponents say disconnecting the safety switch to allow you to start the engine without using the clutch (in neutral of course!) saves the bearings....
I'm not an engine re-builder and can't speak on whether there's anything to this theory...
If you're using a heavy duty or racing clutch with heavier springs you might want to look into it but with a stock clutch I'd guess there's a greater risk of your girlfriend/wife driving the car through the garage door with the safety disconnected than ever having problems with your thrust bearings. But that's just a guess, I'm no expert.....
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There has been a lot of great information, wisdom, and experience posted here since I last posted above. But you are a man of few words and never actually say what you found and whether you have a normal functioning clutch now. In the one sentence you wrote, you mention "adjusting your pedal boat loads" and that the clutch was engaging at 1/2 in. off the floor. That makes me think you were not dealing with free-play or booster system issues only. Free play is the pedal movement that occurs before any part of the hydraulics system is engaged. With the clutch engagement point so low, I'm suspicious that you still have a problem in the hydraulic system somewhere. Where to look requires you to answer a few questions. Was the clutch engagement point normal before you changed the fluid? If so, you likely still have air in the master cylinder, in the lines, or in the slave hydraulic system somewhere. If so, most of the pedal stroke goes to compressing air pockets before the slave starts to actuate against the clutch fork. What clutch fluid did you use? What process did you use to bleed the system? If the clutch engagement point was low before you started, then a master or slave or as @Steve '93ES suggests issues need to be addressed. There are suggestions we can give if needed when the usual bleeding procedure isn't successful.
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Well the hardline is there and since the original owner did 0 mods, I assume that it's still active and functioning properly.
I have other things to do, I’ll get an update posted when I get some time to work on it. I wouldn’t think that there is air in the lines, but I’ll pry try to bleed it again.
Where is the hose at? Is it just the hose running immediately behind the master cylinder?
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More towards the passenger side of the firewall. Kind of in the middle-right (Passenger side) below the solenoid bracket. Follow it back from the slave cylinder, you'll find it!
(You'll probably have to take the intake hoses off)
(You'll probably have to take the intake hoses off)
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