Clutch pedal wont return
04-17-11, 05:37 PM
#1
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Clutch pedal wont return
Hello everyone, I depressed the clutch one day while just feeling how the shifter went between gears and how smooth it was and i let off the clutch and now it wont return! I've tried searching around here and through google and i havent come up with a very definitive answer but from what I've read there could be air in the lines? I've checked around the master cylinder and theres no leaks but the fluid is very black, is this when i should bleed it and re-fill the fluid or will i need to pull apart the master and slave cylinder and re-build them. Thanks for looking!
04-17-11, 05:55 PM
#2
What your suffering from is simple you have either a leak from the slave cyl located on the drivers side of the trans,or worn rubbers from the master clutch cyl,which caused the black fluid best bet replace both add new fluid and forget about it it only happens every30 years, if you want to prove which is at fault, I just clamp a vice grip gently but firmly(totally close of the line ) on the flex line then pump the clutch if you can't push it down,its good if it pushes to the floor its time for a new 1................................................. ...............Fred
04-17-11, 07:04 PM
#3
I had this happen just last month, on a recently rebuilt master cylinder. It had one of those new style plastic pistons. It somehow got stuck in the bore. I had to thread an 8mm x 1.25 thread cutting tap into the rod hole of the plastic piston (really easy and the plastic threads easily). This is the only way I could get the piston out of the bore. It took brute force to get it to move. Very very odd thing to happen to a fairly new part.
The new one was another plastic type, but it went in smoothly. To make sure I wasn't imagining things, I tested the old one, and it was still super tight, although it loosened up a little. The new one slid back in like normal.
I really can't explain why it got all stiff like that. Maybe brake fluid made it expand?
So if you decide to rebuild your master cylinder, you'll probably get a plastic piston. My advice is to reuse your metal piston and swap the rubber seal over (if it fits).
The new one was another plastic type, but it went in smoothly. To make sure I wasn't imagining things, I tested the old one, and it was still super tight, although it loosened up a little. The new one slid back in like normal.
I really can't explain why it got all stiff like that. Maybe brake fluid made it expand?
So if you decide to rebuild your master cylinder, you'll probably get a plastic piston. My advice is to reuse your metal piston and swap the rubber seal over (if it fits).
04-17-11, 07:24 PM
#4
Air in the clutch lines normally shows up as the clutch failing to release fully when the pedal is pressed, and a spongy, soft feel to the pedal.
You've got either a master or slave piston failure (either the stuck piston symptom Jeff discussed, or a blown piston that's bypassing all the fluid - look under the dash for fluid leaking from the master into your carpet), or a mechanical problem with the slave-to-clutch linkage that's allowing it to stick.
The 'black fluid' makes me think it's most likely that your piston seals have just dissolved over time & wear, and it's time to pull both units and rebuild or replace them.
You've got either a master or slave piston failure (either the stuck piston symptom Jeff discussed, or a blown piston that's bypassing all the fluid - look under the dash for fluid leaking from the master into your carpet), or a mechanical problem with the slave-to-clutch linkage that's allowing it to stick.
The 'black fluid' makes me think it's most likely that your piston seals have just dissolved over time & wear, and it's time to pull both units and rebuild or replace them.
04-17-11, 08:53 PM
#5
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here's a quick guide to checking clutch hydraulics for failure:
If the clutch pedal is sticking to the floor then it's very very likely to be the hydraulics and as well will cause shifting problems particularly trying to shift into first or reverse from a dead stop.
1. Check your fluid level and condition
2. Look inside the footwell where the pedal pushrod goes into the back of the master cylinder and see if there is fluid leaking. [bad master cyl]
3. Look at the slave cylinder and pull the dust boot back and see if it is damp and if there is buildup and dampness around the slave itself [bad slave cyl]
4. Check the condition of the flex hose itself, the outer casing will likely be cracked but check for any tearing, dampness, leakage especially around the ends where it's bolted to the hardline or slave cyl.
5. If you can find someone to help you, open the hood, take the cap off the master cyl reservoir and have an assistant pump the clutch a few times then hold it down to the floor. Look carefully at the slave cylinder to see if it holds still in the extended position, if it begins to slowly return while the pedal is still depressed and there appears to be no leak at the slave cyl and the boot is dry and clean. Repeat the pedal pump and hold and this time look at the master cyl reservoir, watch the fluid level and see if while the pedal is held down to see if the fluid returns back on its own, if it does this is a sign of an internal leak in the master.
6. If no leaks or signs of failure are apparent, flush out the fluid and lines with new fluid and see if that helps.
As always it is the BEST practice to replace everything together so you do not fix one thing then have another fail a week or two later because usually when one fails, the other is bound to be on it's way.
RockAuto.com generally has the best prices available for all the parts you will need, try not to get the cheapest master as even though it will last you a long time, you still want a quality product.
When I did my hydraulics I went ahead and replaced both master and slave, and picked up a stainless braided clutch line from Mazdatrix for about $25-30 shipped and IMO well worth it.
1. Check your fluid level and condition
2. Look inside the footwell where the pedal pushrod goes into the back of the master cylinder and see if there is fluid leaking. [bad master cyl]
3. Look at the slave cylinder and pull the dust boot back and see if it is damp and if there is buildup and dampness around the slave itself [bad slave cyl]
4. Check the condition of the flex hose itself, the outer casing will likely be cracked but check for any tearing, dampness, leakage especially around the ends where it's bolted to the hardline or slave cyl.
5. If you can find someone to help you, open the hood, take the cap off the master cyl reservoir and have an assistant pump the clutch a few times then hold it down to the floor. Look carefully at the slave cylinder to see if it holds still in the extended position, if it begins to slowly return while the pedal is still depressed and there appears to be no leak at the slave cyl and the boot is dry and clean. Repeat the pedal pump and hold and this time look at the master cyl reservoir, watch the fluid level and see if while the pedal is held down to see if the fluid returns back on its own, if it does this is a sign of an internal leak in the master.
6. If no leaks or signs of failure are apparent, flush out the fluid and lines with new fluid and see if that helps.
As always it is the BEST practice to replace everything together so you do not fix one thing then have another fail a week or two later because usually when one fails, the other is bound to be on it's way.
RockAuto.com generally has the best prices available for all the parts you will need, try not to get the cheapest master as even though it will last you a long time, you still want a quality product.
When I did my hydraulics I went ahead and replaced both master and slave, and picked up a stainless braided clutch line from Mazdatrix for about $25-30 shipped and IMO well worth it.
04-17-11, 11:39 PM
#6
it's possible that the leak is in the slave. pull the boot back on the slave and see if there isn't fluid in it. the best solution is to replace both slave and master, and the flex hose as well. just reach down and pull the pedal up off the floor and bleed the system out if there's no leak at the slave.
