Clutch Hydraulic fluid dark black w/ glitter in it.

[FourDoorSleeper]

Hi,

I have a '92 GVR-4 and have had a problem with a second gear grinding problem, which was semi-curred by using GM syncromesh and adjusting the clutch master cylinder pushrod as well as putting in new symborski (s/p) bushings.

Well now I have ran into a new problem: My clutch started to slip and the engagement points varied every time I pushed in the clutch pedal. Now the clutch pedal currently has no pressure until I push the pedal about half way (4 inches or so) to the floor than it has pressure. When I release the pedal it will barely come up and sometimes will stick halfway up. Also the car will move with the clutch depressed and in gear when I rev it up(car will move forward).

I suspect that I may have over-adjusted the pushrod and caused the slave/master to leak, but I have no apparent leaks at either one. The clutch reservoir is full, but the fluid is Dark Black w/ what appears to be a Glitter in it. I checked to make sure the pedal assembly is ok by pulling up on the pedal to make sure it is up all the way. I am 99.9% sure that it is hydraulic related, but I have heard about clutch assembly failures as well as clutch fork issues.

Can anyone enlighten me on suggestions/fixes? Much appreciated!!

Cliffs:
-Clutch pedal has no pressure until half-way down
-Clutch not fully dis-engaging (Car will move in gear when revved up and clutch depressed)
-No leaks at master/slave or loss of fluid at reservoir
-Clutch fluid dark black with "glitter" in it at reservoir
-I adjusted the clutch M/C pushrod prior to these problems and than about a week later the clutch starting slipping at full boost (23 psi)and then had problems shifting gears.

Help is greatly appreciated!!

Thank you,

-Nick

 

[Old Mitsu Tech]

"Glitter" could be the master cylinder consuming itself. Most likely you will be replacing both the master and the slave. Flush out your line also. Do it thoroughly. Get the air out and see where you stand from there.

Good Luck

 

[Morphius]

Sound like you may have over adjusted the master cylinder (M/C) input rod. Or just at the critical point, where it may or may not be in cut-off. Your clutch pedal has a maximum swing of x degrees. The M/C also has a maximum amount of fluid it can displace given the a maximum input of the pedal. When you adjust the M/C input rod, you are adjusting the pedal height or amount of swing the pedal can have. Per the service manual, this point is when you have resistance in the first 1/2" of travel of the pedal.

If you over adjust it (M/C input rod adjusted out too far), the pedal will be pushed to it's maximum height and the M/C input rod will now begin to be depressed. This is bad. When adjusted per the service manual, the M/C will go into cut-off in the first 1/8 or so of pedals stroke. Overadjusted, you've now put the system in cut-off early, before you've stroked the pedal.

Cut-off is this: there is a small valve that is internal to the M/C which seals when you first start to push the cluch pedal. This seals the volume of fluid in the M/C, line and slave seperate from the reservior on the M/C. This then allows you to push that volume of fluid through the hydraulic system and not back into the reservior.

When a system is misadjusted and in cut-off, it's possible to not have enough fluid in the system, to pull more fluid in but not let any out (pump-up), or pull air in. It's a gamble as to what exactly it'll do. Erratic it can become.

My suggestion would be to start from scratch. Adjust the M/C pushrod in (move pedal down a little), bleed it carefully, then readjust it so it has resistance in the first 1/2" of pedal travel. I'd also suggest checking your pedals. It's likely you have a worn pedal assembly. Look up under the dash as you apply the pedal, does the input rod move an appropriate amount of pedal travel, or is there slop?

 

[FourDoorSleeper]

Thank you for the replies! I figured that the glitter was probably from the M/C eating itself, but was hoping that was not the case. I currently do not have my GVR-4 with me as I am away in a different state, but I will home this weekend to work on it and hopefully get the car back into running condition (ie: get clutch working properly).

I would also like to add that when I last tinkered with the pushrod after the problems I am having, I adjusted the M/C pushrod all the way in without any difference, and the pushrod currently is as far in as it can go (towards the firewall that is). If I adjusted the pushrod out all the way the the freeplay would decrease but then the clutch would disengage at all.

Basically, I have the pushrod all the way in (towards the firewall) and am able to shift gear with a struggle while the car is running, but I have about 4 inches of free play in the pedal before I feel some pedal pressure.

I have a few more questions if you do not mind:

1. I am hoping to go back home and just bleed the clutch via gravity bleeding and adjusting the M/C pushrod back a bit.
2. If you were me would you order a new Slave and M/C or do you believe that bleeding the system and adjusting will do the trick? (I ask this because I will only have this weekend to get the car running and if I find out I need a slave/m.c. it will take a couple of days for the parts stores to get one in which will be to late for me)
3. I have the pushrod all the way in, how much would you back the pushrod out before I start the bleeding process.. Halfway? all the way? 1/4"?

Thank you again!

-Nick

 

[Morphius]

Thank you for the replies! I figured that the glitter was probably from the M/C eating itself, but was hoping that was not the case. I currently do not have my GVR-4 with me as I am away in a different state, but I will home this weekend to work on it and hopefully get the car back into running condition (ie: get clutch working properly).

I would also like to add that when I last tinkered with the pushrod after the problems I am having, I adjusted the M/C pushrod all the way in without any difference, and the pushrod currently is as far in as it can go (towards the firewall that is). If I adjusted the pushrod out all the way the the freeplay would decrease but then the clutch would disengage at all.

Basically, I have the pushrod all the way in (towards the firewall) and am able to shift gear with a struggle while the car is running, but I have about 4 inches of free play in the pedal before I feel some pedal pressure.

I have a few more questions if you do not mind:

1. I am hoping to go back home and just bleed the clutch via gravity bleeding and adjusting the M/C pushrod back a bit.
2. If you were me would you order a new Slave and M/C or do you believe that bleeding the system and adjusting will do the trick? (I ask this because I will only have this weekend to get the car running and if I find out I need a slave/m.c. it will take a couple of days for the parts stores to get one in which will be to late for me)
3. I have the pushrod all the way in, how much would you back the pushrod out before I start the bleeding process.. Halfway? all the way? 1/4"?

Thank you again!

-Nick

The quick check to see if the system is in cut-off is to climb under the car and see if you can push the slave pushrod back into the slave cylinder. If so, it's not in cut-off. If not, turn the master cylinder input rod in one turn. (you want the input rod to screw into the clevis more) Try the slave rod again. Repeat the adjustment of the M/C rod as neseccary. Once you can push the slave rod in, then proceed to bleed the system.

I'd also strongly suggest checking for play in the pedal. Have you welded the pedal? Watch the clevis as you press the pedal. Does the clevis move an appropriate amount for the equal amount of pedal movement? If you move the pedal 1-2 inches and the clevis hasn't moved at all, you've got a worn pedal assy. You need to fix that before anything.

If the M/C and S/C are not visably leaking, they are likely OK. Obviously, another sign is needing to add fluid on a regular basis.

 

[FourDoorSleeper]

The quick check to see if the system is in cut-off is to climb under the car and see if you can push the slave pushrod back into the slave cylinder. If so, it's not in cut-off. If not, turn the master cylinder input rod in one turn. (you want the input rod to screw into the clevis more) Try the slave rod again. Repeat the adjustment of the M/C rod as neseccary. Once you can push the slave rod in, then proceed to bleed the system.

I'd also strongly suggest checking for play in the pedal. Have you welded the pedal? Watch the clevis as you press the pedal. Does the clevis move an appropriate amount for the equal amount of pedal movement? If you move the pedal 1-2 inches and the clevis hasn't moved at all, you've got a worn pedal assy. You need to fix that before anything.

If the M/C and S/C are not visably leaking, they are likely OK. Obviously, another sign is needing to add fluid on a regular basis.

Ok, the system is not in cut-off then, as I am able to move the slave pushrod/piston back in by pushing it. Do you have any pics/links of the "clevis" on the clutch pedal assembly? I thought that the check for the pedal assembly was to push the clutch in and let it pop back up, then pull the pedal towards you to see if you can pull it any higher? If you could pull it higher you pedal assembly was shot.

I do not have a welded pedal in my GVR-4. Although this is a definate possibly: As the clutch problem is now with the 4 inches of freeplay and lack of disengagment, when I push the clutch in (with the car off) and let it pop up(sidestepping off the clutch pedal as if you were making a quick shift like when racing) the pedal seems to get stuck halfway up and then it will pop up. Basically the pedal not consistently but every couple times will stick on its way back up (roughly half way up) and then slowly come up in its own. Is this a symptom of a bad pedal of is it because of the lack of pressure due to the excessive freeplay? At the point where the pedal sticks is where my freeplay ends and I start feeling pressure.

Thank you,

-Nick

 

[FourDoorSleeper]

If the M/C and S/C are not visably leaking, they are likely OK. Obviously, another sign is needing to add fluid on a regular basis.

As far as this goes I have no visible leaks at either and have not lost any fluid from the reservoir. I do not DD the car and very rarely drive it (Maybe 1000 miles a year if that). The only noticable sign of the hydraulic fluid is the dark "burnt" color and the glitter.

-Nick

 

[95blackGsTurbo]

Master and Slave cylinders don't have to have an external leak to be bad. I have seen people hyperextend the slave cylinder rod on a brand new slave cylinder. It wouldn't bleed right and never leaked one drop but was bad. I would stick with Old Mitsu Tech's post and say they are eating away. Glitter doesn't get in there because there is air in the line. There is something beside's air in it.

 

[FourDoorSleeper]

Master and Slave cylinders don't have to have an external leak to be bad. I have seen people hyperextend the slave cylinder rod on a brand new slave cylinder. It wouldn't bleed right and never leaked one drop but was bad. I would stick with Old Mitsu Tech's post and say they are eating away. Glitter doesn't get in there because there is air in the line. There is something beside's air in it.

I understand that internally Master cylinders can leak, but I am not to concerned about that. I have seen people who overextended their pushrod and the slave cylinder pistons pops out.

By not bleeding right, what do you mean?

Thanks,

-Nick

 

[95blackGsTurbo]

I meant that when he hyperextended the rod he broke the seal and it allowed air in. So everytime we pumped the clutch it reinduced air into the system and never stopped spitting air out. Never built pressure either. I was just saying that if your fluid is glittery, that's not air. Something is going out that needs to be replaced and can't be bleed to be fixed.

 

[Morphius]

Ok, the system is not in cut-off then, as I am able to move the slave pushrod/piston back in by pushing it. Do you have any pics/links of the "clevis" on the clutch pedal assembly? I thought that the check for the pedal assembly was to push the clutch in and let it pop back up, then pull the pedal towards you to see if you can pull it any higher? If you could pull it higher you pedal assembly was shot.

The clevis is the bracket that's attached to the pedal assy that the M/C pushrod screws into. Yes and no. The pedal assy can act like that, may not. It can come all the way up, but it's not engaging or moving the M/C input rod/lever until part way through the pedal stroke.

I do not have a welded pedal in my GVR-4. Although this is a definate possibly: As the clutch problem is now with the 4 inches of freeplay and lack of disengagment, when I push the clutch in (with the car off) and let it pop up(sidestepping off the clutch pedal as if you were making a quick shift like when racing) the pedal seems to get stuck halfway up and then it will pop up. Basically the pedal not consistently but every couple times will stick on its way back up (roughly half way up) and then slowly come up in its own. Is this a symptom of a bad pedal of is it because of the lack of pressure due to the excessive freeplay? At the point where the pedal sticks is where my freeplay ends and I start feeling pressure.

Thank you,

-Nick

The pedal sticking issuse leads me more to the bad pedal assy as the problem. You could adjust the M/C some more (checking each time for cut-off) to see if you can raise the engagement point, but it sounds like the pedal would still do the same thing.

 

[Morphius]

Master and Slave cylinders don't have to have an external leak to be bad. I have seen people hyperextend the slave cylinder rod on a brand new slave cylinder. It wouldn't bleed right and never leaked one drop but was bad. I would stick with Old Mitsu Tech's post and say they are eating away. Glitter doesn't get in there because there is air in the line. There is something beside's air in it.

If they hyperextended it, they misadjusted the M/C input rod. Also, just because they blew it out, doesn't mean the S/C is bad. The slave piston can be carefully put back into the slave and used.

True, you push the piston out, it'll never bleed.

 

[95blackGsTurbo]

No they literally pulled the rod out of the slave cylinder and that is why is didn't bleed. Never touched the M/C. Anyways...did you bleed your system yet and see if that helped?

 

[FourDoorSleeper]

No they literally pulled the rod out of the slave cylinder and that is why is didn't bleed. Never touched the M/C. Anyways...did you bleed your system yet and see if that helped?

I currently do not have my GVR-4 with me as I am away in a different state, but I will home this weekend to work on it and hopefully get the car back into running condition (ie: get clutch working properly).

-Nick