No clutch pressure

Tiny
CHRIS GARRETT
  • MEMBER
  • 1993 GMC SONOMA
  • 4.3L
  • V6
  • 4WD
  • MANUAL
  • 181,000 MILES
Okay, I was driving truck going through the gears as I got up a hill got to the top of hill went to put it in fifth gear wouldn't go in gear, then realized had no clutch pressure. Got the truck home and immediately got to work on taking slave and master cylinder out slave cylinder was shot rod fell out when it was pulled out of transmission. Master cylinder looked good rod was still tight but had it out so replaced it anyways. With new cylinders in still have no pressure. I have bleed the line several times and could get air out bleeding it from the slave cylinder but still wont build pressure. No leaks in lines. Everything is new. Someone please help need my truck back ASAP.
Wednesday, August 14th, 2019 AT 6:25 AM

17 Replies

Tiny
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Hi Chris, thank you for using 2CarPros. Lets get this working.

First question, Did you bench bleed the master or just install it and bleed with the clutch pedal?

Rich.
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Wednesday, August 14th, 2019 AT 6:39 PM
Tiny
CHRIS GARRETT
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Just installed and bleed with clutch.
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Wednesday, August 14th, 2019 AT 6:44 PM
Tiny
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Okay Chris, Here is a link on how to bleed one. You need to bench bleed it first because the shaft attached to the clutch pedal doesn't depress the plunger in the mast cylinder all the way so it allows air to remain in it. When you bench bleed it make sure you push it all the way in till it stops. Also make sure it is upright so the air can get out the top hole. Also note in the video, if your cylinder has an adjuster on it you will need to make sure it is adjusted.

https://youtu.be/3hvaYNM3TVQ

Let me know how it goes!

Rich
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+1
Wednesday, August 14th, 2019 AT 7:47 PM
Tiny
CHRIS GARRETT
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Thanks. Help is much appreciated.
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Thursday, August 15th, 2019 AT 5:14 AM
Tiny
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You are welcome. Tell your friends about us. We are here to help.

Rich
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Thursday, August 15th, 2019 AT 7:51 AM
Tiny
CHRIS GARRETT
  • MEMBER
  • 9 POSTS
Bench bled the master cylinder. So decided to go ahead and take the slave cylinder back out and bring it to bench also with all new line connections still can not get it to build pressure.
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Sunday, August 18th, 2019 AT 7:51 AM
Tiny
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Then you need to take it back and get another one. It is defective.

Rich.
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Sunday, August 18th, 2019 AT 8:51 AM
Tiny
CHRIS GARRETT
  • MEMBER
  • 9 POSTS
Okay, got it to finally work. But my clutch goes all the way to the floor and it engages gear letting off clutch barely at all very sensitive is this normal or is something still not right?
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Sunday, August 18th, 2019 AT 6:19 PM
Tiny
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That is an indication that there is still air in the system, or it is defective. Also make sure the arm that the slave cylinder engages, the one that pushes on the throw out bearing is in its seat properly. A worn out clutch can also cause that on some cars. How many miles are on that clutch?
Rich.
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Sunday, August 18th, 2019 AT 7:21 PM
Tiny
CHRIS GARRETT
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Truck got 181,000 miles on it. Not sure if clutch has ever been changed or not. Already have clutch kit on standby if that is the case.
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Monday, August 19th, 2019 AT 12:40 AM
Tiny
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Well to save the work of dropping the clutch and since you have had bleeding issues I would try bleeding it again and see if it gets any better. If the clutch fork is set right and you get no more air bleeding it then I would drop the clutch and see if there is any meat left on it.

Rich.
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Monday, August 19th, 2019 AT 6:01 PM
Tiny
CHRIS GARRETT
  • MEMBER
  • 9 POSTS
Okay, thanks. Also the truck also makes a whining/grinding noise when I'm just barely giving it enough gas to cost down the road. It was only doing it in fifth but now it doing in third fourth and fifth gears.
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Tuesday, August 20th, 2019 AT 5:32 AM
Tiny
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The fact that it is working its way down through the gears tells me the clutch is worn out. Fifth always slips first and the more worn it becomes the lower the gears get. You say you have a clutch for it, I would put it in and see where your pedal is then.

Rich.
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Tuesday, August 20th, 2019 AT 5:43 PM
Tiny
CHRIS GARRETT
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Okay, my pedal is working fine now, but the other noise I was hearing was my rear end was driving it yesterday and the noise was getting louder like it normally does the longer I drive it and eventually it was so loud I could definitely tell it was coming from my rear end. The truck started jerking like it was trying to lock up but anyways pulled over and looking underneath and my rear end has fluid all over it and is so hot it is smoking. But I'm trying to figure out what my gear ratio is and the only number I finding on it is 26027171. Got any ideas that could help?
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Monday, September 2nd, 2019 AT 9:02 AM
Tiny
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It sounds like the differential was very low on fluid and has now cooked itself. The only way to find the exact ratio is to pull the cover and count the teeth on each gear, then divide the number of ring gear teeth by the number of pinion teeth. That will give you the ratio. The only other way to get it is to have a dealer look up the VIN# but if anyone changed the gears that info will be wrong thus why counting the teeth is the best way.

Rich.
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Monday, September 2nd, 2019 AT 2:57 PM
Tiny
CHRIS GARRETT
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Okay, thanks a lot. Been a lot of help, much appreciated.
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Monday, September 2nd, 2019 AT 3:01 PM
Tiny
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You are welcome Chris, my pleasure. That is why we are here! If you need anything else let us know.

Rich
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Monday, September 2nd, 2019 AT 3:05 PM

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