Help bleeding clutch on 87 halfton - The 1947 - Present Chevrolet & GMC Truck Message Board Network

TylerHuff · 10-30-2017, 09:05 PM

I just replaced the clutch and slave cylinder on my 1987 4x4. I cannot for the life of me get the clutch bled properly. I have tried gravity bleeding, pumping and cracking the bleeder, mity vac, and pushing the rod on the slave cylinder back into the housing. Pushing the fluid back up to the reservoir is the only way I can get any bubbles out but my arms are tired and the clutch still won't disengage. I don't know what else I can do.

B. W. · 10-30-2017, 09:29 PM

I feel your pain, been there more than once. Not that this helps, you can buy a pre-bled master & slave combo, that's what I do now when I change one. Kind of a pain to snake the line down but still way quicker than bleeding. there are also some specialty bleeders that work well but they are pricey.

Just thought about it, the combo kits are made for '88 and up, don't know if they make them for yours.

BossHogg69 · 10-31-2017, 06:47 AM

I just went through this last weekend with a RAM hyd throwout bearing and wilwood 3/4 clutch master, it's a little different than a slave cylinder, but the same principles apply. I tried pumping/bleeding, the MityVac (which works awesome on brakes!) and gravity bleeding - nothing working. I could get some air bubbles out with the MityVac, but couldn't get the pedal quite right. I ended up having to pull the transmission out, and manually pumping the throwout bearing a bunch of times with the m/c cap off and finally got the pedal right. At least yours has a clutch rod/slave cylinder that you can access without pulling the trans. I ran a McLeod hyd t.o. bearing before this RAM and it would bleed just fine using the bleeder screw. In defense of the RAM unit, I'm also using a RAM hydraulic pedal adjuster inline before the t.o. bearing, and it may have been where the air was trapped. You might try unbolting the slave cylinder and working it while tilting the fluid inlet end up toward while working it back & forth to allow any trapped air to exit the system. Sometimes the air bubbles get trapped horizontally in the slave cylinder and are stubborn to get out.

TylerHuff · 10-31-2017, 06:57 PM

Well I took the slave off and pushed the plunger in about a thousand times and got a lot of air out but still couldn't get enough pedal to get the clutch to release. Don't really know what else I can do.

TylerHuff · 11-03-2017, 07:40 PM

Well I took it to a shop and figured out the brand new pressure plate is bad, so looks like the transmission has to come out again. Clutch hydraulics were fine once I got all the air out.

BossHogg69 · 11-03-2017, 09:39 PM

Hate to hear that... Getting new parts out of the box is REALLY frustrating, and happens more than it should these days. Glad you got it figured out.

10-30-2017, 09:05 PM	#1
TylerHuff Registered User Join Date: Sep 2008 Location: Blue Springs, MO Posts: 168	Help bleeding clutch on 87 halfton I just replaced the clutch and slave cylinder on my 1987 4x4. I cannot for the life of me get the clutch bled properly. I have tried gravity bleeding, pumping and cracking the bleeder, mity vac, and pushing the rod on the slave cylinder back into the housing. Pushing the fluid back up to the reservoir is the only way I can get any bubbles out but my arms are tired and the clutch still won't disengage. I don't know what else I can do. __________________ 1987 Gmc sierra 1962 Apache 10

10-30-2017, 09:29 PM	#2
B. W. Registered User Join Date: Nov 2014 Location: Bigfork, Montana Posts: 1,137	Re: Help bleeding clutch on 87 halfton I feel your pain, been there more than once. Not that this helps, you can buy a pre-bled master & slave combo, that's what I do now when I change one. Kind of a pain to snake the line down but still way quicker than bleeding. there are also some specialty bleeders that work well but they are pricey. Just thought about it, the combo kits are made for '88 and up, don't know if they make them for yours.

10-31-2017, 06:47 AM	#3
BossHogg69 motor exploder Join Date: Mar 2009 Location: Pittsburgh, PA Posts: 2,346	Re: Help bleeding clutch on 87 halfton I just went through this last weekend with a RAM hyd throwout bearing and wilwood 3/4 clutch master, it's a little different than a slave cylinder, but the same principles apply. I tried pumping/bleeding, the MityVac (which works awesome on brakes!) and gravity bleeding - nothing working. I could get some air bubbles out with the MityVac, but couldn't get the pedal quite right. I ended up having to pull the transmission out, and manually pumping the throwout bearing a bunch of times with the m/c cap off and finally got the pedal right. At least yours has a clutch rod/slave cylinder that you can access without pulling the trans. I ran a McLeod hyd t.o. bearing before this RAM and it would bleed just fine using the bleeder screw. In defense of the RAM unit, I'm also using a RAM hydraulic pedal adjuster inline before the t.o. bearing, and it may have been where the air was trapped. You might try unbolting the slave cylinder and working it while tilting the fluid inlet end up toward while working it back & forth to allow any trapped air to exit the system. Sometimes the air bubbles get trapped horizontally in the slave cylinder and are stubborn to get out. __________________ Adam 1969 Chevy CST/10 stepside, DART Big M/TREMEC Magnum Extreme/3.73's w/Detroit Truetrac 1965 Chevy Bel Air Wagon (daily driver), 327/TH350,10 bolt w/3.08's 1961 Chevy Bel Air Sport Coupe, ZZ454/M21/9" rear w/3.50's & Detroit Truetrac 2005 GMC 1500 ccsb 2wd, 6.0L/4L65e/3.73 G80 2006 GMC 2500HD ccsb 4x4, DMax LBZ/Allison 6spd/4.56's w/Detroit TrueTrac Use the SEARCH function on this forum - it is your friend!!

10-31-2017, 06:57 PM	#4
TylerHuff Registered User Join Date: Sep 2008 Location: Blue Springs, MO Posts: 168	Re: Help bleeding clutch on 87 halfton Well I took the slave off and pushed the plunger in about a thousand times and got a lot of air out but still couldn't get enough pedal to get the clutch to release. Don't really know what else I can do. __________________ 1987 Gmc sierra 1962 Apache 10

11-03-2017, 07:40 PM	#5
TylerHuff Registered User Join Date: Sep 2008 Location: Blue Springs, MO Posts: 168	Re: Help bleeding clutch on 87 halfton Well I took it to a shop and figured out the brand new pressure plate is bad, so looks like the transmission has to come out again. Clutch hydraulics were fine once I got all the air out. __________________ 1987 Gmc sierra 1962 Apache 10

11-03-2017, 09:39 PM	#6
BossHogg69 motor exploder Join Date: Mar 2009 Location: Pittsburgh, PA Posts: 2,346	Re: Help bleeding clutch on 87 halfton Hate to hear that... Getting new parts out of the box is REALLY frustrating, and happens more than it should these days. Glad you got it figured out. __________________ Adam 1969 Chevy CST/10 stepside, DART Big M/TREMEC Magnum Extreme/3.73's w/Detroit Truetrac 1965 Chevy Bel Air Wagon (daily driver), 327/TH350,10 bolt w/3.08's 1961 Chevy Bel Air Sport Coupe, ZZ454/M21/9" rear w/3.50's & Detroit Truetrac 2005 GMC 1500 ccsb 2wd, 6.0L/4L65e/3.73 G80 2006 GMC 2500HD ccsb 4x4, DMax LBZ/Allison 6spd/4.56's w/Detroit TrueTrac Use the SEARCH function on this forum - it is your friend!!



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