1986 GMC C3500 clutch will not engage or disengage

JARRMAR

MEMBER
1986 GMC C3500
V8
2WD
MANUAL
18,000 MILES

I have an 1986 gmc dump truck 1ton (3500), the throw out bearing went out so I desided just to replace the whole clutch system. I replaced the clutch plate, press plate, pilot bearing, fly wheel resurfaced, throw out bearing and clutch fork. Get it all back together and started the truck and it will not engage. If I start it with it in gear the truck surges forward. I tried bleeding slave but no help. So I removed the trans again to check if clutch plate was in backwards and it was NOT. Its like the throw out bearing in not pressing on the pressure plate enough? Could I need a new slave cyl? It seems to be working fine! Thanks

1 Reply

DR LOOT

MECHANIC
2,311 POSTS

Improved Bleeding Procedure for Hydraulic Clutch Release System TECHNICAL SERVICE BULLETIN Reference Number(s): 01-07-31-002B, Date of Issue: November 01, 2006Affected Model(s):2007 and Prior GM Passenger Cars and Light Duty Trucks (including Saturn); 2007 and Prior Chevrolet and GMC 6-7F T-Series Medium Duty Tilt Cab Models; 2007 and Prior Isuzu F-Series Medium Duty Tilt Cab Models; 2006-2007 HUMMER H3Supercedes:This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 01-07-31-002A (Section 07 - Transmission/Transaxle). Related Ref Number(s): 01-07-31-002, 01-07-31-002A, 01-07-31-002BARTICLE BEGINNINGSERVICE INFORMATION

This bulletin is being issued to inform dealers of an improved procedure to aid in the ease of bleeding the clutch hydraulic system for the above listed vehicles. This procedure can be used anytime air is introduced into the hydraulic system. Following this procedure may also reduce the number of unnecessary parts replaced for low clutch pedal reserve and high shift effort. Verify that all the lines and fittings are dry and secure. Clean the dirt and grease from the reservoir cap in order to ensure that no foreign substances enter the system. Remove the reservoir cap. Fill the reservoir to the proper level with the required fluid. Attach the J 43485 (Adapter) to the J 35555 (Mity Vac), or equivalent. Place and hold the adapter on the reservoir filler neck to ensure a tight fit. In some cases, the adapter will fit into the reservoir opening. Apply a vacuum of 51-68 kPa (15-20 hg) and remove the adapter. Refill the reservoir to the proper level. Repeat Steps 6 and 7. If needed, refill the reservoir and continue to pull a vacuum until no more bubbles can be seen in the reservoir or until the fluid level no longer drops.
CAUTION: The vehicle will move if started in gear before the Actuator Cylinder is refilled and operational. Start the vehicle the first time in neutral to help prevent personal injury from vehicle movement and see if the transmission will shift easily into gear. Pump the clutch pedal until firm (to refill actuator cylinder). Add additional fluid if needed. Test drive vehicle to ensure proper operation.