86 K20 Curb drop = temporary Clutch No Engage

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

viaminveniam1939

Supporting Member
Supporting Member
Joined
Mar 3, 2024
Posts
28
Reaction score
10
Location
Dayton
First Name
Nick
Truck Year
86
Truck Model
K20
Engine Size
350
86 K20 350M (L,1,2,3,R) 4x4

Just installed new clutch master & slave cylinders. I bled the system & am fairly certain I got all the air out. NOTE -I did NOT bench bleed the master. I first went about bleeding the system the old fashioned way… this obviously took a while. So long, in fact, having never bled anything -ever-, I wasn’t sure I was doing it correctly (kept at it tho until I believed I wasn’t see air bubbles. To be certain tho, I bought a Motive Pressure Bleeder and pressure bled the system a bit more… for good measure. The “no clutch engagement” issue seemed resolved (shifting better than I’ve experienced since purchasing truck… DOT 3 was nearly black and leaks evident all about rusty M&S cylinders). FYI - my clutch master cylinder is angled -slightly- down toward engine.

Used truck yesterday (1st time since replacing clutch M & S cylinderls). Clutch did fine for nearly the entire time. At one point tho, I dropped the back end of truck off curb into the street (neighborhood park cleanup and we were moving limestone to flower beds). NOTE - Shocks r shot (new on the way) so such drops/bumps/etc. make u feel like your going to bounce right of truck.

With the drop, suddenly & temporarily, the clutch appeared to not engage (couldn’t find gear, grinding when I tried R… same issue that encouraged my replacing M & S cylinders, hoses, fluid). Finally found 2nd gear, after a short bit, and was able to move out of middle of the street. As I maneuvered truck to new location and killed the engine, the clutch issue kept occurring during this short trip across the park.

After I shut the truck down and let her sit for a bit tho (continued on with park volunteer work), I came back to use the truck and the clutch engagement issue was gone (not other issues since (this was yesterday).

Might I still have air in the system (having not bench bled the system first)?

Ps - all seals r leaking, but it’s not horrible and so I wouldn’t think low transmission fluid would be a factor?

Thanks you :)
 

fast 99

Full Access Member
Joined
Dec 31, 2021
Posts
2,029
Reaction score
2,935
Location
Spokane, Washington
First Name
Brian
Truck Year
81,85
Truck Model
K20
Engine Size
350
Believe it or not bleed those backwards. Suck all the fluid out of the master, leave lid off. Then attach a rubber hose to the bleeder on the slave open the bleeder and pump fluid in from the bottom until master is full. Should work the first time but may take twice. I use a clean or new pump oil can but should be able to do it with a pressure bleeder.
 

SquareRoot

Full Access Member
Joined
Mar 18, 2017
Posts
4,192
Reaction score
8,030
Location
Arizona
First Name
Mike
Truck Year
85
Truck Model
K20
Engine Size
350
Believe it or not bleed those backwards. Suck all the fluid out of the master, leave lid off. Then attach a rubber hose to the bleeder on the slave open the bleeder and pump fluid in from the bottom until master is full. Should work the first time but may take twice. I use a clean or new pump oil can but should be able to do it with a pressure bleeder.
Exactly. I keep telling people to reverse bleed the brakes and clutch and avoid the drama. One man job and 100% effective.
 

WFO

Full Access Member
Joined
Jan 6, 2017
Posts
3,688
Reaction score
5,034
Location
Texas Panhandle
First Name
Dan
Truck Year
1986
Truck Model
K20
Engine Size
350
I just pull the slave cylinder off and hold it hose end up, while pushing the piston in a few times until bubbles quit appearing in the master.

It does take another person to watch the bubbles though.
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
5,449
Reaction score
8,686
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
I stick a wrench and vacuum line on the bleeder,I connect the vacuum line to manifold vacuum,start the vehicle,crack the bleeder ,watch my level drop,tighten the bleeder,fill myvreservoir,put away my vacuum hose and wrench. Works for me.
 

viaminveniam1939

Supporting Member
Supporting Member
Joined
Mar 3, 2024
Posts
28
Reaction score
10
Location
Dayton
First Name
Nick
Truck Year
86
Truck Model
K20
Engine Size
350
Believe it or not bleed those backwards. Suck all the fluid out of the master, leave lid off. Then attach a rubber hose to the bleeder on the slave open the bleeder and pump fluid in from the bottom until master is full. Should work the first time but may take twice. I use a clean or new pump oil can but should be able to do it with a pressure bleeder.
What the best method for sucking fluid out of Master Cylinder? How will I know it’s all out?
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
5,449
Reaction score
8,686
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
What the best method for sucking fluid out of Master Cylinder? How will I know it’s all out?
Use a turkey baster,you aren't going to get it all out,just what you can readily see from the top and don't worry about getting all of it. You actually are just making room in the reservoir for the new fluid you are pumping in. You don't have to remove any,but it will make a big mess when the reservoir overfills and runs everywhere.
 

Latest posts

Forum statistics

Threads
44,163
Posts
950,654
Members
36,276
Latest member
2manysquares2care
Top