sm465 hydraulic clutch problems

[timbo350]

I have a 84 k2o that has the sm465 manual and it had the mechanical clutch setup when i restored it i swapped in the hydraulic clutch setup every thing worked great but now my slave cylinder keeps leaking which in return means i have no clutch ive put in three slaves and every time I do this its shifts fine for a couple of months and then the clutch goes out i used the original pedal and welded the stud on it for the master cylinder rod is there anyhting i can do or is there something someone mite know that will help

 

[crazy4offroad]

Sounds like maybe the clutch master cylinder is pushing too much fluid into the slave cylinder and blowing the seal, from too much pedal travel from the mechanical pedal assembly. Repositioning the rod on the pedal closer to the pivot point may limit the travel but honestly it sounds like a trial-and-error type of situation. It may be quicker/easier/cheaper to just get a pedal assembly already set up for hydraulic.

 

[timbo350]

I have A 1989 obs dually with factory hyrdraulic clutch but the pedal isnt even close to fitting in my bracket even with modification can the pedal assembly from the 89 model be removed so i can put in in my 84

 

[bucket]

I have A 1989 obs dually with factory hyrdraulic clutch but the pedal isnt even close to fitting in my bracket even with modification can the pedal assembly from the 89 model be removed so i can put in in my 84

Yeah, if the '89 is a square body. I do recall the pedal assembly being different for vacuum brakes and hydroboost, but you can still make it work.

One other thing to consider is the pressure plate. There often seems to be issues with using the 3-finger type pressure plate with the hydro setup.

 

[oneluckypops]

HHHHMMMMMMMM Intresting... Ok what did you do for a flywheel? May sound like a stuiped question BUT. If you or anyone else has had ther flywheel surfaced and you didn't use the proper spacing shim, that could cause exsessive travel in the slave cylinder causeing the seal to blow out.

Another thought would be if the Hydraulic set up was installed with used parts. if they were sitting for awhile and some how got Dirt in the system, then the dirt could be getting forced into the slave and scoring the cylinder wall letting fluid leak by the seal.

 

[timbo350]

the clutch and pressure plate are from center force the clutch is stage 2 which is new all of the clutch parts are ac delco and were brand new as of today I went and took the pedal and hydraulics from my dually and installed them in my truck the pedal is different about 3/4 inch so i made up a shim for that and had to bend the master cylinder rod a little now I have great clutch and i dont have to push it to the floor its about 4-5 inches from the floorboard

 

[GreaseDog]

I'd put $20 on the stud being misaligned. Locate the proper pedal assembly and install it. This will require removing the steering column.

 

[HotRodPC]

I'd also make sure you''re using the right TO bearing. There is 2 different ones, one of them has a step in it making it longer. If you have the short one when you need the longer one, that also will further travel. Also make sure your clutch fork isn't bent. Just a couple other things to check, but I too feel your rod is likely the issue since you mention you retrofitted it and welded it.

BUT, <smack> <smack> why would you go with a hydro clutch over Z bar linkage??? Especially in a K20??? Sisssy clutches are for sissy trucks brah. I know I could never do it on a SM465 since they aren't speed shifting transmissions by any stretch, but I've blown slave cylinders apart just speed shifting and side stepping the clutch pedal when racing. Not a fan of hydro clutches at all in a performance truck.

 

[nvrenuf]

Why hydro? Because even with good body mounts the truck can flex enough while wheeling for the linkage to come apart.

 

[HotRodPC]

Why hydro? Because even with good body mounts the truck can flex enough while wheeling for the linkage to come apart.

Good Answer. Makes perfect sense now. And noone will be speed shifting an SM465 to the point of blowing out a slave. Now I"m glad I did save that hydro clutch bell housing.

 

[smurph20]

When i did mine i replaced everything with the same size and all and still had issues with the clutch not wanting to disengage enough to be able to put it in gear. I finally made a new rod to go between the slave and fork to get more throw out of it

 

[timbo350]

I went with hydro just do to bending the clutch rod and binding up all the time when the truck would tweak since doin the hydro ive not had a problem with puttin the truck in a bind as of rite now everything is good yesterday i pulled the pedal and components from another truck that i converted to automatic and my truck is shiftin great so I will see how this goes

 

[GreaseDog]

Good Answer. Makes perfect sense now. And noone will be speed shifting an SM465 to the point of blowing out a slave. Now I"m glad I did save that hydro clutch bell housing.

not all of us are as young as you... we've abused our bodies, and our joints ache after driving for any considerable amount of time in an ancient z bar equipped truck. i'm pulling the 465 out of my 80 altogether and replacing it with an 80E.

 

[HotRodPC]

I'm not young as most here. But, I had a Z bar clutch and a McLeod heavy ass clutch in the 64. Loved that clutch, but granted, it was stiff as hell. Never had a slip with it for sure. That clutch with a Muncie 21 and 22 and Hurst Comp Plus shifter was just about more fun than I could handle and I was only running about 400-425hp sometimes 350-375 depending on which motor I had in it at the time. I think I've pretty much talked myself out of the manual trans. Auto's are to common, to cheap to acquire and to cheap to build compared to manual transmissions and then the headache of dealing with clutches.

 

[timbo350]

my next upgrade will be a built 4l80e from monster transmission with the tci comp controller I have a swamp buggy that im wantin to haul and that sm465 has to long a apuse between shifts