Which throwout bearing?

[79HeavyChevy]

I've got a 79 k10 with the sm465, its still got the mechanical linkage for now but I've got all the hydro swap part coming. My question is to what throwout bearing I need to use when I swap the bellhousing. It lists the same diaphragm clutch kit for both a 79 and a 86, but just the throwout bearing lists two different part numbers. I have to put one in it because my current one is making a bunch of noise.

The 79 lists a 614018, and a 86 lists a 613083. Those are both national part numbers, I've pulled both and looked at them and they look the same but figured there is a difference.

Thanks,
Adam

 

[nvrenuf]

I believe there is a height difference. FYI, the forks are different between mech and hydraulic.

 

[79HeavyChevy]

If I get a chance tonight at work I'll pull them and snap a couple pictures. I thought there was a difference in clutch forks, I believe he is sending me one with the bell housing.

 

[79HeavyChevy]

Well throwout bearing officially bit the dust tonight, about 6 hours after iceman told me my hydro parts were in the mail. Guess it had finally had enough abuse, might as well start pulling it apart now.

 

[79HeavyChevy]

Bringing this back up instead of starting a new thread.

Hydro swaps been done since may and everything works well. My only question is what causes the throw out bearing to sit there and chatter?
Will do it even running down the road with my foot off the clutch pedal. Just a little bit of pressure on the pedal and it smooths out.

 

[diesel4me]

The throwout bearing should not even spin unless the clutch is disengaged--if its still touching the pressure plate with the clutch pedal up either it was the wrong one (too long) or it was not adjusted right and had no free play..

Far as I remember GM had 3 different lengths of throwout bearings..one fit the "flat" diaphram type and was the longer of the three,then there was a "medium" length one used on some of the "raised diaphram" type pressure plates,and the shortest one was usually used on the 3 finger borg & beck style pressure plates...after GM started using hydro clutches I dont know what bearing they used,that was about the time I left the auto parts counters..

I've seen pressure plates that had loose fingers or pivots and they made annoying noises until you pushed the pedal down slightly...maybe it was not the throwout bearing causing the noise--it should have some slop or roughness when you spin it if it was bad...

 

[79HeavyChevy]

I have shredded 2 in the past when it still had the linkage because you could only get it to fully disengage if the throw out bearing rode the pressure plate all the time. When I tried to get some gap it would drag the clutch even with pedal fully depressed.

I don't know of any adjustment in the hydro set up, someone please let me know if I'm missing something. This throw out bearing was a new national bearing I installed in May.

I'll try and get a video of the clutch fork soon, I don't have the trans tunnel in the truck so its easy to notice.

 

[dyeager535]

No adjustment in the hydraulic setup in stock condition. I've seen some aftermarket master cylinders that have a threaded rod to the clutch pedal, but that's not for actual adjustment of fork throw.

 

[offshore]

I think you still need a spring to hold back the lever/fork don't you?

 

[79HeavyChevy]

I was just thinking about that last night, I knew it had a spring on the mechanical linkage but wasn't sure about the hydro setup.

 

[offshore]

I would put one in and try it. the way it sounds now is that it is dragging against the pressure plate but the spring should pull it back a bit more

 

[79HeavyChevy]

No chance to throw a spring on it yet. Thought the clutch felt funny on my way to work and steadily got worse all day. Pretty much useless by the time I got home. Guess I'll be checking things tomorrow and trying to re bleed it after work.

 

[79HeavyChevy]

Bringing this back up, it killed the throwout bearing the following Saturday. I picked up a new throwout bearing and front bearing retainer because I'm wondering if mine is grooved.

I got to looking at the new national bearing I got and noticed that its not sealed, do they make a sealed bearing? I'm wondering if part of my issues are washing the grease out of it on water crossings.