Clutch problems

[Ronw435]

I am having a problem getting the clutch adjusted to allow dis-engagement of the clutch when trying to shift into gear. When I purchased the truck the clutch worked fine except for the fact that the clutch pedal was much higher than the brake pedal. The manual says that they are to be at the same height. I have checked and repaired all the attachment points with bushings to make sure that there is no play in those areas. I have changed the position of the clutch push rod nut from the inner to the outer position on the clutch fork. Still without raising the position of the pedal to allow more travel it still will not dis-engage. I have adjusted the clutch to within 3/16" play.

Any ideas?

Ronw435

[markeb01]

Are you convinced you received/installed the correct throwout bearing? With a low angle pressure plate you should be using the "tall" throwout. Conversely, if you're using a diaphragm pressure plate with the high angle spring fingers, you should have a "short" bearing.

The next thing I'd be checking is the angle of the clutch fork. They are not all the same length, leverage, etc. Just a couple of things that pop in my head with issues like you're describing.

[1963c-10]

Check the bracket where the pedal rubber bumper is also. Very common to find these bent out of shape and that can cause the clutch pedal height to be much higher than the brake pedal.

[padresag]

http://www.lmctruck.com/icatalog/cbe/full.aspx?Page=89 and on the next page 90 is a picture of the clutch pedal assy
a lot of clutch adj problems come from wrong throw out brg( there are 2 - long and short), the wing nut looking thing on the end of the adj rod #3 in the linkage picture on page 89 and there should be a pedal stop rubber #2 on page 90
with the pedal in the appropriate place you should have about 3/4-1" of free play.
linkage ends and worn out holes where they go worn or missing bushings at the top of the pedal also make for slop in the linkage which you say that you have repaired. there can also be a problem with the linkage. last but not least is that there can be a problem with the clutch itself. what did the PO do to it or not do?
ron

[Ronw435]

The clutch, pressure plate, throw out bearing and input shaft bushing are all new and came as a kit. Hopefully it should be correct.
I dont have much slop in the linkage anymore as I corrected 90% of it. I will check and see if the bump stop is bent. The clutch fork is almost at a 90 degree angle (straight) out from the bell housing. When I bought it from the PO the clutch pedal was up about an inch to 1 1/2 higher than the break pedal and I had no problem with it. The kit that went in was the same (looking) as the one that came out. There was nothing wrong with it except for some heat checking on the pressure plate, just wanted to start with new.

Thanks for the comments. The search goes on........lol.

I bought a new wing nut as it didnt even have one on it. I think tomorrow I will adjust the pedal out to where it was before and see what happens, but I hate to have it in that position as that is not correct.

Another note, with the clutch pushed in I can put it in 2nd and 3rd without the truck moving. But it just grinds when I try to put it in rev or 1st. I understand that I do not have a syncro for 1st or rev. and 2nd and 3rd do but the truck does not take off.....lol. You can tell that it would like to but it doesnt.

[padresag]

most would not know of the difference between the throwout bearings . the wrong one has happened many times over the years. perhaps the clutch disc is in backwards.
with the inspection plate off underneath you should be able to check whether or not that there is any clearance between the throw out bearing and the pressure plate. there should be clearance at where the pedal should be normally. if the pedal is in it's normal position with the adj rod backed off that t/o brg should not be touching. if it is touching it is either wrong bearing or the disc is in backwards
ron

[Ronw435]

Yeah I know what you mean pads, I have put probably 20 clutches in my life, the clutch disc had tag showing correct placement so I know that is not the problem, at least I think so but being a senior you just never know.....lol. I had a nova when I was 16 that had a clutch dis-engagement problem. After a new clutch and pp I found the fork was cracked and was letting it flex just enough to not allow it to disengage. New fork problem gone.i inspected the fork good and even painted it before installing it.
I will take the inspection plate off tomorrow and see where the tob is in comparison to the pp.
thanks and will let you know what I find.

[Mackie]

Originally Posted by 1963c-10

Check the bracket where the pedal rubber bumper is also. Very common to find these bent out of shape and that can cause the clutch pedal height to be much higher than the brake pedal.

X2 on that.
My clutch pedal was higher than the brake (kneeing myself in the chin to use it) until I re-aligned the bracket with the bump rubber on it under the dash.

[Ronw435]

Well I just took the inspection cover off and looked up in there the best I can. Without any pressure on the pressure plate it feels and looks like the fingers are bent towards the flywheel. I know that the fingers will compress some when the pressure plate is tightened down but they actually look like the have a radius on them where the throw out bearing touches the fingers. It is a diaphragm type clutch so that is what I am calling the fingers. Looks like it might be a bad diaphragm that bent when the clutch was pushed in. Has anyone ever seen this? I took a picture and it looks to me like the fingers are bent. In the picture there is no pressure on the throw out bearing. Tell me if you think the fingers are bent? The throw out bearing is about a 1/16 of an inch away from the fingers.

[padresag]

with the t/o brg where it is; what is the position of the clutch pedal in relationship to where it should be?. there is still the possibility of the disc in backwards. if you were given a disc that went behind a gmc v6 by mistake the hub is reversed on them( not impossible).
when you depress the clutch pedal . how far down does it go? just some more food for thought. I am just saying that these are possibilities.
at 62 you shouldn't be having these problem( that is still middle aged isn't it?). when you get as old as Stoddard on here then you can call yourself a senior.
ron

[Ronw435]

The clutch pedal is even with the brake pedal. I will be removing it tomorrow to see if the fingers are still bent when it is taken out. On all the clutches I have installed the part that sticks out on the clutch disc has always gone towards the PP. That is how I installed it.

[Ronw435]

The clutch pedal will go all the way to the floor. Your right 62 is middle age....... I sent you a pm also Ron.

[Ronw435]

Ron when you say that the v6 is reversed you dont mean that the center section that sticks out goes towards the flywheel do you?
Ron

[Ronw435]

Well problem might be solved. I guess I was being a little too anal about getting the pedal level with the brake. I adjusted the pedal to the position in the picture and then readjusted the linkage and I can now put it into 1st and rev. Moved the truck forward and backward and it engages about a 1/4 of the way up which is how most clutches have in the past. I knew I was not too far away when I asked the wife this morning to push the clutch in while I watched the pressure plate and it was releasing the clutch disc so I knew it was not in backwards........thank god. I want to thank all that provided information and God Bless this Forum.

Thanks again
Ron