What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Push rod punctured pan on clutch arm...

my kids took the truck

my kids took the truck

1/2 ton status
 Premium
Joined
Dec 10, 2013
Posts
486
Reaction score
122
Location
Oroville, CA
The push rod somehow punctured the pan on the clutch arm.

I have a temporary repair that allows me to drive.

Any ideas how to repair without replacing clutch arm? Has anyone heard of this before?

20180528_175806.jpg

20180528_175754.jpg

20180528_175347.jpg
 
Last edited:
Bent77 said:
That 1/8” hole? That’s factory
Click to expand...

Right. It isn't factory for the pushrod to turn into a ream and push through that hole.

If you look closely you can see the edges of the hole are flared now. From the inside of the pan it is more obvious.
 
Last edited:
You mean that "frown" is the beginnings of a hole, where the push rod is trying to break thru the clutch fork where it pushes against it ?..

Cant say I've seen that before,but I suppose years of movement under pressure and no lube will wear metal thin after awhile..

Seems to me I've seen a clutch push rod that had what looked like a rocker arm ball on it about 1" from the end of it,and the extra length of the push rod went thru a slot on the clutch fork..it probably wasn't on a GM vehicle,I remember thinking it was a better setup,with the ball thing having more surface area to spread the load out on the fork instead of just the center of the "socket" in it for the push rod..

Maybe you can braze or weld the fork there from the back side ,close that hole or slot up and build it up some--and that'll give you more time to use it as is, until the clutch needs to be replaced..

You may be able to replace just the fork without having to pull the tranny or bell housing off thru the "window" in it--I know I was able to install the fork on my '72 K5,but that had the old style cast iron open bottom bell housing with a good sized window ,and it was just a clip that popped onto a ball stud inside the bell housing..
Dorman sells the clutch fork ..
 
I assume you have the fully enclosed aluminum bell housing ?..

I dealt with that type only once,on my '75 2wd Blazer when I replaced the clutch--that had a stamped steel fork,and a different clip on it that slid over the ball stud in the bell housing,looked like the clip that holds a door lock cylinder or the bowtie filter in the air cleaner housing..

If I remember right,that ball stud can be removed from the transmission side of the bell housing,it had an allen head threaded part on it..been so long its hard to remember exactly..but even if that ball stud can be removed,there may still not be enough clearance to fish the fork out or put it back in--it may require pulling the tranny back some..:(
(Edited!)
 
Last edited:
diesel4me said:
I assume you have the fully enclosed aluminum bell housing ?..
Click to expand...

Yes. You know this bellhousing, ball socket, clutch fork combo.

This clutch has been going since 1994. It seems solid. Right now I am not in a position to do any work. If I disconnect the engine I want to rebuild the transmission and transfer case and front drive shaft at the same time. Headers need recoating. You get the idea.

I like your idea of bronzing the fork pan to get back to the factory pushrod

My temp redesign has flaws.

I used a brass acorn nut as a solution. Over time the brass has filled the hole in the pan with a good sized plug (the hole is a 1/4" on the inside and tapers to 1/8"). That makes a good foundation to bronze over.
 
Braze will work,and probably last longer than a weld,being softer it might be like a brass bushing, and some grease on it every so often may get you by for a long time..you might be able to add a washer to the push rod ,or a rocker arm ball,lug nut,etc,that had a tapered surface,that will spread the load over a larger area and prevent it from poking thru again..

If it were me I'd be looking for any other solution,than pulling the tranny out--even to the point I'd cut off a good fork and weld the end on the existing one! :tongue1:...call me a hack,but I'm not fond of hard labor any more with my body aching just sitting here,never mind lying under a truck !..
 
diesel4me said:
...might be like a brass bushing, and some grease on it every so often may get you by for a long time... spread the load over a larger area and prevent it from poking thru again.
Click to expand...

That is exactly what I did with a brass acorn nut. There are three problems: A) the shoulders of the nut catch and change the pedal feel a small bit -- it is not a big deal but annoying; B) the brass wears out every six months driving once a week -- I have a bag of them in the glove box; C) the fast and uneven wear means I need to adjust the clutch every few months -- weekly towards the end and when I first put a new one on as it wears the shoulders in.

None of that is detrimental, however, the OEM pushrod was good for 40 years with adjustments every couple years. That was nice.

My wife stopped driving the blazer because she got stuck at a traffic light and could not shift -- she finally got it into 3rd or something and managed to get out.

Edit: added photo of worn out brass acorn nut -- I just took this one out Friday.

20180615_185417.jpg
 
Last edited:
I wonder if a stainless steel acorn nut would last longer,or if it would just eat through the fork faster..:thinking:..
Those brass acorn nuts are pretty soft,maybe you could harden one up more by heating it up and quenching it in oil or water --wouldn't hurt to try..
 
Nope, Sorry Diesel. That is a really common mistake.
Copper, and of course brass, harden just the opposite of steel. I have been playing around with metals for more decades than I care to think about, and it still sneaks up on me sometimes.
To harden steel, you get it to the proper temp and then quench it. This causes the carbon molecules to become locked in place suddenly and does not let them arrange themselves the way they want to. Thus putting the whole thing in a form of internal stress that makes it hard.
Copper and its alloys have no carbon. They are at their hardest when all the molecules have time to align themselves correctly.
So, to harden them, you heat them up to just under melting temp, Being Careful not to melt them, then let them cool very slowly.
Since he has plenty of nuts to try with, I would put a screw in one to protect the threads, put it in a metal box full of sand or some other hear resistant material, and heat it dull red, making sure to keep it red long enough for the heat to soak all the way through.
Then, set it on something that will not draw off the heat, and out of any wind, to let it cool off slowly.
The sand should hold the heat for a while to let the brass harden.
 
Yeah,I should know that copper and other non-ferrous metals act different,and quenching it doesn't harden it..:doah:..

I hear the term "work hardening" used in GM service manuals in the section that warns you about using copper line to replace steel tranny cooler and other lines on a vehicle..the vibrations make it harden up and get brittle and crack..

Maybe the stainless steel acorn nuts would be the better choice..?
 
My father-in-law thinks a wirefed MIG weld could be done with low voltage and would stay cool enough not to damage the arm. I can then use the OEM steel pushrod.
 
I agree,a MIG can work miracles on many things..and MIG wire is quite hard,it wont wear any any too quickly..the push rod will probably wear ,not the weld ..
 
TIG would be better for heat control. But it requires a much cleaner surface than MIG or stick welding and a more experienced operator. I have seen TIG used down to less than 3 amps for welding extra thin stuff.
I'm not real knowledgeable about that arm, don't remember ever working on one.
But I would use welding as a last resort, if the arm gets burned up, its hard to come back from that.
If the backside of the arm is accessible, and has enough clearance, I would consider a mechanical fix first. Obviously you need some kind of socket there to keep the rod in place.
What if you drilled through the arm socket, and put a small grade 8 bolt in there? The head would be the bottom of the socket, and would be a hard surface for the rod to bear on. You would want to grind it smooth or maybe put a slight dimple in it with a Dremal tool or something.
A good TiN drill bit would probably do it too.
With a new good bottom surface to work with, the original type rod or your brass tipped one would work better. It looks like the hole in the bottom of the socket is causing the brass to wear faster, so the solid bottom would tend to stop that.

You might also consider cleaning the heck out of that part of the arm and rod, filling the cup with some good quality waterproof bearing grease, and trying to seal that area. A rubber boot made out of an old bike inner tube, sealed with Goop and/or good quality electrical tape such as Super88 might keep the grease in and the sand and dust out while not affecting the flex necessary for that joint to work.
 
Fordum said:
TIG used down to less than 3 amps for welding extra thin stuff... use welding as a last resort, if the arm gets burned up, its hard to come back from that.

Consider cleaning the heck out of that part of the arm and rod, filling the cup with some good quality waterproof bearing grease...
Click to expand...

I am nervous about welding in any form.

After wearing through a few brass nuts I thought it would form its own bearing surface. That hasn't happened. I might try grease.
 
If you do grease, you need to try to seal the area as best you can.
Grease is great when its clean. But it collects dirt and sand and acts as an abrasive when exposed. There are dry lubes out there that might work. But, if you can seal it, heavy lube would work best. I would find an old bike innertube, cut out part of one side on the end.
Slide it over the rod, with the straight cut off end first. Put the rod on, with lots of grease under and all around the nut and socket. Adjust the rod, then slide the tube down and partially around the end of the arm as far as you can. Use a good black wire tie on the rod, and use tape, or whatever works best on the arm to seal that end.
BTW, Black wire tie, because the black ones are UV protected. The white ones with get brittle and fall off after a while from sunlight.
 
Fordum said:
If you do grease, you need to try to seal the area as best you can.
Click to expand...

That was excellent advice. It also scared the daylights out of me.

The end of the story here.

The last brass acorn nut filled in the hole in the pan with a plug of brass. As the end of the acorn nut wore off the last bit broke off in a chunk and got packed in.

I am going to see how long the next brass acorn nut lasts. So far with driving once a week and a few long drives (four hours) a year, I go through an acorn nut every six months. I bought a bag of them and put it in the glove box.

At the next clutch or t-case rebuild. I will get a new clutch fork.
 
You must log in or register to reply here.

Latest Posts

Top Bottom