Honda CB750 Sandcast

Restoration of Sandcast #97

markb · 814 · 285330

Steve Swan

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Believe me, i'm all for whatever solution works to remove that pin, never will hurt to use another solution other than AeroKroil !  We all have our own experience of what products works for us !  

That steel pin has alot of surface area to form rust and oxidation on the wall of the hole in the aluminum to make removal stubborn !    

I agree with Wayne, tapping is good, just as long as one does not drive/imbed the pin further in the hole.  

I'm wondering if using a propane torch head with MAP gas to get the case as hot as possible could work along with screwing in an EZE-OUT to the i.d. of the pin, to have something to pull on the pin in an attempt to remove it.   In addition to the EZE-OUT, would be if you get that area of the case hot and use some dry ice to cool/contract the EZE-OUT inside the pin and try pulling it out.  Put some dry ice in a nylon sock and wrap around the EZE-OUT to cool it off to contract the pin............  ?

I am thinking out loud......  Using a EZE-OUT will spread the split pin, but only against the aluminium.  The aluminium keeps the shaft from turning when the pin is in place.  Other than that, the aluminum serves no purpose, so if there is a little distortion to the aluminum to remove the pin that is no big deal, as the only purpose for the aluminum is to hold the pin/shaft unit from turning.  The pin is not pressed into the aluminum, it is pressed into the steel shaft  These split pins are usually a brittle spring steel, i have had to break them out from time to time, but not where the pin protudes from steel though to aluminum.  The worst that could happen is wallowing out the hole in the aluminum and having to put in a steel insert to size the hole back to the o.d. of the pin.

The other option i can think of is to gently use a Vise-Grip to the point of not crushing the pin, then use dry ice to chill the vise grip and the pin and then try turning the pin to aid in eventually pulling the pin out.

The more i think about it, the less i like my EZE-OUT idea.  The pin will just spread and the EZE-OUT will not get enough 'bite' to hold the pin to attempt turning the pin.

This is one where it is better to take all the time necesary to take the appropriate measure in removing the pin to avoid a complicated or costly repair.  In the mean time, keept using penetrant, heat and gentle tapping.

This is probably a situation where you'll want to wait to hear what other ideas/experience other members have to share.

Just my 2 cents worth............



kp

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Mark, tough one. I agree with Steve, MAP gas is the stuff that gets the job done. Don't heat up the cases too much as they will distort, but heat up the steel shaft and hopefully the cotter pin will let go using Steves vice grip idea. I've not heard of the stuff Wayne has used but sure sounds the ticket. Sounds like it is a product with a very altered pH value.
Sorry I can't offer a better solution but certainly let us know how it works
As for your broken stud, Ive never heard of the process but sure sounds like it works a treat. I think what you've done is wise as you will never replace those cases and a breakage will only make you me and the rest of us cry  :'( KP
Yabba Dabba KP



markb

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OK, I think I have a plan.  I was talking to one of the guys in the shop about welding a rod onto the end of the pin and doing the slide hammer thing again.  I would use a thin piece of sheet metal with a hole in it to protect the aluminum.  Then he suggested trying a dent puller.  He's got one I can borrow.  The trick will be to get the threaded tip to bite into the pin.  If I keep soaking it (I'll even try the Liquid Wrench) and use heat on the case it just might work.  If not I'll try the welding thing and if that doesn't do it I have it burned (EDM) out.  That will definately work.  I feel better just having a plan.  Thanks for all the input.  Sometimes it just helps to kick it around a bit.
Mark
Mark B
1969 CB750 sandcast #97 restored - Sold Restoration thread link
1969 CB750 sandcaxt #576 - Sold
1969 CB750 sandcast #1553 - Sold
1969 CB750 sandcast #1990 - Sold
1969 CB750 sandcast #5383 restored - Sold Restoration thread link
1970 CB750 K0 restored - Sold
2010 H-D Tri Glide Ultra Classic (Huh?)


myhondas

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Mark,
Rather than going through the process of welding the rod to the split pin....get a tap and thread the entire length of the split pin. screw in a harden bolt and then use your slide hammer to gently pull out the pin, using the liquid wrench or PB blaster and heat along with the hammer will surely do the trick. IMHO


markb

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That is exactly what I'm going to try first.  The pins are pretty hard though so the trick will be to tap the pin without breaking off the tap.  Thanks again for everyone's suggestions.
Mark
Mark B
1969 CB750 sandcast #97 restored - Sold Restoration thread link
1969 CB750 sandcaxt #576 - Sold
1969 CB750 sandcast #1553 - Sold
1969 CB750 sandcast #1990 - Sold
1969 CB750 sandcast #5383 restored - Sold Restoration thread link
1970 CB750 K0 restored - Sold
2010 H-D Tri Glide Ultra Classic (Huh?)


Steve Swan

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Just an idea, as long as that split pin is, probably not necesary to tap full depth threads, could use a smaller diameter tap, the threads would not be full depth, but the chances of twisting off the tap would be less and as long as the i.d.of the pin is, if you screw in a  hardened screw full length there should be enough thread surface area to allow the pin/screw to be pulled out.


markb

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Sometimes the dog bites you and sometimes you bite the dog.  Tonight I bit the dog.  I got the spring pin out using a dent puller!  First I drilled out the center of the pin with a drill about .010” bigger than the standard tap drill for a #10-24NC thread.  It only went down about a ¼” before the bit got dull.  Then I carefully ran a #10-24NC tap in as far as I dared.  I got maybe 2-3 full threads.  If you haven’t hand tapped before, I don’t recommend it.  I’ve been soaking it (even tried some Liquid Wrench) and I put some heat to it and used a piece of bar stock to rap it on each side with a hammer a couple of times.  Then I took the collet off the end of the puller and put a #10 screw through it and screwed it into the end of the pin.  I also used a vice grip to squeeze the protruding part of the pin as tight as I could on the screw.  Then I screwed the puller onto the collet and applied more heat – I’m throwing everything I have at it.  I started with a couple of light taps and after a couple of hits I checked and it looked like it had moved a little so I kept at it.  Once it started moving it came about ¼” at a time.  Here it is just before it popped out.  The actual pulling only took about a minute.


Here’s the pin hanging on to the end of the screw in the puller.


Here’s the tool…


…and the hole where the pin was!  If I were to try it again I’m not sure I would try the tapping.  I’d drill it out enough so I could force the screw into the pin and then clamp on it with the vice grip.  With slot in the pin I think it would flex enough to clamp onto the screw and be less risky as far as breaking at tap.  For what it’s worth.  At least it’s out.  Thanks for everyone’s input.

Mark B
1969 CB750 sandcast #97 restored - Sold Restoration thread link
1969 CB750 sandcaxt #576 - Sold
1969 CB750 sandcast #1553 - Sold
1969 CB750 sandcast #1990 - Sold
1969 CB750 sandcast #5383 restored - Sold Restoration thread link
1970 CB750 K0 restored - Sold
2010 H-D Tri Glide Ultra Classic (Huh?)


Wayne

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Nice work Mark! Care to drop by and fix up a couple of my wee challenges for me?  ;)
« Last Edit: December 16, 2010, 08:05:25 pm by Wayne »
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myhondas

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Whew......I was concerned about the tapping, but I thought that it would give you the best possibility of pulling it out. Thought about using a SS sheet metal screw, but figured that would be spreading the pin more than the machine screw would. Glad it's out and you're moving on to some more fun things. Did you get that liquid wrench? I've used it and PB Blaster and they both work great.


Wayne

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I too was concerned about tapping a roll pin. Although they come in different grades they are usually pretty darn hard. I've watched Mark's work through a couple of threads now. He didn't just fall off the turnip truck yesterday so I figured he would fare OK! I've heard good things about PB Blaster as well. I think I'll get some of that as well as some Aerocroil to have around.
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kp

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Good stuff Mark. And you've done a pictorial of the process which is worth a thousand words Yibbida Yibbida KP ;D
Yabba Dabba KP


markb

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Whew......I was concerned about the tapping, but I thought that it would give you the best possibility of pulling it out. Thought about using a SS sheet metal screw, but figured that would be spreading the pin more than the machine screw would. Glad it's out and you're moving on to some more fun things. Did you get that liquid wrench? I've used it and PB Blaster and they both work great.
I did get the Liquid Wrench.  Not sure that was the key, I had already been soaking it with the Aero Kroil too.  The thing I liked about the Liquid Wrench is it didn't seem to evaporate as much, maybe sits there more and has more of a chance to soak in.  Who knows.  I still have some stuck stuff on the other side.  Then I'll start cleaning up the cases including running a tap in every threaded hole and a drill in every oil passage.  I'm thinking of soda blasting the cases, inside and out, to clean them up good.  Any comments?  For the final paint prep on the outside I'll probably do like I have in the past and blast the surface with a very fine grit sand and then paint right away.  I have no sign of paint coming off on my last two projects. 
Mark B
1969 CB750 sandcast #97 restored - Sold Restoration thread link
1969 CB750 sandcaxt #576 - Sold
1969 CB750 sandcast #1553 - Sold
1969 CB750 sandcast #1990 - Sold
1969 CB750 sandcast #5383 restored - Sold Restoration thread link
1970 CB750 K0 restored - Sold
2010 H-D Tri Glide Ultra Classic (Huh?)


Wayne

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Mark, I would get the cases hot tanked and Ultrasonically cleaned to avoid blasting with anything, at least on the inside.

Alfa Romeo Engine - Ultrasonic Cleaning-Large_2.m4v

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