The Stovebolt Site Forums The Shop Area General Truck Talk 46 pick up round head bolts??

working on removing the driveline trans and engine of my 46 1/2 ton pu. on the P-brake lever, and rear trans mount, I have encountered several round headed bolts. is there a special wrench for securing these during removal and installation, or is a universal vise grip the tool of choice? i have used the vise grip but it seems to chew the heads of the bolts and i cant imagine restoring a truck with that effect on finished parts. what would be the prefered replacement bolt? Thanks for any info.

Ed

Are they 12 point bolts? These bolts have double the amount of points needed for a typical 6 point socket to fit.

Jeff

If the round head spins when your are trying to loosen it you could grind two sides of the round head so the vice grip will hold on. Otherwise grind the head off and punch it out.

heads are perfectly round...like a flat button. i was able to get the nuts loose by grabbing the round head with the vise grips. hadn't encountered a fastener like this and was looking for some OEM info on them. when they assembled the truck they had to hold them somehow to tighten the nuts??? just wondering how they did it and what they used.....then and now???

and these bolts are .... where?

Are you sure you're not talking about a Clutch Head screws???
Those are round head and have a bowtie shaped hole in the middle. The principle is
similar to an Allen screw.
The Clutch Head tools have been discussed at length here on the forum many times, grab
a search for them and you'll find tons of discussion.
If the key is stripped out then as Jim posted, just grind the head off and use new ones.
Denny Graham
Sandwich, IL

A photo or two of the bolts/heads would help the speculation?

you can try making a slice into the top of the head to fit a flat head screw driver into, thats how i get old carriage bolts out when they just spin

If I understand correctly, the fastners being described are rivets instead of bolts. These hold the bracket or mount on the cross member that in turn supports the transmisson. At least that what are used on my '46 half ton (DP Model).

The parking brake assembly on my '46 is bolted to the side of the transmission with two 1" hex cap bolts 3/8" diameter and 16 threads per inch. The parking brake assembly is held together with rivets.

This assumes (yes dangerous I know) that the previous owner didn't monkey with any of this. I think that is unlikely, but possible.

I'll try to get pictures and a link posted if needed.

Thought he said he was trying to get the nuts off and wanted to hold the head.

DG

This thread started with a two-part question, Denny:

Part 2:
" . . . what would be the prefered replacement bolt? Thanks for any info."

For either question, a photo or two might result is more pertinent answers.

Maybe it is a bolt similar to a lug stud with a splined and/or tapered shaft. At the factory, as it would be tightened, the tighter it gets the spline and/or taper would lock into the hole. The design would have to assume they would never need be removed.
EDIT: I found what they are called, Ribbed Neck Carriage Bolt.

sorry i have left a few things out...including a picture.. i should know better. these bolts mount the rear transmission mount to the crossmember and to the tail section of the trans itself.. 9/16 or 5/8 nut. the other two i have encountered mounted the p-brake lever assembly (under cab section) to the p-brake rod and spring assembly..rod and spring connects to the rear cables through puleys. will try for a few pics during the week

thanks for all of the ideas

ed

ed, when you have a question it might be a good idea to always be complete with details and send pics as well; otherwise you'll have a dozen guys giving worthless advice.

I know what you are talking about and I have the same one on mine. I used a peice of rubber on the back/round side with a lot of pressure on it to keep it from turning. You dont go real tight so it worked in the same way when I reinstalled. if you want original, dont ruin it. I have not seen replacements.

Boy, this discussion has been going on in the fog for a couple of weeks now. I wish
someone would post some concrete documentation as to just exactly what these mystery
fastener look like. The is about the best example of what I mean when I oh so often use
the term, “A picture is worth a thousand words”, or in this case, two weeks and two pages
of discussion.
Not having the luxury of a 1/2ton AD sitting in my back year means that I can’t crawl
under and look for myself. These bolts/screws/fastener or what ever are non-existent on
the ¾ ton trucks that I do have access to.
Are you guys talking about carriage bolts, or what????

Denny Graham
Sandwich, IL

I thought it was the knid of bolt that results from several hours of frustration using vice grips!

Fred, have you been looking at my truck? Hahahaha!

Does Stovebolt offer "Errors and Omissions" insurance? Give us a picture Big Ed.

That's what persuaded me to get that acetylene cutter. lol

finally got pics of the infamous round head bolts.

first pic is of the bolt, lower bolt in pic, as it is equipped on the undercarriage side of the brake lever assembly.

http://pic80.picturetrail.com/VOL1958/10783339/19208600/399739771.jpg

next pic is of the same style bolts, as they are installed in the transmission mount. These two bolts are bolted through the mount plate at the tail end of the trans. Trans is on the left, crossmember on the right.

http://pic80.picturetrail.com/VOL1958/10783339/19208600/399739773.jpg

all three bolts are secured with hex nuts as seen in the brake lever pic, top nut.

hope this helps, sorry for the quality, but it should do.

thanks for all the help to those who have posted or will post.

sorry for the delay in info. as is everybody else i am busy with life and on the list of things to do,the truck isn't even on page 2. get to it when i can with what i can.

Good advice! I believe I'll follow it!

just wanted to throw this to the top one last time just in case someone missed it with the pics.

thanks again to all who have helped

The transmisson mount is removed by 4 bolts through the cross member and the two bottom bolts through the bell housing covering the universal joint. The two round circles are like rivets. Its part of a vulcinized mount. Chevs of the 40's has a picture on page 106. Its part number is 594117. The rubber on these is typicaly turned to mush and needs to be replaced. On my truck the parking break bolts in your picture have flats two flats on the thin rounded side and a typical nut on the other. I hope that helps.

I found the photos of the flat topped and round headed bolts I was referencing above that are in the E-brake handle. I placed a couple photos on my FAQ page on www.46chevytruck.com

FAQ page with photos

I added a couple photo's in my photobucket page of the same parts you are showing except rebuilt. I hope that helps. http://s1095.
photobucket.com/albums/i470/GWWirth/

thanks for all the info....outstanding to now have grip on the situation....no pun intended.(roound head bolts) ....anyway thanks to all.