factory rivets

[chevyfan420]

how strong are the factory rivets on the frame? is it worth my money to knock off all the rivets and replace with grade 8 bolts?

[Southedisto]

The only factory rivets that I have seen shear were due to a wreck.

[boxrodz]

I believe the factory rivets are a better choice as a frame fastner than high-grade bolts. Aside from their strength as a fastner, rivets 'expand' to fill the hole of the attaching parts.

[454HO]

Originally Posted by boxrodz

I believe the factory rivets are a better choice as a frame fastner than high-grade bolts. Aside from their strength as a fastner, rivets 'expand' to fill the hole of the attaching parts.

That maybe true for a new frame off the assembly line IF they are actually put in tightly. But by the time the frame is 20 years old, they will have loosened up some due to the frame flexing. Also, you can imagine that the rivots are much cheaper (read quicker) to install in the factory than bolts.

[SanitysBane]

True, but rivits don't work loose and have part of them fall off, usally. If you were to also install some lockwashers, and tighten the crap out of them and check them everyonce in a while, and willing to go threw all the work to do it and make shure they stay tight, then go for grade 8 bolts. Otherwise keep the rivits.

[boxrodz]

Originally Posted by 454HO

That maybe true for a new frame off the assembly line IF they are actually put in tightly. But by the time the frame is 20 years old, they will have loosened up some due to the frame flexing. Also, you can imagine that the rivots are much cheaper (read quicker) to install in the factory than bolts.

Good point. Personally, I've never noticed any rust/movement stains indicating movement between the rivet(s) and the chassis. And, the ones I had to remove were still very tight.

If rivets have to be replaced, I'd go with fine-thread, grade 10 bolts/thread locking nuts (if available) and thread locking compound. Use the largest bolt that will fit tightly into the hole. Since the holes are sometimes odd sizes, some may have to be reamed out to the next larger size. Then, be sure not to over torque.

I know they supply rivet kits for the Model T and Model A. I wonder if it's possible to use replacement rivets using a bucking bar and a ball peen hammer with a hand-held rivet tool or an air hammer with a rivet attachment.

I would guess that rivets may be cheaper than high-grade bolts/nuts, but I imagine the cost to install the rivets are probably more expensive since operators use large hydraulic presses that are suspended to press the rivets in place. Today, I wonder if that process is now fully automated. (Maybe, Jeff's GM video has a clip of a 73-87 chassis being assembled.)

[454HO]

I wasn't trying to imply that all the factory rivots should be replaced with bolts just for the sake of replacing them. But, if you have a need to replace a part that was originally rivoted, or if you are completely stripping the frame rails down to paint them, then reassembling with bolts should be just as good if not better than the factory rivots.

When I stripped the front of my truck's frame I did find that some of the rivots were loose. The cross brace that is in front of the engine crossmember is one place. And a sway bar mounting bracket was another place. Also, I found significant amounts of rust behind the radiator core support mounting brackets. Seems like that is a good place for dirt to collect and trap moisture.

And yes, I had to use a step drill bit to enlarge the rivot holes to the next standard bolt size. I used all grade 8 bolts with grade 8 flat washers on both sides, but I used ny-lock nuts which are grade 5.

As for periodic maintenence to check the tightness of the bolts, I suggest you check them just as often as you check your engine crossmember and tranny crossmember bolts.

[ureckme]

When I replace rivits at the body shop I use 8 grade bolts and tack weld the nut to the bolt

[MylilBowTie]

But isn't there also the harder a bolt is the grater its change to just shear off? Kind of like a bolt extractor set, the taps are really strong but very brittle.

[boxrodz]

Originally Posted by 454HO

.
When I stripped the front of my truck's frame I did find that some of the rivots were loose. The cross brace that is in front of the engine crossmember is one place. And a sway bar mounting bracket was another place. Also, I found significant amounts of rust behind the radiator core support mounting brackets. Seems like that is a good place for dirt to collect and trap moisture.
.

OT

454HO, how's your build-up coming along?

[454HO]

Originally Posted by boxrodz

OT

454HO, how's your build-up coming along?

I haven't touched it since October. Two trips to China, Thanksgiving, Christmas, New Years and a few other incedentals have gotten in my way of working on it. But I'm back here to get inspired and motivated to start working on it again.

[1976K5CHALET]

Factory rivets persay on class 8 trucks are called "huck" bolts. Pretty damn tuff...but require a expensive hydraulic gun and pump set up on a cart to install. I think a better bolt might be a flange bolt and nut...not sure on the grade but they are pretty tough. I have them holding my winch and bumper on my 79 K5...bit more pricey than a grade 8 bolt but they do the trick.


DW