Bolting the Front Crossmember

Leathernek

Leathernek

Senior Member
Hey Guys,
I'm bolting my front crossmember onto my car since I'm not set up to do the correct riveting. I'm using grade 8 bolts with nylon locknuts in every hole where there would have been a rivet (14 total). My question is......Is there anything I should or shouldn't do when bolting my crossmember in? Thought I'd ask y'all since i couldn't find nothing in Andrew's book or by using the search function.

Thanks in advance,

Josh
 
Before tightening I would ck and double ck the frame for "squareness". I, personally would use regularnuts w/lockwashers WITH loctite. JMO
Paul in CT
 
Leathernek said:
Hey Guys,
I'm bolting my front crossmember onto my car since I'm not set up to do the correct riveting. I'm using grade 8 bolts with nylon locknuts in every hole where there would have been a rivet (14 total). My question is......Is there anything I should or shouldn't do when bolting my crossmember in? Thought I'd ask y'all since i couldn't find nothing in Andrew's book or by using the search function.

Thanks in advance,

Josh
Click to expand...
Josh,
For what it's worth, I think your way is dandy and stronger than rivets, I'd do the same with a drop of blue Loctite. Loctite just makes me feel GOOD!:D
If I were ever to build another car for dependability, I would replace EVERY castrated nut with self locking nuts, and, OH YES, that little drop of blue LOCTITE! Bill W.
 
You couldn't go wrong with loctite, lock nut, and lock washer if you are bolting it in.
 
Josh, I used bolts in my front cross member on my 29 huckster when it was an old beat up CCPU back in the 50's. The bolts are still there and going strong.

When I pull the engine from my 29 coupe I am going to have to replace the front cross member also. I plan to bolt it back in.
 
A friend has a bolted in front crossmember in his '32 Ford and is happy with it. I believe he has counter sunk head bolts on top that have an Allen head socket.
 
As mentioned, the top six must be countersunk. This is required for clearance and Allen head type screws are all you can get that aren't junk,

If done well it will last forever. The only side effect should be subtle squeaks and such that most folks think are normal for a model A. They won't show up for awhile.
 
So to muddy up the water a bit, why the need for Loctite? Over time the frame will twist & flex, and just as Marco has said, there will be subtile squeaks ...but why the squeaks? The obvious answer is because the bolts are loose but is it because the nuts backed off, or because the fastener has stretched? My thoughts are that the fastener has more likely stretched but I would like to hear your thoughts.
 
BRENT in 10-uh-C said:
So to muddy up the water a bit, why the need for Loctite? Over time the frame will twist & flex, and just as Marco has said, there will be subtile squeaks ...but why the squeaks? The obvious answer is because the bolts are loose but is it because the nuts backed off, or because the fastener has stretched? My thoughts are that the fastener has more likely stretched but I would like to hear your thoughts.
Click to expand...

Since the screws have threads and not solid metal, the threads wear down due to the flexing and produce a loose fit as if a smaller dia. bolt was used?
 
You probably won't be driving this car every day as it was designed to do, but there's a reason why they engineered rivets in these cars, and I would stick with the original intent if you can. Maybe find someone that can put rivets in for you.

Tommy-
 
I did one years ago using flat head Allen socket screws,I believe were fine thread along with split l'washers and nuts either 5/16 or 3/8 (don't remember). These are the black oxide strong machine screws and never had a problem with loosening up.
 
Typically rivets are best suited for shearing loads applications over tension loads. High strength bolts are better at tension loads over rivets. Any joint looseness could be attributed to the nut coming loose or wear on the bolt shaft due to shearing forces from the frame flexing. I would think grade 8 fasteners could replace the frame rivets.
 
Bolts will never replace rivets. When a rivet is installed, the rivet swells in the hole creating an interference fit. When a bolt is torqued, the stretch actually cause a slight reduction in cross sectional area. That said, the correct bolts will work. Use a fine thread bolt. For a given torque, it has more clamping force and a larger cross section at the minor diameter than a coarse thread bolt. Also, try to find a bolt that has an unthreaded portion to go in the hole. You may have to buy longer bolts and cut them to length to get the correct unthreaded portion length.

Bob
 
Worry, worry, worry! Most of the twisting & flexing will be absorbed in the length of the frame rails.
Why rivets originally: Probably faster and cheaper, and I doubt they were grade 8.
Don't forget, a number of years back, Ford trucks had rivet problems in the frames causing all kinds of horrible popping and groaning sounds. You can re-tighten bolts, if they ever loosened, but it would be a "BEARCAT" to re-tighten rivets. Yes, I know it's not PROPER, but sometimes we have to be practical. Bill W. Oh! and why Loctite, why not??
 
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BILL WILLIAMSON said:
Worry, worry, worry! Most of the twisting & flexing will be absorbed in the length of the frame rails.
Why rivets originally: Probably faster and cheaper.
Don't forget, a number of years back, Ford trucks had rivet problems in the frames causing all kinds of horrible popping and groaning sounds. You can re-tighten bolts, if they ever loosened, but it would be a "BEARCAT" to re-tighten rivets. Yes, I know it's not PROPER, but sometimes we have to be practical. Bill W.
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I gotta question or two, ....if you have used Loctite on the threads, how you gonna "re-tighten bolts" once it has hardened??

Also, to re-tighten those bolts, how do you gain access to the top of the bolt to hold it while you attempt to tighten the nut when the fender is covering the bolt head? Maybe I am wrong but it don't seem too practical to remove the headlights & wiring, the headlight bar, radiator apron and the fenders just to be able to put a wrench on that bolt head!! Maybe I am overlooking something and if so, I apologize in advance for my ignorance in this.

.
 
I really don't see them loosening up in normal use.I have taken a lot of old frames apart with bolted crossmembers,I usually have to cut the bolts off.Most seem to have a few original rivets left,so it appears they were rebolted to tighten rather than replace.I did some on A's years ago,but I used bolts with a short shank that almost fit through both layers of steel.I don't know what they look like now,but they are all still being driven.I have a 96 Dodge 3500 with a Cummins in it,it has a two piece frame that is riveted and the rivets are shearing.I have to take it apart anyway as the back of the frame is rusted.I will just bolt the rear section of the frame back on.I use frame bolts,or I believe they are called body-bound bolts.The threads just fit through the holes,but you have to hammer the rest in.
 
BRENT in 10-uh-C said:
I gotta question or two, ....if you have used Loctite on the threads, how you gonna "re-tighten bolts" once it has hardened??

Also, to re-tighten those bolts, how do you gain access to the top of the bolt to hold it while you attempt to tighten the nut when the fender is covering the bolt head? Maybe I am wrong but it don't seem too practical to remove the headlights & wiring, the headlight bar, radiator apron and the fenders just to be able to put a wrench on that bolt head!! Maybe I am overlooking something and if so, I apologize in advance for my ignorance in this.

.
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Loctite comes in a lot of different gripping powers, red, the least, blue, next higher, then there's a green, a purple, and I don't remember if there's more. They even have a "stud & brearing mount" for severe applications. I don't think the bolts would ever loosen, if it did they could be re-tightened with blue Loctite. Multiple screws in my full leg braces always fell out until I put "THE BLUE TO THEM!" (No, I'm not a Loctite Distributor:D) Bill W.
 
BILL WILLIAMSON said:
Loctite comes in a lot of different gripping powers, red, the least, blue, next higher, then there's a green, a purple, and I don't remember if there's more. They even have a "stud & brearing mount" for severe applications. I don't think the bolts would ever loosen, if it did they could be re-tightened with blue Loctite. Multiple screws in my full leg braces always fell out until I put "THE BLUE TO THEM!" (No, I'm not a Loctite Distributor:D) Bill W.
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Hey Bill, I thought RED was the strongest:eek:. Have to use the torch to remove it, at least here on the east coast:confused:

Joe,,,
 
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