can cross members be bolted in? info please

[herodcreekfarms]

ok im at the point with my truck where im getting ready to get the frame powder coated. i have been taking bracket off and behind everyone there is rust.
is it acceptable to cut out all the rivets and then replace them with grade 8 bolts?

are there any things i should be worrying about when doing this?

and the one concern i have is whill the powder coated cross members fit or will i have to do some persuading?

[70 Suburban]

YOUR CROSS MEMEBERS ARE WHAT KEEP YOUR FRAME SQUARE. i WOULD NOT LEAVE THAT UP TO A BOLT.

[Gray Ghost]

I have done this before when moving the tranny crossmember back for a transmission change. I'd make sure there are lock washers in place, though.

As to fit, there's always a bit of trouble getting the parts back together...just the nature of the beast.

[herodcreekfarms]

so ive got one yes and one no, need more help

[Gray Ghost]

There are several crossmembers on your frame. IF you took them all out at the same time you'd have to worry about it. If you are only removing one, it shouldn't be an issue.

[herodcreekfarms]

as of now i only have two that are actually still riveted in. and what would i have to worry about if i took them all out?

[Gray Ghost]

Removing them both at once you'd face a slight risk of getting the frame out of square, but one by one shouldn't be a problem.

[LockDoc]

-
I would use grade 8 bolts to replace the rivets and make sure they fit snug, even if you have to drill the holes out to the next size. I just changed a rear end from leafs to coils and that is the way I did it on the rear cross member...

LockDoc

[herodcreekfarms]

Originally Posted by Gray Ghost

Removing them both at once you'd face a slight risk of getting the frame out of square, but one by one shouldn't be a problem.

well my plan was to pretty much have it totally apart, like completely. would i have to take some meaurments or something?

i really would like to get all the rust before i pay to get it powder coated

[cdowns]

don't take the frame apart you're just asking for trouble!!!

[herodcreekfarms]

ok so if i dont take it apart i just for get about the rust

[Gray Ghost]

Originally Posted by cdowns

don't take the frame apart you're just asking for trouble!!!

Yep...gotta agree with that.

[my67chevytruck]

Originally Posted by herodcreekfarms

ok so if i dont take it apart i just for get about the rust

Have the frame blasted to remove the rust( this is a required step that the PC should do before coating). What the guys are saying is remove one crossmember at a time, fix the area if needed, reinstall the removed crossmember as lockdoc mentioned, then move on to the next crossmember etc. you can leave out the tranny xmember and have the front complete crossmember removed, but i would leave the 1st forward crossmember, the trailing arm crossmember and the rear crossmember attached when sending off to the Powder Coater.

[herodcreekfarms]

Originally Posted by my67chevytruck

Have the frame blasted to remove the rust( this is a required step that the PC should do before coating). What the guys are saying is remove one crossmember at a time, fix the area if needed, reinstall the removed crossmember as lockdoc mentioned, then move on to the next crossmember etc. you can leave out the tranny xmember and have the front complete crossmember removed, but i would leave the 1st forward crossmember, the trailing arm crossmember and the rear crossmember attached when sending off to the Powder Coater.

i guess i will do that, but my only issue is that the only cross memebers that arent bolted in are the trailing arm one, which has been cut out on the bottom b/c of 4x4 conversion. and then the one behind it. the transfercase, front, rear crossmemebrs are bolted in. i dont really wanna get the powder coating done over the bolts, i think that would look quite crappy.

[my67chevytruck]

i would remove, and replace/repair what was needed. in my opinion by leaving those 3 xmembers i mentioned bolted in , it would keep your frame square, and that it would not look crappy having the bolt heads pc'd, atleast no different from having the rivet head pc'd. Good luck with your rebuild.

[Kayotic]

How bad do you think the rust is? (from what you can see)...

If very little, then treat the area chemicaly with a rust converter. These products have come a long way.

The liquid should be able to seep into the area.

[70 Suburban]

I agree. leave them be. use a rust converter. Im not sure how ad the rust is. but I havent seen many rustout from there. when you powder coat it it will seal it in and the rust will slow to a hault. rust needs O2 to continiue. if you are realy woried about it the befor it goes to powder coat use por 15. what dosent get blasted off will keed the rust from moving any further

[herodcreekfarms]

ok guys thats probally what i will do, its just surface rust really, and ill try the rust converter, ive got a few different kinds.

[Skirkpat]

I do not personally know the other people posting, but I will give you my credentials and advice, I worked as a machinist (7years) building progressive punch dies, Developed and maintained their Computer Assisted Design dept. for 3 years, Went to Ford Motor Company and worked for 13 years eventually working on the Design and launch Team of the Hybrid Escape...I worked everyday(for 3 years) with Ford's top engineers, Went between the Pilot plant in Detroit, and the local assembly Plant in K.C. Hand assembled prototype builds for FTSA Crash testing, etc....that being said I know quite a bit about the subject. If you ever plan on driving the vehicle, DO NOT CHANGE THE FASTENING SYSTEM THAT THE FACTORY USED.

I know there are small amounts of rust under them, the integrity of that frame is much more important, I am going to get replies saying I am wrong, that is fine, but I have worked in the industry, and can tell you that they put rivets where rivets belong, you may or may not be able to "bolt" a crossmember where it was riveted, but it is not a good Idea. I know people do it, I have done it but it still not a good solution, especially just to get at some rust for asthetic reasons. Rust (oxidation) takes two things to occur, water and oxygen. Seal it right ( Por 15 , or some other encapsulator) and it will not progress. Remember you are building a truck, not a watch, you will probably never get it perfect. If you have to have perfection, this is a bad hobby. JUST MY OPINION.

[Skirkpat]

I see that as I typed my longwinded response, that yo got some other Great advice, I am always a little late it seems, one other thing though, you should talk to your powder coater, I do not know if POR 15 will mess up the powder coating, but he will . I have tlked to body guy's and they hate working with the stuff, almost impossible to get off and you are not supposed to paint dirrectly over it . It might not matter but I would ask him before I did anything.

[70 Suburban]

I am also icar platinum certified, also ase master certified. And now run a mack truck service department. You should never change the fastening sys from the factory. Fsm says to install whith huck rivits.

[70 Suburban]

Originally Posted by Skirkpat

I see that as I typed my longwinded response, that yo got some other Great advice, I am always a little late it seems, one other thing though, you should talk to your powder coater, I do not know if POR 15 will mess up the powder coating, but he will . I have tlked to body guy's and they hate working with the stuff, almost impossible to get off and you are not supposed to paint dirrectly over it . It might not matter but I would ask him before I did anything.

thats why i said usr por 15 then have it blasted. use it in the seams so it will seal the rust. but should not effect the powder coat as it will be sand blasted from where ever the powder can reach

[Kayotic]

I would love to have access to Huck rivits. Used to use all day long on rail cars (frieght trains). Who has a gun though?


Have a look at todays frames - there welded. Of course there is a lot of science behind those welds.

By the time I unbolt the front Crossmember, remove the tranny mount, replace the trailing arm crossmember with ECE's (16 I think rivits), replace the most rearward crossmember for fuel cell 4 rivits -

All that is left is:

1 - The shock mount(which will be removed for a bridge notch) 12 rivits, 16 if you seperate completely...

2 - The angled crossmember(where the upper panhard mount is, drivers side) 4 rivits

3 - The extreme forward crossmember(under crank pully) are all that remains untuched. 4 rivits

WELL spare tire mount. 2 rivits

Case in point - I will be completly disassembling my frame, cleaning, inspecting for cracks and then bolting welding back together...

Getting it square and level is a challange.


I am not ASE cert, or work on Mack Trucks, I did work on rail cars. Everything else was designed to reach speeds over 200mph.

[70 Suburban]

I have a huck gun. We use if for replaceng components on macks

[Kayotic]

Yeah thanks, In Texas.

I wonder if anybody rents them - are any steel buildings fastened with them?

That is without a doubt the way to go!