Rear Frame Cross Beam 86'ed

octongue · 05-14-07, 04:01 PM

So for those of you to warned me against buying this truck, you can gloat now...

the crossmember on the back of the frame that the shocks mount to (the part sitting on the underside of the bed) has rusted through on both sides...

I thought I was in deep shizz but one of the press guys at work (who is an accomplished welder and fabricator) offered to help me replace the rusted piece with a fabricated crossmember (2" square tubing).

Is there somewhere that I can get the exact measurements of the size of that crossmember? I don't feel comfortable measuring what's left of the one that's there.
Also, what kind of shocks should I replace the namelesss blue ones with when I hack them off?

It's starting to slap (bottom out sound) a bit when I hit speed bumps so i'll have to move quick on this. I will post pictures of the fabrication and of the swap out when it actually happens.

Chock it up to a learning experience --- time to go to school.

cruiser_guy · 05-14-07, 07:53 PM

You don't need exact measurements. I had that fabbed up and it was fine for two more years while I searched for a frame and swapped it out. Make sure that the shop uses bolts clear through the crossmember. They welded the stubs from the old crossmember onto the new one and they broke off several times till I went nuts with the welder. A through bolt would eliminate that problem.

Man Jerk · 05-14-07, 09:44 PM

This is what I wish I had done when I replace mine.

What I did do was cut a piece of tubing to fit between the frame rails, and welded it in.

What I wish I had done, was use a hole saw and saw a hole through the frame just larger than the old crossmember. Then slide an appropriate sized tube all the way through the frame from one side to the other, then welded it to both the inside and outside of the frame. It would be much easier this way as well.

If you look at the original crossmember, this is pretty much the way it is from the factory.

octongue · 05-15-07, 06:59 AM

sounds good...hopefully i can get my hands on a hole saw that will go through the frame. now...how about those shocks?

DirtyLittleSecret · 05-15-07, 10:09 AM

Gee, I dont have any frame problems...
I probably wouldnt try cutting ANY additional holes in the main frame unless you intend to possibly weaken the frame. Would rather cut/weld in a new crossmember with some nice shock mounts. Keep it simple and bombproof.

Man Jerk · 05-15-07, 12:09 PM

Quote:

Originally Posted by DirtyLittleSecret

Gee, I dont have any frame problems...
I probably wouldnt try cutting ANY additional holes in the main frame unless you intend to possibly weaken the frame. Would rather cut/weld in a new crossmember with some nice shock mounts. Keep it simple and bombproof.

There pretty much is a hole already there, it's filled with the original shock tube. You are just cutting in a slightly larger one. I can't see how it would be weaker.

Not speaking from experience, I have heard that the OEM shocks are pretty affordable. If your's is stock height that is an option. Do a search.

mainlander · 05-15-07, 01:04 PM

I just used a 2x2x1/4" piece of angle iron welded to the inside frame.

I agree with MJ that the frame would not be any weaker due to pushing the tube through the frame. Just make sure you weld both sides and your good to go.

I sure like my new OME shocks I just installed with the new springs on the BJ.

octongue · 05-15-07, 04:17 PM

here's a thought:
since I am going to be welding a piece of square tube to my frame, and adding new shock mounts, is there anything that i can do in the process of adding this that will (in the future) lend itself to complimenting another upgrade? Or in other words, is this 'part of another upgrade' that i should do in a certain way to fascilitate the rest of the future upgrade? Does that make sense? (i.e. i do plan on doing a spring over axle eventually...is there a place that i should put the current shock mounts that will work for the SOA, or can i put two locations in at this time?)

In addition, maybe i should make more supports and weld THEM in while I am down there.

Maybe I am over thinking it, but if i am going to be under there cutting and welding and such, i want to get the best bang for my buck.

thanks for all your input so far.

Heartworm · 05-15-07, 07:23 PM

You can use OME Shocks on a stock spring suspension; at least I did. OMEs are pricey, but once you have them, then it makes the cost of the lift a lot less painful. OME shocks=good.

brian · 05-15-07, 07:49 PM

had the same problem.

i cut what was left of the oe member out and replaced with a straight shot of either(don't recall what it was) 1 1/4''(~1 5/8'' O.D.) or 1 1/2''(~1 3/4''O.D.) sch 40 pipe...all the way through both frame rails....like it was originally. that way it's a much more solid mount. you can grind the little bit of the oe member off that protrudes through the frame as well as it's weld.
i was also able to salvage the shock mount pins off the rusted member, if your guy is any kind of welder he should be able to do the same for you. drill holes is the new member for them first, though they will need to be welded in after the pipe is slide through the frame, once agian your welder should'nt have a problem with this step.

no pics of during, cam is toast so none availible now.

octongue · 05-30-07, 01:13 PM

I've decided to use a piece of 2x2x.25" square tubing to create a new cross member. For those of you who've done this, do you remember the measurements that you used? I can climb under there and measure what I think it needs to be, but since it's all the way through on both sides (and hence sitting lower than it should) I can't get it right. What i really need is how high it rises from the frame to the apex of the crossmember (where the shock mounts are).

thanks!

zebrabeefj40 · 05-31-07, 07:38 PM

If/when the shock mount crossmember on my FJ60 fails my plan is pretty simple:

1. Cut old shock tube off flush to the inside of the framerails.
2. Weld a piece of 1/4" thick plate to the inside of each rail. Center each plate over the old shock tube location. Plates sized to extend up from frame to just below the floor to allow the longest possible shock.
3. Cut/weld in a piece of tube (square or round, what ever I can find free or cheap; doesn't matter to me) between the 1/4" plates up near the floor. Drill for shock mount bolts before welding in place.

Drilling out the old tube is too much extra work IMHO. Seems to me that the shock tube was bent up towards the floor anyway so shoving a piece of straight tube through from rail to rail means the shocks need to get shorter to fit. That doesn't help suspension flex at all.

Nick

octongue · 05-31-07, 08:05 PM

i've priced the 2 inch square tubing i spoke of and was quoted $58.00 for 8 feet of it, which sounds pretty reasonable to me. my idea is similar to yours, but instead of plating, includes using 6-10" pieces of the square tube. i will weld it over the old holes, perpendicular to the frame, and weld a long piece between them to mount the shock to.

I am really just curious if anyone knows how long to make the pieces that i weld to the frame.

my truck is stock, with stock length springs. i'd like to maybe make it sit a little higher in the back, but i don't want to screw anything up either.

2badfjs · 06-01-07, 12:06 AM

58.00 for 8 ft is rediculous.
i pay about half that for 20 ft.

i have some 2x2x .120 wall i can measure off my 60 on how much you need.

pay the shipping and it's yours. i have enough to spare.

jim

octongue · 06-01-07, 07:42 AM

Quote:

Originally Posted by 2badfjs

58.00 for 8 ft is rediculous.
i pay about half that for 20 ft.

i have some 2x2x .120 wall i can measure off my 60 on how much you need.

pay the shipping and it's yours. i have enough to spare.

jim

i really appreciate that; and the offer to measure. let me know the weight and i will price shipping and send it to you. remember when measuring that i need 3 pieces, two to weld to the frame and one to go across. THANKS!

2badfjs · 06-01-07, 08:22 AM

Quote:

Originally Posted by octongue

i really appreciate that; and the offer to measure. let me know the weight and i will price shipping and send it to you. remember when measuring that i need 3 pieces, two to weld to the frame and one to go across. THANKS!

are making it like an "arch" ?

how bout you measure and tell me what you need

chuckirons · 06-01-07, 11:13 AM

I'm in a similar boat as you and wondering what I should do.

In the meantime, I'm wondering if I should move it at all, let alone drive it. When I did drive it it seemed fine, I'm just wondering how far is too far...

octongue · 06-01-07, 02:07 PM

i have no choice but to drive mine; i drive it every day. i am just very, very careful to not hit speed bumps or pot holes. The whole back end goes apeshit when that happens (bouncing up and down, since there's no stabilization)

it's okay on the highway.

chuckirons · 06-01-07, 02:16 PM

I keep imagining going down the highway and the entire rear end falling off.

but then again, mine doesn't go very fast down the road anyway, so maybe it wouldn't be such a big deal

octongue · 06-01-07, 04:33 PM

Quote:

Originally Posted by 2badfjs

are making it like an "arch" ?

how bout you measure and tell me what you need

how 'bout YOU measure, fabricate, and SELL me a crossmember?

(I am serious....PM me. if you are going to ship me steel, i'd rather pay for you to construct it).

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