A bumper question for fabricators, builders or installers

[Hedgehog]

I bought my CJ with a terribly under strength PO designed bumper. He essentially removed the rear cross member and installed a 2"x4"x1/8" tube. It looked good on the outside but was a mess in places you can't see. So, today I removed it and was happy to find the rear of the frame unmolested.

So, here is my question. Originally it was my intention to use a remanufactured rear cross member to return the frame to it's original configuration. Then building a complete heavy duty bumper and attach it to the stock configuration cross member. Not a bad idea if you can ignore the fat that the cross member isn't very strong. The thought that I could build up the cross member with a /-1/4" plate hidden in the channel behind or hidden from sight. That would make a super strong cross member.

Then I got to thinking. Wouldn't that be similar to building two bumpers? Would it be better to just build my bumper to attach to the back of the frame with extensions designed to attach to the inside of the CJ frame.

So, builders, how would you or how have you attacked this sort of problem. Make one strong bumper or make a strong, stock looking cross member and attaching a strong bumper to that?

 

[Kane]

With my CJ5 I built the bumper and bolted it to the factory location on the cross-member. On my scrambler I am not going to spend the money on a cross-member but do like you said and make a bumper that will solidly attach to the frame rails. The scrambler does not have to deal with the gas tank mounts so it is an easier mount and I do not need to build the tabs for the tank skid. Throttle down customs does that same thing to the frames they make. They integrate the bumper right to the frame and weld it solid. I want mine removable though for any future needs so it will be bolted. I plan to make separate tabs for the rear ward body mounts.

 

[Posi]

I left my factory crossmember on and attached my bumper to a 1/4" L bracket tied to the frame rails.

L bracket not shown (behind crossmember)



I would also recommend through bumper clevis mounts.

 

[007]

I did something similar based on something Torxhead built. Mine is 3x3x1/4" angle iron with a ACME bumper mount receiver welded to it. This one is bolted directly to the existing holes on the crossmember. While I agree with Posi that clevis mounts are nice, they can rattle at times. I decided to get a hitch mounted clevis insert instead for when I thought I might need it. I also put a receiver up on the front bumper for the same purpose.

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[Hedgehog]

The mount I'd make wouldn't be welded to the frame, it would be bolted. Yesterday I was more on the fence, today I'm thinking, "Rebuild so it looks and handles as a stock cross member, but reinforcing plates inside the channel making it much stronger." Then bolt the new bumper to it. I hadn't considered how having the gas tank in place would affect bolting the bumper on. Welded in place nuts would work for that.

The finished bumper will have all the goodies on it, recovery points, receiver hitch, tire hanger with 2 cans (1 water, 1 fuel), I'll be using a great taper bearing hinge given to me by one of the board members (thank you again). All the added strength is accommodate the weight of the goodies and very occasional towing.

 

[Posi]

My L brackets are bolted onto the frame rail and rear bumper, all done with the tank in place.

 

[007]

...mine was all done with tank in place as well.

 

[Hedgehog]

007 - I like the simplicity of your "L" bracket and there's a little voice in my ear saying "Do it! The design is simple and strong, very jeep like." But I'm also thinking that all the extras would be best suited with a semi step type bumper.

Kane/Posi - Did you have any trouble getting to the bolts behind the tank? It might be apples and oranges though. I'm adding an aftermarket 21 gallon tank with slightly different mounting points.

Another question: Is there any reason why the pin in a receiver hitch needs to be horizontal and not vertical. Yes, I know the hole in the hitch would need to be drilled in a vertical configuration. The drill for that is in my tool box right now.

 

[hondo]

i was originally going to remove the rear crossmember and replace it with either a 2x3 or 2x4 steel tubing bolted on like the original crossmember. but i didn't want to go to all the work of dropping the tank and removing it. so what i ended up doing is welding a l bracket off the new 2''x3''x4.5' bumper with holes to bolt it to the frame then i put a triangle piece of plate going between the bracket and the bumper then cut the ends off of the crossmember and bolted it to the frame and used the triangle top plate as my new body mounts. i put in both d-ring mounts and a receiver hitch the d rings don't make any noticeable sound unless you are bouncing off of rocks, and i have had about 1000# on my receiver without problems.

 

[Woolyworm]

I kept the stock channel and added a 4x4 square tube. The tube bolts to the frame from the inside with those bolts welded to a steel plate which is then welded to the end the of the tube since they are to far in to get to. Then I boxed the ends up. I left the channel because it wraps the top and bottom of the frame which I think provides some torsional strength to the frame. I then added some bracing on the inside of the stock channel to support the outward twisting that wants to happen due to the weight of the stuff on the bumper.


Wooly

 

[gr8dain]

On the frame that I recently picked up to swap under my Scrambler, I am removing the stock cross member. It is in bad shape and I am putting on an aftermarket one that is much thicker and sturdier. I just ordered it today (it has shipped too). It comes with angle brackets.

My Runck rear bumper currently mounts to the outsides of the frame rails. I am going to have to figure out how to connect it to the new rear cross member. May have to cut the mounts off of the bumper. Probably will. The bumper has a tire swing so I want it to be secured very well. But don't want to weld it on. When O have everything, I will have to see what to do. I also want it to sit closer to the tub. But the tire swing will hit the tail lights unless I swap to flush mounted lights. Frame swap has to start first and then see what happens with the bumper.

 

[Hedgehog]

I admit to thinking that you guys wouldn't understand what the heck I was talking about. It's great to see that all of you that responded seem to fully understand. All the replies are great and either have supported my ideas, given me something to think about or pointed out something I hadn't considered like the new expanded tire swing hitting my tail lights. Thank you!

 

[gr8dain]

Good luck. I hope your tire swing clears it. I got confirmation last fall when I was rear ended. The grill of the Lexus hit my spare. The tire swing latch gave/stretched and the swing hit the driver side tail light busting it up a little. Replaced the lens, tightened the loop on the latch. All was good again.

 

[yellow85cj]

Using "L" brackets pretty much takes the strength of the rear cross member out of the picture. I made my "L" brackets out of 1/4" angle and added gussets (got a little carried away with adding the gussets). The brackets are bolted to the frame and then to the bumper mounts. So the cross member is sandwiched between the brackets and the bumper mounts.

I did replace my cross member with one that was made for a CJ to YJ tub swap. It was considerably thicker than the original.

Had room to clear the stock 15 gallon tank. Won't be really easy to get the nuts off, but do able. How many times does the bumper need to be removed?

One other thing to think about with your build, weight of the bumper and rear springs. My bumper and tire carrier are 96 pounds with out the spare.

Which brings up a question. Do I really need to carry a spare with local street driving? When was the last time you had a flat on the road. Long trip or trail, carry a spare. Other wise, my spare may be a cell phone and a friend to pick me up to go home and get the spare.

 

[Hedgehog]

Yellow85CJ - Nice job. you have a newer CJ with the boxed frame. Mine is only boxed in certain areas. It would be nice to have a fully boxed frame like yours. I have one suggestion. While your building, if you are still building, I would put a reinforcing sleeve between the sides so the bolts don't tend to crush the frame.

Last night after doing additional clean up on the frame rail ends, I did a test fit of the replacement cross member. While there I was considering the actual need to FULLY reinforce the member. After all the unboxed frame is only so strong back there, why add extra weight. I think I'll do almost the unthinkable. My frame has a tab that bends over at the very end and that is where items like bumpers and trailer hitches are bolted. To make the end of the frame stronger I'm considering cutting off the tab so fairly heavy steel can be added to the inside of the channel with tabs very similar to yours designed long and heavy enough for the new bumper bolts to bite into. I'd like to add cross bracing, but the gas tank will be in the way for an easy solution.

Maybe someone can help me here. The original factory tow hitch mounted to the cross member with heavy straps going up to the to the apparent channel above the bumper and below the bed. Where did they attach to the frame or maybe the body?

Gr8dain - It figures you'd be hit by my nemesis, a Luxus. The driver probably thought it was all your fault. How dare you slow your clunky old vehicle while there was a shinny new Lexus behind.

 

[gr8dain]

Gr8dain - It figures you'd be hit by my nemesis, a Luxus. The driver probably thought it was all your fault. How dare you slow your clunky old vehicle while there was a shinny new Lexus behind.

While the driver was an idiot, he knew it was his fault. He was on the phone. I was at a light behind someone. The light turned green. He hit the gas. The guy in front of me was still stopped. All I could do was let up on the brake a little to give my CJ room to go forward as he bumped me. I watched it all in my rearview. And there was a cop a few cars back. No problems with him. He offered to pay cash for any damages. I had it checked out. He bought me a new tail light. His grill was gone.

 

[Hedgehog]

Good experience there. The Lexus thing is a bit of a rolling joke with me. I just got a kick out of you mentioning the Lexus. I know perfectly well that most are very decent people.

 

[007]

Maybe someone can help me here. The original factory tow hitch mounted to the cross member with heavy straps going up to the to the apparent channel above the bumper and below the bed. Where did they attach to the frame or maybe the body?

It bolted up into the usual threaded inserts in the bottom of the frame as well as through the crossmember.

I can post a picture later as I have one sitting in the garage.



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[yellow85cj]

Sorry, didn't know about the older model frames. But the angle could still work. The front end of the frame isn't boxed. I also used a top and bottom piece. Don't think top and bottom would work for you but bottom only might if the shackle mounts aren't in the way.

Did add crush sleeves. And unfortunately am still building.

 

[Hedgehog]

No sorry necessary, at this point everything is still adaptable for my needs. I was just commenting that I would like to have had a frame like yours. With that being said, my old frame has stood the test of time for 40 years, it'll keep on going for a little longer.

I will be doing something very similar to your front end configuration. My rear frame section is nice and straight allowing for a simple plate, maybe even angle iron or tubing to go in and lay along the inside of the frame for extra support. I've been trudging along with engineered parts like the axles for so long doing this feels like complete freedom to do as I see fit. The trick is to make the work look as professional as possible.

So, are those Harbor Freight roll around garage chairs worth the money, I've eyed them a number of times.