Advice on rear bumper build LX470 (15 Viewers)

Joined
Mar 25, 2019
Messages
550
Location
Gulf Breeze, FL
I've took the leap and removed my stock rear bumper last night, and started fabricating some mounts. The overall look is going to depend on how I mount the tire carrier though and I was hoping to get some input.

I was originally planning to go the traditional spindle route, but then I noticed Coastal Offroad's style and I really liked it, but it will only work if I use hiem joints so I can mount the swing arm on the outer edge of the bumper. What do you think of the idea of using a 5/8" bolt through 2 hiem joints with a piece of steel tubing as a bushing? I'd like to copy the way coastal offroad does the ends of the bumper but without the tubing protection.

It seems like doing it this way would keep the tire and carrier a little further from the back gate when closed as well which might be a good thing I dunno. I think the spindle looks cleaner, but at the same time it means I have to extend a flat section out to fit the spindle which I don't like the look of as much.
IMG_8336-7.jpg

DSC1833-1-scaled-2.jpeg
 
Joined
Mar 25, 2019
Messages
550
Location
Gulf Breeze, FL
I got my mounts mostly finished today, not welded yet but the test fit up went well. Now I just need to figure out the design and swingout hinges to use.

I need to figure out how to gusset the swing arm pivot point because I'm building this from 10 gauge to save weight. I know if I just attached a hinge on the outer face of the bumper like the coastal style it will flex like crazy.

I built the mounts from 1/4" and plan to bolt up to the hitch mounts on the frame.
 
Joined
Mar 25, 2019
Messages
550
Location
Gulf Breeze, FL
I ordered this bracket this morning.

Capture1.PNG


I'm thinking I can mount similar to this and put a 5/8" bolt through 2 hiem joints with a steel spacer fit in between the hiems.
Capture.PNG


It would look like this, I'm wondering if I should use 3/4" hiems like below or if the 5/8" would be fine.

Capture3.PNG


Also kind of like this design using hiems.
Capture4.PNG
 
Last edited:
Joined
Mar 25, 2019
Messages
550
Location
Gulf Breeze, FL
A little progress tonight. I haven't tacked anything together yet but I did get the cuts to size for the top plate and front main plate.

Still need to reem the holes out a little for the mounting brackets 9/16" is a little too tight to get those M14 bolts to thread in well. Once I get that straight and clean out the threads in the frame I will tack this part together and start figuring out my shapes to get around the body.
20201117_221027.jpg
 

suprarx7nut

The YotaMD Guy
Supporting Vendor
Joined
Sep 28, 2010
Messages
3,195
Location
Colorado
 
 
Glad to see you go with what I'm going to call the "Dissent" approach. I say that because his was the first I saw taking that approach with an upper and lower plate surrounding the spindle and bearings. Most other new bumpers seem to have that now.

Good luck! The final fitment and refinement is what makes or breaks a good rear bumper, IMO. If latches, hinges, etc... aren't just right, you just end up with a heavy pain in the ass hanging off the rear. Get that stuff right and you're gold.
 
Joined
Mar 25, 2019
Messages
550
Location
Gulf Breeze, FL
Glad to see you go with what I'm going to call the "Dissent" approach. I say that because his was the first I saw taking that approach with an upper and lower plate surrounding the spindle and bearings. Most other new bumpers seem to have that now.

Good luck! The final fitment and refinement is what makes or breaks a good rear bumper, IMO. If latches, hinges, etc... aren't just right, you just end up with a heavy pain in the ass hanging off the rear. Get that stuff right and you're gold.
Thanks, yeah this is really my first big "fabrication" project. All I've made so far is a workbench, a picnic table and a solar panel mount. Getting the angles right on this to get around the body is tough. I messed with it a while last night, but the cardboard I have doesn't cut cleanly and isn't stiff enough. I'm going to try and see if a craft store might have something better.

I'm having the most trouble figuring out the panel to transition from a 45 degree angle at the corner around to the fender. Basically the panel pointed out in the picture below from the coastal offroad site. I may go with a more squared off design if I can't get it right. Good thing I have plenty of steel haha.
Capture.PNG
 

AlpineAccess

Overlanding is an expensive word for car camping.
Joined
Apr 16, 2019
Messages
1,212
Location
Colorado
Looks good! Like your design inspiration.

Not sure how much welding you're doing with the bumper hung on the vehicle, but make sure the battery is disconnected, and this is a good time to use a glass mat if you've got one! Cheap insurance, even if your shielding is perfect and you have no spatter that mat will block a lot of heat from paint, wire loom, and rubber gaskets.
 
Joined
Mar 25, 2019
Messages
550
Location
Gulf Breeze, FL
Looks good! Like your design inspiration.

Not sure how much welding you're doing with the bumper hung on the vehicle, but make sure the battery is disconnected, and this is a good time to use a glass mat if you've got one! Cheap insurance, even if your shielding is perfect and you have no spatter that mat will block a lot of heat from paint, wire loom, and rubber gaskets.
I only tacked the plates together with it hung on the truck. I didn't disconnect the battery when I tacked the mounts , but I did when I tacked the main face plates together yesterday.

I plan to do the main welding on the bench but will tack the plates in with it mounted
 

AlpineAccess

Overlanding is an expensive word for car camping.
Joined
Apr 16, 2019
Messages
1,212
Location
Colorado
I only tacked the plates together with it hung on the truck. I didn't disconnect the battery when I tacked the mounts , but I did when I tacked the main face plates together yesterday.

I plan to do the main welding on the bench but will tack the plates in with it mounted
Very nice! Should be a great project. Are you documenting the build? I know many including myself would be interested in your measurements for future reference/use.
 
Joined
Mar 25, 2019
Messages
550
Location
Gulf Breeze, FL
Very nice! Should be a great project. Are you documenting the build? I know many including myself would be interested in your measurements for future reference/use.
I'm trying to. Once I get all the plate shapes figured out and cut ill document the measurements. Although, not sure anyone will want to follow this haha. I cut a few plates today, and once I get my new axle seal installed tonight I will work on it a bit more.

If someone with the rear coastal offroad bumper could take some photos of the corners near the quarter panels and looking up from below id appreciate it lol
 

hotdiggitydamn

SILVER Star
Joined
Jun 29, 2019
Messages
276
Location
Peachtree City, GA
Love it! As soon as I finish my front bumper I’ll likely be doing a rear as well this winter! Your motivating me!

To Hijack: why do swingouts use actual bearings? Seems like way overkill. I get poly bushings but I would be tempted to go with bronze bushings myself. Is there a concern these would crack with flex? Bearings just seem way heavier/complicated than necessary for something that only swings 100 degrees MAYBE 5000 times in its life.
 
Joined
Mar 25, 2019
Messages
550
Location
Gulf Breeze, FL
Love it! As soon as I finish my front bumper I’ll likely be doing a rear as well this winter! Your motivating me!

To Hijack: why do swingouts use actual bearings? Seems like way overkill. I get poly bushings but I would be tempted to go with bronze bushings myself. Is there a concern these would crack with flex? Bearings just seem way heavier/complicated than necessary for something that only swings 100 degrees MAYBE 5000 times in its life.
I agree on the bearings and spindle, I'm either going with 3/4" hiem joints or a 1" bolt and brass bushings. Mounted in "double shear" style

Made a little progress today...



20201120_111512.jpg


20201120_111528.jpg


20201120_131744.jpg
 
Last edited:

hotdiggitydamn

SILVER Star
Joined
Jun 29, 2019
Messages
276
Location
Peachtree City, GA
Only ripping your cardboard templates?!?! Bold move Sir! I too have never trusted scissors. Joking aside that’s looking damn good! I need to grow a pair of truck nuts and do something similar.

I like the idea of a bolt and bushing but also think the idea of the double heim is cool. Especially as you can adjust the angle of the arm/deal with sag possible under load.

looking great! Thanks for sharing!
 
Joined
Mar 25, 2019
Messages
550
Location
Gulf Breeze, FL
Only ripping your cardboard templates?!?! Bold move Sir! I too have never trusted scissors. Joking aside that’s looking damn good! I need to grow a pair of truck nuts and do something similar.

I like the idea of a bolt and bushing but also think the idea of the double heim is cool. Especially as you can adjust the angle of the arm/deal with sag possible under load.

looking great! Thanks for sharing!
HAHA, yeah these were definitely the "rough draft" for those panels. I actually did cut them with a razor, but the cardboard I had was real soft and kind of s***ty. I'm going to use some stiffer stuff to make the final templates before I cut any steel.
 
Joined
Jun 6, 2016
Messages
778
Location
Magna, UT
Looks like you have it figured out mostly, but for future--manila folders work great for templates. Cut easily, fold easily (and straight, unlike cardboard), but are still stiff enough to do the job. If you need larger, poster board. :)
 
Joined
Mar 25, 2019
Messages
550
Location
Gulf Breeze, FL
I've got everything tacked in place and it's off the LX almost ready for the full weld out. Next I'm going to plate a piece of 10 ga ( or maybe 1/4") on the back side of the corner section like the photo below. Then run a gusset from there to the bottom plate per the line in the photo. I'm hoping this will help that corner plate from bending with the weight of the swing on it.
20201123_091412.jpg



Once that is welded in I will figure out the dimensions for the cap piece to cover from the corner back to the side wings.

20201123_091345.jpg
 

AlpineAccess

Overlanding is an expensive word for car camping.
Joined
Apr 16, 2019
Messages
1,212
Location
Colorado
Looks like you've got this well under control! Great progress.

My only comment would be that (in particular on the wing connections) is try shorter stitches to keep heat down with the thinner gauge you're using. My experience is that when I get a lot of heat into work like this I end up with more movement and 'warping' than I'd like and my fitment ends up wonky.
 

Users Who Are Viewing This Thread (Users: 9, Guests: 6)

Top Bottom