BIO Rear Bumper Install and Air Lift 1000 Repair

[marcfj60]

I know everyone likes Cruiser mods and pics so I figured I'd post my Bump It Offroad rear bumper install. I won't have time to do it all at once so I will update with photos as the Christmas week progresses and I find a few minutes here and there.

Background:
I've owned my '99 since 2009. I'm slow to modify and it's mostly stock vehicle still, except for some decent tires, MetalTech sliders and some Airlift 1000 airbags in the rear. I go off road several times a year and my rear bumper had seen better days. I finally bit the bullet and ordered a bumper from Mike Smith at BIO. He's a really stand up guy and makes a great product. The main reason I chose his bumper is because it required little or no modifications to install it and it allows the spare tire to be kept in the original location under the rear. My wife drives the cruiser more than I do and she's a little woman. She didn't want to have to deal with a swingout tire carrier for mall-cruising and grocery-getting duties.

I still wanted a swingout tire carrier though, for getting the tire out from under there when wheeling. So I ordered a spindle cover that will protect the spindle in most situations. When I go wheeling, I can mount the spare tire carrier. I also tow a couple different trailers regularly and wanted to maintain towing capability. You can leave the receiver hitch in place with his bumper. I opted to get the integrated receiver. Mike clearly states that it is not rated for towing, but I'm sure that's for liability reasons. I am a mechanical engineer and I can see that the bumper with integrated receiver is more stout than the factory hitch. And everyone I've spoken to who tows with one if his bumpers has no reservations about it.

So my build was his standard bumper, with adjustable swingout tire carrier, extra spindle cover, integrated receiver, cutout for a 7-pin trailer connector, powder coated black. I ordered it in May and he delivered it to me at the Hundreds In The Hills event in July. Cost was about $1,900.

One of the things you have to do if you get the integrated receiver is notch out a chunk of the rear crossmember. The integrated receiver sits a few inches higher than a stock hitch which will be good for ground clearance. Cutting the frame made me a little nervous but the crossmember is being reinforced with a very stout, 1/4" plate bumper so I finally decided I was ok with it.

When I took off the receiver hitch, I discovered some surface rust on the bottom of the frame rails, so I got out my wire wheel and sanding pads on my angle grinder and got rid of it. I also has some boogered up threads in the 4 weld nuts on each side that the bumper and wing supports will bolt to so I had to spend some time with a 14mm X 1.5mm tap. The nice thing is that this is the same size and pitch as the lug nuts/studs, which I had to buy a tap and die for several years ago when I bought the cruiser. So after a few hours of bumper removal, rust cleaning and thread chasing I had to quit work for the day. With family coming over today and tomorrow for Christmas, it will be a couple days before I can get back to it. I want to primer and paint the bare metal where I sanded off rust and made the cut in the crossmember before I install the new bumper, so that will add a little more time as well.

 

[marcfj60]

Some of the parts that had to be removed. This was quite easy. Removed the receiver first to gain access to the bolts holding the bottom of the bumper in place. Then I removed the mudflaps and reinstalled any screws needed to keep things in place. Lastly, removed the bumper cover and inner support pieces.

 

[marcfj60]

And then I got to work on the notch. I made a cardboard template that fit inside the new bumper, referenced the two bolts that will secure the center of the bumper to crossmember. I made sure to make the notch wide enough to clear the fillet weld and not just the receiver. I went with 3" of width to adequate clearance.

 

[marcfj60]

Sharp corners make for high stress concentrations so I marked the cutout to include a radius cut in the corners. I used a center punch, pilot drill and then a step drill up to 1/2" diameter to make the corners.

 

[suprarx7nut]

I just installed my BIO Rear Bumper! I had much more corrosion to deal with. 3 of my weld nuts for the main 4 mounting bolts needed a helicoil. I might still go back and weld on new nuts, but we'll see how it goes over time. If I can hit the required torque levels when I retorque in a month or so with the helicoils I'll leave it be.

Mike told me to install the wings before hand, but I didn't really understand until I got to that part. I'd recommend loosely installing the wing supports before resting the bumper on the car. I can't recall which direction they go (they're not symmetrical), but I'm sure there's a pic floating around somewhere. They're still a pain to tighten up, but getting them started off the car makes things easier.

I didn't realize the notch had to go clear to the front wall of the rear frame piece until I tried to mount up the bumper and hit the remaining frame.

Overall, awesome product and it really transforms the look of the car with the tire on the back and no hitch dangling below the bumper.

Kudos to Mike for an awesome Colorado-made product!

 

[Grego]

I have his rear bumper also. I have been very pleased with it. I was rear ended at a traffic light earlier this year by a lifted f150, the tire carrier flexed when it was hit by the grille of the truck and dented the rear hatch. The bumper itself showed no damage. I transferred that bumper over to the truck I have now and am still using it. One recommendation I would make on your install is to drill two holes in the bumper where it lines up to the holes on the end of the frame rail that are used to bolt the upper reinforcement to the original plastic bumper. I had more movement in the tire on the tire carrier when driving on certain roads. At certain speeds the tires would start shaking enough that you could feel it in the drivers seat. Using the two existing holes/weldnuts in the frame provided another mounting point near the spindle that helped control the movement.

 

[marcfj60]

I just installed my BIO Rear Bumper! I had much more corrosion to deal with. 3 of my weld nuts for the main 4 mounting bolts needed a helicoil. I might still go back and weld on new nuts, but we'll see how it goes over time. If I can hit the required torque levels when I retorque in a month or so with the helicoils I'll leave it be.

Mike told me to install the wings before hand, but I didn't really understand until I got to that part. I'd recommend loosely installing the wing supports before resting the bumper on the car. I can't recall which direction they go (they're not symmetrical), but I'm sure there's a pic floating around somewhere. They're still a pain to tighten up, but getting them started off the car makes things easier.

I didn't realize the notch had to go clear to the front wall of the rear frame piece until I tried to mount up the bumper and hit the remaining frame.

Overall, awesome product and it really transforms the look of the car with the tire on the back and no hitch dangling below the bumper.

Kudos to Mike for an awesome Colorado-made product!

I was wondering about mounting the wing supports. So you're saying to mount them loosely to the bumper before bringing the bumper in place on the cruiser? I was thinking I should bolt them to the frame first, then set the bumper in place. There weren't any sort of instructions in the box of goodies so I've just been winging it. I didn't even think to check his website to see if there were any on there.

 

[marcfj60]

I have his rear bumper also. I have been very pleased with it. I was rear ended at a traffic light earlier this year by a lifted f150, the tire carrier flexed when it was hit by the grille of the truck and dented the rear hatch. The bumper itself showed no damage. I transferred that bumper over to the truck I have now and am still using it. One recommendation I would make on your install is to drill two holes in the bumper where it lines up to the holes on the end of the frame rail that are used to bolt the upper reinforcement to the original plastic bumper. I had more movement in the tire on the tire carrier when driving on certain roads. At certain speeds the tires would start shaking enough that you could feel it in the drivers seat. Using the two existing holes/weldnuts in the frame provided another mounting point near the spindle that helped control the movement.View attachment 1597221 View attachment 1597218 View attachment 1597220

I was wondering about reusing those two nuts on the vertical part of the frame rail. I was also wondering about using a couple of the weld nuts on the bottom of the crossmember where it is in the straight section in the center.

 

[Grego]

The wing supports are easy either way. I mounted the bumper on the frame then attached the wing supports after. I don't think the weldnuts engage any part of the bumper support along the bottom of the rear crossmember. Biggest thing is to have a second person to help lift it onto the frame without dinging the quarters. I used a motorcycle jack to lift it up this last time as my help wasn't around.

 

[marcfj60]

I was thinking I would use my floor jack with wheels along with two teenage kids to support each wing as I lifted and guided it into position. I've lifted it by hand with the help of another adult male and we barely could move the beast.

 

[marcfj60]

Got things finished up a couple days ago.

 

[marcfj60]

I had Mike put in a cutout for and include a 7-pin trailer connector. The cut was off about 3/8" from the center of an existing hole in the crossmember. I'll pass that info along to him. I need to get some metal cutting die-grinder bits before I can tackle cutting out the clearance. Thankfully, I'm not planning to tow anything for a couple of months. If I have to, I can rig something up with the old harness and tucked up out of the way. Another thing to note, which Mike had suggested, was to put some spacers between the bumper and the two bolts above the receiver because there would be a small gap. Putting in the spacers allowed me to really torque down those two bolts and get a tight bond/fit between the cross member and bumper right around the receiver. So you can see that gap in some of the pictures. I used two stacked zinc plated square washers donated by a buddy from his hi lift mount. The gap was about 5/16". I think a spacer from 1/4" - 3/8" would work.

 

[marcfj60]

A few other shots from below to show how things bolt together.

 

[marcfj60]

 

[marcfj60]

And some local Cruiser Heads that helped me get things mounted up: @slimbuddha @pappy @Dumpolina

 

[marcfj60]

Being under the cruiser doing this gave me an opportunity to notice a problem with my Airlift 1000 airbags installation. There is a hole in the spring perch that the nipple on the bottom of the airbag sticks through and you connect the airline. It turns out this hole is not in the center of the springs. I enlarged the hole when I installed the airbags but not enough and the nipple was being bent off to the side. So I made the hole a LOT bigger. Things look a lot better now.

 

[marcfj60]

From the original hole, I made two more holes at about 60 degrees apart, toward the rear of the vehicle. Then I cut the small bits of metal connecting the three holes and cleaned it all up. The original hole was located directly below the #4 on the tape measure.

 

[marcfj60]

It's tough to get a clear picture of the final results but the nipple/airline now come out right in the center of the much larger cutout.

 

[geanes]

Great write up! I'm going to do a rear bumper this summer. The BIOR is my first choice and this is perfect for me to install.

Thinking of running the AirLifts on my 98 LX. How do you like them so far? My AHC needs some help if I add weight in the rear (drawers on the way).

 

[marcfj60]

Great write up! I'm going to do a rear bumper this summer. The BIOR is my first choice and this is perfect for me to install.

Thinking of running the AirLifts on my 98 LX. How do you like them so far? My AHC needs some help if I add weight in the rear (drawers on the way).

I really like the airbags. Before I had them and if I had a lot of junk in the cargo area or a heavy tongue weight trailer, the cruiser really sagged in the back. And going over bumps there was a lot of movement up and down. My popup camper has a cargo deck up front and even with some effort to not put much weight ahead of the camper axle, my tongue weight can frequently push past 400 lbs. The airbags really stiffen things up, level out the vehicle and provide a lot more stability/control when towing.