T-100 belly pan...

[BamZipPow]

From my ToyotaNation thread...
Under belly pan... - Page 3 - Toyota Nation Forum : Toyota Car and Truck Forums

Had to pull my belly pan today when I noticed my side skirts were drooping more than it should. The main support beams had cracked at the fastener point even though I had some basic round washers on there. I guess it's from all the bumps in the road. At least it didn't fall off while I was on my road trip...

Looks like need to go with some rectangular washers or with some thicker "C" channel...maybe in aluminum. Might be kinda pricey though. I'll have to check with the local metal scrap yard and see what they might have.

[baldlobo]

was it solid mounted to your truck, some rubber might fix it; and is that wall framing?

[BamZipPow]

Originally Posted by baldlobo

was it solid mounted to your truck, some rubber might fix it; and is that wall framing?

Yes...it was solid mounted to the truck frame...the link I provided shows that. Not sure rubber will fix it as the belly pan and side skirts hang off of this support.

Yes...the material you see is a metal wall framing stud I got from Home Depot. It was cheap and wouldn't git water logged/warped/burn like wood would. It was easy to work with and provided me the opportunity to learn.

I'm thinking that a metal plate sandwich might keep it from flexing and cracking. Time to figure out how long it has to be...

[euromodder]

Originally Posted by BamZipPow

Yes...it was solid mounted to the truck frame...the link I provided shows that. Not sure rubber will fix it as the belly pan and side skirts hang off of this support.

I beg to differ about why it's cracking ...

Looks like you mounted it too solidly with 2 bolts (tightly fitting in the holes ?) at either end, taking the ability to flex out of it.

The car flexes, but the support is so solidly mounted that it can't flex with the frame to the same degree.
So the support beam flexes , then cracks, where it can - beyond and outboard of the washers.


Give the new supports a chance to flex with the frame.

One bolt either end, or bigger holes (and possibly bigger washer) on one end and not tightening it too hard (using locking nuts or threadlock to keep the nut on) so one end can slide a bit.

[BamZipPow]

Originally Posted by euromodder

I beg to differ about why it's cracking ...

Looks like you mounted it too solidly with 2 bolts (tightly fitting in the holes ?) at either end, taking the ability to flex out of it.

The car flexes, but the support is so solidly mounted that it can't flex with the frame to the same degree.
So the support beam flexes , then cracks, where it can - beyond and outboard of the washers.


Give the new supports a chance to flex with the frame.

One bolt either end, or bigger holes (and possibly bigger washer) on one end and not tightening it too hard (using locking nuts or threadlock to keep the nut on) so one end can slide a bit.

Thanks fer yer insight and opinion...

I inspected the rear crossbeam (same setup) and there are no cracks on that piece. Wouldn't the rear have the same cracks as the frame flexes there, too? I know the low side skirts contact speed bumps as I'm driving over them as well as the oscillations of the road impacting the supports. Those impacts may have contributed to the cracking.

There's no way I can have the belly pan crossbeams have any sort of play with the side skirts and belly pans hanging off of it. The T-100's boxed frame has boxed crossbeams near the same point and they are welded in place. Those haven't cracked over the 375,000 miles on the T-100.

I will have to go with a thicker support...maybe extend the 2x4 inserts to include the fastener points and about 6" inwards from that point. I will have to include a thick steel plate on the bottom where the washers were in order to distribute the forces across that plate. I guess I could even go with 2x4 wood beams all the way across along with the metal stud as an outer protective shield. I will have to git more steel studs along with the new 2x4 studs. More brainstorming must commence before I move forward on this...

[euromodder]

Originally Posted by BamZipPow

Thanks fer yer insight and opinion...

I inspected the rear crossbeam (same setup) and there are no cracks on that piece. Wouldn't the rear have the same cracks as the frame flexes there, too?

You got a point there.

I know the low side skirts contact speed bumps as I'm driving over them as well as the oscillations of the road impacting the supports. Those impacts may have contributed to the cracking.

If that's the case, then you could extend the wood further into the crossbars, and shorten the PVC tubes accordingly, so any upward push on the crossbar is spread over a much larger area than the 2 bolts, PVC pipes and washers on either end.

There's no way I can have the belly pan crossbeams have any sort of play with the side skirts and belly pans hanging off of it.

It doesn't have to be loose, it just needs the ability to give and take a little.

The T-100's boxed frame has boxed crossbeams near the same point and they are welded in place. Those haven't cracked over the 375,000 miles on the T-100.

But they're not made out of the same material.
Steel for frames does have some flexibility in it, or it'd destroy the frame.

We usually don't think much about it, but stresses on a car are relentless.
So some play needs to be built in, or it'll rattle and shake itself apart.

...maybe extend the 2x4 inserts to include the fastener points and about 6" inwards from that point. I will have to include a thick steel plate on the bottom where the washers were in order to distribute the forces across that plate. I guess I could even go with 2x4 wood beams all the way across along with the metal stud as an outer protective shield.

Sounds like a good plan.

[BamZipPow]

Finally got my front crossbeam rebuilt and installed. Went with a 2"x4" whitewood stud that I cut down to fit inside a new metal stud. I chopped the height of the stud down to 1 3/16" and it was a tight fit in the metal stud. Used the old crossbeam to mark my holes so I can reinstall everything without trying to make new alignment holes. Had to cut the PVC spacers down to allow fer the wooden stud. It bolted right in.

The real test will be the main belly pan and if it will bolt in or not. I believe I made enough allowances when I made the first crossbeam...so it shouldn't be a problem Tomorrow will tell...

Since I have the belly pan off...I'm gonna take another stab at making a heat shield fer floor pan. The aluminum flashing on the belly pan reflects the heat from the exhaust system right back on the floor pan and this is the perfect time to address that issue. I have some leftover aluminum flashing to attach to the existing heat shield. I know I need a good air gap to allow fer the aluminum flashing to dissipate any heat it absorbs so it minimizes the heat transfer to the floor pan. Since I have the belly pan in place, I don't have to worry about the road beating up the thin aluminum flashing.

[BamZipPow]

Piccies!

New crossbeam...




New heat shield...


Heat shield not installed...


Heat shield installed...


I'll be going out fer a test run later today to see if I git any noise from the heat shield...hopefully not.

[mcrews]

nice!
makes you appreciate the thought and engineering that goes into car parts!

[BamZipPow]

Since I had to pull the rear belly pan and rear diffuser off to git the rear axle bearings and seals replaced, it gave me an opportunity to address a small issue and take a shot at seeing if my solution will fix it.

Since the beginning of my belly pan project, I installed various bungee cord and rubber cord supports fer the back end of the rear belly pan. Going over bumps, the wooden stops would strike the rear axle housing from the rebounding of the bungee cord and the bump. While not extreme, I wanted to see if zipties around the rear axle housing and the rear belly pan supports would keep the back end of the rear belly pan tight to the rear axle housing. I installed the bungee cords just in case it snaps while I take it out fer a spin. Yes, the front of the rear belly pan and back end of the rear diffuser are mounted on hinges to allow the rear axle to extend up and down without ripping the fasteners out...at least that's the theory.



Well...40 miles of city roads at differing speeds and road conditions haven't yielded any extra bumping noises from the belly pan and the rear axle. A quick peek underneath shows that the zipties are holding up.

I'm thinking of gitting some conveyor belt material and building up a multi-layered vertical stack to replace the wooden stand offs. The stack will be secured to the rear axle with 8" stainless steel hose clamps and the stack will contain a captive nut fer a bolt to pass through the bottom of the rear belly pan and into the stack so it will be easier to remove the rear belly pan when the time comes. The stack will also allow better flex movement which the wooden standoffs are very limited in flexibility.