Man I hate rattles & squeaks!!

[DJs74]

Now that my Bronco is finished (I know, they are really never finished) and I'm driving it more and more and enjoying myself immensely... I had a curve ball thrown at me the other evening! Usually I fly solo or have the Mrs. riding shotgun because the boys are always here and there & everywhere but the other evening we took a ride for ice cream and my youngest son (14 years old and weighs about 110 pounds) was riding in the rear seat and we noticed the most annoying rattle / squeak coming from the rear cargo area. At first I thought something had come loose underneath or maybe something was happening in the rear wheel area but the sound and pitch seemed to change with the road surface, turning left to right etc.
When we returned home I went on an immediate hunt underneath and in the wheel wells and there was nothing to be seen. The I got to thinking about my rear passenger and that this never happened until some weight was applied on the rear seat, so I hopped back there and started squirming around and sure enough, I was able to duplicate the noise! Hurray, right. Not! I still don't know where / what exactly it is. I thought maybe it was my leather seat covers squeaking on the seat frame but not - then I thought it might be the seat mounting feet on the tub floor - not. It seems the floor itself is making the noise between the seat and tailgate but I don't know why? Everything is tight, the seat is mounted tight to the floor and there is carpet and padded jute between the seat brackets and steel floor (I also applied bedliner roll on prior to the padding and carpet).

I am assuming the floor in just one piece / one thickness construction just like the floor of a truck bed. I never really did anything in that particular area during the restore but now I'm wondering if there might be material overlap (steel folded on steel) in that area? Can't see it from underneath due to the fuel tank / can't see it from inside due to the carpet.

what I know for sure: noise is generated somewhere between the seat and tailgate in the floor and it only does it when weight or someone is sitting on the rear seat so that leads me to believe that something between the seat and floor is up but everything looks normal underneath directly below the seat area. The one thing I had to do when I reinstalled the rear seat is use bolts and nuts because the factory welded on square nuts were gone somewhere prior to me but the floor was 100% solid. I always assumed that the PO simply wanted to take the seat out at some point and the bolt threads were corroded due to road grime exposure so they just cut them away and installed bolts / nuts


any ideas as to what this mystery noise could be is appreciated.

My next step will be to take the rear seat out, remove the carpet hold down strips, peel the carpet back and get in there to inspect

*Edit* I forgot to say, after we arrived home fresh off the ice cream run and after the initial inspection, I went for another ride solo and no noise. That's how I came to the conclusion that is was all driven by weight / force applied to the rear seat - strange...............


thanks,

DJs74

 

[savage]

Does it sound like its coming from the seat it's self, like the springs in side the seat?

 

[Toddpole]

Check the body mounts in that area. If they are not tight enough a little added weight could compress one and let the bolt squeak. Good luck. I too, hate squeaks and rattles!

 

[75MIKE]

I was under the impression they came from the factory with rattles and squeaks.

 

[DJs74]

Does it sound like its coming from the seat it's self, like the springs in side the seat?

I thought at first it was coming from the seat itself but I don't think so.

If I sit on the rear seat, grab the roll bar on the driver side and rock the Bronco left to right while placing my right hand flat on the floor board behind the seat, say several inches from the tailgate (that is a trick and I probably look ridiculous when doing it), you can feel the floor pan itself squeaking or kind of rattling - but actually "squeak" and "rattle" really isn't exactly right... just the best way I know to describe it. Maybe "resonate" is a better word? Kind of like an old nasty rusty hinge where the friction resonates away and through whatever touches the hinge.

I am pretty sure it is the floor pan or maybe as stated by Toddpole - could be body mounts squeaking and the floor pan happens to be my amp??

I will check those body mounts!

thanks,

DJs74

 

[DJs74]

Check the body mounts in that area. If they are not tight enough a little added weight could compress one and let the bolt squeak. Good luck. I too, hate squeaks and rattles!

Good call! I will check those out, that is very possible and also supports (no pun intended) the weight being added causing it theory.

thanks,

DJs74

 

[DJs74]

I was under the impression they came from the factory with rattles and squeaks.

They did.

My dad's buddy bought a brand new 1973 Bronco that had only 18 miles on it and they were on their way to go hunting one morning and the Bronco began to violently vibrate & shake at cruising speed - they pulled off the road (in the dark) and realized that the rear universal joint was ready to fall out and that both u-bolt straps had never been tightened. Checked the font ones and same thing!

DJs74

 

[BRONCROB]

May just be your rear spring bolts are too tight causing the noise.Spray a little wd40 on there and see what happens.

 

[DirtDonk]

Old crushed original rubber body insulators/cushions/mounts can easily create the right circumstances for funny noises, but may also have created a monster over time. If your mounts are old, I'd replace them whether you think they're the culprit or not. Just makes good sense to have them in good condition and supporting the truck's body better.
One thing that came to mind when you were describing it was the under-body support channel. I think it's right around the area of the seat belt bolts maybe? Haven't looked under a body to verify, but there should be one in that area at least. It's possible that over the years some of the spot welds have come apart, or that brace was never properly welded in at the factory and body flex is making itself known as a noise.
I don't think I've ever actually heard of this happening, but knowing Broncos it seems possible.

Sounds like a good argument for multiple people testing it so one can sit in the seat while the other(s) look/listen for the sound.

Good luck. Be interested to hear what you find. Might end up being something really odd like the parking brake cables hitting the body or some such stuff!

Paul

 

[erics667]

If you can ...have someone else drive it around while you sit there and listen.

 

[zonian]

If mine didn't squeak and rattle I would be worried something was wrong, same way that slow oil drip reassures me at night..........

 

[Rustytruck]

Make sure you don't have a hose clamp tail or something coming up from the gas tank. its the only thing up in that area. Check the skid plates especially the one under the transfer case with the self stripping bolts.

 

[69red]

the lift gate on mine makes a jittery, high pitched squeek if the strikers are dry. its tough to tell where its coming from due to the high frequency.

a little gear oil on the back side of the strikers quiets it right down for a couple of months at a time.

 

[m_m70]

My spare tire carrier makes some strange noises when moving. Of course it rattles but the rubber rubbing against the bars makes a weird sound as well.
Figured it out when I had to drive it with the tire off the carrier.
Just a thought.......

 

[Pa PITT]

... I bet your rattle is in the rear seat as some one said have some one else drive it & you set in the seat and listen for the rattle. Then crawl over in the back & see if your weight changes anything if your in the back but not in the seat. .. You may have to take the seat out and squirm around in the back area.
... My Running Buddies Tailgate to top .. Chirps & Squeaks so bad But after the 1st year we took it hunting.. We wrap the locator Pin with Duck tape. Last about 2 days. then re-wrap and good until end of hunt.
... GOOD LUCK .

 

[half cab]

Seat bolt you add isn't rubbing fuel tank is it?

 

[DJs74]

Thanks Guys for all the responses.

I didn't get a chance last night to do anymore investigating but wanted to respond to some of the suggestions.

* I have applied lubrication to all areas of the tailgate & liftgate
* leaf spring bushings in good shape
* no loose clamps or anything touching the floor on the underside
* no spare tire carrier on this one
* even though it seems like the seat, I can feel the noise on the floor behind the seat
* I plan to plop my can on the rear seat and have someone drive it
* the 4 seat bolts are pretty short and only protrude through the floor about 1/2" plus the nut
* I will take a look at the body mounts for sure & the cross support

The thing that really has me scratching my head is that is doesn't make a peep until someone is sitting on the rear seat

I'll be on the hunt this evening and during the weekend if necessary

Really appreciate all the thoughts!

DJs74

 

[Rox Crusher]

Is the floor itself rusted to the point that it is flexing under load and maybe allowing seat bolts or seat belt bolts to rub fuel tank ?

 

[DJs74]

Is the floor itself rusted to the point that it is flexing under load and maybe allowing seat bolts or seat belt bolts to rub fuel tank ?

The floor is 100% solid. When I fist bought it, the PO had just installed new carpet (generic type) and when I rolled it up to look, I was amazed that there wasn't even any surface rust or anything. Since then, I've sanded the floor boards down inside and out and have coated both inside and out with bedliner roll-on urethane type.

I suspect and as mentioned by Dirtdonk and others that it might be the rubber body bushing mounts. I can see them and they look good but I don't know how old they are - can't tell if they are factory or if they have been replaced at some point. Man, I wish I would've replaced them when it was sitting there as a bare tub - I just didn't think to and they actually looked very good.

Might still have to???


Thanks,

DJs74

 

[DirtDonk]

Take a couple of quick pics of a couple of the mounts and we can probably tell. If they look good, they probably are. My originals were already visibly crushed by 60k miles, but it had a hard early life off road too.
Still kind of hard to imagine originals being good after 40 years though. But hey, as we say, your results may vary. And some get lucky.

If they're all the same height, at about 3/4 to 1" if I remember, then you should probably keep looking for your squeak.

Paul