Help needed to stop me throwing money at my CUCV, Hopping/Vibration

[CUCVLOVER]

I get some rattles and hums at idle from the interior of the truck. Usually I just slap the dash and all is good.

These trucks do vibrate and rattle a little.
They are not Cadillacs. Just saying

 

[Ackevor]

These trucks do vibrate and rattle a little.
They are not Cadillacs. Just saying

HAHA no doubt, I don't expect a caddy type experience, it just seems a bit over the top of the usual hums and noises. I can feel it in the seat and it resonates through the body. Possibly just hitting the right frequency to get all the sheet metal singing and will clear up once I get some soundproofing laid down in the cab and under the hood. I am more than ok with things so long as it wont cause problems.

The idle vibration is not really whats concerning at the moment, its the one that starts at higher rpms when in gear and no prop shaft installed. I have a lot more diagnosing to do still... just wish we had 28 hour days haha.

 

[cucvrus]

Sound proofing in a PA truck. That is a rust whorehouse. Trust me. Remove everthing you can that will hold moisture. These vehicles are looking for an once of mud stuck fast, mud to hold moisture and continue to rust. The only thing I found that does not hold rust is the spray in Line X. The jute sound proofing on the back of rubber mats / carpeting and rubber mats alone of any type are rust havens. I have had great luck painting the floors with a couple good coats of CARC paint. But in PA keep the floor bare or professionally cover with a spray in liner. I had the Durabak rolled in and the in 2 years the heel of the foot at the gas pedal was thru and rusting. I spent countless hours with chemical stripper getting the brush in line out and getting the Line X sprayed in. Others have seen my vehicles. I am not making it up. It works. Stay away from anything that absorbs water. Rust never sleeps or takes a break. It remains hungry forever. Even the firewall has that sound proofing material. I remove that because it is worn out and a moisture holder. Do as you wish. Have a great day in PA.

 

[Ackevor]

This is what I ordered to insulate the truck claims no moisture absorption. http://www.amazon.com/ESP-Low-e®-Ez...e=UTF8&qid=1446130593&sr=1-2&keywords=ez-cool

I hope it doesn't end up rusting out like you mentioned. I supposed that's why it was as rusted when I pulled up the rubber liner bolted to the floor. Rust just about anywhere water got under it. Wouldn't a few good coats of liner and then laying down the non absorbing insulation be ok though? as long as moisture had no way of getting to the base metal I figure it cant rust. The insulation should prevent abrasive wear on the coating as well.

 

[cucvrus]

I would NOT leave it to chance. That is me. Do as you wish. I know how bad they rust in PA. I have no coverings in any of mine but CARC or sprayed in Line X.

 

[Ackevor]

I would NOT leave it to chance. That is me. Do as you wish. I know how bad they rust in PA. I have no coverings in any of mine but CARC or sprayed in Line X.

How well does the line X keep the noise down? I mainly use this truck to haul ATVs to wherever we ride, my wife and son ride along. As it is now, the truck is a box of noise and we cant hear each other without yelling, which could be a good thing when it comes to wives haha. Still I plan to install some type of radio and without, i cant imagine being able to hear anything.

knowing my floors were already rusted pretty good, I wire brushed, cleaned, laid down rusty metal primer and sprayed with duplicator bed coating, I imagine its just a matter of time before they rust again. With this in mind I supposed I could be a guinea pig and try the insulation anyway and see how long it lasts, and how well it works, reporting results back some time later.

 

[cucvrus]

Yes if it is that far gone you would be wasting your money on Line X. It does a good job of noise reduction. But it is what it is. This is not a modern vehicle. It will be noisy. i never even had the noise insulation on the firewall under the hood like the civilian ones do. Yes so do what you have to. But it is not a quiet machine no matter what you do. Unless you like to sit parked and talk and listen to music. Acoustic quality is not that good with the steel cab roof and lack of door and side insulation. Sort of like a stereo in a steel boxcar. I am glad i do not have one as my only form of transportation. It does wear on you after a bit. 20 + years of driving my own and I do get tired of the noise and discomfort at times. But i still like the concept and design.

 

[jpg]

I know when it idles it vibrates everything and all the interior stuff hums to life. but if I give it just a bit of fuel the vibrations stop .

I have a belt that thrums like a guitar string when idle. It's a new belt, the right size, and properly tensioned. It stabilizes at higher RPMs. This might be part of your idle vibration. It is for me.
https://www.youtube.com/watch?v=FaQa3nKBVqk

 

[tim292stro]

This is what I ordered to insulate the truck claims no moisture absorption. http://www.amazon.com/ESP-Low-e®-Ez...e=UTF8&qid=1446130593&sr=1-2&keywords=ez-cool
...As long as moisture had no way of getting to the base metal I figure it can't rust...

...Knowing my floors were already rusted pretty good, I wire brushed, cleaned, laid down rusty metal primer and sprayed with duplicator bed coating...

That material is a closed-cell foam with an aluminum liner bonded to it. Kind of a joke to say it blocks 97% of radiant heat and then install it somewhere that doesn't have an air space, where most of the heat will be conducted...

I just did a post this week in the HMMWV forum about someone asking for a good sound deadening material - that's kind of the wrong way to go about it. You need to first start with where your most objectionable noise is coming from, and address that as close to the source as possible. For example, if your worst offensive noise is coming from your intake, putting Dynamat on the doors and floorboard isn't going to do much... (however, covering your intake filter can halves with Dynamat/Dynaliner and adding a GM ducted resonator to the filter can intake and routing it to the cold air intake hole in the core support on the passenger side will)

As for rust, think about the water getting to the floor from inside and outside to sheet metal. Sure, you can bond a dynamat or other pad directly to the floor with some 3M 90 contact adhesive, but if you get a hole from the outside of the sheet metal letting water into the footwell, it can create a pocket of water behind the deadening material right at the hole (where your coatings are less effective). .

I have a belt that thrums like a guitar string when idle. It's a new belt, the right size, and properly tensioned. It stabilizes at higher RPMs...

I'm guessing (without having watched that video) that the belt goes to an alternator. Alternators are notorious for belt shock loads as each armature passes a coil - it's harder to push a rotor armature past a stator armature (towards the peak/trough of the phases output), and easier to pull away a rotor armature from a stator armature (zero-crossing for the phase).

That shock load is also bad for the belt, modern cars are addressing this with overrunning clutches and torsional dampeners on the alternator shaft, while relying on the rotor's inertia to carry it through the zero crossing unload.
https://www.youtube.com/watch?v=4EXYP1CmL9Q

 

[Ackevor]

My belts do the same thing as well, im sure it all stacks up haha.

tim929stro: thanks for the tips, thread and advice. I do have some dynamat type material, left over from a friends trunk job. I planned to cut sections of it to properly perform on larger metal surfaces that resonate. From what I understand you dont need to completely cover the surface, usually only sections as little as 1/12th of overall coverage area. This alone will absorb vibration which is typically what causes most noises heard. The ez cool I got to just add an extra layer to reduce road noise and maybe keep it a little cooler in the summer. If it doesnt end up working,... then I guess im out $70.

As far as putting it on the floor. I need to find out where water is getting in and pooling in picture below. I replaced all seals dealing with the door, less the vent seal because of the difficulties with rivets and such but they havnt let water in during heavy rain. A friend suggested a possibile cowl leak under wipers near firewall but the only areas wet are the floor and puddle on the new weather seal ( that I wiped away before I took the picture...)

 

[CUCVLOVER]

Is your vent window closing completely?
They can leak water also.

 

[Ackevor]

Just realized my passenger door must have been replaced, it has the m1008 upper door seal that screws to the door, as well as a different window crank handle. Driver side doesn't and passenger area is bone dry.

 

[Ackevor]

Is your vent window closing completely?
They can leak water also.

Yeah, driver side vent window has a good seal, the passenger side isnt as good, and has a broken spring pin assembly to boot but it hasnt leaked either.

Ill sit inside and have my wife hose all around the door or something... one of these days.

 

[icecreamman]

Looks like everything does the "shake, rattle and roll". IMO, I would try an "on vehicle" tire balancing job. It's not easy to find a shop that still can do this. They can compensate for small discrepancies.

Although it wont look "military", I always swap the stock steel rims on any vehicle I ever buy with aluminum rims. I do commercial HVAC work formerly for national accounts------always Ford F250s.


I have a set of eight lug Ford aluminum rims as a spare. Kind of funny, my rims follow me.

 

[Hasdrubal]

Can leak from under the windshield weatherstrip at the bottom corners. Rust can form under there on the sheet metal lip, pushes up the rubber and water flows thru. Had water dripping on passenger floor, even onto the inside of glove box when its closed. Last time I fixed this, I used a lot of silicone sealant in the weatherstrip channel to seal this area for good.

 

[NovacaineFix]

Had the same leakage issue on my 1009 that still had the original rubber mat with the factory sound deadening underneath. Problem with that factory mat is that any cracks in the rubber will allow water to get into the sound deadening material and will sit on the floor and cause the rusty floorboards.
Mine was from a cracked windshield and it dripped down under the mat. Luckily the CARC held some of the rust at bay. I sandblasted the floors after removing the mat, welded up the rusted spots and applied a Rhino type liner onto the floors. Best thing you could do for your truck.

As for your vibration issue, man I wish you luck, but I would have to agree with that drum. From the video, that seems like a lot of movement. Mine needs leaf springs, the fronts are gone but the rears seem pretty decent for the age.
Good Luck Man!

 

[Jeepsinker]

Both rear axle shafts may be bent. You don't know the history of the truck. Easy to tell though, theyou are full float axles. Just pull the axle shafts one at a time and try it. Otherwise it may be the center support ball in the double cardan joint of the front driveshaft. I had a jeep Cherokee doing that until the cardan joint failed on the highway and ripped half my transfer case off 500 miles from home.

 

[cucvrus]

Can leak from under the windshield weatherstrip at the bottom corners. Rust can form under there on the sheet metal lip, pushes up the rubber and water flows thru. Had water dripping on passenger floor, even onto the inside of glove box when its closed. Last time I fixed this, I used a lot of silicone sealant in the weatherstrip channel to seal this area for good.

You sealed it for good. You sealed them hungry rust monsters in there and they are eating 24/7. They love sealed up areas. They multiply and pull moisture from the next pin hole they make. The only way you are going to slow them. I said slow you will never stop them unless you park the truck in a climate controlled garage and drive it only in dry weather. Any way the only way to slow them and detour them away from the leaky area and the rusty area. Is to remove the windshield and the windshield rubber. Cut the rusty area out and or sand blast the area. Weld the area treat both sides if possible. Apply a good rust inhibiting primer seal it with a paint sealing primer sealer and apply several good coats of paint and not from a spray can. That will stop it for a while. But it will come back with use again. But just smotsing sealer caulk or silicone on it will just make it rust worse. It seals the area and it never gets to dry out. Rust never sleeps and works overtime for less then straight time on new bare metal. It has no friends that can truly stop it and will turn into a big mess over night if left to chance and snake oil remedies. Don't ignore rust it will not go away. It likes it when you give it no attention. These CUCV's are buffets to the rust monsters. You are never more then 2 inches from rust when you are sitting in a CUCV.

 

[Ackevor]

Both rear axle shafts may be bent. You don't know the history of the truck. Easy to tell though, theyou are full float axles. Just pull the axle shafts one at a time and try it. Otherwise it may be the center support ball in the double cardan joint of the front driveshaft. I had a jeep Cherokee doing that until the cardan joint failed on the highway and ripped half my transfer case off 500 miles from home.

The front drive shaft doesn't spin unless its in 4WD, how would the cardan joint create a vibration?

Also with one shaft pulled, will the diff fluid leak out or should I plug it somehow? I wish I could bring some of these parts into work and set them on the granite table in a set of V blocks and indicate along the shaft and get an exact reading. But I think they would frown upon some greasy non aircraft parts being checked on our nice clean table haha.

Looks like everything does the "shake, rattle and roll". IMO, I would try an "on vehicle" tire balancing job. It's not easy to find a shop that still can do this. They can compensate for small discrepancies.

Although it wont look "military", I always swap the stock steel rims on any vehicle I ever buy with aluminum rims. I do commercial HVAC work formerly for national accounts------always Ford F250s.


I have a set of eight lug Ford aluminum rims as a spare. Kind of funny, my rims follow me.

Is there a good source for another set of wheels? I also called around my area and no one does on vehicle balancing. Maybe I should call a truck service station or something?

As far as the leak ideas, thanks for giving me places to look. I am overwhelmed with stuff I need to check and do with this truck... having regrets putting 300+ hours of work into this summer and still have issues. with the snow coming and no garage big enough to work on in the winter, I fear I wont have time with everything else going on... I can't believe we aren't buried with snow already.

 

[Hasdrubal]

You sealed it for good. You sealed them hungry rust monsters in there and they are eating 24/7.

Allow me to clarify; I use to do professional auto restoration for a living. The rust was only minor and on the surface,not right through. I sand blasted the rusty spots and finished with phosphoric acid, then applied red-oxide primer. Only then did I use the sealant. So it is a sound practise. This will prevent water from migrating around the windshield rubber in the future. So, it will stay dry on the inside.