# MLV Placement for Road Noise Reduction



## mino922 (Oct 8, 2010)

I am getting ready to apply a layer of MLV throughout the interior of my 2008 Acura TSX. The cabin is quite loud when driving on the highway and I am trying to reduce the road noise. I already have CLD in my doors and I am wondering if I will achieve better results by applying the MLV to the doors or the floor? 

The doors are pretty "tinny" and the CLD drastically reduced the tin, but I feel like I still get air born noise inside the car. I also feel like a lot of air born noise comes from underneath the car. If I do the floor first, I will apply a layer of CLD and then place the MLV on top. 

Any suggestions?


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## mino922 (Oct 8, 2010)

Anybody?!?


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## SkizeR (Apr 19, 2011)

sound deadening has got to be the most asked about topic, yet has all of the answers at the tip of a search. 

Sound Deadener Showdown | Sound Deadener Showdown


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## mino922 (Oct 8, 2010)

Never came across this site, I guess searching for the wrong things. Thanks!


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## Alrojoca (Oct 5, 2012)

25% coverage of good quality CLD on the floor and 1/4" CCF under the MLV or skip the CLD on the floor and use only 1/4" thick CCF and MLV


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## mino922 (Oct 8, 2010)

Should I do the doors or floor first? Trying to get the best bang for my buck.


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## Alrojoca (Oct 5, 2012)

mino922 said:


> Should I do the doors or floor first? Trying to get the best bang for my buck.


MLV on the doors is hard to do, takes a lot of time to get it right. I would do the doors last, or just add CLD on the doors and seal the inner openings.

The floor is faster once seats are removed. 
The firewall also needs some treatment.


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## vwdave (Jun 12, 2013)

So far Ive done CLD in the doors and floors and MLV in the doors. I have a. Inch left for the floors I just haven't getten around to it. All of that made an improvement but the best improvement was tires. Turns out that lots of factory tires are pretty noisy. I replaced mine with some that had a great rating on noise.

Seems to. E like road noise is one of things where right after you some sound proofing it sounds much better, but then the more you drive the more you notice it's still there and over time it just gets more and more annoying.


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## bbfoto (Aug 28, 2005)

I agree about having quiet tires. It will make a huge difference.

The problem with MLV is that it is intended to work as a barrier, and if it does not completely cover and seal the entire area, it's really not going to be effective. Think of the MLV as your driver-side door's window glass. If it's completely closed and sealed it works great to keep out noise. But as soon as you open it up even an inch, it loses a lot of its effectiveness as a barrier, and will let quite a bit of noise into the cabin.

So for MLV to make a substantial difference, you really need to completely cover and seal as much area as possible, i.e. the entire floor, transmission tunnel, firewall & behind the dash, rear seat back support, rear deck/parcel tray, doors, etc. The more openings or gaps you have the less effective it will be.

IME, A LOT of road noise enters through the front wheel well/kickpanels/ front door jamb area. Check to see if there is already a vertically-oriented OEM foam block in the front fenders/front door jamb area behind where the front door hinges are. If not, treating this area will make a big difference, and adding to what is already in place can help a lot as well.

I'll try to come back later and post a tutorial of what I've done on a lot of cars that makes a huge difference. Some late model vehicle manufacturers (in the last 3 or 4 years or so) take care of this issue pretty well.

But if this seems to be a problem area, I take a yoga mat sized piece of 3/8" thick Rubber Neoprene CCF, combined with a layer of MLV, and then roll them up together until it is the right diameter to be wedged or tightly press fit into the front fender well, so it is up tight against the inner door jamb. It's important to seal the full vertical length of the door jamb, or I guess I should say, "the full vertical height of the door jamb".

You can cut the pieces of foam and MLV in an oval-, almond-, or eye-shaped pattern so that it is thicker in the center portion and tapered on each end when it's rolled up together. It should look like a marijuana joint so as to fit the crescent-shaped space better. It helps if you cut the MLV about an inch smaller around the full perimeter as compared to the CCF. Also make sure to roll up the CCF/MLV combination so the CCF ends up on the outside of the roll.

You'll have to remove the wheel well/fender well liner to access this area, and it makes it a lot easier if you remove the wheel before you begin. Use speaker wire or zip ties around the roll to keep it wrapped up. Don't tie it up too tightly because you want it to be able to be press fit into place. Now place the roll inside an industrial strength, tear-resistant trash bag and squeeze out any excess air. Then zip tie the bag closed to keep moisture & water out. Now simply press fit it into place.

You can also make a CCF/MLV/CCF "laminate" and adhere it or panel clip it to the back side (inside) of the plastic fender well liner. You'll have to be careful with the placement and size of this so there are no obstructions and so you can still get the liner back into place securely. Silicon caulk or a similar rubberized adhesive works well to glue the laminations together and to attach it to the liner. This type of application works great for the rear wheel wells, too. This technique works to disperse and/or reflect the energy before it can enter the cabin. It will help to keep wind & road noise from exciting or vibrating any of the metal panels or cavities.

There are also purpose-made, automotive two-part flexible or ridgid expanding foams by Lord-Fusor and 3M that are made to go in the A-, B-, & C-pillars to cut down on wind noise and vibration in and around the glass. These special 2-part Urethane foams cure by chemical reaction, and do not require air to dry or cure, unlike "Great Stuff" expanding foam that will stay gooey forever inside a cavity. However, these special foams are very expensive and require a special application gun. But, this stuff works fantastic! It also works very well in the ceiling crossbeam supports.

You can find these foams at autobodytoolmart.com

Fusor® 121/124 Flexible Foam (Super Fast) | LORD Corp


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## Spud100 (Mar 30, 2015)

Great idea about making a better noise barrier in the rear open end of the front fenders towards the front edges of the front doors.
I have seen several cars that have a lightweight piece of foam that is encapsulated in plastic.

In my car, a 2015 Focus, it appears that the wheelarch liner is quite strong so it may be possible to place a flat piece of CCF/MLV/CCF from the top of the liner back down in front of the A pillar.

The other place that a lot of noise comes from is the rear wheelarches on a hatch / sedan. for example a Mazda 3 especially when the road is wet is exceptionally noisy. 
Putting foam/MLV over this area has a dramatic effect. CLD over sheet metal in the areas where water directly hits helps as well.

Gerry


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## Rudeboy (Oct 16, 2005)

mino922 said:


> I am getting ready to apply a layer of MLV throughout the interior of my 2008 Acura TSX. The cabin is quite loud when driving on the highway and I am trying to reduce the road noise. I already have CLD in my doors and I am wondering if I will achieve better results by applying the MLV to the doors or the floor?
> 
> The doors are pretty "tinny" and the CLD drastically reduced the tin, but I feel like I still get air born noise inside the car. I also feel like a lot of air born noise comes from underneath the car. If I do the floor first, I will apply a layer of CLD and then place the MLV on top.
> 
> Any suggestions?


CLD on the floor of a TSX isn't going to do much - the floor is pretty thoroughly treated at the factory. CCF and MLV will make a big difference there.

Whether to start with doors or floor is a choice I would make based on your temperament. Doors require considerable patience but offer the advantage of being discrete chunks you can do without disabling the vehicle. Getting to the floor requires gutting the interior and will take most people two days.

Partial treatments almost always have some unexpected results. If you were to treat all four doors and nothing else, you'll be drastically reducing noise entering through the sides of the vehicle. It will also get that portion of engine and front wheel noise entering through the front edge of the front doors and rear wheel and exhaust noise entering through the rear edge of the rear doors. Overall noise levels will be reduced. Because of that, and because you have reduced noise entering the passenger compartment from the sides, it will be easier to hear and localize noises entering through he front and rear. It's common to perceive engine noise as louder than it was before treatment - it's not, engine and all other noises will be reduced, you'll just be better able to hear the engine noise.

Treating the floor will get more road noise.


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## Babs (Jul 6, 2007)

MLV is definitely the way to go. 

A couple things:

1. Decoupling.. Don, I assume but asking, you'd still need to decouple it even on floor with layer of CCF between floor and MLV layer.

2. As much coverage as possible.. MLV loses a lot of effectiveness with even small openings. So cover as much as humanly possible. SubterFUSE I believe even has two layers in his Audi with fleece in between. I think they even repositioned OEM wiring over top of the MLV so it's still serviceable.

I still need to do my Civic, but I know it's gonna be some coin to get it here, and a metric ton of work with another full tear-down but I certainly know the value in it. I did CLD recently throughout and the difference is pretty much negligible. Combined with CCF/MLV layer thoughout I believe the difference should be dramatic.

Headliner area and pillars transmitting noise is a huge issue as well. Unfortunately MLV isnt very feasible at all for that, just CLD and maybe some batting that would be a far cry from MLV.


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## Rudeboy (Oct 16, 2005)

Babs said:


> MLV is definitely the way to go.
> 
> A couple things:
> 
> 1. Decoupling.. Don, I assume but asking, you'd still need to decouple it even on floor with layer of CCF between floor and MLV layer.


Correct. I use 1/8" CCF. On most vehicles I'll put a single layer between the floor and MLV with 2 layers in the bottoms of the foot wells - where feet rest. This is both to avoid compression of the CCF and to further isolate your skeleton from the vehicle. Then the stock padding and carpet on top of the MLV. In some cases it is possible to use the stock padding between the floor and the MLV as a decoupler but that leaves the carpet directly on top of the MLV which will change the feel of the carpet under foot and may cause extra wear to the carpet. As much as possible, add the CCF and MLV and then put things back as they were.



Babs said:


> 2. As much coverage as possible.. MLV loses a lot of effectiveness with even small openings. So cover as much as humanly possible. SubterFUSE I believe even has two layers in his Audi with fleece in between. I think they even repositioned OEM wiring over top of the MLV so it's still serviceable.


Multiple layers of MLV with a decoupler or absorber between them will mostly improve high frequency attenuation. Also remember that the improvement a barrier makes depends on how much it increases the mass/area over *what was already there*. The target for audible improvement is doubling the mass of what you started with. If the the stock floor with factory applied vibration damper is .5 lb/ft², adding a layer of 1 lb/ft² MLV will more than double it. The second layer doesn't even come close. You get into a geometric progression that becomes impractical very quickly.

While it's true that you want to shoot for 100% coverage, small gaps don't render the exercise useless. In practice, most of what we think of as breaks in the barrier really aren't - if you cut a 1/2" hole to allow a 1/2" bolt to pass through, you don't have a gap. Just adding heavy floor mats will make an audible difference, maybe covering 25% of the area?



Babs said:


> I still need to do my Civic, but I know it's gonna be some coin to get it here, and a metric ton of work with another full tear-down but I certainly know the value in it. I did CLD recently throughout and the difference is pretty much negligible. Combined with CCF/MLV layer throughout I believe the difference should be dramatic.


When the site was just testing and reviews of vibration dampers I heard from thousands of readers. The comment I heard more than any other was: I treated my entire vehicle, exactly as the seller instructed and heard very little difference. If you're just going to do vibration damper, do the doors, quarter panels and roof. Whenever anyone asks me about doing a vibration damper only treatment on the floors, i discourage them as much as I can.



Babs said:


> Headliner area and pillars transmitting noise is a huge issue as well. Unfortunately MLV isnt very feasible at all for that, just CLD and maybe some batting that would be a far cry from MLV.


In six years I've had one customer who had a good reason to add MLV to his roof - he drove his truck all day long at an airport. Barriers are meant to block airborne sound coming at the vehicle in a straight line. There aren't enough overhead noises sources to justify the puzzle of hanging the MLV from the roof and adding that much weight, that high in the vehicle. The glass is always going to be the weak link, so blocking above the glass line doesn't make much sense.

Vibration damper on the roof - particularly if there is no sun roof - is huge for air turbulence and rain noise and also for resonance energized by a wide variety of sources. Before I treated my Civic, a sudden downpour would startle me. The loud noise made driving in heavy rain even more unpleasant than it normally is. After treatment, the only rain sound if from the windshield. Kind of cool.

The gap between the roof and headliner is one of the best places to add an absorber.

If pillars are a problem, it's because they are transmitting sound from one place in the vehicle to another. You could literally stuff a sock in them to prevent this.


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## bbfoto (Aug 28, 2005)

Rudeboy said:


> If pillars are a problem, it's because they are transmitting sound from one place in the vehicle to another. You could literally stuff a sock in them to prevent this.


This is the main application of the expanding foams that I posted about. It works great to stop the transmission of sound and vibration through any type of pillar or cavity. And compared to stuffing premade foam chunks, polyfill, or any other type of insulation material in a pillar or cavity, the expanding foam adheres directly to the sheet metal, which further dampens the vibration/noise, increases mass loading, and there is a better chance of it completely sealing the airspace.

When this expanding foam is used in the A-Pillars, it works really well to reduce the transmission of sound from the windshield glass to the A-Pillar sheet metal and further into the cabin. The sound of rain on the windshield will be greatly reduced, at least in the higher-frequencies ranges. But I wouldn't advise this if there is OEM wiring inside the A-Pillar. The rear hatch lid is another place that this foam works well.

The expanding foam also works great in the cavities inside the car that are just forward of the rear wheel well...between the rear wheel well and the rear upright area of the door jamb.


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## Spud100 (Mar 30, 2015)

If pillars are a problem, it's because they are transmitting sound from one place in the vehicle to another. You could literally stuff a sock in them to prevent this.[/QUOTE]

Ford England foamed up the A pillars on the MKIV Cortina from memory in the 70's for that reason.
Gerry


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## T3mpest (Dec 25, 2005)

I had very good results in noise reduction just doing the floors and rear part of the vehicle. Here is what I did.

1. 40% coverage of CLD on the floor. I had product to burn and always cover the large flat parts that seem easy to cover at least half way in the center.. I just covered the large flat parts, got near the rear hatch very well. My subs load off the hatch, so I gave it 100% coverage, or as close as possible. Rammat was my choice for traditional CLD as I had it available already. The hatch also has a decoupler and MLV on the plastic side, all the way up to the glass line.

2. I used a denim thermal barrier product as a decoupler for my MLV link below
UltraTouch 48 in. x 6 ft. Radiant Barrier-30000-11406 - The Home Depot

3.Budget MLV along the floors and hatch, etc this stuff is 1.5lb/foot. Not as good as the some products, but it seemed to do quite well for me.
4 ft. x 8 ft. Acoustical Barrier-DB348X96BX - The Home Depot

4. The rear pillars had foam from the factory, so no need to do that, however I did deaden the rear quarter panels. The sheet metal of the car was quite flexible and rattled/flexed when bass hit. I could push on it with a few lbs of force from my hand and move the panel a good 1/4inch. Stanard deadener was't fixing that, so I got some ampere vibraflex. I can now lean on the panels full force and they literally don't move. The large empty cavity behind those quarter panels is now filled with polyfill. The space wasn't big enough for me to get fiberglass back as the opening was too small. I line my fiberglass in thin plastic bags, The polyfill isn't super effective, but it is better than nothing. When I do the doors, I'll use fiberglass.

As a note, when driving with the rear seats out one empty cavity was picking up noise from the road, made it sort of sound like running water through a pipe. Once I stuffed it with polyfill the noise stopped, that was good enough for me to justify using it.

5.The rear wheel wells had a form fitting foam/mlv layer from the factory that fits on using plastic clips. I removed those, added another layer of MLV back onto them and then put them back on. That area was where most road noise came from stock, I can't say I'm surpised they treated it, just wish the stock treatment did more!

6. The large plastic panels that cover my rear hatch area, lower quarterpanels and wheel well area, I gave them a MLV treatement too. They are covered in a layer of cotton from the factory. I left that layer on and used it as a decoupler and put a full layer of MLV along the panel, as much coverage as I could and allow the clips to fit.


The car had a lot of road noise in the rear, loudest when untreated. so a second layer seemed appropriate.


Lastly,as every panel went back I covered the edges of all metal clips with some ensolite with the sticky backing. I also glued some of the larger flat plastic panels with radiant barrier denim material. One particularly flimsy panel even got fiberglassed! The panels didnt' have a great fit from the factory after being taken off in the past, so at least now they can't rattle 

Anyways just doing this to the rear of my car REALLY cut down on the road noise from the rear. I have one rattle where my carpet lifts up to get to my wrench to remove tires. I just need to get back into it and fix it. Other than that it seems quiet, no rattles when I drive from back there and road noise is either from the doors, above the glass line or up front. I'm hoping when the sub goes back in, I'll still be as pleased. I used Raamat on my hatch, I hadn't gotten vibraflex at that point. I have a feeling I may go back in the future, open it back up, make sure the MLV is holding and remove that and put Vibraflex in it's place. My quarter panels sound much more dead than my hatch, and pretreatment the hatch was one of my sturdiest sounding panels and the quarter panels were the worst.. 

Vibraflex is AMAZING, it's just a pain to apply, but worth it, especially on a "weak" panel that not only rattles but flexes. 

Yes, I probably should have done a build log, it was so much work I didn't want to stress myself out more by trying to document it all. This was in a SUV, 2009 Cadillac SRX


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## bbfoto (Aug 28, 2005)

^Great write-up.

I'd be interested in trying some of the Vibraflex.

Did you buy the Ampere Audio Vibraflex direct from their web site or from a shop/dealer?

Did you get the "80" or the "160 Extreme"?


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## Alrojoca (Oct 5, 2012)

Rubber grommets in between metal assemblies attached to walls work good also, anything that uses a bolt like seat belt Retractor, brackets holding motors, or that are touching the outer rear wall. sometimes cutting grommets in half works if they are too thick.


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## seafish (Aug 1, 2012)

I have been looking at vibraflex for awhile…apparently it is used in Europe a lot. 

I WISH that Toostubborntofail could test some!!

Here is a link--

AA-Vibraflex BS 80 | Premium Sound Dampening

The download manual link at the bottom has LOTS of tech info in it.


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## TOOSTUBBORN2FAIL (Jan 31, 2011)

I have some of the 160. Next weekend it will be both heat and vibration tested. As I've made the permanent decision to test from 500hz and down, next weekend will be a full two days of testing.

All future tests will be from 500hz and down. That's really where the big differences are being seen with all products anyways. After doing a full restore I'm still having the same problem with rew, so without moving to another computer/operating system that's the best I can do.


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## seafish (Aug 1, 2012)

TOOSTUBBORN2FAIL said:


> I have some of the 160. Next weekend it will be both heat and vibration tested. As I've made the permanent decision to test from 500hz and down, next weekend will be a full two days of testing.



That's great news..I didn;t realize you had some VibraFlex to test...VERY curious whether its performance justifies the price.


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## TOOSTUBBORN2FAIL (Jan 31, 2011)

It's a recent addition, I'm not even sure who sent it although I thank them for it. Interestingly enough, the sheet says NOT to use it on the roof without some mechanical support.


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## seafish (Aug 1, 2012)

Thta's for the 4mm version,but it's also too bad, because I wanted to use it on my trucks roof and I am not sure how I would use mechanical fasteners except at the mid support brace. Still, its nice to know that they are taking care of their customers by advising proper fastening techniques so people don't just slap it up overhead where t might get too hot on a sunny day and then pull their headliner down…lol

They DO make a thinner version (2.5mm) "lite" that is suitable for overhead application, though it likely has different damping characteristics.


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## Alrojoca (Oct 5, 2012)

If did the math right, that stuff is over $10 a square foot and over a pound and half per s/q


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## seafish (Aug 1, 2012)

Alrojoca said:


> If did the math right, that stuff is over $10 a square foot and over a pound and half per s/q


Thats about right math wise …like I said, it will be awesome to see if the results justify the cost, which is the entire point of too stubs thread. VERY much looking forward to the results and HOPING that the SQ gods keep his life free from trauma and drama so that he can continue to test it and others!!!


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## TOOSTUBBORN2FAIL (Jan 31, 2011)

At this point I'm in a "calm before the storm". It's going to get very bad at one point, early to mid next year. I want to finish stuff before that.


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## TOOSTUBBORN2FAIL (Jan 31, 2011)

Alrojoca said:


> If did the math right, that stuff is over $10 a square foot and over a pound and half per s/q



That's not too bad in price compared to another product I have that' costs $60 per square foot.


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## mino922 (Oct 8, 2010)

I already purchased 13 sq. ft of Damplifier Pro, 36 sq. Ft of Luxury Liner Pro and 9 sq ft of OverKill Pro. My plan is to do about 30-40% CLD coverage on the floor and full MLV coverage on top. I will also use CCF as a decoupler as needed on the floor. 

If I have remaining MLV I will do the rear wheels and then I also plan to do the trunk lid with CLD, as my woofer really rattles that. I already have my front doors treated with CLD and that made a huge difference. 

Hopefully I will have some good results from the floor and if I need to do the doors, I will do that in the future. One step at a time!


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## Alrojoca (Oct 5, 2012)

TOOSTUBBORN2FAIL said:


> That's not too bad in price compared to another product I have that' costs $60 per square foot.


Wow! Very interesting, look forward to find out more details and tests results when your valuable time allows it.


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## Alrojoca (Oct 5, 2012)

mino922 said:


> .
> 
> Hopefully I will have some good results from the floor and if I need to do the doors, I will do that in the future. One step at a time!


I'm sure you will have noticeable results, and it's good to take it slow to hear the results after some areas are done and do more later if needed


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## TOOSTUBBORN2FAIL (Jan 31, 2011)

Luxury liner pro works good, I used that in my last build. Too thick for my current one.


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## TOOSTUBBORN2FAIL (Jan 31, 2011)

Alrojoca said:


> Wow! Very interesting, look forward to find out more details and tests results when your valuable time allows it.


It's a 15mil stainless steel constraining layer with a super super thin adhesive that is supposed to be viscoelastic. The only reason I have some to test is because it was supposed to have been developed by 3m.


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## mino922 (Oct 8, 2010)

I'm running into my first issue. I have the seats out and I am trying to get the carpet out and it seems that the carpet runs basically under the dash.

Any ideas on how I get this out?


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## Rudeboy (Oct 16, 2005)

mino922 said:


> I'm running into my first issue. I have the seats out and I am trying to get the carpet out and it seems that the carpet runs basically under the dash.
> 
> Any ideas on how I get this out?


See if you can get a look at the shop manual for the car. Should be a section on carpet replacement or RNI. You have to cut it on the Hondas I've worked on.


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## TOOSTUBBORN2FAIL (Jan 31, 2011)

If you remove the emergency brake lever, you can lift it out of the way of the carpet. My neon was the same way. In mine, the dash also had to be removed to pull the carpet in one piece. The other option as Don said is to cut it.


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## Rudeboy (Oct 16, 2005)

TOOSTUBBORN2FAIL said:


> If you remove the emergency brake lever, you can lift it out of the way of the carpet. My neon was the same way. In mine, the dash also had to be removed to pull the carpet in one piece. The other option as Don said is to cut it.


I was very surprised to see cutting as the Honda recommended solution. It's just the front most piece. Shop manuals are great for stuff like this. I encourage everyone to find one before doing these projects - pays for itself in clips and trim that don't get broken.


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## TOOSTUBBORN2FAIL (Jan 31, 2011)

It wouldnt surprise me if that was recommended for mine as well, as I doubt they'd say to pull the dash just for the carpet. Luckily I was pulling in anyways and it was simple in that car. The new car is going to need a manual before I rip it apart.


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## Babs (Jul 6, 2007)

Yep, with those small pieces that go under stuff in the console, just snip 'em in the middle and pull her out. Goes back in the same and the console covers it all up anyway.


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