Repair 2000-2004 Ford Focus Air Cleaner Box for Under $25





Introduction: Repair 2000-2004 Ford Focus Air Cleaner Box for Under $25

Hello, I am a former farm machinery repairman and as some would say just a cheap skate who does not like spending my hard earned money if I can help it.

So when I went to change my air filter on my 2002 Ford Focus and could not get the screws out because the nuts were stripped out of the plastic housing.

The mechanic said it would cost over $300 for a new air box plus labor to install it.
I decided to repair it.

This pictures is of the box ready to go back into the car.

Step 1: Gather the Needed Tools and Supplies.

You will need a screw driver to loosen the clamps.

A 13/64" drill bit and something to drive it with. (I used a drill press,) a hand drill would work.

A 1/4"-20 Tap and tap driver.

A vise grips, a 8mm wrench and something to mark the holes I used a 5/16" transfer punch,) any way to mark the center and make a punch mark.

A small hammer and a sharp chisel to remove the gussets or a dermal tool, (I used a Dewalt RotoZip tool with a 1/8" bit).

4 each 1/4"-20 stove bolts 1 1/4 or 1 1/2" long

A tube of RTV Silicone Make A Gasket, I used red Permatex Brand.

2 pieces of 1/2" square stock 9 1/2" long either steel or aluminum will work, I used 1/2" square steel key stock because I could buy 12" long pieces at Tractor Supply Co. on Memorial day when I decided to do the job. Aluminum would have been easier to work with.

Once you have the items you need, you are ready for step 2.

Step 2: Remove the Hose From the Air Cleaner to the Intake Manifold

First loosen the clamp on the hose at the air cleaner.

Next loosen the clamp at the end of the hose connected to the intake manifold.

Grasp the hose and lift it off of the intake manifold and then slip it off of the air cleaner.

Lay it aside and go to the next step.

Step 3: Disconect Vent Hose and Electrical Plug.

Grasp the crankcase vent hose and remove it from the valve cover, if it is stuck you may need to give it a twist.

Press the release on the electrical plug and gentle pull it off, don't force it, it should not be real hard to remove.

Step 4: Remove the Air Cleaner Box.

Grasp the air cleaner and lift it out, (I could only show one hand as I needed the other to take the picture) one hand on each end, it may be necessary to give it a slight jerk as it sets in 3 rubber grommets.

Step 5: Removing the Gussets

To remove the gussets I used a RotoZip tool with a 1/8" bit.

Now I could clamp onto the stripped nuts so I could remove the bolts.

Remove the gussets toward the center of the box, leave the ones toward the outside of the box.

You could use a sharp chisel and a small hammer and gently shave the gussets away, just don't try to take to much off at one time or you may crack the box.

Step 6: Remove the Old Nuts.

Clamp a stripped nut with a vise grips and using a 8mm wrench or socket wrench, remove the stuck screws, and remove the cover from the box.

Replace the old 6mm bolts in the cover with new 1/4"-20 stove bolts 1 1/4" or 1 1/2 " long.

Using one of the old bolts screw it into the old nuts and tap them out of the plastic box housing with a small hammer.

Your box housing should look like the last picture, and is ready for the bars.
Time for step 7.

Step 7: Fitting, Drilling and Tapping the Bars.

Now is the time when you are ready for the 1/2" square Aluminum or steel bars 9 1/2" long.

Put them up under where the old nuts were, and you will see where the corner on each end needs to be rounded.

With a file or grinder round the corners so they will fit up against the bottom of the bolt flange and in tight against the sides of the box.

Once they fit, it is time to mark where the holes need to be drilled.

I used a 5/16" transfer punch and tapped it lightly with a small hammer, I could not show tapping it as I needed one hand to take the picture.

I used a drill press to drill my 13/64" holes where the transfer punch had made the marks but you could drill it with a hand drill.

Use a little light oil on your tap to make it easier.

Step 8: Installing the Bars With RTV and Installing the Air Filter and the Cover.

I used Permatex Red Hy-temp RTV silicone gasket maker but any RTV silicone would work.

I put the RTV down one side with the air filter in place then put the cover in place and tightened the 1/4"-20 stove bolts just snug, this held the bar in place while the RTV dried.

I did the same to the other side and then went right on to the next step as the silicone will harden even if you get it into the car and running down the road before it hardens.

WOW it's fixed.

Now lets put it back in the car.

Step 9: Put It Back Together, It Is Fixed.

Make sure nothing is down under where the air filter goes.

Set the box down in place and wiggle it to be sure that it is in the grommets, press it down firmly.

Plug the electrical connector back onto the box.

Connect the crankcase vent hose back to the valve cover.

Replace the air box to intake hose, slip it onto the air filter housing then down onto the intake manifold and tighten the hose clamps.



You have just repaired you air cleaner box.
You probably just saved your self about $300 or more.



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    What I found that I think works better is that after you knock out the nuts in step 6, I coated the the outside of the nut with super glue and reinsert it back into the plastic air cleaner box (ie. superglue the nut back into the box), and then coated the outside with super glue (making sure not to get the super glue in the actual threads in the center). The super glue holds it in place really well. Then I would make sure to coat the bolts with anti-seize to make sure it doesn't get stuck again.

    just wanted to thank, my problem was exactly the same as yours my solution was slightly varied from yours as i used simple nuts and bolts for now, all i had to work with. now i just need to find a substitute filter sponge for the crank case vent filter. 300$ just for that....... LOL thanks again

    Jiffy lube has been telling me for a while that mine on my 2003 focus are stripped and I just now looked to see what was going on. there was no "nut" like yours has, just the plastic tabs so if it ever had them they fell out. I was assuming there may have been some clip on nuts at one time that the techs at jiffy lube had just lost them till I saw your pics. Anyway I plan to try clip on nuts to fix mine. temporarly I just put some plane 6m nuts to keep it from sucking in dirt. my local auto parts store sells the nuts in the help section. here's an example|GRP2037_____

    if they fit the next issue will be to hope the crew at jiffy lube doesn't lose them

    for anyone else looking to do this - consider an ebay search first, also check your scrapyard...


    1 reply


    I actually had this exact problem last month, and like carpespasm said I just zip-tied it in place. This is a much more elegant solution though!

    3 replies

    The problem I see with zip ties is if one breaks or you do not get then tight enough you could loose the seal between the air filter and the cover which would let dirt get sucked into your engine and wear the piston rings causing your engine to start using oil. This would be bad. But then again perhaps I am just too cautious.


    A late post, my daughter's Focus had the same issue & I had no clue how to proceed until I found this site with your neat tip. This was several months ago, I'm just writing to say thanks for the info & the saving of $$$$$. Also your pictures were a big help.


    I would be afraid a zip tie brake or not be tight enough then there could be a leak between the air filter and the box cover letting in dirt that would go right into your intake and into the engine which would wear the piston rings and ruin you engine very quickly. This would not be good. But then perhaps I am just too cautious.

    Why did you use carriage bolts? For the life of me, I can't see how you can tighten them (No machined heads, & shoulders that will eventually sink into the plastic of the box). I would have inverted the carriage bolts, and used nuts on top. Saving the time & effort of fabricating the bars; or you could use angle iron (as a stiffener) with standard nuts epoxied in place.

    3 replies

    Rick, I have no idea what you are talking about, where do you think I used carriage blots?? I used hex head bolts very easy to remove, but you can use what ever you want. As for the bars, I used what I had, you can do it your way, it is up to you.

    My Bad, Mr. Steiner, My eyes saw "stove bolts", and my befuddled brain screamed "CARRIAGE BOLTS"! Senility is painless, unless you get caught! I apologize.

    No problem, I just did not understand your comment, Oh well you know what they say about what goes first? Now what was it? Have a good day!

     Thanks for the instructions and suggestions.  I had exactly the same problem.  I used an X-acto knife to cut away the grommets to get vise grips on the nuts.  Then I cleaned the old bolts and nuts with WD-40.  I re-used the old nuts by putting them back in the plastic housing with JB Weld.

    HeHe, I would have used a dremel on the old nuts, made some grip on them, and jb-welded them. not quite as pretty, but easier, and quicker.

    3 replies

    It might have worked but the first problem was getting the old rusted bolts out. That is why I had to remove the gusset so I could get a vise grips onto the nuts. This was a real easy fix, took less than an hour and it is definitely permanate. I could have wire tied it but I don't trust wire ties to keep it tight enough to keep dirt and dust out. My way is just a suggestion. I am sure there are many ways that haven't even been mentioned.

    Very true, and for rusty bolts I recommend aerokroil, I use it on exhaust bolts and nuts, the stuff is kinda expensive, but well worth it, I have seen it loosen rust frozen bolts that I would have broken off by trying after 24hours of soaking in wd-40.

    For rusty bolts I recommend JB Blaster, has always worked well for me. Still can't get to the nuts without removing the gussets once the nuts spin in the plastic housing.

    A nice fix and you don't have to worry about the nuts on a new 300 dollar air box doing the same thing next time you need an air filter. Some folks would have simply zip tied it in place.