2000XJ8

I was going to clean my MAF with CRC Mass Air Flow Sensor Cleaner & could only get one of the 2 screws out! It easily came out but the other is stuck. Now, I have chewed up the head of this very tiny screw.

Assuming I am able to eventually remove this screw (I’m not sure the products made for screw extraction work on tiny screws), I would prefer to have a replacement screw on hand. My plan B is to remove the good screw & take it to Home Depot or ACE Hardware to find a match. I’m posting in case someone here knows the exact screw & how to buy one. I doubt Jaguar will sell me the screw or even has a part # for it. I think they sell the MAF already mounted:

LNE1620CB
MASS AIR FLOW SENSOR for 2000 Jaguar XJ8|LNE1620CB

I’m concerned trying to eyeball match it will not be accurate or it may be dropped/lost. It is very small! This is my only car so, I would need to drive my car to the hardware store, stop & open the hood & remove the screw & then when leave the store, open hood & replace the screw. In the parking lot. Prefer to not do it this way.

 

looks like you'll have to. It shouldn't be a trouble maker. I'd carefully drill the head off the stripped one, with the MAF out the way you can get mole grips on it. Maybe replace with stainless.

 

Steve,

What Sean and his U.K. mates call "Mole Grips" we Yanks call "Vise Grips."

Cheers,

Don

 

Thanks for the replies. I Googled Mole grips b4 reading Don’s reply & saw it was vice grips
I was hoping someone would have had the same exact issue & knew the exact size replacement screw. I know there is a number for the thickness of the screw & also a number for the threads. I may just need to match the length so it does not poke out too far & head size to fit in the round depression & get a sheet metal screw a bit thicker to bite into the plastic essentially tapping a new threaded hole. Or a machine screw a bit thicker?

I tried a few tricks I fond online for removing stripped screws & all failed; placing a rubber band between screwdriver & stripped head, using a torx screwdriver, using a flat screw driver small enough to fit in the Phillips head stripped area.

@ Sean, so, if I remove the good screw & drill the head off the stripped one I can pull the MAF out & then use mole grips to twist out the shaft of the broken screw, right? That is probably what I will need to do after I find a replacement screw.

I took some photos, probably unnecessary. 2 of my MAF with stripped screw visible & one of the dark brown good screw next to ruler for size.
Maybe someone who knows screw sizes, types can tell me what it looks like? I’m thinking machine screw. Also have photo of MAF screw with a possible match on either side from my odds & ends bin. Neither was a match, I knew the heads were too big but the screw shafts seemed like a match. Neither would screw into the threaded hole. Although one started to bite but if I pushed, It would probably cut/tap new thread.

BTW, I think I misunderstood exactly what is the MAF. I now think the entire assembly is called the MAFS & the part I wish to remove with those 2 screws is just the sensor portion. So when you replace the MAF, you just unclip the wiring harness & do not bother unscrewing those 2 screws, rather you remove the entire round MAFS assembly on one end attached via hose clamp to the snorkel (air hose) & on the other attached to the upper lid of air filter box by bolts. I’m thinking of all those old defective MAFS that are probably trashed with 2 perfectly good screws! Tempting to ask Jaguar but doubt they would want to help since DIY. Since those screws are so tiny I bet more than one mechanic has dropped/lost one. I remember years ago I needed a new MAF & Jaguar said they do not clean them, they just replace them. So, they probably do not have the screws anyway.

 

Don't drill unless you have the experience and use a left hand bit.

The problem with cross head screws is that they may be a phillips,
or in the case of Jaguar, more likely a Pozidrive. The driver must
fit the screw head tightly.

To remove a stubborn cross head screw, take a well fitting screwdriver,
fit to screw, tap smartly on the handle with a small hammer to break
any corrosion, put palm of left hand on handle, put chin on left hand,
apply pressure into screw with left hand and chin to avoid slippage,
rotate with right hand. The pressure into the screw is the secret to
avoiding damage to the screw head. With current condition of the
screw, this may still be enough to get sufficient grip to rotate it
out.

The screw is metric.

You already know the length and diameter.

Just go to wherever and buy every likely metric screw of the
same length and diameter. Shouldn't be too many.

A machine screw will either thread easily or it's not the
right thread. There is no almost fits.

 

@ Plums, Thanks!
I have never drilled out a stripped screw. I am unfamiliar with left hand bits. My drill is reversible. I can buy left hand bit.
Makes sense.

I had never heard of Pozidrive but, if that is what is securing the MAFS to the MAF body, it makes it easier to strip it as I have done.
I found this: “What's the difference between Phillips, Pozidrive and Robertson (square) screws?”
http://hafele.com/us/services/haefele-library/4300.htm

Great idea to simply buy every size metric same length & diameter.
My MAF screw seems to be 3/8” from top of head to bottom of shaft. Or 10mm. And just under 4mm diameter (widest part of thread.)

If this were a screw in a sturdy object, I would have no issue pressing down very hard as you suggest or tapping with hammer. I am concerned about doing that given the location & damaging either my MAFS or the housing it sits on. Neither of which is sturdy!

 

I finally fixed this early November. Waited till bought 2nd car so, can leave Jag in Garage when remove ‘good’ screw rather than doing in a parking lot. Took screw to ACE hardware. Checking with nut, OEM screw is 0.70 Thread Pitch Metric. ~8mm long from under the head to end. Found a screw with same thread pitch but slightly shorter & slightly larger head & also a longer one that had head ~ same size but was allen wrench type head. (3mm). Then purchased Irwin Ex-1 Spiral Screw Extractor & Drill set.

Instructions said: Drill pilot hole in stripped screw with included 5/64 drill bit. Tap Extractor into pilot hole. Use wrench & turn extractor counter clockwise to remove stripped screw. I easily drilled pilot hole but despite tapping I could not get extractor to work at all! It just would spin in the hole. No grip at all! Worthless!
Finally out of desperation I took a small Phillips screwdriver & jammed it in & easily removed the stripped Screw! Voila! I bet the tapping helped to loosen it up.
Easily removed the MAF & spray cleaned it. Let dry.

I had disconnected the battery during this so the computer could re-learn the MAF now that it is cleaner. Tested both screws & Allen screw fits better, other one’s head is slightly too large to fit into recessed area & would need to jam it.
Note: I used Allen screw on side closest to side of car where the shaft that accepts screw is much longer than other center engine side! Reinstallation of MAFS went smoothly!

Car seems to have better acceleration now! OBD-II shows P1111, all 7 tests passed, so disconnecting battery for 1.5 hrs. did NOT require the tests to run again!

I attach 3 photos, Screw extractor that failed to work, 2 new screw candidates on either side of my OEM “good screw” & the final completed repair.

 

it's funny I had the problem with an XK and took a dremmel to it, made a slot just big enough to fit a flat driver and the replacements are button head allen bolts - nice to know yours is fixed Steve.

 

It’s great to have fixed this w/o having to purchase a complete MAFS from Jaguar for $$$$$. (LNE1620CB MSRP $267.00)

It’s nice that you had a Dremmel & knew how to use it. I don’t. How difficult was it for you to find the right size button head allen bolt. Did you take out your good, unstripped screw to help size the replacement?

Steve