Fuel tank shield can be an im­por­tant safe­guard

Winnipeg Free Press - Section F - - AUTOS - JIM KERR

QUES­TION: I have a 2000 Mazda Pro­tege with a 1.6L en­gine and the car is a com­plete rust bucket. Re­cently, part of the fuel tank shield rusted off and as a re­sult it is now par­tially at­tached with the other part touch­ing the ground. I was won­der­ing how es­sen­tial this part is and weather you would ad­vise me to re­place the shield or just go with­out the shield con­sid­er­ing the age and con­di­tion of the car. John

An­swer: There are a cou­ple rea­sons man­u­fac­tur­ers place shields around fuel tanks. One is to pro­tect the fuel tank from the heat of a nearby ex­haust pipe or muf­fler. An­other rea­son is to pro­tect fuel fit­tings and con­nec­tions from stones, and the third is to pro­tect the fuel tank it­self from im­pact with gravel and other ob­jects thrown up be­neath the ve­hi­cle.

I un­der­stand you do not want to spend any money un­nec­es­sar­ily on your ve­hi­cle, but if the pur­pose of the shield is to pro­tect the fuel tank from heat, then I would rec­om­mend fab­ri­cat­ing a shield of some type. If the pur­pose of the shield is to pro­tect the tank from gravel etc. then you could op­er­ate with­out it, es­pe­cially if you are driv­ing on pave­ment most of the time. Old cars in the ‘60s and ear­lier usu­ally didn’t have any shields and the ve­hi­cles worked fine.

Q. I have a bizarre prob­lem with my 1967 Pon­tiac Fire­bird, 400 CID, four-speed car. The other day I started the en­gine, pressed the clutch pedal, (my shifter is a lit­tle sloppy) so I usu­ally run it through a cou­ple of gears and re­verse to wake it up, and usu­ally ev­ery­thing is ok. Then for what­ever rea­son I re­leased the clutch pedal to do some­thing else for a mo­ment. Then I pressed the clutch down again to put it in re­verse to back out of the garage, only to find out it would not go com­pletely into re­verse, as it would only grind. So I pulled it out of re­verse and went to put it back in first, only to find out the whole shifter was com­pletely in­op­er­a­ble. I couldn’t get it to go into any for­ward gear. So I tried re­verse again and it still would only grind.

So now I’m think­ing there must be some­thing wrong in the clutch as­sem­bly, but I’m also think­ing, why is my shifter screwed up? So I stopped the en­gine, pressed the clutch and the shifter im­me­di­ately worked OK in all gears in­clud­ing re­verse. I read­justed the clutch pedal and took all the free play out, but that didn’t seem to help. Be­cause the shifter could be part of my prob­lem, I took it all apart to tighten it up Now the shifter feels ok but my orig­i­nal prob­lem is still ex­actly the same. The shifter gets screwed up and re­verse won’t en­gage af­ter the clutch is re­leased and re-en­gaged the sec­ond time af­ter restart­ing the en­gine? Is it pos­si­ble there is some­thing wrong in the trans­mis­sion? De­nis

A. The symp­toms would in­di­cate a clutch prob­lem rather than any­thing wrong in­side the trans­mis­sion or with the shifter. It could be that the clutch disc is bind­ing on the trans­mis­sion in­put shaft but I would ex­pect this to oc­cur even the first time you start the ve­hi­cle so it would be dif­fi­cult to shift at any time. In­stead, I sus­pect you have a bad pi­lot bush­ing.

The pi­lot bush­ing (bear­ing in some ve­hi­cles) is pressed into the back of the crankshaft and sup­ports the front end of the trans­mis­sion in­put shaft. Nor­mally the pi­lot bush­ing would al­low the in­put shaft to ro­tate at dif­fer­ent speeds than the crankshaft when­ever the clutch is re­leased, but if the bush­ing is bad, it can seize onto the trans­mis­sion shaft and turn it even when the clutch is re­leased. This would then make it dif­fi­cult to en­gage any gear when the ve­hi­cle is not mov­ing. Re­plac­ing the pi­lot bush­ing isn’t a dif­fi­cult task but you do have to re­move the trans­mis­sion and clutch as­sem­bly to get at it. While re­plac­ing it, you can also check the clutch disc for wear to see if it needs re­plac­ing.

Q. I have a great 2008 Mazda3 but it left me stranded the other day. I was out in the coun­try­side and had a flat tire. No prob­lem — I know how to change a tire. Well, I got ev­ery­thing ready to change the flat and af­ter I un­bolted the wheel nuts, I couldn’t get the wheel off the car. I tried kick­ing it and bang­ing it but it just wouldn’t budge. I had to call a tow truck and have the car towed to a garage. I have never had this hap­pen be­fore, but am won­der­ing what to do to pre­vent it hap­pen­ing in the fu­ture.

A. The prob­lem is caused by cor­ro­sion be­tween the wheel and the cen­tre of the axle hub on the car. The cor­ro­sion holds the wheel so tight it is dif­fi­cult to re­move. Man­u­fac­tur­ers don’t rec­om­mend greas­ing wheel nuts, studs or con­tact sur­faces where the wheel sits on the hub, but on some ve­hi­cles I have found a very light coat­ing of an­ti­seize just on the very cen­tre open­ing of the wheel will pre­vent this cor­ro­sion and al­low the wheel to be re­moved eas­ier. Jim Kerr is a me­chanic, in­struc­tor of au­to­mo­tive tech­nol­ogy, free­lance jour­nal­ist and mem­ber of the Au­to­mo­bile Jour­nal­ists’ As­so­ci­a­tion of Canada.

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