A common problem with the Fiero is a sticky door lock that takes multiple button pushes to get to lock or unlock. Over time grease and dirt build up on the internal workings of the latch and make it hard to move, and there are multiple pivot points inside the latch just for the lock/unlock function. Spraying lube into the latch with it still mounted in the car is only a temporary fix at best. I just completed a repair on a fellow PFF member's car today for this very issue so I figured I'd post some pics and do a little write-up on it.

First off is to remove the inner door panel, I did not take pics of this because there are multiple threads on how to do this.



After removing the panel, I used a digital fish scale to test how much pull it took to move the mechanism and lock/unlock the doors. The passenger side door took 5+ lbs to lock and 3+ lbs to unlock, the drivers side door was as high as 7 lbs to lock and 3+ lbs to unlock.

Lock force before:



To gain access to the inside of the door and make lock rod and latch removal easier, punch out the stem and drill out the five 1/4" aluminum rivets holding the metal door brackets on.



Next remove the 4 bolts (circled) holding the window track in the door and remove the track from the door. This give great access to the internals.



Now for the tough part. There are 3 separate rods that attach to the latch, 1 for the inside door handle, 1 for the inside lock rod, and 1 for the outside lock rod. They are held to the latch using these clips:



To remove them, you need to carefully pry up on the "tang" end and slide it over to release the rod. I did this for both inside rods, the outside rod can be disconnected from the lock cylinder arm as its much easier to see and get at. Once the rods are disconnected, unplug the connector for the ajar light and remove the 3 torx bolts holding the latch to the door. Using a screwdriver to put the latch in the "latched" position will make it easier to remove it. Slide the latch down and disengage it from the outside door handle rod and remove it from the door. Here is what the latch on this door looked like:



It was quite gummed up and hard to move the lock pivot. I used CRC brake parts cleaner to spray out all the internal parts of the latch, paying special attention to the lock pivot points. Use a blow gun to dry the latch and repeat brake cleaner as needed to get out all of the old grease and gunk. Once cleaned I used a SMALL amount of white lithium spray grease to lube the pivot points. I worked it in by operating the latch and then used the blow gun to remove the extra grease and to force the lube into the pivot points. Here is a pic of the cleaned and lubed latch:





Before installing the latch back in the door, install the rod clips back on to the latch arms. Make sure to engage the outside door handle rod into the latch to save the trouble of having to take things apart again. Once installed, test the operation, if it still seems a little sticky, make sure the rod moves smoothly through the black plastic guide clip. If necessary, clean the rod with some brake cleaner on a rag and put a little lube in the clip.



On the one I did, the passenger side was good but the drivers side needed to be cleaned and lubed.

Checking the lock/unlock force again, the "lock" force was 2.5 lbs and the "unlock" force was less than 2 lbs. Both latches have a good "snap" when moving from the "lock" to the "unlock" positions just like the day they rolled off the assembly line.



I used 1/4"-20 bolts and nuts to reattach the metal brackets. I made a small plastic retainer to hold the bolt in place so I could install the paper shield and then the brackets.







I reinstalled the door panel and tested the operation again to ensure there wasn't any binding anywhere from the panel or handle trim plate and I'm done This method is the most work but will yield the best and longest lasting results. Total job time was just under 2 hours per door. A good pic set will help with removing the rod retaining clips. Be sure not to flex the "tang" end of the clip too much as it will break.

[This message has been edited by seajai (edited 10-25-2014).]

Thanks. Good write up. Something I know I must do in the future

Excellent write-up. I had to do this back in early September when my drivers door lock jammed in the lock position. I followed almost the same procedure and the difference in power lock performance was amazing. The only part I did differently was that I only removed the small cross bar above the door handle bracket and it gave me enough room to access the lock. The above procedure will definetly give more access. Great job!

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I sprayed my latches down inside the door with brake clean, spayed brake clean also when actuating to get all the old crud out of the latch... I then used this stuff called HHS-K that sprays like penetrating oil, but jells up into a high temp, very sticky grease that is resistant to dirt buildup. When I worked for Porsche it was reccomended to use the stuff on for years on sunroofs when they started binding in the tracks. Never gave us problems again after using it. Highly reccomended to go that route as well to save some time....

Link if you want to check the stuff out. I swear by it! Saved me and my old shop so much time on squeeks from doors and sunroofs with dried grease in there.

[This message has been edited by Shho13 (edited 10-27-2014).]