PFF - Pennock's Fiero Forum, PDA Edition

Gen1 Headlight Motor Shorting Out after rebuild.??? (Page 1/1)

Dennis LaGrua

APR 10, 02:45 PM

Had a non-functioning Gen1 headlight motor on my 85GT. The motor ran but would stop before the headlight raised all the way up. Purchased the Fiero Store rebuilding kit and took the motor apart. The problem was the inserts in the gear had deteriorated. The limit switch contacts and brushes were very clean so I left them alone and didn't remove that assembly. I removed the shaft , the nylon gear (it was in good shape) , the rotating inner member, replaced the bumper inserts and put it all back together. The replacement of parts went fine and the two motor halfs assembled easily BUT when I tried to test the motor by applying power on the bench to to the blue lead (ground) and either of the green or gray wires(up or down) , I now read a short. The shaft spins fine when turned by hand What could have gone wrong??

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

[This message has been edited by Dennis LaGrua (edited 04-12-2020).]

Dennis LaGrua

APR 10, 05:12 PM

On the fingers that activate the limit switches are there supposed to be insulators on them? Placed insulators-no change so far.
That doesn't seem to be a problem. Looking more like a short in the motor circuit somewhere. Looks like one brush fell off the copper holder but it stilt contacts the rotor.
UPDATE: Was testing the unit wrong but still need a new motor brush that fell off the tab. Order to Rodney tomorrow
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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

[This message has been edited by Dennis LaGrua (edited 04-12-2020).]

Dennis LaGrua

APR 14, 06:41 PM

Motor all assembled, with new Fiero store gear inserts and re-indexed. Now just waiting on a set of new motor brushes and conductive epoxy to mount them on the brass holders. As indicated earlier I was testing the motor incorrectly so it should be fine. If your drive gear is in good shape all that you will need are the rubber gear inserts from the Fiero Store some silicon grease and a set of new motor brushes from Rodney Dickman. Rebuilding these Gen 1 motors is not hard but you to be careful to use the right procedure. Provided the motor is not burned out the units should be re-buildable.
TIP: If the main nylon drive gear is stripped, Rodney offers a high strength aluminum gear.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

Dennis LaGrua

APR 20, 06:34 PM

OK I thought that I'd share the outcome with everyone as it was a successful rebuild. As I said before the motor was not shorted, I was just testing it wrong. Finally traced the circuit and after applying power the motor went on. I purchased the Fiero store rebuild kit, disassembled the motor and added the hard rubber inserts into inserts into the gear, cleaned and greased everything, being very careful to replace the stator assembly, bushings, and upper shaft bumper in the case in the right orientation. The gear looked in very good shape it was left in place. OK was I done? Nope one motor brush was missing so a call to Rodney Dickman and new a new brush set and conductive epoxy came in the mail. Brushes replaced limit switches cleaned and it was good to go. All in all the DIY rebuild parts cost about $40 and that's without the new gear. Add the gear and the cost goes up by about $30. I am not going to outline the whole rebuild procedure here as it has been shown on You Tube many times. Just wish to advise that this rebuild requires precise attention to detail but if there any questions I will be happy to answer them but i sill share one important tip that has not been covered much. Before you begin a rebuild score the lift arm and the motor shaft so that they have an index point. His insures that on upon reassembly the shaft and arm are in the exact same position as before for proper operation.

fierofool

APR 20, 10:55 PM

Dennis, I've never worried about the location of the motor shaft and the short lift arm that goes on it. Once the motor is assembled and the lift arm is installed, I manually rotate the knob on the motor to position the lift arm so that it will pass through the keyhole-shaped housing opening as I offer the motor to the housing. The triangular piece that attaches to the short lift arm can be tipped the wrong way but raising and lowering the headlight by hand will reveal that situation. Disassembly usually isn't required to correct that situation. The two major things that require attention is the orientation of the stator and the rubber D weather seal at the top of the housing.

One must be careful about applying power to the limiter switch while the motor is out on the work bench. I have blown a limiter switch by doing that. If the motor was working prior, and the only problem inside is related to the gear and the brushes are still attached to the spring arms, it shouldn't need to be bench tested.

Dennis LaGrua

APR 21, 12:42 AM

quote

Originally posted by fierofool:

Dennis, I've never worried about the location of the motor shaft and the short lift arm that goes on it. Once the motor is assembled and the lift arm is installed, I manually rotate the knob on the motor to position the lift arm so that it will pass through the keyhole-shaped housing opening as I offer the motor to the housing. The triangular piece that attaches to the short lift arm can be tipped the wrong way but raising and lowering the headlight by hand will reveal that situation. Disassembly usually isn't required to correct that situation. The two major things that require attention is the orientation of the stator and the rubber D weather seal at the top of the housing.

One must be careful about applying power to the limiter switch while the motor is out on the work bench. I have blown a limiter switch by doing that. If the motor was working prior, and the only problem inside is related to the gear and the brushes are still attached to the spring arms, it shouldn't need to be bench tested.

This was the first Gen 1 motor that I rebuilt so you can say that it was a learning experience. Before starting I decided to use the hard rubber gear inserts and not the epoxy fill as in one of the Buddy Craig videos. Epoxy gives no padding to the gear function and I would say shortens their life. In another You Tube video it said that the short lift arm must be put back exactly on the gear shaft as it was before , other wise you will lose indexing. That's why I dimpled both members. Right or wrong this is what I did. Also had one very worn brush and one missing brush so I used my Dremel with a small wire brush to clean those springs to the metal and put on two new brushes using conductive silver filled epoxy. I've read where you can solder those on but figured that I would stay with Rodneys tried and true method. Had to give up on bench testing but tested on the car. The rebuild was successful but since you rebuild these motors for others, you undoubtedly know them better than I do. After completing one rebuild, I would not suggest this DIY method to anyone but a seasoned professional. I guess that you fill the gap there. Thanks for the comments.

fierofool

APR 21, 09:12 AM

Thank you, Dennis. It did take a while before I figured out how to eliminate unnecessary steps and how to get things to work on first try. Well, almost every time on the first try.

In all my years of doing these things, I've only had 2 or 3 come back to me due to my own shortcomings. The last motor was about 3 weeks ago on a car I built for someone over 10 years ago.

I will be writing an article on the repair of the Generation 1 headlight motors soon. It will be published in the Georgia Fieros Monthly Newsletter as the publisher/editor sees fit.

For those who don't receive our newsletter, it can be found on our website message board. As Joe Nameth says, "IT'S FREE!" We also welcome articles from our readers.

fierofool

APR 21, 09:18 AM

Thank you, Dennis. It did take a while before I figured out how to eliminate unnecessary steps and how to get things to work on first try. Well, almost every time on the first try.

In all my years of doing these things, I've only had 2 or 3 come back to me due to my own shortcomings. The last motor was about 3 weeks ago on a car I built for someone over 10 years ago.

I will be writing an article on the repair of the Generation 1 headlight motors soon. It will be published in the Georgia Fieros Monthly Newsletter as the publisher/editor sees fit.

For those who don't receive our newsletter, it can be found on our website message board or if you would like, send us a request to be added to the mailing list at GeorgiaFieroClub@Gmail.Com As Joe Nameth says, "IT'S FREE!"

We also welcome articles from our readers.