First let’s start out with the physical identification and components of the Ford PMGR starter. There are two basic designs for this family of starter. Although they are similar in structure, most of the parts will differ, so the proper rebuild kit must be identified. The most common type is the closed nose style. Some ford trucks have the open face external gear style.
PMGR is an abbreviation for permanent magnet gear reduction. Here are the disassembled components of the ford PMGR starter. The field housing is composed of alternating pole, man made magnets. Alternating pole means the north and south powers are reversed as you move circularly around the housing.
The gear reduction portion is referred to as planetary and is common throughout the industry. It gets its name because of the 3 gears that rotate around the center gear, creating maximum power delivery at the drive end. This is the drive end, this is the commutater end. The major components are : Rear plate. Brush holder ass’y & screws. Solenoid. Armature. Magnet Housing. Thru bolts. Planetary ass’y. Three movable planetary gears. Ball bearing. Planetary cover plate. Grommet. Fork. Drive. Clip ass’y. Drive end housing or nose.
The most serious problem with the entire family of starters is rust. However, extreme rust does not make a rebuild impossible, just more time consuming. As long as the starter can be removed from the vehicle without breaking the drive end housing, a successful rebuild will be accomplishable. New housings are available on request, though.
Once a starter has been cranked for so long that smoke came out of it, it will not be rebuildable without a new armature. When you open one of these starters up, there is a strong burnt smell. When you smell this very strong odor you must get a new armature which is available upon request or buy another core.
If any parts are damaged after removing the starter from the vehicle, then go to Car-part.com. Enter your vehicle information. Arrange the display in cost order. Look at the bottom of the page and click on the gray shaded area, where the lowest prices are. Find a salvage yard near you. Ask the salesperson if he would be kind enough to fix you up with a starter that has as little rust as possible.
Now let’s begin the tear down process. Remove the 13mm nut from the bottom solenoid post and take the hot lead off the post. Clamp the solenoid tightly in the vise. Remove the two T-25(?) torx head bolts that hold the solenoid on. These rarely break loose because of the taper fit. Use a 1/4”x6” extension and hammer drive it straight down onto the heads of the bolts. Now, tap the torx bit into the bolt and break loose. Remove the solenoid. Use a 6mm to remove the two brush holder screws. Use a 5/16 socket to remove the 2 thru bolts.
Tap the back plate with a hammer while pulling on it with your other hand . Take the housing ass’y off the planetary gear ass’y. In the hole, where the shaft of the armature was, is the ball bearing. Take the planetary cover off, take the 3 planetary gears off their shafts. Smack the ass’y upside down on the bench top and the ball bearing falls out. If it won’t come out, put a little dab of grease in the hole and leave it in there.
Place the housing ass’y in the vise and tighten semi-firmly with the shaft sticking out to the left. With the wood end of the hammer handle push the armature shaft to the right. When enough of the armature appears to the right of the housing grab it firmly with your other hand and pull it out. Grab firmly and pull because you’re fighting the magnetic pull of the magnets. Pop the brush holder ass’y off the commutater.
Armature. Scour the copper commutater with a scotch brite. Inspect the bars on the comm. closely. These comms. are bad and are not repairable, another armature must be obtained. Even one bad bar will destroy the integrity of the armature and is considered unusable. These comms. are OK to reuse. The copper in each individual bar is intact. Clean any rust off the body of the armature and paint only the metal area with any color enamel spray paint. Don’t get any overspray on the commutater.
Housing. This housing is not that rusty and can be washed out with electric motor cleaner and painted internally. Buff the top and bottom areas where the metal contacts the aluminum nose. Apply a thin coat of white lithium grease. Many ford truck housings are too rusty and cannot be used as is. The problem is: rust forms on the inside of the housing between the magnet and the shell. This pushes the magnet outward, and causes the magnet to rub on the armature. On housings with a lot of rust, you may even notice rub marks on the magnets when you tear the unit apart.
Extreme rust on housing. The following is for housings that are extremely rusty. This situation is most common in the F series pick-ups. Place the housing on a flat surface with the large U slot up. For organizational purposes we will dis-assemble and re-assemble in a clockwise fashion, working left to right. There are two types of magnets in the housing: North and South. They are arranged alternately, N then S, three times, total of 6 magnets.
Start with the magnet just to the right of the slot. Using a blunt screwdriver and a hammer, tap gently downward a few inches till the magnets hit the bottom of the bench. They actually break loose very easily. Hold the housing in your hand. Use care to follow the place one magnet on the left pile, place the next magnet on the right pile method we are about to explain.
Pull the first magnet (the one that is just to the right of the U slot) out of the housing. Place it to the left of the bench. Pull the 2nd magnet (working clockwise) and place it to the right of the bench. Pull the 3rd magnet (working clockwise) and place it to the left of the bench. Pull the 4th magnet and place it to the right. Pull the 5th magnet and place it to the left. Pull the 6th magnet and place it to the right.
Obviously, you will finish with two piles: north and south. It doesn’t matter which side of the magnet was up or down. Only that when you reassemble, you start with the left pile of magnets, and it must be inserted where it was (just to the right of the U slot, with the housing sitting with the U slot up).
Now, let’s de rust the ferrous portion of the housing. Grind or D.A. as much rust as you can, off the outside of the cylinder. Hand sand as much rust as you can, out of the inside of the cylinder. Where the most serious rust was, apply an ultra thin coating of lithium grease, but don’t coat the whole inside of the cylinder, just get the small areas where the rust was the worst. Lightly paint or silicone spray the inside of the cylinder. Apply a thick coat of anti-rust spray paint to the outside of the housing. Let it dry. Buff the ground path circles at the top and bottom of the housing. Apply a light coat of white lithium grease.
Install the magnets the exact same way they were removed. Start with the left pile. Place it in the first spot to the right of the U slot with the U slot facing up. Proceed clockwise using the right pile for the next magnet, then the left pile again for the 3rd magnet as you work clockwise. It is not important, which side of the magnet is up or down, only that the left pile was installed in the number one slot and that the following magnets are installed alternately working clockwise. Adjust the magnets up and down so that they are all parallel.
Drive end planetary assembly. Closed Nose. Remove the metal bottom grommet from the aluminum nose casting. Tap the drive end assembly on the bench till the shaft assembly and fork fall out. Remove the retainer cover from the shaft. Lay the shaft ass’y so the horse shoe retainer is facing up. Adjust a pair of channel locks to the width of the shaft. Lay them sideways on the U shaped clip so that they are larger than the shaft, but resting on the tops of the clip. Smack the channel locks on the side with a hammer. Several blows may be necessary. The secret is to smack the channel locks so that both jaws push down simultaneously on the retainer.
Remove the old drive gear. (some people call this the bendix). Remove the plastic fork from the plastic on the drive gear. Polish the shaft with the scotch brite. Apply a thin coat of oil. Count the teeth on the new gear to make sure you’re installing the right gear. Install the new gear drive. Place a drop of red loctite on the groove where the new horse shoe clip goes. Steady the new clip on the groove. Use channel locks to install. Install retainer cover and thrust washer. (thrust washer is not in OEM ass’y but we highly recommend it’s use for a rebuild). Install fork on plastic portion of drive gear. Place a small blob of grease on the outer shaft.
Drive end planetary ass’y. Open face nose. First smack the ass’y on the bench to get the steel ball bearing out. If it won’t come out, put a dab of grease in and leave it there. Remove the retainer ring at the end of the shaft. The proper tool would be nice, but you can use a sharpened nail set or small wire cutters since a new one will be supplied.
Pull the shaft out of the gear. Take the plastic fork off. Pull the clutch ass’y to the end of the shaft to expose the u-clip. With a pair of needle nose and a hammer, tap the u-clip off the shaft. Push the clutch ass’y back towards the planetary and rotate it till you hit a spot where the internal teeth line up and you can pull the clutch ass’y off the shaft.
Scotch brite the shaft. Place a few drops of oil on the shaft and place the roller clutch ass’y back on the shaft. Push it down into position on the shaft and give it a turn so it’s locked on. Pull the clutch back out of the way and install the u-clip. If this is a manual transmission, clean any clutch dust out of the gears. If it’s an automatic transmission just wipe most of the grease out of the gears with a rag.
Buff or lightly DA the aluminum housing where the mounting bolts will go. Clean the drive end aluminum housing with brake cleaner. Apply a thin coat of white lithium grease where the mounting bolts will go. Place a few drops of oil on the bushing. Install the plastic fork on the clutch. Push the shaft through the nose cone, then into the gear. Place a few drops of red loctite in the groove on the shaft then install the retainer clip on the shaft. Place a few drops of oil on the moving part of the roller clutch drive.
Apply a generous portion of white lithium grease to the stationary planetary gear. Note the flat spot on the stationary gear goes towards the solenoid and install it in the aluminum drive end housing. Install the steel bottom rubber grommet. Place a few drops of oil on the posts where the movable planetary gears go.
Place a generous amount of white lithium grease to the 3 gears and install them. Install the cover plate so that the small posts on the plastic go up through the raised tangs on the cover. Make sure the through bolt holes are lined up. Install the ball bearing in the hole and put a dab of grease on it.
Nose. (Drive end aluminum housing). Place the aluminum drive end housing in a vise. Center punch so the drill will be perfectly in the middle. Drill the end out with a 7/16 drill. Use a 1/4 x 6” extension and a ball peen hammer to knock out the bushing or needle bearing. This is the needle bearing which we will be replacing with a brass bushing.
This is the bushing. If you have a needle bearing, be sure to rest the 1/4” extension on the outer race of the bearing before driving it out. If you hammer on the center of the bearing, it will shatter and you’re left with the problem of digging out the outer race by itself. This is time consuming, but it must come out. A little heat on the aluminum housing will reduce the risk of shattering the needle bearing. Buff or DA the ears where the mounting bolts go. Clean with brake cleaner a put a thin layer of white lithium grease on the areas that contact the bell housing.
Flip over the nose. Set the new bushing in position perfectly straight. Use a 3/8 x 6” extension to tap in the new bushing. There are 2 bushings with 2 different outside diameters. The larger OD replaces the needle bearing, the smaller OD replaces the brass bushing.
Install plastic fork on drive gear. Set gear ass’y in nose. Note the flat side of the plastic gear going toward the rubber grommet and the holes lining up with the through bolts. Install metal bottom grommet. If you have a manual transmission, clean any clutch dust out of the rotating and stationary gears. If there is not much dirt in the gears, we recommend NOT cleaning with solvents. Just wipe everything clean with a rag. Place a generous amount of white lithium grease all the way around the stationary gear.
Put a few drops of oil on all three planetary posts. Place a generous amount of grease on all three planetaries and install them. Place the ball bearing in the hole and put a little dab of grease in the hole. Place the metal cover over the gear ass’y with the two raised up tabs lined up onto the plastic pins in the stationary plastic gear. Check to see if you can see the holes where the through bolts will be screwed in.
Armature brush holder ass’y. Place the armature comm. end up in the vice. Center the brush holder ass’y (with plastic insulator up) over the center shaft of the armature. Quickly push straight down. Discard the black plastic tool. Push all the brush wires as far to the internal structure as you can.
If the brushes accidentally pop out they’re not that hard to load manually. Remove the flat plastic insulator. Remove all the springs. Place the brush holder on the comm. Place the brushes where they belong. Compress the springs with index finger and thumb. Shove into place. For last spring, to get more room, push the assembly towards the empty spring cavity with your other hand. Install the flat insulator by sliding the ground tab out of the way with a pocket screwdriver. Install the flat insulator then tap the ground brush back into position. Push all the brush wires as far to the plastic brush holder as you can.
Assemble. Place the magnet housing in a vise: U slot up and facing to the right. Put a drop of oil on the positive brush grommet for ease of assembly. Grab the armature/brush holder ass’y with the right hand. Place your left hand inside the housing’s left side. Due to magnetic pull, there is a huge tendency for the armature to snap out of the brushes as you position the armature assembly inside the housing. To prevent this, cup your right hand fingers around the brush holder gently, but hold onto the armature firmly with your finger tips.
Then, as you begin placing the assembly inside the housing, use your left index finger to stop the armature from sucking in too fast. Move both hands to the left simultaneously and carefully line up the positive brush grommet into the U slot.
The brush with the threaded metal tab is the ground for the entire starter. Sand the back plate with 80 grit paper where the screw goes thru on both sides. Apply lithium both sides. Put a small amount of grease in the end plate bushing. Install the 2 brush holder bolts and push the 2 thru bolts through the housing.
Set the gear ass’y with gears face up in a vise. Set the armature housing ass’y on the gears by aligning the thru bolts into the holes and the shaft into the hole. You often need to shake it while pushing down to get it to snap into position. You can also move the gears a little if this method doesn’t seem to work. Tighten the thru bolts.
Test. This is a good time to “free run” the starter. We will double check it later after the solenoid is installed. With an ordinary set of jumper cables, install positive and negative cables to a vehicle battery. Lay the starter on the ground or hard surface. Place the positive lead on the brush wire coming out of the starter. Put your foot on the body of the starter, it’s going to kick a little bit. Install the negative cable to the bottom of the starter. It should sound like this…. Do not over run or allow motor to rev more than 15 seconds. Keep fingers away from gear area. New bushing areas may be hot due to friction. Sometimes a series of short bursts are necessary to break in brushes and bushings. Also a light tapping with a large screwdriver can help everything settle into place. Check torque on thru bolts and brush holder screws.
Solenoid. Place a small amount of oil on the plunger. Spread it around with your finger. Get the plastic hump in the plunger behind the fork. Install the T25 (?) solenoid mounting bolts, after noting the terminal with the solder joint attached to it, is down. Place white lithium grease on all terminals of the solenoid. Place the hot lead on the motor terminal post of the solenoid. Tighten nut.
All push on spade connections, coming to the solenoid from the ignition switch, are to be updated to the ring terminal style. This is not an optional update. If you have the old push on spade, cut it off 1/2” away from the end. Strip the wire 1/2 “ back. Dip the wire in white lithium grease. Fold it in half and shove it inside a yellow terminal connector with a big enough inside diameter to fit over the small solenoid post. Mash the connector with the proper electrician’s pliers, NOT an ordinary pair of pliers.
Test. With an ordinary set of jumper cables. Hook the two cables at one end to a vehicle’s battery. Place the other red cable on the hot post on the solenoid. Buff, DA or sand the aluminum nose housing in two places where the jumper cable can conveniently clamp to. Put your foot on the starter to keep it steady. Keep your fingers away from the gear area. Use a pocket screwdriver to bridge between the hot post and the ignition post. Make sure the starter is turning the right direction. Facing the drive end, the gear should be rotating clockwise.
If you take the starter in to be checked at a part store, listen to make sure your starter sounds similar to the one in the video when it winds up to speed. The amp meter is the only reading you need to observe. The starter might not start out at 80 amps DC or less but it should be able to get there as it winds up to speed. This would typically take a few seconds. Never let a starter free run more than 15 seconds without a break of 30 seconds.
When the starter reaches top speed, there should not be a 3-5 amp fluctuation while letting the starter run for 5 seconds. This indicates a bad armature or brush spring.
When installing the starter on the vehicle, buff the mounting bolts with a stationary wheel or buff with scotch brite. Apply a thin coat of white lithium. Sand front and back all of the cable eyelets. Again apply white lithium grease. Apply a generous portion of white lith to the all the threads on the solenoid also.