If the pics do not show up, right-click on them and select "show picture". It should work
Welcome to the Do It Yourself starter troubleshooting, replacement, repair and upgrade thread. I had the idea of creating this thread after my many bad experiences with vw/bosch starters on my diesel.
Last week I had to replace *again* the starter on my diesel mk2. I had to do so at work (inside the hardware store between two cash register counters) because I don't have access to a heated garage. This time I replaced the bushing as well. I hope it's the last time I replace it before my engine swap
Having a working but weak starter in my hands I thought I should open it up and see how it's made and why they stop working. I was amazed by how it's made but more so by the obvious weaknesses (once opened) the bosch starter has.
NOTE: the starter I took appart is a diesel starter, gasser should be the same. They are interchangealbe but a gas starter on a diesel will prolly die soon after as they are not designed for such high compression engines.
There are no differences between 16v, 8v and diesel solenoids. They are pretty much the same as they all fit 020 trannies. On the other hand, I don't think an auto solenoid will work on a manual. However, IF they are the same, I wouldn't pick one up from an auto. Simply because auto starters often get heat soaked by the exhaust manifold which can cause internal damage (remember that there's plastic in there )
The best upgrade you can do to a gasser is swap the entire gas starter for a diesel starter. They are much more powerful but they weight a TON, which might offset it's advantages.
Table of contents
1: How it's made!
2: Upgrading it!
3: Replaceable parts!
---1: Lots of starter issues are wiring related
---2: Sometimes it starts, others not
---3: Starter stays on even when driving or after the car is shut off
---4: It grinds like a mofo!
---5: Ok the starter is out, how do I know if it's good?
---6: Slowwwww cranking
---7: The starter spins, but doesn't engage the flywheel
5: Replacing the starter
First up: How it's made!
The starter consists of two main parts: the solenoid and the motor. Basically the solenoid pushes out the motor's drive gear to engage the flywheel and tells the motor to spin. As we all know, the solenoid can be replaced as a unit. I also discovered that some parts of the motor are available thru aftermarket stores (Drive gear, armature, brushes and bushings).
To make things easier, I took the liberty of snapping a bunch of pics while dissassembling the starter. I know you guys like pics.
The starter itself, side and rear view:
To remove the solenoid, first remove the 13mm nut holding the starter motor's power wire (bottom stud on solenoid). Then remove the three philips screws holding the solenoid to the casing. You will feel it pop out of the casing. When the solenoid is activated, it pulls on a metal barrel (pictured below, has a spring coming out of it) and pushes out the drive grear using a series of levers. The spring you see is used to push back the metal barrel once the solenoid is off, therefore disengaging the drive gear from the flywheel. Replacing the solenoid doesn't require adjustment once the new one is installed.
Normal position, drive gear not engaged to flywheel:
How to open up the casing: First remove the two 7mm bolts located behind the starter. They are friggin long but have very few threads.
Then pull the aluminum part off.
You can see in the picture above the levers used to engage the drive gear onto the flywheel. Yes they are made of plastic!!! The blue lever rests on a piece of rubber. You can also see the metal barrel I talked about earlier. The levers can be taken off simply by prying then off.
Close-up of the aluminum part (basically the mounting bracket)
Close-up of the levers and driving gear. You can see that on the right of the black lever there's a gear. It's used to spin the drive gear's shaft a bit when engaging the flywheel, making it easier to engage. On the left of the black lever, you can see a part of a high strenght spring. It serves as a "shock absorber" when engaging.
Next step is to simply pull on the driving gear's shaft to separate it from the armature. Once off, you'll notice that the white part is also made of plastic!!! Looking at the back you'll see a cover plate.
Remove it by prying it off. Revealing three small gears
These gears are spun by the motor and are attached to the driving gear's shaft. The white plastic doesn't move but does take some load when cranking. You can see a large crack on mine.
Taking appart the driving gear's shaft is simple. First you'll have to pry off a small metal cover to reveal a circlip at the end of the shaft. Then remove the said circlip (above the screwdrive is the circlip, below is the pryed off metal cover).
Once this is off, at the base of the white part, there's another circlip to be removed (can be seen on eighth picture from the top)
You can then pull everything appart. You end up with this.
Next you can pull out the armature and brushes from the case. This is what it looks like. You can see some cut-outs in the armature. My guess is that material was removed to balance it. Note the rusty bolt.
Inside the casing are six high strenght magnets.
Close-up of the brushes and armature. There are four brushes. The power wire goes thru a rubber gasket and then to the brushes. The brushes are in direct contact with the armature to provide current, it explains why they wear out over time. Note the amount of crud in there and the absence of gaskets to seal the casing and rear plate.
Remove the two philips screws left behind the rear plate. Again, no gasket or sealant. You might have to tap on the plate to free the "nipple" part. Remove to circlip and the washer. You can then pull off the rear plate and the brushes.
This is what you end up with.
Close-up of the brushes and their mounting hardware.
Close-up of the armature.
Congrats!!! You have now taken appart a starter, installation is the reverse of removal
By now you can see what I meant by obvious weaknesses. The use of plastic for the levers is ok as they have a shock absorber to prevent them from breaking but that's it for plastic! Using a plastic thoothed part on the driving shaft is a bad idea as you can see by the large crack on mine. I don't know the effect it had on my starter but I don't think it was good.
The other MAJOR weakness is the lack of any kind of seals and gaskets. Not even a damn rubber O-ring. The amount of crap and rust I found in there is amazing! Note that this starter is a rebuilt unit only a few months old!!! The casing is rather thick and so is the rear plate but that's it. The two 7mm bolts are really weak and not very rust proofed. The screws don't last very long.
Part two: Upgrading it!
Now the starter is constantly exposed to road salt, water and dirt. The original paint is rather cheap, thin and doesn't resist well to rust. It doesn't take long before rust appears. The first step to upgrading a new/rebuilt starter would be to have the casing, rear plate, "nipple" cover and solenoid powder coated or at least sandblasted, with two coats of primer, three coats of color and two clear coats. That way it'll resist rust much longer and look nice longer.
I recommend that you seal everything together: aluminum end to casing, rear plate to casing, "nipple" cover to rear plate, seal the screws and bolts, even put sealant on the rubber parts (lever and power wire), seal the solenoid to the aluminum end and the screws too and finally use sealant when installing the starter to the tranny! Clean the tranny's mating surface of course. Also cover the electric connections with dielectric grease to keep corrosion away.
Any kind of automotive sealant will do as long as it can resist salt, engine oil and such chemicals found in cars. The best would have to be rubber gaskets but you'd have to find sheets of rubber and cut them to the desired shape.
It's quite amazing that a device constantly exposed to the elements is barely sealed and not extremely rust resistant.
Unfortunately, nothing can be done to replace the plastic parts inside the casing. Upgrading the wiring will also make sure the starter pulls as much power as needed (covered below in troubleshooting).
Part three: replaceable parts!
The solenoid can be replace only as an unit. Everything is press fitted in there. The motor has some replaceable parts: bushings, armature, brushes and drive gear. I stongly recommend against replacing any of these parts (except the solenoid) as they will cost you much more than a rebuild unit costs. For example, the brushes sell fo about 20 bucks each and the drive gear from 50 to 100 bucks alone.
Replacing the solenoid is straighforward: Disconnect the battery, remove all electric connections from the starter (batt, ignition, motor) and remove the three srews holding the solenoid to the starter motor. Pop out the old solenoid and put on the new one. Screw it on and connect everything back.
Part four: Troubleshooting
I faced prolly every problem one can have with starter issues: grinding, slow cranking, starter not shutting off while you drive, dead starter, bad wiring... you name it.
---First things first: Lots of starter issues are wiring related.
I once replace a starter thinking it was bad when it wasn't. The new one didn't work either because the wiring was old, corroded and didn't carry enough current. I ended up rewiring the battery, alternator, starter and grounds.
Check for proper battery power and wiring!!! If you are still using the original battery and wiring, I STRONGLY suggest you get a new battery and replace all the wiring and connectors. There are lots of batts available, I personally use a 1000amps AC/Delco battery. Works really good and is strong as hell! As for wiring, gauge 1 from the battery to the starter will allow for max power going to it. Gauge 4 from the alt to the starter is more than enough. It's also a good size for grounds. Check the ignition wire going to the solenoid (red wire). If it's corroded and hard, you should replace it as well (gauge 8 I think). Replace all your connections and battery leads. Crimp them really good and use shrink tubing or a good amount of QUALITY electric tape to seal them off from corrosion. Also use dielectric grease on connections.
---Second: Sometimes it starts, others not.
Check the ignition switch before you replace the starter/solenoid. Also check the wiring for corrosion, rust, bad grounds, faulty ignition wiring.
---Third: Starter stays on even when driving or after the car is shut off.
You'll have to shut off the starter first. Either hit the solenoid with a heavy object (lug wrench, brick, head) or disconnect the battery. Pulling on the ignition wire (red wire on solenoid) won't work (don't ask how I know). The problem is either the solenoid or the wiring. Check the wiring first. If it's good, replace the solenoid. Note that if the starter was litteraly smoking when you popped the hood, it's prolly a good idea to replace the whole thing instead of only the solenoid.
---Fourth: It grinds like a mofo!
Simple really. The starter's bushing needs to be replaced. It's a small piece of bronze colored tube. Any auto electric parts store, vw shop or dealer has it it stock. It is press fitted into the transmission's bellhousing and accessed only with the starter removed. However, it is not an extremely tight press fit. A bolt extractor or even a concrete fastener (like i used) will work. If you want to go fancy, buy the VW tool. To install the bushing, get a bolt about the same size as the bushing and thread a nut on it. slip the bushing on the bolt, thread the nut so the bolt's end is flat with the bushing's end. Align the bushing into the bellhousing's hole and tap the bolt gently until the bushing is all the way in. You have to align it straight or else you'll damage the bushing. If the bushing and starter are new and it still grinds, inspect the flywheel for missing thooth.
---Fifth: Ok the starter is out, how do I know if it's good?
Good question! Grab the casing and wiggle the shaft a bit (by holding the end of the shaft). There shoud be very little movement. The bushing in the tranny is there to control this movement. Now grab the drive gear and wiggle it. Again there should be very little movement. If you feel it's loose it means it's pretty worn out (either from time or bad tranny bushing). If the solenoid is good, the ignition switch is good and the wiring too, the next thing to look at the the levers and brushes. Take it appart and check for any cracks in the levers or white plastic part on the shaft. Look at the brushes, they might be worn to death. In any case of loose parts, cracked parts, worn brushes, or faulty internal wiring, replace the whole starter.
---Sixth: Slowwwww cranking.
Check the wiring and battery charge first. Do you have the proper oil weight? This is critical for ultra cold starts. Jello-ed up oil is hard on the engine and starter. If it's not any of the above, the starter is prolly going the way of the dodo. You should replace it as soon a possible.
---Seventh: The starter spins, but doesn't engage the flywheel.
Either the driving gear's shaft is stuck, the levers are broken or the solenoid isn't doing it's job. What's happening is that the driving gear isn't being engaged thus not cranking the engine. You need to remove the starter, open it up, clean up and lube the shaft. If the levers are broken you need a new starter. If it's all lubed and still spins without engaging, replace the solenoid.
Part five:Replacing the starter
Tools required: Lifting jack, two jack stands, 12 point 8mm tool (I think it's an 8mm), various metric sockets, plank of wood, dielectric grease, multipurpose grease, your brain and beer.
-Pop the hood, disconnect the battery and then the starter's connections.
-Then raise the car and put it on the jack stands. Stands should ALWAYS be used in pairs.
-Take the plank of wood, put it between the oil pan and jack. You have to support the engine before removing the starter. Supporting it from the oil pan is a good idea but you have to spread the weight if you don't want to dent the pan.
-Lift the engine slightly! You just have to support the weight of it.
-Drink a beer
-From the engine bay, loosen the first starter bolt (12 point). Don't remove it yet. There are three bolts holding the starter to the tranny.
-Then remove the two bolts from under the car (one is a standard bolt, the other is a 12 point).
-Back to the engine bay, remove the first bolt you loosened and hold the starter so it doesn't fall. You'll notice that these bolts are also holding the front motor mount to the engine! Hence the "support the engine" thing.
-Next replace the starter's bushing (see above in troubleshooting)
-Take your new "upgraded" starter, lube the end of the shaft with multipurpose grease and put it in place. It's a good idea to seal the tranny and starter with sealant (RVT...). Don't let it hang from the tranny without bolts, you could damage your newly installed bushing. Install the top bolt. You might have to fiddle a bit with the mount to thread it. Don't tighten it yet.
-From under, install the two bolts. Again you might have to fiddle with the mount or even the jack supporting the engine. Once they are in, torque all the bolts to 43lb.
-Remove the jack from under the engine and drop the car on it's wheels.
-Reconnect the battery and starter. Use dielectric grease on the connections.
-Double check everything then start the car!!!
-Have another beer. You are done.
I know it's an extremely long read. I may have forgot something or some things aren't right. If so just tell me and I'll edit my post.
Oh and forgot to add:
Flat head screwdriver: 1
Edit: Added number seven in troubleshooting
Edit: Added a few things
Edit: Added table of contents
Edit: Changed picture host
Modified by Black Smokin' Diesel at 4:09 PM 9-20-2006
Modified by Black Smokin' Diesel at 12:41 PM 9-23-2006
Modified by Black Smokin' Diesel at 2:43 AM 3-10-2007