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With all motor cars, the starter motors are mainly of two kinds – it may be the kind which has a cylindrical commutator with brushes on the side or it’s the face type commutator which has a flat disk towards the outer end and brushes which bear against the disc. In both cases, you will need to go through troubleshooting measure before you actually make up your mind that it’s actually the starter motor which isn’t working properly.

We’ve covered on these measures step-by-step in the previous section and also gave a brief on how to check up on your starter motor by looking towards the front of your vehicle and what to look for exactly in such a case.

Now, let’s move on to how to fix your starter motor. It is frustrating when you find that your car won’t start, what’s more – it’s even more so when you find that you’d probably have to drop it off at your mechanic for further repairs, which let’s face it will cost you a lot of dollars.

But before you actually call in a tow service, maybe you can be helped by this DIY about how to fix starter motors, and save yourself a hefty bill.


As common thing with all starter motors, the brushes which are made from copper and carbon alloy are placed safely in housings on the end plate of your starter motor. Now occasionally there might be just two brushes but more than often there are four of them. Chances are that if there is indeed an issue with your vehicles starter motor it will need to be removed, partly dismantled and then repaired. This is necessary in order for you to properly inspect and if need be replace these brushes. Note that at this point some starter motors will have removable bands which let you check at least two of the brushes while the motor is still at its designated place.

Now, this does make the job much easier for you. If this is the case with your vehicle then you are able to replace the brushes while the motor is still in place through a hole which is at the side of the endplate. If you have a face type commutator then the brushes can be replaced without the need to remove the commutator itself.

You should have a service manual which came along with the car, it’s helpful to consult it to find the maximum allowable brush wear. If, however, you don’t have your service manual (a lot of people don’t know where they put it) a safe assumption would be that there is at least a minimum of 8 mm of brush beyond the lead. Before actually placing them in check if the new brushes you’re installing slide smoothly in their guides or not. But if they stick it’s always a good idea to remove the raised spots by using a fine file.

The next step is easier and since you’re already on your way all you need to do is clean the commutator with a methylated spirit which allows for smoother function as well. Be patient and let is dry out before you being to reassemble all of the various parts. Remember – petrol is not recommended for this process as due to its chemical composition, a spark may ignite inevitably causing an explosion. And no one wants that to happen.

At this stage if the commutator is still discolored, you need clean it up again using a very fine glass paper. If, however, the surface is badly worn out, you might as well just get a new starter.



We’ve assumed so far that your motor has an inspection window, now let’s look at the possibility that it doesn’t.

If it doesn’t, you can still check the brushes and even clean the commutator – but the actual replacement of the commutator is a job best left to an auto-electrician. The reason as to why this is, is because the lead present is insulated in a way which makes soldering a new brush impossible. Similarly you’ll have a tough time reaching the brush assembly as well. To do so you’ll need to remove two long, slot-headed bolts which are in place holding the motor together.

You can take off the endplate in order to pull out the armature and the check the commutator. Once done release the brush assembly, but remember to do it from the inside of the endplate – this can be done by removing the two screws present at each end. After this, simply lift each brush out of its place in order to measure them by pulling the coiled springs just at the top of the brush by pulling the brush up at the same time.

It gets a bit tedious after this. You will need to actually lift each brush out of its guide, measure and put it partway back into the guide which should comfortably sit at the wedges and the spring which are at its side – by doing so you ensure that the spring does not push in the brush completely. This step is essential because it allows for the commutator to be inserted back between the brushes and that to without damaging them during reassembly.

In most cases you need to understand that the starter motor brushes are probably worn out. We’ve already touched on how you can determine this and make proper amends. The steps mentioned are recommended if you are comfortable in taking apart parts of your vehicles engine and have had some or any prior experience in doing so. The aim here is to ensure that you do not go to your mechanic completely blind and have some semblance of what exactly might be the matter with your start motor.

At each step, do ensure that your starter motor during reassembly is put back together by following the proper steps. This will help you in the long run and will cause minimum discomfort in the future as well. If at any stage you do not feel that you are able to properly assess the issue – call you mechanic before you proceed any further and possibly make your car’s condition even worse.


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