Car alternator brush replacement.

[Agile]

A typical car alternator has two rotor slip rings at the rear end.

Whats the correct way to hold the brushes in their guides until the rotor is fully in place?

How easy it it to get replacement brushes anyway?

Tony

 

[Softus]

Whats the correct way to hold the brushes in their guides until the rotor is fully in place?

Typically the brushes are mounted in an assembly, so can be removed and installed after inserting the rotor.

How easy it it to get replacement brushes anyway?

About as easy as buying a punnet of strawberries, and they don't go mushy as quickly.

 

[Agile]

I need to be more specific!

What about an AC Delco where the rear part does not permit the brush assembly to be removed after the rotor is in place and so the brushes have to be held back to enable the rotor to be inserted?

Tony

 

[Softus]

Well I'm sure there's a professional method, but in the absence of that you'll have to get devious with it.

For example, you could tie the brushes in their retracted position using some fuse wire, or nylon fishing line, or 'cotton' sewing thread, then release them once the rotor is in place.

 

[Agile]

Yes, I was thinking of the fishing line but wondered if there was a more professional method.

Tony

 

[JohnD]

you mean so they don't pop out on springs?

it is sometimes possible to do it with a flexible shim (or a feeler guage or a bit of cardboard)

p.s. you seem to be having a lot of trouble with your car lately, have you bought a lemon?

 

[Agile]

you mean so they don't pop out on springs?

it is sometimes possible to do it with a flexible shim (or a feeler guage or a bit of cardboard)

p.s. you seem to be having a lot of trouble with your car lately, have you bought a lemon?

No, its not a Citroen!

Actually these problems are across two cars but mostly on the Frontera Sport. Its more that its been lying idle for nearly a year before I bought it and it has been rather messed about as well.

The brake switch failing, leaking petrol pipes and then the alternator are just those things which seem to happen just after you have bought it.

Its still fun to drive when its going!

Tony

 

[Joe Malone]

Its a while since I've worked on these things but the old ac delco units that Vauxhall used to use have a hole in the outer casing that precisely aligns with a hole in the brush box. You simply slid a pin through the casing and brushbox which then holds back the brushes, connected both sides of the alternator together then pulled out the pin once the alternator was assembled.

 

[Agile]

Its a while since I've worked on these things but the old ac delco units that Vauxhall used to use have a hole in the outer casing that precisely aligns with a hole in the brush box.

Thanks Joe, thats exactly the tip I was waiting for!

The reason I had not seen that hole myself, is because its blocked on the outside with mastic and does not continue through the far inside wall of the inner brush guide.

I almost decided to reassemble it right now so that I can go out with it this evening but as I dont have new brushes that would be wasting my time as they are well worn.

How easy is it to get replacement brushes for the AC Delco?

Tony

 

[Joe Malone]

Very easy, any auto electrical dealer should be able to supply you with a set for £2 to £3. Failing that try a company that reconditions or repairs alternators and starter motor. Many years ago when I was still in the trade we got our parts from a company called woodauto who I'm sure are still trading and have a website.

Incidently these units are generally very good, common failures were the triode and the regulator. Very rarely had to replace brushes.

 

[Agile]

The actual fault was the negative bar from the diodes to the chassis tag had snapped but the brushes are well worn and only about 6 mm left on one. One slip ring is deeply scored and roughly cleaning this will increase brush wear so I want to start with new brushes.

The needle roller bearings are dry looking and the front one is very noisy. I will probably just grease them and reassemble as I dont expect to use this car for such a high mileage.

Thanks for help.

Tony

 

[Joe Malone]

You can get a new slip ring but it'll need a bearing puller to get it off and will also need desoldering then soldering onto the rotor wires, still a cheap relatively easy job.