Jump to content

rebuilding starter motors

Recommended Posts

If they are genuine ones and they just start clicking and for a while eventually starting but then give up altogether it is probably the small engaging cog (technical term!) that has seized on its spiral shaft. Very easy to dismantle, soak in easing oil. Knock it up and down on the bench a few times, slap some grease on and it will be as good as new. If its a cheap Britpart one then i'm afraid its knackered!!!!

Link to comment
Share on other sites

All three of them are genuine ones and have done exactly as Orgasmicfarmer said they click for a while then work but progressively get worse and then just click, sounds like it may be possible to fix them

Also when they were almost gone they would turn over really slowly.

Link to comment
Share on other sites

use some brake cleaner or similar to clean the bendix run & lightly oil it afterwards, the bit that spins out to engage the ring gear should move easily by hand & not be stiff along is run & should spring back to the diusengaged position when you release your grip.

Link to comment
Share on other sites

bendix run as O.F has noted above, seems strange, my 200Tdi is still running with it's original starter from new [nearly 15 years now] & I've never had any start problem with it.

if the lazy starting still persist after cleaning, it maybe a soleniod fault or just dirty connections, clean the engine to chassis earth lead terminals before you do the first start after refitting the starter motor.

Link to comment
Share on other sites

Solenoids are available for about £30 and they are usually held on with just a couple of screws/bolts/frame fixings.

The solenoids can't be dismantled other than removing the plunger and spring, which should be clean and only lightly oiled. The plunger connects to a lever that pivots on the alloy casing and then connects to a one-way clutch/bendix gear that sits over the end of the main motor shaft. The solenoid does two things - it connects power to the main starter motor and also flings the bendix gear forwards to engage in the flywheel. There are two heavy contacts in the back of the solenoid to provide power to the main starter, and the plunger moving forward due to a magnetic field, engages the gear with the flywheel. You can test the electrical side of the solenoid by checking current flow in the exciter wire (the thin one) when the ignition is turned to the start position. With the ignition key held in the same position - there should be current in the thick wire that goes from the back of the solenoid to the starter main body. When you remove the solenoid - pay attention to how the plunger is connected to the arm, where the pivot point is, and how it's attached to the bendix gear. Remove the solenoid, unbolt the alloy nose casing, and remove it - along with the pivot arm, directional clutch/bendix gear. On the opposite end of the starter is the brush pack (4 carbon brushes). Unscrew it and lift it away (it'll still be attached by a high-temp soldered joint). The brushes may be stuck in their slides or worn (they should pop out to the limit of the spring/wire that retains then in their respective guides. Stuck brushes can be freed off with brake cleaner and careful manipulation, but be careful - they are quite brittle and can break quite easily. If the brushes are worn, you will have a job getting them and you will need a high temperature soldering iron to attach them. Clean the area that the brushes contact, and when you come to refit the brush pack - there is a small hole in the plate. You push each brush back into it's housing, then put a paper clip or similar through each hole and release the brush. The clip will retain each brush back in the housing. Clean and regrease the bush in the centre of the brush pack and refit the pack. Once in place, remove the clips and the brushes will spring forward into position. Clean the bendix and shaft end and then slide the bendix gear back onto the shaft and check it runs up and down smoothly, clean and regrease the bush in the nose of the alloy housing. The gear and shaft are designed to run dry, so if you put grease/heavy oil on the shaft and gear - clutch dust etc, will stick and may gum up the bendix again in the future. The directional clutch will only turn one way - this is so that when the engine starts, the flywheel runs away and the clutch allows this to happen without the engine running the starter.

Most common problems with starters are poor electrical connections (earth as well), dirt on the bendix/jammed solenoid plunger preventing engagement (motor whines but doesn't turn the engine). Solenoid failure (nothing happens at all). Worn/disengaged brushes (click, but nothing else).

Very noisy starter motor - it's come loose or it's knackered.


Link to comment
Share on other sites

right over lunch i decided to test 2 of the motors the results were:

1. the gear/bendix thingy was seized so it just clicked but i assumed the motor would probably be fine.

2. the gear/bendix thingy looked brand and but the motor didnt work.

so i pulled both apart and i used the solanoid, bendix gear part and bolted that to the motor that i assumed worked and tested it and it worked a treat so i now have one working starter motor. Im going to try and work out whats wrong with the other one but will put this one on the vehicle first. :)

Link to comment
Share on other sites

i will take a picture of my shed with a starter motor shaped hole in it later :lol:


You might also like to have a close look at the braided lead which runs from the solenoid into the

motor casing. They have been known to corrode away inside the rubber gromit. Less cable thickness

results in less power to the motor, and any broken ends arcing burn more strands until there are none

left = motor doesn't turn. While a new "pig tail" can be obtained, modern motors seem to have alloy

windings, which makes it difficult to attach a new lead. The original (copper) lead is somehow fused

to the alloy. What price progress?!

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Create New...

Important Information

We use cookies to ensure you get the best experience. By using our website you agree to our Cookie Policy