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Bmw 745I Starter Armatures

Bmw 745I Starter armatures

Starting at $76.95, AutoBuffy stocks 1 starter armatures from Bosch for the Bmw 745I. The armature is the rotating core of the starter motor — its copper windings convert electrical current into the mechanical torque that cranks the engine. When windings burn out or the commutator wears, the starter fails entirely and the engine won't turn over.

Signs your Bmw 745I needs a new starter armature

  • Engine cranks slowly or unevenly, as if the starter is struggling to build full torque
  • Starter spins freely but fails to turn the flywheel — a symptom of burned or open armature windings
  • Grinding or rattling noise from the starter that persists even after the pinion gear is confirmed intact
  • Starter draws abnormally high current (detectable with a load tester) due to shorted windings generating excess heat
  • Visible burn marks, dark discoloration, or a burnt electrical smell when the starter is removed and inspected
  • Starter works intermittently — starts the engine on some attempts but spins dead on others with no clicking from the solenoid

Which starter armature should you buy for your Bmw 745I?

Starter armatures are wound to match the voltage, rotation direction, and physical dimensions of the original starter assembly. Before buying, confirm whether you need a standalone armature to rebuild an otherwise sound starter housing or a complete replacement starter — armatures are only sold separately for rebuildable units. Match the commutator diameter and shaft spline count to your existing starter.

OEM-Equivalent Remanufactured Armature
Best for
Restoring a salvageable starter to factory performance at lower cost than a full unit
What you get
Rewound coils, turned and undercut commutator, balanced rotating assembly — meets original specs
New OE-Spec Armature
Best for
High-mileage vehicles or fleet use where long service life is the priority
What you get
Fresh copper windings, full commutator depth, no wear — longest expected service life of any option
Rebuilt/Surplus Armature
Best for
Budget repairs on older or low-value vehicles where cost is the main concern
What you get
Reconditioned core, functional but with less remaining commutator material than new — inspect before install
Complete Replacement Starter
Best for
Armature damage caused by heat or water intrusion that may have compromised the field coils or housing too
What you get
Entire starter assembly replaced at once, eliminating the risk of cascading failures in related components

Starter armatures brands we stock for your Bmw 745I

Bosch
1 option · from $76.95

Replacing a starter armature on a Bmw 745I

Advanced⏱ 2–4 hoursSocket set and ratchet (metric and standard)Screwdrivers (flathead for brush retainers)Multimeter or growler testerBearing puller or bench press (if bearings require replacement)Parts cleaner and clean rags

Disconnect the battery, remove the starter from the vehicle, then disassemble the starter on a clean bench — marking the through-bolt orientation before separation. Slide out the old armature, transfer or replace the bushings and brushes as needed, then reassemble and test the starter off the vehicle with jumper leads before reinstalling. Torque the through bolts and mounting hardware to manufacturer specification using a service manual for your specific starter model.

Frequently asked questions

How much does it cost to replace starter armatures on a Bmw 745I?
Parts start at $76.95 at AutoBuffy. A standalone armature is the lower-cost route if the rest of your starter is sound, but factor in labor if you're not doing the rebuild yourself — shop rates for starter removal and bench rebuild typically add to the total. A complete starter swap is often faster and comparably priced.
Can I replace just the armature, or do I need a whole new starter for my Bmw 745I?
You can replace just the armature if the starter housing, field coils, brushes, and solenoid are all in good condition. Inspect those components before committing to an armature-only repair. If the starter has high mileage, heat damage, or corroded internals, replacing the complete unit is more cost-effective and reliable in the long run.
What causes a starter armature to fail?
The most common causes are heat buildup from repeated long cranking attempts, which burns the copper windings, and physical wear of the commutator surface from normal brush contact over time. Water or oil intrusion can also short the windings. Using a weak or failing battery — which forces the starter to work harder — accelerates armature wear significantly.
How do I test a starter armature to confirm it's bad?
Remove the starter and disassemble it to access the armature. Use a growler tester to check for shorted windings, or use a multimeter to test continuity between adjacent commutator segments — shorted segments will show near-zero resistance. Check for open windings by testing between each segment and the armature shaft; any reading indicates a fault.
How long does a starter armature last on a Bmw 745I?
Armature service life varies widely depending on climate, battery health, and how often the engine is started. Under normal conditions they often last the life of the original starter — many tens of thousands of start cycles. Frequent short trips, a weak battery, or a hard-to-start engine condition (low compression, fuel issues) shorten armature life considerably.
Will any armature fit my Bmw 745I, or does it have to be vehicle-specific?
Armatures are not universal. They must match the starter motor's frame size, commutator diameter, shaft dimensions, and winding voltage. Using the Bmw 745I's year, make, and model — along with the starter part number if available — ensures the correct fit. AutoBuffy's 1 listings are application-matched, so filtering by your vehicle returns only compatible starter armatures.

Shop starter armatures by year for the Bmw 745I

20052004

More parts for your Bmw 745I

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Starter armatures for other Bmw models

Bmw 740iBmw 318isBmw 528i xDriveBmw 335i xDriveBmw Z4Bmw X6