EURORELIC

34 31 1 151 850 –Brake master cylinder (D=20,64MM)

Supersededchecked 2026-10-07source: bmwpartsdeal.commarket: US (EU: not checked)

BMW part number 34 31 1 151 850 (34311151850) is the Brake master cylinder (D=20,64MM), a brakes part catalogued for the E21 (318i, 320i). As of our last check (2026-10-07, bmwpartsdeal.com), it has been superseded by 34311120032.

⚠ Safety-critical part. Have a qualified mechanic verify fitment and installation before driving.
  1. 1 New from BMW
    Order the replacement number 34311120032
  2. 2 Aftermarket new
    No sourced aftermarket equivalent yet
  3. 3 Used / NOS
    Search live listings on eBay US/DE.
  4. 4 Interchange
    No cross-model match in our data
  5. 5 Kit / reman
    None recorded yet
  6. 6 Community fix
    No forum workaround recorded yet
  7. 7 DIY guide
    No guide yet
  8. 8 Paid hunt
    We search dealers, breakers and forums for you.

Buy new

Replaced by 34311120032. Order the newer number.

View 34311151850 at bmwpartsdeal.comCross-reference 34311151850 on RealOEMCatalog diagram (bmwfans.info)

Aftermarket options (0)

No sourced aftermarket equivalent recorded yet. We only list brand numbers that a brand catalog or vendor page explicitly cross-references to this BMW number.

Where to buy

Every link opens 34311151850 at that seller: “View” = the part’s own page, “Look up” = the seller’s part-number page, “Search” = the seller’s search pre-filled with the number (successor 34311120032 where shown). You can order from either region.

United States

Europe (DE · UK · DK)

“Ships internationally” is shown only where we read it on the vendor’s own shipping page (checked 2026-09-28); otherwise check with the vendor. Import duties and taxes are the buyer’s responsibility. Amazon links carry our Associates tag, so we may earn a commission; other seller links are not affiliate links today.

Supersession chain

34311151850→34311120032

Older numbers on the left, newest on the right. Numbers without a record open a lookup.

Used & NOS listings

Cross-model interchange (0)

No interchange recorded. That doesn't prove there isn't one; it means we have no sourced match yet.

Community fixes (0)

No forum workaround recorded yet. If you know a thread, the hunt team wants to hear about it.

Kits, reman & retrofits (0)

No kit or reman service recorded yet.

DIY

No DIY route recorded yet.

Repair guides & how-tos (0)

No repair write-up or video linked for this part yet.

Notes & sources

Successor 34311120032 listed at $711.68 on bmwpartsdeal (InStock). SAFETY-CRITICAL (brakes/steering/fuel/airbag): have a qualified mechanic verify fitment and installation.