Dorman M631000 brake master cylinder for the 1999 BMW 323i and other vehicles turns pedal force into hydraulic pressure for the brake lines.
- Part of the Dorman First Stop line
- Aluminum cylinder body
- Rubber components made of EPDM compound for resistance to glycol-based brake fluid
- Made entirely of new materials
- Built to meet SAE International standards
Quick facts
- Part: Dorman M631000 brake master cylinder
- Fits: the 1999 BMW 323i and other vehicles
- Material: Aluminum
- Condition: New
A soft or sinking brake pedal, or fluid showing around the cylinder, can mean the master cylinder is worn. Before you replace it, rule out a leak elsewhere in the brake lines or calipers, which can feel much the same. The car has one master cylinder, so a single unit is all it takes.
Fits
This master cylinder fits the 1999 BMW 323i and the 1999 BMW 328i.
Specifications
Fit and size
- Quantity per vehicle: 1
- Bore diameter: 0.875 in
- Number of outlets: 5
- Rearward outlet size: (3) M12 x 1.0
- Secondary outlet thread diameter: (2) M12 x 1.0
- Mounting holes: 2
Build and materials
- Material: Aluminum
- Condition: New
- Country of origin: Taiwan
In the box
One new brake master cylinder. Mounting hardware, mounting bracket, reservoir, reservoir cap, sensor, bleeder hoses, push rod and brake booster are not included, and the old fasteners may not be reusable, so plan on new ones.
Interchange: 100-4165 · 130.34111
34311165584 · NM55473 · F142333
This part cross-references / interchanges with the following part numbers:
100-4165, 34311165584, 130.34111, NM55473, F142333
Frequently Asked Questions
Does the Dorman brake master cylinder M631000 fit the 1999 BMW 328i?
Yes. Dorman M631000 fits the 1999 BMW 328i as well as the 1999 BMW 323i.
Does the Dorman master cylinder M631000 come with a reservoir or brake booster?
No. Dorman M631000 is the master cylinder only. The reservoir, cap, push rod, booster, bracket, sensor, bleeder hoses and mounting hardware are not included.
What bore size and outlet threads does this brake master cylinder have?
The bore diameter is 0.875 in. It has five outlets: three rearward outlets and two secondary outlets, all M12 x 1.0.
Will the rubber parts in this master cylinder handle glycol-based brake fluid?
Yes. All the rubber components are made of an EPDM compound, which resists glycol-based brake fluid.
Is 34311165584 an interchange number for this master cylinder?
Yes. 34311165584 is listed as an interchange number for Dorman M631000, along with 100-4165, 130.34111, NM55473 and F142333.
