Dorman M39871 brake master cylinder for the 1987-1995 Chevrolet W4500 Tiltmaster and other vehicles turns pedal force into hydraulic pressure for the brakes.
- Dorman First Stop line
- Cast iron cylinder housing
- Rubber components made of an EPDM compound for resistance to glycol-based brake fluid
- Made entirely of new materials
- Made to meet SAE International standards
Quick facts
- Part: Dorman M39871 brake master cylinder
- Fits: 1987-1995 Chevrolet W4500 Tiltmaster and other vehicles
- Material: cast iron
- Condition: New
A soft or sinking brake pedal, or brake fluid leaking around the master cylinder, can mean the unit is wearing out. These signs alone do not prove this part is the problem, because air in the brake lines can produce a soft pedal too.
Fits
This master cylinder is a direct-fit replacement for the 1987-1995 Chevrolet W4500 Tiltmaster, the 1992-1995 GMC W4500 Forward and the 1987-1995 Isuzu NPR. Its housing is constructed to match the casting material of the original part.
Specifications
Fit and size
- Bore diameter: 1.25 in
- Number of outlets: 2
- Rearward outlet size: M10 x 1.0
- Secondary outlet thread: M10 x 1.0
- Primary outlet thread pitch: 1 mm
- Quantity per vehicle: 1
Build and materials
- Material: cast iron
- Rubber components: EPDM compound
- Condition: New
- Standards: SAE International
- Country of origin: China
In the box
One master cylinder. The reservoir, sensor and mounting hardware are not included, so plan on new mounting hardware, as the old pieces may not be reusable. This listing holds one master cylinder, and the fitment calls for one per vehicle.
Interchange: 83-24003 · 83-24010 · 100-2722 · M-62003 · 13-3488 · 11-3488 · 11-3746 · 130.76003 · 355-37014
18M480 · M900687 · 13123 · MC252600 · 94406618 · 97107355 · 8944066180 · 8944066181 · 8971073550 · MC39871 · F122226 · F128442 · F131790 · MC128442 · MC131790
This part cross-references / interchanges with the following part numbers:
18M480, 83-24003, 83-24010, M900687, 100-2722, M-62003, 13123, 13-3488, 11-3488, 11-3746, 130.76003, MC252600, 355-37014, 94406618, 97107355, 8944066180, 8944066181, 8971073550, MC39871, F122226, F128442, F131790, MC128442, MC131790
Frequently Asked Questions
Is this the right 1987-1995 Isuzu NPR brake master cylinder?
Yes. Dorman M39871 fits the 1987-1995 Isuzu NPR, and the fitment calls for one master cylinder.
What is the Dorman brake master cylinder body made of?
Dorman M39871 has a cast iron body. Its rubber components are an EPDM compound that resists glycol-based brake fluid.
Does the Dorman master cylinder come with a reservoir?
No. This listing is the master cylinder alone; the reservoir, sensor and mounting hardware are not included.
What bore size and outlet thread does this brake master cylinder have?
The bore is 1.25 in. It has two outlets, and the rearward and secondary outlets use an M10 x 1.0 thread.
Can a worn brake master cylinder make the pedal sink?
Yes, a worn master cylinder can let the pedal sink or feel soft. Have the brakes inspected promptly by a shop rather than driving on them.
