Autolite 4100 Carburetor Secondary Diaphragm Rocker Arm 85-101

Autolite 4100 Secondary Diaphragm Rocker Arm

Restore proper secondary throttle operation on your classic Ford or Mercury with this new replacement secondary diaphragm rocker arm for Autolite 4100 carburetors. Designed for use with early-style diaphragm assemblies, this plastic rocker arm features a male connection and can also be used to replace the original metal-style rocker arm found on some factory carbs.

 Product Specifications

• Part Number: 85-101

• Material: Durable molded polymer (replaces original metal rocker)

• End Type: Male – requires a female-style secondary diaphragm

• OEM Replacement: Ford C5AZ-9853-A

• Condition: New, current production

• Manufacturing: Made in the USA

 Fitment

This rocker arm is used on Autolite 4100 and Motorcraft 4100 4-barrel carburetors from the 1960s and early 1970s.
Common applications include:

• Ford Mustang (1964–1969)

• Ford F-Series and full-size cars (1960s–1970s)

• Mercury Comet, Cougar, and full-size models

• Any vehicle using a 4100 with the early-style secondary diaphragm pump

 Key Benefits

• Direct-fit replacement for factory rocker arms

• Replaces worn or broken metal types found in older carburetors

• Improves secondary throttle performance and drivability

• Drop-in design—no modifications needed

• Made in the USA for long-term reliability

 Frequently Asked Questions

1. What does this rocker arm fit?
It fits Autolite/Motorcraft 4100 carburetors that use an early-style secondary diaphragm with a female connection. It's common in 1960s–early 1970s Ford and Mercury vehicles.

2. Can this replace the metal-style rocker arm?
Yes. This molded plastic rocker is designed to replace the original metal rocker arm found in some factory-installed 4100 carbs. It's a direct fit and performs the same function with improved durability.

3. What diaphragm does this connect to?
It connects to a female-style secondary diaphragm. If your diaphragm has a male end, you will need to update it to a female type for compatibility.

4. Is it a new part?
Yes, this is a brand-new, USA-manufactured part—not a used or refurbished component.

5. What OEM part number does it replace?
It replaces Ford C5AZ-9853-A.

6. How do I know if this will fix my carb’s secondary issue?
If your secondaries aren't opening properly under load and your rocker arm is worn, bent, or missing, this part is likely the fix.

7. Will it work with other carburetor models?
This part is specific to the Autolite and Motorcraft 4100 series. It is not compatible with other carburetor families.

8. How soon will it ship?
Orders placed before 12 PM PST (Mon–Fri) typically ship the same day.

9. What about shipping costs?
Shipping is calculated at checkout. See our Shipping Policy for details.