I need to pick up a replacement power brake booster for a 1984 EA81 GL. Looking at the NAPA website they're showing two. One is a 7" diameter diaphragm and the other a 7 1/2" diaphragm. Did they actually use 2 different sizes? If so what were the applications of each, and are they interchangeable (same mounting mounting pattern, same pedal push rod dimension, same master cylinder use)? Looking at subaruparts.com they show 2 for my year application, the only difference being "brake booster - wagon" vs. "brake booster w/o wagon". Really? Wagons used what I'm guessing would be the bigger diameter unit?

 

Without popping the canister open how do you measure for the correct diaphragm diameter?

 

Also, if anybody has one for my application laying around and want s to trade for cash let me know.

Edited July 3, 201015 yr by ettev

More snooping on the NAPA website. Looks like the 4-door wagons and Brat's had the bigger 7 1/2" diameter boosters.

 

Learn something new every day.

 

So if anyone has a verifiably good booster from a '82 thru '84 4-door wagon or '82 thru '87 Brat that you want to purge let me know.