We all know there are only two brake boosters- 9 inch from start of '78 through 8/1/79 (ie early 80 production, through 92A0800750), and 10 inch, '80-95. Easy..

But then it gets a little bit more complicated - in the 1980-84 tech spec book, there is a 10" booster with a 3.0 assist ratio for cars with floating frame brakes, and one with a 3.8:1 assist ratio for floating caliper brakes.

Then you get to 1986 ROW cars with S4 brakes, and now the booster has a 4.5:1 internal boost ratio. In ’87 there’s the same ratio but the ‘pedal free travel is shorter’…. The next mention of boosters in the WSM is for the GTS in 1992, which also has the 4.5:1 ratio.

So three different booster ratios, all with the same diameter. How many rebuild kits are out there for the rebuilders to use?

Then you look at those blue stickers on the Ate boosters. Absolute mayhem. I can’t make any the couple of examples, so I’d like to ask: Please post a pic of the sticker on your brake booster, the year of your car, whether it’s an S or a non S. The goal is to get enough examples to understand what the Ate numbers are so that there’s a chance to be able to ID which booster is appropriate for a given car.

I’ll go first: 1986.5 automatic:






Late 1993 5-speed:

 

Learn something new everyday, Thanks Rob.
I will see what I can find on the cars I have

 

My 84 Euro S 5-speed.

 

1987 Auto

 

86.5 manual.
ATE 4.5 3.6862-1201.4
928.355.025.24

So, apparently the same as your 86.5 auto. However, the sticker is slightly different (larger 4.5 with a comma, and Porsche part number differently spaced).

 

Here is mine
1991 Automatic

The first 4 numbers of second row appear to be the date of manufacture.

 

Early 1980 5-speed, VIN 92A0810536. Non-S, with "floating frame" calipers.

 

Yep, looks like the XXXth day of the year, then 7X for 1970s and just X for 1980s.

 

86.5 US

86 Euro 32V

 

1989 GT

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How the heck did you guys get your camera down there

 

My 1978 5 speed US, VIN 9288200342. ATE 3.6852-1701.4
342773st. This second line seems to correspond to my VIN (build # 342 during 1977).

 

From a recent core

 

Further to above.

 

Another early USA '80 auto - 92A810654

 

I was pretty sure my booster had been replaced, but based on Ken's info I would now say it must be original.