Air-Cooled Porsche 911 After Summer Hibernation

Recently, our air-cooled Porsche 911 (964 C2) woke up from a short summer hibernation of about a month and a half.

いとしの空冷ポルシェ911（964）に久しぶりに乗る。

After the summer break, my husband has been driving it around nearby and using it for commuting. However, there were a few repairs needed, so he took it to the shop recently to get them fixed.

When I asked, “Is it really that worn out?” he said,

When I brake at high speed, there’s a judder (a shaking vibration). When I bought the car, the brake discs were resurfaced, so it didn’t happen for a while, but it started after returning from a touring trip in Shikoku. It’s a bit better now, but it still feels off, so I decided to fix it. Also, I wanted to try changing the ATF (automatic transmission fluid).

The shop we asked this time was Be-Force, a local place where we had the oil changed before: Be-Force. We brought the 911 in and first requested the ATF change and to fix the brake judder. After checking other parts as well, they found more areas that needed repair beyond what my husband had expected.

Since fixing everything at once would be overwhelming, we decided to proceed step-by-step, gradually making repairs and monitoring the situation. The repairs were completed in about a week, and the final work included:

• ATF (automatic transmission fluid) change
• ATF strainer replacement
• ATF strainer O-ring replacement
• ATF oil pan gasket replacement
• Front brake rotor replacement
• Rear driveshaft boot replacement
• Front and rear brake pad chamfering and greasing

Details of Air-Cooled Porsche Repairs

ATF (Automatic Transmission Fluid) Change

When I asked, “Why change the ATF?” he explained:

The maintenance records show the ATF was changed in the past, but when I took it in for an oil change before, the Be-Force owner said, “The ATF drain bolt looks dirty and doesn’t seem to have been loosened before. Maybe it was changed previously, but it’s been quite a while either way.” So I thought I’d try changing it once more.

I wasn’t quite sure, as some new terms came up, so I asked, “What happens when you change it?”

It depends on the car, but generally, shift shocks get smoother, shifts become quicker, and the slipping feeling in the automatic transmission goes away. Personally, I love changing ATF. Almost every car I’ve owned has had it done at least once. For example, the Honda Legend Coupe (KA8) showed dramatic improvement after an ATF change. The SLK350 (R171) didn’t change much, though.

This time, they replaced about 12 liters of ATF in total, using the A.S.H. brand recommended by the shop owner, in three flushes.

Brake Rotor Replacement

We also replaced the brake rotors. When I asked, “Are brake rotors those disc-like things behind the tires?” my husband said,

Yes. The owner said there are various causes for judder, including bad disc condition, brake caliper problems, or worn bushings in the shafts extending from the steering. To find the cause, they tested the car extensively and suggested, “Let’s start by replacing the front discs.” So we went ahead with that.

Rear Driveshaft Boot Replacement

When I asked, “What’s a driveshaft boot? I can’t even imagine what kind of part that is (-_-),” he explained,

It’s a rubber boot around the shaft that connects the engine to the wheels. It contains grease inside. This time, when they happened to remove the rear wheels, they discovered that the rubber was torn wide open on both sides. If the boot tears and the grease leaks out, it can cause serious problems.

Indeed, it’s torn and split into two pieces!!

Mastering the 964

After the repairs, my husband drove the air-cooled Porsche and said,

The brakes feel amazing now. They don’t shake at all even when braking from high speed. The owner said, “It’s not perfect yet; if you want to go further, you should replace the steering bushings too,” but for now, this is enough. I’ll refresh those parts next time.

He also said,

The automatic transmission is smooth! Well, this car’s AT didn’t have much shift shock to begin with, but it feels like the drivetrain friction has decreased. You can’t really tell in city driving between 2nd and 3rd gears, but when merging onto the highway and flooring the accelerator, the acceleration is noticeably better. The shift speed feels a bit quicker, and the power delivery after lock-up is especially smooth. It feels really great.

However, he also said, “My driving has gotten worse.”

I’ve been driving the GT3 (991.2) a lot lately, and the car’s performance helped me out. Now my skills have gotten rusty. On tight winding roads like Rokko, I can’t shift weight smoothly like before, and my driving isn’t as fluid. I’m not fully in control of the car, so I need to practice again. Air-cooled Porsches really are deep machines…

I see… It seems the latest Porsches come with many driver-assist features. When I test drove the 911 (991) Cabriolet before, it was incredibly easy and fun to drive.

Cars are endlessly fascinating. I’m sure my husband will soon set off on a long tour with the air-cooled Porsche, practicing and improving his skills (I wonder what exactly he’s aiming for, haha).

By the way, I need to learn to drive the GT3 soon too!