Shimmy when braking 993

[911TerryT]

I have a shimmy in the steering wheel and felt in the car when I apply brakes but the shimmy is not consistent. Seems to happen in the 40 -50mph range. I thought brake rotors but it's not consistent enough across different speeds/braking to seem like rotors. I gave a look for loose anything but everything seems snug. The car does not pull to either side when braking. Car cruises and runs great. No service lights on.
97 Carrera C2 with 97K miles.

I would think that if rotors I would have a more consistent pulsation.

Looking for a suggestion on where maybe to look...maybe it is rotors but don't want to start replacing stuff.

Thanks for any pointers!!

[AOW162435]

If your front control arm bushings are original, I'd bet that's your issue. Can you get the car on stands? If so, take a pry bar and get between the front 'head' of either control arm and the subframe. If the bushings are original, you'll probably distort them easily and see cracks in the rubber.


Andreas

[Marine Blue]

Originally Posted by AOW162435

If your front control arm bushings are original, I'd bet that's your issue. Can you get the car on stands? If so, take a pry bar and get between the front 'head' of either control arm and the subframe. If the bushings are original, you'll probably distort them easily and see cracks in the rubber.


Andreas

Agreed, that was the first thing that came to my mind since the rotors were ruled out already.

[911TerryT]

Thank you....stay tuned. Home next week and will look. If that's the problem, where to get replacements?

[wesleyc]

Originally Posted by 911TerryT

Thank you....stay tuned. Home next week and will look. If that's the problem, where to get replacements?

I had the shimmy’s and installed Chris Walrod bushings. Totally cured the problem. I bought them from FD motorsports. They have a tutorial on installation as well.

[AOW162435]

Originally Posted by 911TerryT

Thank you....stay tuned. Home next week and will look. If that's the problem, where to get replacements?

Reach out to Darin at FD Motorsports.


Andreas

[Junkseller]

Cut be warped brake rotors

[Correyyt]

Measure rotor runout with a dial gauge, that will tell you in 10 minutes whether they’re the culprit or if you should keep chasing suspension.

[heliolps2]

Front Brake Vibration — Finally Solved?

Hey friends,

Just wanted to share an update on an issue that’s been driving me crazy for a while now. I’d been dealing with a front-end vibration under braking in my 965. Naturally, I replaced the front rotors a couple of times and tried new Pagid pads, but the problem kept coming back. I double-checked that all suspension components were torqued to spec — everything looked fine there.

Since the issue persisted, I replaced the front bearings, but then the calipers started to feel like they were sticking. I flush my brake fluid every two years, so I ordered a caliper rebuild kit and went through that process — still no real improvement. At this point, I honestly wasn’t enjoying driving the car, and had been spending more time in my 944 Turbo.

That’s when I remembered a similar issue I had in my 944, which was solved only after replacing the front hubs. Then it clicked: I once hit a large rock on Rt. 66, which badly bent my wheels — it’s totally possible the hubs were damaged at that time too.

So, I decided to order new hubs from Porsche… but of course, they were backordered for months. I finally got them last week!

In the meantime, I also decided to switch from Pagid to Textar pads when ordering new Sebro rotors from FCP Euro — and wow, what a difference. Turns out the "sticking caliper" feeling was actually the lack of initial bite from the Pagid pads, not the calipers themselves. Big shoutout to FCP Euro for honoring their lifetime replacement guarantee and taking care of the rotor/pad swap — excellent service as always.
Here's what I ended up replacing:
Front wheel bearings
Caliper rebuild
Front hubs (finally!)
New Sebro rotors & Textar pads
Full brake fluid flush/bleed
So far, everything feels great — the vibration is gone and the braking is smooth and confident. Fingers crossed it stays that way. Hopefully this helps someone chasing down a similar issue.

[911TerryT]

I finally got my 993 to the shop to be looked at. The mechanic looked and tested every busing/bearing and could not find a culprit. He went for a 30 min test drive over hills etc. Got back and measured the temperature of the rotor and found the rotor varied by over 100 degrees in places. He was pretty sure that the pulsation was constant and to replace the rotors. The rotors are original and have 90K + miles.
That's my next move....looking at options now for rotors and pads so any suggestions welcomed. Will also do a fluid flush with dot 4. thanks

[Noah930]

Rotors would have been my first guess. It doesn't matter that the shimmy was only experienced while braking in a certain speed range. It's rotors until proven otherwise--at least in my experience.

I have a street-driven car/canyon carver. I went with Zimmerman rotors and Hawk (yellow) pads up front. Hawk doesn't make a rear set for my early 964, so I went with Textars for the back (kept the stock rear rotors).