Dumb parking brake questions for your entertainment

[megerian]

With all kinds of free time this weekend, I finally got started on an overdue project to address the parking brake on my 88 Turbo Look Carrera. I have both the Bentley and Wayne 101 projects book. While these things seem so straightforward in the books, I am still managing to struggle

Question 1: Looking at the first photo of the left rear rotor with the wheel removed, where should I expect to find the little star sprocket thing? The caliper is at 3 oclock looking at the wheel, despite the improper rotation of this photo



Question 2: Both Wayne's book and Bentley say that I need to use a screwdriver to move the brake pad away from the rotor to allow it to spin. Dumb questions: why was I able to move the wheel before I removed it? Is the pad always putting pressure and its just the extra torgue from spinning a large wheel compared to a small rotor that makes the difference? Most importantly, I can't see where I am supposed to put a screwdriver to push the pad away from the rotor. Using photo 2 as a guide, am I just supposed to wedge it between the inner portion of the caliper? Won't I damage the rotor?



Question 3: This photo is what I believe to be where the brake cable comes into the brake assembly. Some other posts said this is where you can do big adjustments and the star sprocket thing is for small adjustments. Given that my parking brake handle goes up about 7-8 clicks and still doesnt hold well, I would think I need to do big adjustments. How do I achieve this using these two nuts? Do I loosen them up and back the cable out to tighten it?

[yelcab1]

1. Go to Oreily's parts store and buy a set of Torx bits (sockets). Get the big ones that fit those bolts. Damn Germans love Torx bolts.
2. You insert a thin screw driver at the BACK of the calipers, in between the pad and the rotor and gently wedge until there is a gap.
3. 7 or 8 clicks is way too much. Having said that, adjust it at the star thingy, inside the brake rotor.

[brp914]

The star sprocket thing is inside the rotor. You can access it thru the large hole in the rotor that's at about the same radius as the wheel studs. You turn the star different direction on different sides of the car, and right now I don't remember which side goes which way.

I would just take the rotors off to make sure the shoes aren't worn out. But to do that you've got to take off the rotor and remove the hydraulic line. There's a good chance the hydraulic line will get trashed. You'll need an offset 19mm wrench to get the caliper off (atleast on my non-turbo cars). If the shoes are worn this job goes down hill in a hurry and you may want to leave it to a pro.

[megerian]

What about the adjustment of the cable in the 3rd photo? Can someone explain that part to me? In the Bentley guide, it says that if the parking brake needs more than 4 or 5 clicks, the cable should be adjusted at that point, but it's not clear to me how to do that.

[Noah930]

I just messed around with my parking brake today, too. Star sprocket thingie is either at roughly the 3:00 position (or driver's side) or 9:00 position for passenger side. Mine was spin it forward to tighten (spread) the brake pads, and spin it aft to release/retract the brake shoes. Meaning, the part of the star sprocket that's closest to you--the part your screwdriver will actuate--is to be rotated to the front of the car in order to spread the shoes apart.

Here are pics with the calipers/rotor off. My first time delving into this. Obviously someone (not me this time) drove for a bit with the brake engaged, so all the lining's gone. I had a suspicion this was the case, so looks like I need to buy a set of shoes and replace them next weekend.

Driver's side:

[Noah930]

Passenger side:

[Mike Andrew]

IIRC. the cable thingy is much like a bicycle brake cable. Loosen nuts and expose more of the threaded sleeve to shorten cable between its seat and the brake shoe spreader. This will reduce the amount that the handle moves. It does need some slack to avoid dragging the shoes. I would try to adjust via starwheel first.
Did the shoes last winter and there is some good info here via search. I found the spring installation to be the most difficult part of the whole filthy process, especially keeping the spreader located properly.
I despise drum style brake work. Carry over from working in a gas station as a teen and being the low man on the pole who got brakes and exhaust.

[famoroso]

My uncle is a Porsche factory trained master mechanic. He owned an independent repair facility in Palo Alto for ~30 years that I used to work at on weekends / summers. Among many other things he was a stickler that 911 parking brakes engage at three clicks (four was pushing it for him). So, when we were doing a major service on my '88 M491, you better believe the parking brake mechanism got adjusted to three clicks...

[brp914]

I did this miserable job a couple weeks ago. Afew things:

the springs at 6 and 12 o'clock - I found you can thread a couple strands of bailing wire thru coils, compress them in a vice, then twist the wire so the spring is already compressed. Otherwise it's nearly impossible to compress them on the car because the hub is in the way. Then snip off the bailing wire


have a flashlight handy to verify the inner spreaders are engaged on the brake shoe pins after stretching on the spring. They can get dislodged in the process.

clean the threads on the star wheel bolt so you'll be able adjust clearance easily. Spin it down to its minimum for reassembly so you don't have to stretch that awful spring so much.

If you take off the boot at the e-brake handle you'll see 2 inspection holes at the rear of the cover plate. This so that as you pull the handle you can verify that each cable is pulled equally. Adjust the jam nuts at the other end so that this is the case.

[sugarwood]

Kudos for having the courage to ask questions you knew may invite ridicule and scorn.

Unfortunately, Wayne's book was probably the worst thing that ever happened to 911 DIY
It is not useful as a step-by-step technical manual. At best, it's a cursory coffee table book.
As a side effect, in 20 years of this forum, it detracted others from creating actually useful tutorials that are commonplace with dozens of other enthusiast cars.
Why? All threads just say "Refer to Wayne's book" Easy peasy!
But, as we can see in this thread, that superficial book is not helpful to those who have not done the repair already.
Excellent example of a thread that shows how weakly documented 911 cars are for beginners.

I shot a quick videos when I adjusted my brake. Maybe it will help you visualize this repair.



My old notes from this repair:

I found it impossible to adjust the star with the rotor on.

Trying my first parking brake adjustment.
I could barely see into the rotor view hole with my light.
Didn't see anything that looks like a sprocket.

So, I decided to try removing the rotor to look inside and adjust it and see what's happening.
I got the lower caliper bolt off using 3/8" ratchet with 19mm socket.
Had to use a pipe on the ratchet to break it loose.
Then I just used a ratcheting wrench to spin it off (a few degrees at a time)

It wasn't clear if you need to detach the hard brake line to move the caliper.
Some insisted you need to detach the brake lines and re-bleed the system.
But, I was able to move the caliper aside without opening the brake lines.
This was done by prying off the retaining clip at the hard/soft coupler.
This allowed me to push the entire brake line back and rest the caliper on the suspension.
I had to remove the brake pad sensor clip in order to have room to pry properly.

On a related note, I was struggling with how much to adjust the parking brake shoes so they would not rub even when disengaged.
What I did to test for rubbing was to reset the brake to “zero”. Then I put the rotor on and spun it to see what the baseline should feel/sound like (no rubbing)

It was too difficult for me to adjust the sprocket with the rotor on. (Expand until fully engaged, and then back off 4 clicks) So I had to repeatedly remove/adjust/replace until it felt close. At one point, the rotor would not go back on, then I backed off the parking brake a bit.
I was told this was wrong, so this might be a repair best left for a professional.

In my final config, there was a minor rubbing sound only for like a few degrees of rotational travel. Not sure if this just meant the entire mechanism just needs to shift and settle (since it can be shifted around) I figured if it was too tight, it would be rubbing at all 360* of rotation.

[sugarwood]

I would be interested if OP can figure out the crap that needs to be done at the handbrake lever.
Removing the heater controls, etc.

I never did figure out what the hell this photo even means.
Maybe you'll have better results.

[sugarwood]

Originally Posted by Noah930

Obviously someone (not me this time) drove for a bit with the brake engaged, so all the lining's gone. I had a suspicion this was the case, so looks like I need to buy a set of shoes and replace them next weekend.

I think I need to do this also.
Can you take a video of how to replace the brake shoes?
If you don't know how to take video, can you take a lot of photos?

[brp914]

Those holes in the cover are there so as you pull the brake lever you'll be able to tell if each cable is pulled equally. Adjust the jam nuts on the other end so that this is the case.

[Locker537]

Don't mess with the cables unless you are confident you need to. Start with the adjuster at the shoes.

[Locker537]

I ran into a bunch of challenges replacing the parking brake shoes. Some of them were first timer questions, and others were real challenges.

911 SC - Rear brake rotor removal

Biggest lesson for me was the cheap aftermarket shoes were horribly out of spec. OE Porsche shoes fit perfect, to the tune of over $300.

[Mike Andrew]

I got lucky with aftermarkets and they fit right out of the box no problems.
Believe I remember your struggles a few months ago.
I did clean and lube the star wheel threads prior to reassembly which did help with adjustment thru the tiny and near worthless adjustment hole.

[sugarwood]

Originally Posted by brp914

Those holes in the cover are there so as you pull the brake lever you'll be able to tell if each cable is pulled equally. Adjust the jam nuts on the other end so that this is the case.

What are you looking for inside the holes?
How can the cables be pulled unequally if they are attached to the same lever?

[sugarwood]

Originally Posted by Mike Andrew

I got lucky with aftermarkets and they fit right out of the box no problems.

What aftermarket brand did you use?
Can it be an SC vs. 3.2 issue?

[sugarwood]

Oh damn, look at what someone published in Jan 2020 !!
This is the best write up I've seen on this subject

How To Replace The Parking Brake Shoes And Rear Rotors On A Classic Air-Cooled Porsche 911
https://tinyurl.com/tc3z9e9

[brp914]

Originally Posted by sugarwood

What are you looking for inside the holes?
How can the cables be pulled unequally if they are attached to the same lever?

The brake lever pulls a part that looks like an anchor. Each hook of the anchor pulls the cables to the left and right sides. If the cable lengths are unequal, the anchor will be tilted to one side or the other such that maybe only one wheel is braked, if at all. The hooks should come into view equally as you pull the lever.

And Locker is right, try to adjust the stars before the jam nuts.