Parts Parts Parts Parts

Yes, the 911 needs more parts. Brake parts this time. Brake parts fuel the brake saga and what's a car without a saga? Last Saturday was spent trying to get the proper brake pedal feel. I bled and bled the brakes. I can bleed brakes in my sleep; right rear, left rear, right front, left front over and over again.

After the pedal was firm enough, it had too much travel. Jack the car up again, take the wheels off. There's a good one MM between the pad and the rotor. In brake land, that's too much. A couple of failed attempts at erasing that one millimeter, I realize there is a ridge about one MM tall running around the circumfrence of the rotor. This ridge is where the brake pad does not touch the disc. One millimeter of steel is ground away from the rotor. It is impossible to get the pads any closer with the rotor ridge. I measure the rotor thickness and they're right one the edge of needing replacement.

Cross-drilled front rotors $111 each.
Ferodo front brake pad set $140.

The brake saga continues.

Smell the Brake Fluid Sea

Brake fluid has a distinctive smell. It's the most obvious when the pressure is released from the caliper when pushing the pistons out with an air compressor. Some fluid gets mixed in with the air to form a close proximation of vapor in the rush to escape. The pop of the pistons releasing from their machined hollows within the caliper are remeniscent of a far off blast. My fingers were out of the way by chance the first time the piston popped.

I set out to rebuild only one caliper. After finishing that one, the difference was significant. So much, that I decided to rebuild all of the others. It turned out that the inboard piston could be pushed out with about 20psi. The outboard pistons were not as willing, 125psi if at all. I had to resort to rust desolver in two cases. They weren't completely seized, but pretty close. The scotchbrite pad took what little hard gunk and rust there was off.

After reattaching the calipers, the front discs spin freely like a bicycle wheel. The rear ones don't (on account of the transmission). I can tell the pads aren't binding though.

I ran out of fresh brake fluid before being able to completely bleed the system, but I am excited to see how the brakes work now. They should be significantly more powerful than before.

Completed:
- Rebuilt all four calipers

The pictures:

Front caliper off the car

View of piston with seal removed. Note the rust.

Pushing the pistons out with compressed air. The clamps prevent either piston from shooting out.

Both pistons are out, brake fluid everywhere

View inside the piston housing on the outboard side. Look at all the rust above the inner seal.

Detail of gunk build up on rear caliper piston

Detail of piston after removing gunk with a scothbrite

Ready for reassembly, new seals and "plastilube" on the right

Close up of pistons

Front caliper reassembled and ready to be remounted on the car

Sticky Calipers

Cricket Bowlers are frustrated by sticky wickets. A sticky caliper is the source of the 911's brake woes. All of the brake lines have been replaced by shiny stainless steel lines (see pictures). The brake fluid has been replaced with ATE blue racing fluid (DOT 4). It took about 5 hours to do the job including 1 hour of messing around with floor jacks. There was also a brake fluid spill to contend with.

The bleeding was easy easy. Three times around with the pressure bleeder. One time around pushing the pedal manually. Speed bleeders are highly recommended. Not once did I need help.

Holle looked a tad worried when I told her I was going for a test drive. "If I don't return, avenge my death." Without doubt, I returned intact. The 911 was immediately jacked up to see if any calipers where sticking. (When I last checked, both front calipers were sticking.) All pass except the driver front. That will get a rebuild next weekend. It's not the master cylinder. Whew.

My brake failure theory is this: One or more of the calipers was sticking causing the pad the drag while the brakes were not being applied. The friction created by this drag will get hot enough to boil the brake fluid. This leads to the no brake condition I encountered a few weeks ago.

Now the pictures:


Before picture of a front brake line.


Before picture of a rear brake line. Note how tight the space at the far end is.


Comparison of old front brake line to new front brake line.


New front brake line installed.


New rear brake line installed.


Bleeding the brakes, waiting for the blue fluid to come through the hose.


All done bleeding with the reservoir topped off.

Completed:
- Replaced brake lines
- Flushed fried brake fluid
- Installed speed bleeders

Revelation!

I always thought the ring surrounding the headlight was beige to start with. Apparently, they were grey when the car rolled off the factory floor. How do I know this? The replacements I ordered are grey. The portion of the original rings that was not exposed to the elements was grey too. Wow.


Here's the original installed.


Here's the original side by side with the new.


Here's the new installed.

A Sampling of Artifacts

Digging beneath the seats, lifting the carpets, removing the door panels; these activities have revealed a wealth of artifacts from times past. His signature toothpick in cellophane wrapping will always remind me of my Father. Amongst my other favorites:



No fewer than three video club memberships take me back to the heyday of the VHS cassette. The high-tech of the three features a bar code.



This receipt for a fill-up in October of 1987 is timely gem.