Damm Front Brakes

Newfie911s · 10-22-2012, 02:01 PM

So I bought a 77 911s Targa and its my first Porsche.

The car was sitting for a long time and needed some mechanical work. The owner provided me with the front brake calipers and tonight I mounted them, pads and had the fronts bled. While bleeding the rear brakes as there was a lot of air in it I heard a pop and my son (brake pumper extrodinaire) indicated the pedal went straight to the floor. Looked at the left front caliper and it was leaking. Pulled it off, dust cap and here is what I found.

Any suggestions why this would have happened?

I'm just glad it didn't happen while driving the car.

jpnovak · 10-22-2012, 02:25 PM

A split in the seal channel lip is generally caused by corrosion on the piston that increases the diameter.

Where these calipers rebuilt prior to installation?

The good news is that the Steel A calipers are easy to find for very little money.

ninesixfour · 10-22-2012, 03:33 PM

If just the piston is cracked you can replace it without replacing the whole caliper or as mentioned above, those calipers are cheap and easy to find used.

Newfie911s · 10-22-2012, 05:27 PM

Being new to the Porsche Community where would I find a used one?

lsf911 · lsf911's Garage

I am sure there are many places to pick up calipers including our host but if you are looking for inexpensive calipers you can try ********.com

They have a rebuilt front left caliper for a 1977 911 for around $75.00.

fitchn · 10-22-2012, 07:03 PM

Apparently this cracking can happen when caliper pistons are REALLY stuck. You should send pictures to Eric Shea @ pmbperformance.com, he'll set you straight.

steve911T · 10-23-2012, 04:35 AM

I had the back left brake caliper that was bad, piston stuck. I went to advance auto and they had a rebuilt one for around $80. This was for an '89 3.2. Put it in several years ago. I did rebuild the left rear and will do the fronts this winter. Luckily for you, these calipers come up almost weekly here and if you need one sooner, place a WTB ad in the buy sell forum. Good luck, Steve

wwest · wwest's Garage

There is a retrofit kit that allows you to mount early Boxster calipers, at least there was for my 78 & 88.

Newfie911s · 10-23-2012, 08:21 AM

Interesting about the boxster units. I tracked down the supplier and the are replacing under warranty.

Eric_Shea · Eric_Shea's Garage

Quote:

********.com They have a rebuilt front left caliper for a 1977 911 for around $75.00

That's what got him in trouble in the first place.

Take a look at the first picture. Here's what I see:

1. A crappy reman (read ********/A1 Cardon) caliper with all of the protective zinc finish vibratory polished off. This is their MO.
2. With no finish, there's only a light film of oil to protect them.
3. With fresh steel on steel, the piston has rusted to the bore cavity. The pressure from the hydraulic fluid is immense. This is what caused the dust boot flange to crack.

They also vibratory polish the fasteners. No finish on those either. In about 2 months the oil finish will wear off and those calipers will be covered in rust.

A-Calipers are coming into the era where we are beginning to see this. It is uncommon but happens often enough. They need to be rebuilt and rebuilt properly. They need new protective coating inside and out. Fasteners also need to be protected to last another 30 years.

Please don't buy ******** junk for your Porsche. Especially brakes...

Newfie911s · 10-23-2012, 01:43 PM

Where do I find a kit to mount the Boxster Calipers?

This could be the solution to future problems as right now I'm want the car drivable.

Eric_Shea · Eric_Shea's Garage

Don't know...

Do you need Boxster calipers? If your current calipers can lock up the wheel tire combo you have now, they've done their job. I'm going to guess they can.

You'll spend thousands on kits that could go to better use in your new project car. Great calipers, Porterfield pads and proper bedding process should be able to throw you through the front windshield. It is a Porsche afterall.