Just started driving the car a bit and noticed the front brakes are a little sticky and one side drags a little bit.

After taking a look I realized and remembered that one of these star clips broke before when I removed the calipers the first time. But it was on the side that wasn't dragging. Dragging side has a clip.

I assume these are required to drive with? or uneven braking?

Car is a 1970. Are these the same for a 911? AA shows part number 901 351 916 16.
Are these used in the rear as well?

Also says NLA but repros going for $8-$10 a piece...seems really high and I need four.
Click to view attachment

Very necessary but will not cause dragging, the piston is probably sticking in the bore, or the flex line is clogged. You can rivet the clip back together though and avoid purchasing another.

Those parts are Essential for proper braking, and to push Back the pad, to prevent the brakes from overheating/ rapid pad wear/warped rotors etc....they are hard to find, and their are complete kits with cross pins and clips...The front and rear are different...With all due respect they ARE necessary if you appreciate good breaking. I dont recommend reusing /repairing the old parts., as over time and heat they take a "set" and loose their tension..............................................AA used to carry them under part number.....R90135191616..(expanding spring set-front)......AND....R311615269 (expanding spring set-rear).

For your car, they're the same as a 66 911 or a 912 with solid rotors. Later springs are wider (later 911 works here).

Fronts and Rears can be had at Pelican. Fronts come in a kit. Rears are springs only:

911-352-951-00 (front kit... this will do both calipers)

311-615-269 (rear spring only)

They ain't cheap but they are necessary. If it's dragging a "little bit" it may just be the pad cavity holding up the pad. This is a good time to get in there and clean out the pad cavity. Check for torn boots, etc.

Dragging is usually because of gummed up pistons or, as George mentioned, bad soft lines (they swell internally). If it's sat for a while, I would check and expect both.

IMO, they have nothing to do with pushing back the pad. They are loaded in the wrong direction. They hold the pad tight against the pin and probably lessen the possibility of chatter. The rubber boots actually function, along with slight runout of the rotor, to hold the pad away from the disc as you motor along with your foot off the brake pedal. As has been said earlier, internal swelling of the brake hoses, sticky pistons on the calipers, or damaged piston boots cause the brakes to drag. The clips also function as a stop to prevent the outer area of the pad from collapsing into the disc as the pad material wears away. Other manufacturers use a much simpler version of this part, without the folded short arms.

The Cap'n

With all due respect (and a bad drawing), I'd have to disagree on a couple of points and agree on others:

I believe it is the bore seal that pulls the piston back. The knockback mechanism is the self adjusting ratchetting device that also keeps the piston high in the bore and adjusts to the pad depth, but the seal pulls against this to bring the piston back. - The dust/water seal you mention is just that... a dust/water seal. It doesn't have the elasticity to pull a piston back into the bore.

Agree - Runout helps knock the pad back for the most part. These keep everything tight. They keep the pads tight against the piston and it is important that the pins are not inhibiting this travel as well.

A long time ago a member here had a pretty neat trick where he put his pins in a drill and used a ScotchBrite pad on them... whatever works, pins and springs should be in place to help keep your brakes functioning they way they're supposed to. The cavity needs to be clean as well.

I'm guessing this car hasn't been driven and the pistons are gunked up though.

Thanks for all this info. Drawing looks spot on and seems logical.

I just went in there and took off the caliper. I think I am missing another part.

Is there some kind of plate that wedges in between the piston and the pad? Parts diagrams show a plate. the end of the piston is like a semi circle.

edit...this sucks

The rebuild kits I got from pmb had new ones. I probably stll have the old ones in myy junk box. I think you need rebuilds and new lines though. If you need them let me know and I'll see how many I have.

ok..at AA for the front tension spring:

1966 911 shows G90135293611 at $4.60 each

1966 912 shows G90135191611 for $4 each

1966 911 shows G90135191615 at $10.73 each

1970 914 shows G90135191616 at $7.72 each

1970 914 shows R411615269A at $13.75 each



according to the info here are all these the same? this seems ridiculous to me or I am missing something...

You don't need that plate if the pistons are set at the correct 20 degree angle.



66 911 - M-Caliper - Non vented
66 912 - M-Caliper - Non vented
66 911 - M-Caliper - Non vented
70 914 - Rear M-Caliper casting, Larger piston - Non vented = same spring
70 914 - Rear M-Caliper casting, Larger piston - Non vented = same spring

Don't know what to tell ya.

If the pistons are not set properly, you should probably take everything apart and rebuild. DO NOT try to turn them in the bore.

Eric

What is the part number that will work on later cars (like my 73)?

Is it this one?

911-351-951-00

No... those are A-Caliper springs. They're too wide in the pin spcaing. You'll want M-Caliper spacing. I need to double check the bore depth as well but I know the pins are identical spacing.