Frozen Brake Caliper (Frozen Disc)

First off let's get the terminology right.

The "disc" is the part (also known as a "rotor") that the brake caliper acts upon to stop the car.

It appears that you have caliper "pistons" that are frozen.

This is almost certainly due to rust, a result of moisture accumulation in the brake fluid.

Another possibility is that the flexible hose connected to this wheel has deteriorated internally and is preventing fluid movement.

Either way, the only responsible thing to do is to flush/bleed the system with fresh fluid (observe carefully whether fluid bleeds out of the affected caliper). If yes then it will be necessary to disassemble and rebuild the stuck caliper.

If you are unable to bleed one or more wheels then you likely need new hoses.

There is nothing you can spray to free the stuck piston and while you might get it loose with some application of force, the rust will most certainly result in pretty severe leaks.

What I am describing here is an absolute minimum amount of work. What I would recommend is that your entire brake system be carefully inspected and probably rebuilt.

 

If on a limited budget, you could remove the offending caliper, free off and remove the pistons, clean them and replace their seals, replace the flexi hose that feeds that caliper (its cheap), refit, bleed the system and very carefully test drive.

If during the bleeding process the fluid comes out filthy or if the piston or cylinder walls are badly corroded, you will need to spend more money.

Giles Amos
308 GT4
Alfa 1750 Berlina
Alfa 2000 Berlina

 

I see a pair on ebay. Also Porsche used the same caliper on one of their 911 cars.
Charles

 

If the piston is stuck, you really should do more than just try to free it up. There is obviously an internal problem that needs fixing, whether it is rust or a bad seal or the brake line delaminating.

IMHO, you should remove both front calipers and rebuild them (don't do just the right one, you want both front calipers working exactly the same to avoid pulling). The stock brake calipers are made by ATE, and repair kits are readily available for them, as are replacement pistons. If you don't have the mechanical skills to rebuild them yourself, there are plenty of places that can do them for you. The fronts are the same at the late 70's - early 80's Porsche 911. No big deal to have them done. I had mine done by East Coast Jaguar in Delaware last summer. ([email protected]), but there are lots of other places that can do them. Check the sticky on parts interchange in the 308/328 forum and you'll get the info on the repair kits. Also, replacement calipers are not that expensive, if you buy them from a Porsche parts supplier. I had looked into it myself and IIRC, they were around $250 each from one of the big Porsche parts houses. But these are easily rebuildable, and you don't need a "Ferrari expert" to do them. Any brake shop that works on foreign brakes can do them, as they are NOT Ferrari-specific parts, with the exception of the rear parking brake mechanicals (but even those can be serviced by anyone).

BTW, treat your car to some stainless steel braided brake lines, front and rear, and some new pads. While you have the calipers off, have the front rotors resurfaced at a local auto parts store or brake shop. Your car will thank you for it. And check the rear rotors as well. This is a good time to service the entire system.

Hope that helps.

Steve

 

Good advice.

You don't need to spend a fortune (relatively speaking of course) but brakes are no place to cut corners.

 

And Alfa's too, the 308 GTB front caliper is the same as my '69 1750 Alfa, except the Ferrari caliper has an alumnium spacer between the caliper halves ( to allow for the thicker vented disk used on the GTB ). BTW Caliper is made by ATE / Germany.

Also, if you have a stuck piston in the caliper, you do need to have the caliper rebuilt - even if you manage to free it up, it will begin to leak - and brakes is something you don't want to take chances with.