1984 900S -- brake caliper seized in cold weather

I recently bought a 1984 900S to replace my old 1984 900S, which met an unceremoniously early demise when I was broad-sided by someone who ran a stop sign (the car was unfortunately totaled).

This morning, the front right brake caliper was temporarily seized up. The car moved, but it didn't roll very well. I drove a few blocks hoping it would release once it warmed up. When I pulled over, the caliper was smoking. I started the car up again, and pumped the brakes and engaged and disengaged the parking brake a few times, and the caliper released.

We've had the coldest weather of this year in Rhode Island (teens F at night, forecast to be in single digits F the next few nights). My old 1984

900 S never had this problem, but this is the coldest it's been since buying the current car.

Any ideas why this might have happened? Or suggestions for how to avoid happening again?

As always, any information much appreciated!

Thanks,

-jw

--

1984 900 S 198K miles Rhode Island, USA
Reply to
jw
Loading thread data ...

Don't set the parking brake when it's going to be cold and the car will sit for any extended period.

The piston can/will freeze in whatever position it happens to be in. If it is retracted, the hydraulic force applied with the brake pedal will easily break it free, but if the brake is applied there is no such force which may be exerted to retract it as the whole braking system is designed only to exert force in one direction. The spring in the brake pedal is the only thing pulling brake fluid back from the caliper to the reservoir, thus retracting the piston.

dave

Reply to
Dave

Quick fix: Lubricate the lever on the caliper with generous amounts of WD40 or any other light oil. Make sure it gets right into the pivot pin hole.

Long term fix: Replace/rebuild the front calipers. If they haven't been done, 20 years is a long time.

Reply to
Grunff

Thanks for the info, Grunff and Dave. I didn't set the parking brake last night, and I'll lube the caliper while I hunt down new calipers... My local Saab mechanic (Conn-Tech in Warwick, Rhode Island, highly recommended) usually has some kicking around.

-jw

--

1984 900S 198K miles Rhode Island, USA
Reply to
jw

WD40 is not a lubricant. It's a cleaner. Use a lubricnat after you use it.

-klaus

Reply to
klaus

???

CLEANS: WD-40 gets under dirt, grime and grease to clean. It also dissolves adhesives, allowing easy removal of labels, tape, stickers, and excess bonding material. DISPLACES MOISTURE: Because WD-40 displaces moisture, it quickly dries out electrical systems to eliminate moisture-induced short circuits. PENETRATES: WD-40 loosens rust-to-metal bonds and frees stuck, frozen or rusted metal parts. LUBRICATES: WD-40's lubricating ingredients are widely dispersed and hold firmly to all moving parts. PROTECTS: WD-40 protects metal surfaces with corrosion-resistant ingredients to shield against moisture and other corrosive elements.

Reply to
Simon Putz

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.