teej

Hi,
i have a '66 912 which has developed this weird problem, which I hope someone can help me narrow down on the problem:

- brake pedal is erradic - sometimes very stiff and raised - sometimes soft and drops by 2-3 inches at rest - these variances can occur during the course of a single trip
- calipers are sticky - the car wouldnt roll freely, so i raised it to check - all the calipers seem to be equally sticky / enagaged
- no brake fluid is leaking

- i was going to bleed the brakes first - then if that doesnt work, change the master cylinder

any thoughts or similar experiences?

thanks, tj (teej@teej.com)

The912guy

Classic symptoms of a bad master cylinder. Replace it and check the pedal assembly bushings while you're down there-if the master cylinder has been leaking brake fluid, it will cause the bushings to swell and stick. Replacement bronze bushings are the way to go-beware of the clutch cross shaft retaining pin-they can be a real pain to remove.

912Driver

This may not be the best advice but this happened to my car and i bled the brakes and rplaced most of the fluid, also the bearings could be shot and the master cylinder is probably shot if you check out these you shouldnt have a problem

Bill Gregory

If you press steadily on the brake pedal, and the pedal slowly goes towards the floor, the master cylinder is shot.

On sticking brakes, if your rubber hoses are more than 10 years old, replace them. Over time they swell internally, which impacts the hydraulic pressure and the ability of the pistons to relax after braking. People have rebuilt "sticking" calipers only to still have the problem afterwards, with the solution being new rubber hoses.

If you find you've had brake fluid leaking on your plastic bushings, as 912guy points out, bronze bushings are a good replacement item, not expensive. Make sure you grease them up good when you install them. The retaining pin is smaller on one end, so make sure you tap on the right end when you remove it.