rupert

Hi,

Can air trapped in the brake lines cause caliper sticking ?

Also, I've seen two mechanics replace brake fluid directly from the reservoir, instead of bleeding from the caliper.

Is this the proper procedure? If so, does it mean air cannot enter the system from the reservoir?

Thanks

'85 5000S

team6.003K

I always use a vacuum bleeder, best $40 I've spent on a car tool. I know air in the lines/brake cylinders can cause the pedal to be super soft and results in lack of braking abilities.

Sticking calipers are usually just sticking caliper pins, they can be removed, cleaned up and regreased. You may have to replace the rubber dust boots on the pins when you pull them depending on how brittle they are from age.

Quattrogirls_dad

Having done this on my '87 5000CS, the answer to your question (Can air trapped in the brake lines cause caliper sticking ? ) is no. Air trapped in the brake lines will make the brakes feel very "spongy" but will not make the calipers stick. That's caused by dirt (or whatever) in the pistons, like team6 said.

The replacement brake pads are retained in the carrier by springs (normally supplied with a replacement pad kit). The caliper is held on with a long pair of bolts; you can change pads by removing the lower bolt (if I remember correctly) and "pivoting" the whole assembly up and away from the rotor. I'm not sure what you mean by "guide pins". 'Splain, please?

When changing brake fluid, it makes life much easier if you have a tool like team6. Your alternative is to "bleed" the brakes by opening the 4 valves at the brakes, one at a time, and letting the old fluid drain out while adding new fluid up above into the reservoir. It took me a while to even find the bleed valves on mine because they were completely buried uder several years of road goop!

rupert

Thanks for the bleeding info; I think that the caliper sticking problem may be as simple as team6.003K has said.

The guide pins are part of the brake pad carrier, and they have their own rubber boots (open on the hex nut end).

I need to know whether I can remove these (without having the whole thing fall apart) by just removing the pins and replacing them w/ fresh grease.

Thanks

Quattrogirls_dad

Ahhhh! I did not have to remove those myself. So I'm not sure. I did not have to any further disassembly after removing the old pads and clipping the new pads on. It does take a fair amount of "finger power" to push the pistons back in so the pads can clear the rotor. A word of caution: the brake fluid reservoir will probably overflow if you don't suck some out first!