Disc brake drag

[incautious]

ONE very important thing about disc brakes, make sure that you lubricate the caliper/pad pins(#14 in the above diagram) with silicone grease.the calipers are all of the "floating" design and the grease helps them to retract. once a brake job has been performed you should be able to move the caliper back and forth easy when installed. Also i use a file and remove any rough edges on the pads this also helps on keeping them from hanging up. Something to consider, back in the day drag racers would use only cars with front drum brakes and adjust them back so as to reduce front brake drag. That's how much effect front disc drag had on the difference between winning and losing. there will always some drag with disc brakes, but they are better now a days.

[Piwoslaw]

Originally Posted by RH77

I read this in an old $1-Store copy of a book on how to save gas:

To reduce the amount of friction on front disc brakes when not in use (before a long highway trip), make a swift left and right turn to slightly push the pistons inward (or fully retract). The slight caliper compression returns when the brakes are used again.

I'm not sure how valid this is, but it kinda makes sense.

RH77

.

[Piwoslaw]

I can't get rid of my dragging brakes It isn't as bad as before the first major brake cleaning back in January, but it's still louder (sometimes MUCH louder) than it should be.
Today my bro-in-law/mechanic and I took off the rear wheels to see what is scraping. The discs had lots of rust and filth on them. They were worn down about 1mm where the pads touch, but terrible elsewhere. It turned out that the scraping noise was not from the pads, but from the gunk that was caked on the edges of the discs, which would rub against something. We knocked as much off as possible with a small hammer, then filed down what was left, on both sides of each disc. Then we filed down the pad edges so that they are easier to move. The wheels now rotate more freely, and are much quieter.

The left wheel looked much worse than the right, this is also the louder of the sides. There is water inside the left cable housing of the e-brake, which may cause the pads to slightly stick on frosty mornings. The reason may that the car is usually parked facing east, so the left (north) side doesn't see any direct sunshine, while the right side quickly warms up and dries during the day. Our dog also seems to prefer the left side of our car when doing his peeing rounds.

[Frank Lee]

Back the car in the parking spot on alternate days?

Sure is room for improvement in parking brake activation systems. Locked-up cables are a chronic problem here in the Rust Belt. You either have to use the parking brake all the time, or not at all. If you tend to not use parking brakes, then one day decide to use them, they probably will not release.

[Piwoslaw]

Originally Posted by Frank Lee

Back the car in the parking spot on alternate days?

Not an option: It's a very tight spot which is hard to maneuver into backwards, but impossible to get into forwards. That's what I get for having a long car.

[euromodder]

Replace the cable, and stuff the new cable's liner with a water repellent lubricant.
WD40 would do temporarily.
A friend of mine used a home brewn mix of graphite powder and a liquid molybdene-lube (or similar) on cables on his motorcycles.
The graphite makes the lube stick to the cable, and is a lubricant by itself.

[phw]

I have a 1992 LaBaron that had a LOT of brake problems which was cured after remembering what a friend told me to check the brace on the rubber hose feeding the wheel. It rust and shuts off the return but the hydrolics will apply the brake. All you have to do is expand the brace and stop safely. SORRY about the spelling.

[Frank Lee]

Also internal failure of rubber brake line has been said to happen where it may look OK from the outside but inside a loose flap of rubber closes off the flow (I've not seen this myself though).

[Christ]

I can vouch for that, Frank. I had a rubber line that was only a month old separate and internally collapse the plastic line inside the rubber. The brakes would apply, but not release for several hundred feet on that side. Eventually, they wouldn't release at all. Caught the poss on fire momentarily on Gerald.

[user removed]

Originally Posted by Frank Lee

Also internal failure of rubber brake line has been said to happen where it may look OK from the outside but inside a loose flap of rubber closes off the flow (I've not seen this myself though).

Seen the brake hose "check valve" syndrome back in the 1980s on Mercedes in particular.

Best test was hit the bleeder and release the residual pressure, then reapply the brakes and see it lock up again.

Eventually I got to the point where I would clamp off all four hoses. This allowed the master cylinder to be tested, then each wheel individually by releasing the clamps in sequence. Helped a lot to quickly diagnose the frozen floating caliper pins.

One time a friend brought his old tired 280 Z in the shop with a brake pull. The left caliper was practically frozen. Not paying attention I put my hand on the rotor and had "min dia 10.5 MM" branded on the callouses at the point where the fingers meet the hand. The callouses were so thick it took too long to feel the burn. Never blistered.

regards
Mech