Brake Diagnosis - HELP please

[archtech]

I rebuilt my M calipers on my 71 because they were sticking. Installed them on and bled the system. I drove the car and it was still sticking and stuck when I parked it! UGggh.. I was going to get some new calipers, but remembered some problems other people had with old brake hoses. I went back to the car after a week and was able to push the car around. Made me think that it was the brake hoses since the calipers retracted. To test again, I jacked up the concerned wheels, jammed on the brakes, and found one of the wheels not releasing. I opened the bleeder screw on that caliper and fluid came out of the SpeedBleeder.... meaning it was still pressurized inside the caliper? and now the wheel was able to spin!

So Im on the assumption that the caliper rebuild is fine with no leaks and retracting when the pressure is relieved. Im going to next replace all the hoses with steel braided lines.

Is my thinking correct? Reason I ask is I need to put an order into Pelican ASAP to get the parts by this weekend. I dont want to have to order a set of calipers of if I dont have to. Thanks!

[cbush]

Couple of simple things are making sure the piston is turned to the right angle, and that the metal clip on top of the brake pads (the one held on by the pins) is fairly new. Then I would look at brake lines as the next alternative.

[4sd911]

Probably at clogged rubber brake hose.

[Bill Verburg]

Originally Posted by archtech

....

Is my thinking correct? Reason I ask is I need to put an order into Pelican ASAP to get the parts by this weekend. I dont want to have to order a set of calipers of if I dont have to. Thanks!

Sounds reasonable to me.

[rfloz]

FWIW, new lines cured my sticking front calipers, although they were not nearly as bad as you describe.

I don't see a mention fo flushing out your brake system with new brake fluid. You might want to do that when your put in the new lines. Old fluid can have water and other contaminants.

[archtech]

Got my stainless lines from Pelican! Went to install them and after pulling the front two lines, found that I cant even blow or suck thru them! Brake fluid drained out of the hard line from the prop. valve, so I know that wasnt clogged. As I unscrewed the hard line from the caliper, one of the lines busted. I was lucky to have a spare one from some stuff i got. Looks like the front was all still original lines.


As for the rear, all the fittings look to be in really good shape.. not original... even the lines looked new once wiped off. Was going to leave them, but noticed that there were no brake retaining clips. Im really concerned that without them the movement could end up busting some lines.... so looks like I'll replace them too once I get the retaining clips.

Anyway, hopefully the inoperable rubber lines up front were what was causing me to have sticking / stuck calipers!

So lesson learned... anytime you have to replace or rebuild your calipers, get new brake lines! Cheap insurance... I also heard that the stainless lines dont really give you that much braking improvement... using the rubber ones would keep the cost down that you may do it more often!