New Calipers, Duds?

[tima01864]

Howdy, I bought new calipers last year to replace seized calipers and a broken bleeder. The one problem I have is the E-Brake, I can get them to work once to pass inspection after that no good. Finally decided to inspect, compare old and new and take look at the Bellville washers. There are a few differences, One is the seating for the hose and bleederis not spot faced and the piston is larger at contact with the pad. The new caliper does not screw in the piston when I use the actuator on the bench, As the old caliper screws it right out. I think the new caliper is not right and that is why i have no e-brake, What should I do? Eat the new calipers and buy a new set from a different vendor?
Or how do I fix this? I did not get the new caliper apart to inspect the washers, I bought these through one of our vendors, Not from a parts store or ebay.

[tima01864]

If I put pessrue on the piston with a screwdriver they will function correctly, So I opened it up and positioned the Bellville washers as in another post. The washers were not as in the previous post, A pain getting it back together but still not functioning. Any way why should i even be doing this?

[tima01864]

[quote="tima01864"]If I put pessrue on the piston with a screwdriver they will function correctly, So I opened it up and positioned the Bellville washers as in another post. The washers were not as in the previous post, A pain getting it back together but still not functioning. Any way why should i even be doing this?

[spider2081]

Have you talked to the vendor you purchased them from ??

[tima01864]

They are a year old now with a thousand miles on them. I am not even sure they are not functioning correctly. All I have to go on is how the old calipers are working, And about the washers and a non functioning e brake. The piston does move with tha actuator, Forwrad and then recedes, Maybe a 1/4 inch, not adjusting to the pad. I got the e brake to hold but only for a few miles to pass inspection. The best I could do is take them to a FIAT mechanic and have them evaluated. So that i am sure

[18Fiatsandcounting]

From the above info, it sounds like the e-brake actuator is moving the piston outward, but not far to press against the rear pads enough to sufficient "clamping". That sounds to me like either the emergency brake cable is way out of adjustment, or the self-adjustment mechanism inside the pistons isn't working right.

If you raise one rear wheel off the ground and spin it and then push on that 2 inch lever on the base of the rear caliper, does moving this lever (perhaps using a pair of large pliers) have any effect on the spinning tire? How about the other rear wheel?

If actuating the emergency brake lever by hand on each side right at the caliper stops the spinning wheel, then the problem could simply be an issue with the emergency brake cable.

-Bryan

[tima01864]

Maybe, I adjusted the cable with the hand brake lever. Removed the slack on the cable and pumped the brakes. Then two clicks on the lever and tightened the cable mechanism until the car would not roll. Put it in gear and adjusted again until the car would hold in first. After driving a few miles it stopped working. Hate to be a PIA but should the piston push (screw) forward with each movement of the lever?

[18Fiatsandcounting]

I would have adjusted the cable a little differently, but I think your method would work as well. The emergency brakes shouldn't stop working just like that, so it sounds like your emergency brake cable, or its housing, stretched or slipped out of one of the holder fittings. I'd check that the cable and housing are all connected where they should be. Both ends of the housing on each side should be in their fitting: towards the front of the car, it's a metal bracket welded to the underside of the body, and towards the rear of the car, the cable housing should fit in the round "barrel" that is attached to the caliper.

If both ends of the cable housing are not where they should be, on both sides of the car, the emergency brake won't work right.

-Bryan

[18Fiatsandcounting]

PS. The way I adjust the emergency brake cable, not necessarily ideal but it's always worked: Get the hydraulic brake circuits all working as they should. Fully release the emergency brake lever in the car. Put the rear of the car up on jack stands, and tighten the two 13mm nuts on the threaded rod that the cable goes through, until you feel a slight resistance to turning the rear wheels. Pull on the cable occasionally to make sure that the cable in centering between both left and right sides. Once you feel a slight resistance that is equal on both sides, back off the nuts slightly until no more resistance, and tighten the two nuts against each other. Pull up on the brake lever in the car, one click at a time, and both wheels should become hard to turn at the same time. If it takes more than 1 or 2 clicks before the wheels are hard to turn, tighten the nuts some more. Lower the car, start the engine, and with the emergency brake lever pulled up 3 or 4 clicks (maybe 5, I forget), it should be noticeably hard to move the car even in first gear.

-Bryan

[tima01864]

All, as you say, mechanically is in order. I will give it another go. But should the piston push while not under load as i tried to describe? Thanks for the help Bryan.

[18Fiatsandcounting]

Tim, I'm not sure what you mean by "push while not under load". The piston will push out of the caliper through due to the pressure of hydraulic fluid behind the piston, or because the emergency brake actuator rod is pushing against the underside of the piston. Moving the piston outward compresses the brake pads against the rotor, which stops the car.

If the caliper is out on your workbench (that is, with no brake pads to stop the piston), working the actuator lever should move the piston outward just slightly, but then it should return to the original position when you release the rod. The piston should not be slowly forced out of the caliper just because you operate the lever over and over.

-Bryan

[tima01864]

Okay then, My new calipers are functioning correctly and the old ones are not.

[18Fiatsandcounting]

I have to admit I'm kinda stumped on this one. One more question, though: Does the inside of the piston for the new calipers contain all the necessary parts, the parts that go around the threded actuator rod that does through the Belleville washers and is operated by the emergency brake lever outside the boot on the caliper?

Inside that piston, there should be a circlip, a retainer plate (round but with two flat sides if I recall), a "nut" (what the actuator rod screws into), and a coiled spring between this nut and the underside of the piston.

-Bryan

[tima01864]

I did not remove the innards, Lacking retaining ring pliers( in my tool box at work). But visually it looks as you describe. I will go further and take that apart. I am working with a new "extra" caliper I have, not on the Spider, So I am not grounding the car. I am thinking now that the old piston is not moving freely so that is why it does not retract as you say or as the new one does. So I will take out the old piston and clean it up and then see how it functions. Sound like a plan?

[18Fiatsandcounting]

Yep, sounds like a plan! Figure out how the old one works (and what was wrong with it) and then compare to the new one.

-Bryan