Parking Brake acting up

[BigMacDave]

Hello all,

I have a weird situation, and before i start going all tear it apart happy, i wanted to get some input.

My parking brake doesn't seems to want to work

Ok, so what i mean is, with the handle all the way up and locked, the mechanical part on the caliper squeezed tight, i can still rotate the tires. When i am under the car and have someone pull on the handle, i can see the cable pull the mechanical parts forward all the way on the caliper (rubber boot fully compressed) and yet the wheels have zero drag or lock on them like it isn't even engaged.

The brakes work fine so i know the hydraulic parts is ok.

what can i look at or adjust without taking the caliper and everything off

Thank you,

David

[spidernut]

You need to adjust the cable tension. The emergency brake cable pulls on the levers built into the rear calipers. If the cable tension is not properly adjusted, the cable fails to pull the levers far enough to actuate the piston which presses the brake pads against the rotor. The travel in the emergency brake mechanism is very minimal, so it is critical that the tension is adjusted correctly.

[BigMacDave]

I'm not sure where that would be. I can post picture later, but if you are looking at the back of the caliper where the cable terminates, when i pull up on the handle, that lever (on the back of the caliper) pulls at the way forward. It can not move any more or get any tighter, the pivot that moves (the very end of the cable is attached to it) and the holding bracket (next to the very end of the cable) almost touch each other when you pull up on the handle. in that position it looks like the brake should be super tight.

Thats why I'm puzzled because i would think if the piston isn't moving, then the hydraulic portion would also not be working, but the brakes work as they should. Its almost like the mechanical pin inside is frozen and not pushing, but its doing it on both sides so its a head scratcher for sure

[azruss]

have you had your rear calipers apart. There is a steel wedge that is pushed when the e-brake is applied. It sits in a asymmetrical slot. Your activator arm may have worn pivot holes. The wedge may be missing, worn, or installed backward.

[spidernut]

Your handbrake lever should not pull "all the way up". From underneath the car, you can see the emergency brake cable and how it is connected to the rod coming from the e-brake handle. There's a nut on a curved bracket that adjusts the cable tension. Simply tighten the nut until the handbrake stops at about a 30 degree angle when pulled upwards. Check out this thread because it has photos:
http://www.fiatspider.com/f15/viewtopic.php?t=15755

The lever on the rear caliper should not pull all the way forward. It normally will lift no more than a 30 degree angle.

If the lever pulls up more than that, it means either:
1. E-brake cable tension is not adjusted properly
2. Brake pads are worn out
3. You need new brake calipers in the rear

[BigMacDave]

Thank you all,

I 100% know its not the cable. I can pull on the handle and see the cable pull on both of the calipers evenly and together. When i say all the way up, i mean with the handle in the up position the mechanical part of the brakes has moved forward to the position that the brake should be engaged and tight. Im starting to think the PO might have done something with the little pin behind the lever. since they both act the same way and the hydraulic portion works great.

Im gonna take them off and bench test them and see what happens when i engage the e-brake since its purely mechanical, before i tear them open. If i don't see the piston move, then i know that pin is either missing or bent or in backwards or something crazy. Remans are only 65 on rockauto so its not the end of the world, but if i can simple fix it thats always better. Maybe the PO didn't even realize it has never worked right.

Ill post more when i see for sure. maybe it will help someone else down the road.

David

[spidernut]

Just so you know, about 1/2 of the rear calipers are rebuilt incorrectly per a local Fiat mechanic. Bench testing them will clearly indicate if they're working or not.

The pistons in the rear brake calipers screw in and out versus push in and out like the front ones. If they were screwed in too far, the brake pads won't contact the rotor when the e-brake is pulled. You may just need to adjust them.

[BigMacDave]

Just so you know, about 1/2 of the rear calipers are rebuilt incorrectly per a local Fiat mechanic. Bench testing them will clearly indicate if they're working or not.

The pistons in the rear brake calipers screw in and out versus push in and out like the front ones. If they were screwed in too far, the brake pads won't contact the rotor when the e-brake is pulled. You may just need to adjust them.

Thank you for that tip. So on that note, when i have it secured on the bench, and squeeze the "puller" (for lack of a better word) or very end of the cable mounting spot on the caliper, i expecting to either see or not see the piston move even if its slightly. Are you saying the piston might be too far screwed back and that would cause it not to come out enough to engage? Part two would be, would that also indicate that the hydraulics are not really working right and they are simply pulling the outer pad in instead of squeezing with sides? I have no clue what i am about to see, but I'm pretty sure thats where my issue is, only because when I'm under the car and have my helper pull the hand brake, i can see the both the "pullers" (again for lack of a better word), pull in unison and go as far forward or close to the cable holding bracket on the caliper as it will go. But have no effect on the wheels.

Thank you

[micbrody]

(From my memory):
My right rear brake hydraulically works fine; but the emergency lever never moved to piston. The reason was the wedge (called a pawl) was missing.

The pawl essentially transmits the lever arm tension from the cable to a push rod that mechanically pushes piston.
If your hydraulics part of caliper works, then there shouldn’t be an issue as to needing to screw/unscrew piston

[BigMacDave]

ok, i have one of the calipers off and on the bench.

things i notice:

if i pull the dust shield back and watch the mechanism as i push on the spot where the cable would pull on, i can see that part turn and the wedge or pawl push forward in the cylinder area. it goes about 1/8-1/4 inward. I assume that is the action that pushes the piston out.

when i do that action, the piston does not move at all. not even budge.


before i take the whole think apart, is there some way to test see whats what? the seals are good, i don't see ant leaking. however i can not turn the piston (not sure if should be able to) but it feels very "stuck"

[spidernut]

The piston will be hard to remove when you screw it out, but it should move. You may have frozen pistons.

[tima01864]

Did you ever find an answer why the e-brake was not working?

[DieselSpider]

ok, i have one of the calipers off and on the bench.

things i notice:

if i pull the dust shield back and watch the mechanism as i push on the spot where the cable would pull on, i can see that part turn and the wedge or pawl push forward in the cylinder area. it goes about 1/8-1/4 inward. I assume that is the action that pushes the piston out.

when i do that action, the piston does not move at all. not even budge.


before i take the whole think apart, is there some way to test see whats what? the seals are good, i don't see ant leaking. however i can not turn the piston (not sure if should be able to) but it feels very "stuck"

If its stuck that bad then the self adjusters likely will not work. Few people give the self adjusting mechanism and its clutch any attention when they rebuild a caliper since its all hidden inside the piston. When you take the piston apart you may find it all rusted and gummed up inside which is a condition that doing the mandatory but often missed brake flush every 2 years helps prevent.

Its all about maintenance.

[Glacier]

I also have same issue. All brakes working good (and evenly) -> hydraulic is ok. Handbrake is affecting to cam lever and those are rotating evenly on both sides. Not stuck at all, possible to turn by hand. Handbrake doesn’t work on passenger side but works on driver side.

It would have been interesting to know if for starter of this thread problem was found or not.

Edit after opening things:
pawl is in, well creased. Piston is in correct position.

Tried to tighten piston by rotating it in, I left it in correct position. Put everything on and started car. Pressed pedal few times and readjusted handbrake. I made a bit too tight for driver side and it’s still not working properly on passenger side. It just started to break, not breaking fully.

What should I try next?

Videos explaining a bit more,
Video 1: https://youtu.be/0gkJfzpBSCs
Video 2: https://youtu.be/Xtd6e4ndZWc

ps. All parts look like new, those have been changed by previous owner.

[18Fiatsandcounting]

What should I try next?

Here's a little trick that I figured out, and sometimes it helps (and sometimes not). Make sure when you pull the handbrake lever up that both levers on the rear calipers are rotating as they should, although it sounds like you have done this. Sit in the car (engine off), and alternately press the brake pedal and pull up on the handbrake lever, then release both, many, many times. Don't just do this several times, but I mean do it for a least a hundred times and perhaps two hundred. Continue until until you are cursing the name of this "18Fiatsandcounting" idiot.

If the self-adjusting mechanism is working even the slightest little bit, sometimes this helps move it into position and fixes the problem. Or at least improves things. Let us know if this helps and we can go from there.

-Bryan