Handbrake not working after rear caliper rebuild

[bobthecabbage]

Originally Posted by ww1dm1

There is a limiter for both the minimum position and the maximum. I attached a random picture off the internet (look at the angle depicted in bottom right). In that one the lever is sitting at the minimum position, touching one part of itself to the caliper body. If you turn it, it will eventually hit the caliper with the part where the spring is held - it reaches it's maximum position. As I mentioned, this probably shouldn't happen normally, but happens in my case if I engage the handbrake as far as I can.

The lever sits nicely near the minimum position stop when the handbrake is released, so I don't believe any tensioning is needed. Balancing - maybe, as the sides don't engage at the same time, but it should hold anyways as eventually both sides max out.


You had the same problem? I can only decipher ATF as automatic transmission fluid.

Okay, I couldn't see a stop in my minds eye. Its been a while since I fitted mine.

Are they within 1mm when the handbrake is released? You shouldn't be able to get anything thicker than a hacksaw blade between the lever and the stop in its at rest position. If not then it won't self adjust, no matter what you do. Sounds like you may have to back off the handbrake nut to lengthen the cables slightly. There is no facility to balance them, there is a balancing bar but it goes where it wants to. The only way to balance them is let both sides self adjust at the calliper. (if they are way off with the same travel on both levers then its new cable time)

The only thing left to do is to work through it, perhaps starting with 'resetting the handbrake mechanism' on the calliper. Then as long as those levers are just touching their stops, it should all be fine.

[ww1dm1]

Originally Posted by bobthecabbage

Okay, I couldn't see a stop in my minds eye. Its been a while since I fitted mine.

Are they within 1mm when the handbrake is released? You shouldn't be able to get anything thicker than a hacksaw blade between the lever and the stop in its at rest position. If not then it won't self adjust, no matter what you do. Sounds like you may have to back off the handbrake nut to lengthen the cables slightly. There is no facility to balance them, there is a balancing bar but it goes where it wants to. The only way to balance them is let both sides self adjust at the calliper. (if they are way off with the same travel on both levers then its new cable time)

The only thing left to do is to work through it, perhaps starting with 'resetting the handbrake mechanism' on the calliper. Then as long as those levers are just touching their stops, it should all be fine.

Alright, no balancing then. In that case one side engages before the other probably because one of them gets a little work and actually grabs the pad, while the other is completely loose.

They are within 1mm of the stop, but I put the arms on in such a way that they would be there at rest, there is no other reference. The cable is almost tight at rest, I'll do the final tightening with the nut after I get the handbrake to actually hold something.

[ITSv40]

As far as adjusting the handbrake cables is concerned: the handbrake levers should be on the stops when the handbrake is in the off position. Adjust the nut under the handbrake lever so that the handbrake holds at the 5th notch on the handbrake ratchet. Double check that the levers are still on the stops when the handbrake is off, job done.

This thread proves how complicated the rear callipers are and how easy it is to chase your tail in resolving issues.

Personally, I would start from scratch and rebuild both callipers, following the guide and advice on here. Fit them to the car, bleed and then operate the handbrake levers with a lever to check that both sides are working. Then connect the cables and adjust those last. It is the only way to ensure everything is as it should be.

[druid]

Originally Posted by ww1dm1

You had the same problem? I can only decipher ATF as automatic transmission fluid.

In this case ATF is ALL TO F@@K

[bobthecabbage]

Maybe we are approaching the root of the problem.

So the handbrake levers have been off for the strip down and there is no reference for re-fitting them (I'm assuming)? I think this maybe your problem.

I'm wondering if there is a proper procedure to reset everything to its start point.

Something like winding the piston all the way in and turning the bit the lever bolts on to, backwards till you feel resistance and then bolting it on there so that it is sitting on the stop.

There must be a setting procedure along these lines I would have thought.

Anyone know what it is?

[ww1dm1]

Originally Posted by bobthecabbage

Maybe we are approaching the root of the problem.

So the handbrake levers have been off for the strip down and there is no reference for re-fitting them (I'm assuming)? I think this maybe your problem.

I'm wondering if there is a proper procedure to reset everything to its start point.

Something like winding the piston all the way in and turning the bit the lever bolts on to, backwards till you feel resistance and then bolting it on there so that it is sitting on the stop.

There must be a setting procedure along these lines I would have thought.

Anyone know what it is?

I'm still thinking the problem is the piston lash that wasn't cleared properly after a rebuild. I just fit the levers to be as close to the stops as possible, as normally when the handbrake is released that's where they should be (assuming the caliper does not stick, but a rebuilt one doesn't).

[ww1dm1]

Finally found the time to hit the garage!

Turns out there were two problems. One side started working properly after fully screwing in the piston, screwing it out approximately to the pads and not touching the handbrake mechanism until everything was fitted, bled and the piston was in it's normal position. I remember messing around with the handbrake arm on the caliper many times after the rebuild to make sure it's working, and now I realize that I shouldn't have. This placed the piston in a very disadvantageous position in relation to the handbrake mechanism. Even pulling the caliper arm all the way to the stop didn't clear the lash to squeeze the pads, so the handbrake didn't hold.

Sadly, this wasn't enough for the other side. It started working a little better after doing the same procedure, but it behaved oddly - pulling the handbrake slowly felt as it's engaging and then it suddenly released again, reducing the force needed to pull and going all the way again. It felt as if the handbrake mechanism squeezes the pads and then pops out of place from the excessive force. So I disassembled the caliper again to see what's up and turns out the handbrake mechanism retaining ring wasn't placed in it's groove. And it was obvious why - I just couldn't do it with the special pliers alone. It wouldn't go deep enough no matter how much I tried for some reason, as if the mechanism was unable to go as deep as it should in the bore. I ended up hammering the ring into the groove after placing it as deep as I could with the pliers. I'm still not 100% sure if all of the ring is sitting nicely in the groove (I could clearly see that the part with the holes was, but not sure entirely about the other side), but after doing this and the same procedure as with the first caliper - the handbrake works like a champ!

So basically, the x40 handbrake is not as simple as it seems. Use the reset procedure bobthecabbage posted if you messed with it after removing the caliper and make sure you put those rings all the way in if you had removed the handbrake mechanism during a rebuild.

Thanks for everyone who contributed, I'm off now for some FWD handbrake drifting on the snow!

[anmu]

An extra comment from my experience with these rear calipers. Handbrake cables very out of balnce, and I suspected a stuck piston. Bought a rebuild kit including new piston, and took the suspect caliper apart. Top of piston a bit rusty, but everything came apart easily and looked fine on the sliding surfaces - definitely not stuck. The new piston did not have the internal threaded socket fitted (some do, some don't). So I went to remove the relevant bits from the old one, and that's when I found the problem. Had to use a torch to free the parts, and it turned out there was a small patch of rust between the end of the socket and the bottom of the inside of the piston. Just enough to stop it turning, and so prevent the handbrake adjustment taking up the slack. Cleaned it up, new seals, and everything is working as it should. I've had problems with loose handbrake cables before on another V40, and always thought it was dirt in the lever mechanism. Now I wonder...