rear brake stuck when exposed to freezing overnight temps ?

[jack's lack]

So last week we had about 5 days with 20º F temps here in the SAV, which may not sound bad to most of you, but trust me it is quite unusual here.
After the first day of making my commute on my bicycle as usual and freezing my face off I decided to drive the rabbit instead.
I cycled the glow plugs a few times for good measure and it started right up. It puffed white smoke for about 30 seconds until it warmed up a bit, and off I went.

When I drove the car i noticed a fair amount of resistance like the e-brake didn't let go. When I got to work I held my hands near the rear brakes and only the left side was hot.
When I drove the car back home at lunch all was well. The mercury may have climbed to 40º by that time. Every freezing morning the problem persisted, however today we saw 60º temps, but they were calling for rain, so I drove and no problem.

The brake system is as follows: All work was done maybe 2 years ago.
22mm master cylinder from a MKIII w/ reservoir.
10.1" vented up front with slotted Brembo rotors & Hawk pads Girling calipers from a 16v rocco
16v rocco proportioning valves. I bent & flared all new hard lines and replaced the rubber with braided stainless steel
ATE super blue racing fluid bled with a micro vac
rears were converted to disks (eurospec kit) which included slotted and drilled solid rotors, generic pads, and MKIV calipers
I am using e-brake cables from a 16v rocco

so for the synopsis: left rear e-brake does not disengage only when overnight temps are below freezing. Ideas as to a cause/remedy would be greatly appreciated.

cheers,
Ryan

[8v-of-fury]

I am guessing you have a faulty cable. It is possible some water has gotten in to and is harboring inside the cable so that when you engage it after driving.. and it freezes over night.. it will not slide back through in the morning..

It is all I can come up with, short of the little lever that pushes the piston manually getting stuck?

[Vincent Waldon]

Where you using your emergency brake, or is the caliper sticking on its own?

Many folks in habituallu cold climates avoid the emergency brake in the winter since water can get into the cables all to easily.

Having said that, MK4 calipers have a reputation for sticking all on their own in cold weather...although it has never happened to me personally.

[RadoTD]

This happened to me last winter and will probably return once I start driving my car again. You'll have water in your ebrake lines, so when it freezes, it grabs onto the cable and the spring return on the caliper isn't strong enough to pull the cable back out.

Easy solution is to not put your ebrake on when it's cold out. I was carrying a piece of wood and hammer because it's easy to get at the lever that engages the ebrake and knock it back out. You should see the lever pretty quickly if you look at the caliper

[jack's lack]

Thanks all. We have seen a fair amount of rain here lately and it seemed like the cable was not moving when I put the e-brake handle down, so ice in the cable seems to be a likely culprit. I am not parked on a hill so I should be fine just leaving it in gear when it is cold out.

[R.O.R-2.0]

my bet is the cable has some water in it. vw cables are notorious about getting water in the cables where it joins up to the tubes that run in the body. i put a little silicone on the end of the cable that slides into the tube.

maybe try taking the cable off and working some oil thru it? i did it on my gti, and then it worked like a champ. the pass side brake caliper on the back used to stick a bit.

[Syncroincity]

Cables rust at the caliper and jam, also the caliper actuator arm siezes... I seem to be getting about 30K miles out of a set of rear calipers on my MKIII Jetta before they lock up and need replaced. Done it twice so far.

[R.O.R-2.0]

mine rusted at the body, not the caliper..

[jack's lack]

I rotated the tires yesterday so I took the opportunity to get a good look at what is going on. The e-brake seems to be returning just fine. I think part of the problem is that the scirocco cables are stretched to their limit to fit the rabbit, and as a result they are tight up against the rear axle beam and the fore of the trailing arm. At this point the rubber has been rubbed off of the cable so it is easy to see how water could get in there. Also the exhaust runs right over top of the same axle beam which could possibly have aided int the deterioration of the rubber, but on the other hand the hot exhaust pipe may aid in thawing the ice in the cable.  

I think the longterm solution is going to be to replace the cable and put some sacrificial material between the cable sleeve and the trailing arm.

[Vincent Waldon]

I think the longterm solution is going to be to replace the cable and put some sacrificial material between the cable sleeve and the trailing arm.

Yup... that's the money shot right there.

I have a short roll of rad hose in the garage... a short length slit up the middle gets ty-wrapped to every emergency brake cable I've ever installed.   Over time either that cable rubs against the trailing arm or takes enough hits from road gravel that the plastic coating breaks down.

I also tend to do a little bit of RTV where the metal end of the e-brake cable butts into the backing plate...dunno if it helps much but I figure it's one more water entrance point, so it can't hurt.  

[R.O.R-2.0]

my new cable i put on my GTI a while back had thicker sheathing anywhere it came in contact with something.. anywhere it rubbed the axle, it had a thick piece of plastic to rub thru before it even wore into the actual cable.