[Langley968]

I went out in the 968 for a nice Sunday evening drive with the wife and we ended up getting home with the car on a flat bed! [img]style_emoticons/<#EMO_DIR#>/mad.gif[/img]
We were cruising on the freeway when suddenly there was some loud grinding noise and it felt as if the E-Brake locked up. Luckily no one was following us too closely so I was able to quickly pull over. Once on the shoulder I noticed that if I moved forward there were grinding noises. I would back up a little and after a few feet it also would grind and lock up. When testing the E-Brake handle I noticed that there was no resistance left. A few miles earlier (at much lower speed) we heard a sound like a metal "clunk". I slowed down and listened but there did not seem to be any more noises so we carried on. I thought it might have been something bouncing up and hitting the underside of the car (wishful thinking).
I have searched through the Forum but have not been able to locate any previous posting that describes any type of E-Brake (Hand Brake / Emergency Brake) failure.

I just read this out to my wife and she says that the noise seemed to come from the right rear wheel (?).

Looking forward to some insight! [img]style_emoticons/<#EMO_DIR#>/dry.gif[/img]

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[firefish]

It is more than a P-brake than E-brake. I know of a couple of failures that can be addressed to using the parking brake on the go.

Checking it is however easy. Simply pull the wheel and remove caliper and brake disc. The calipers have hard lines to the so be gentle not to crack or bend them. Hopefully there will be no internal damage and all that is necessary will be to fit new brake parts. You can remove the damaged parts and re-assemble the car so it's driveable but you have to remove EVERYTHING and secure the cables.

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[Monstrous4Banger]

What he said. Its inside the right rear rotor. Sometimes the springs break. Youll see when you open it up.

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[flash]

my bet is the retaining pin on the shoe - those things snap

it is definitely a parking brake and not an emergency brake

rule 1: NEVER move the car with parking brake engaged - not one inch - forgetting about this will lead to the pin snapping

rule 2: do not engage the parking brake when the brakes are hot

rule 3: don't use the parking brake unless you have to (i.e. a slope) - just leave it in first if you can

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[968 GUY]

with the problems I have heard about starters suddenly engaging, I always engage the parking brake. If not on a hill, I take the 6- speed and the 951 out of gear. Just went through the brake systems on all 3 cars. Inspected and maintainenced the park brake, found nothing wrong though. There are two phillips head screws holding each rotor, make sure to reinstall them.

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[flash]

the starter wiring degradation is an issue to be sure - it is amazing at how many cars have that problem, and people don't know it, because you cannot see it upon inspection because it lives inside a sheath with another wire - when that wiring goes, the starter engages by itself - i saw it happen a few weeks ago - very scary stuff

however, that shouldn't mean that you do what we have all known to be a bad idea for decades

engaging the parking brake while hot forces heated metal to be pushed outward and then cool in that position - this causes balance issues - in the days of drum brakes, it also causes rear braking issues

if you let the brakes cool first, and don't forget to release the brake before you move, then there is no problem with using the parking brake - however, like many, i am forgetful - i've snapped that pin myself, and gotten stuck just like langley

pick your poison i suppose

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[Langley968]

Wow - you guys never sleep! Thanks for the feedback.
Although I was dressed for work already, I just had to go out there and remove the right/rear wheel.
A word of advice to: <b>NEVER jack the car up WITHOUT blocking the tires!</b> In my rush I forgot to block the tires but I had placed some wood underneath the rear axle (made sure it was not in the way of any lines/wires). Before I had a chance to rest the axle on the blocks, it rolled forward off the jack and was saved by the blocks. [img]style_emoticons/<#EMO_DIR#>/ohmy.gif[/img] And my driveway is completely FLAT!
I did quickly look at the brake caliper, but other than a strong odor, I was not able to detect anything visually. I will pull it off after work. I will post again after that.

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[968 GUY]

most people just drive normally and don't heat up the brakes to the melting point. I am sure that if there had been a problem with heat issues from just driving around town and having the rotors warp from setting the parking brake, it would have shown up. Older drum brakes are much larger in diameter and proportionally thinner than the internal park brake on the disc cars.

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[flash]

the rotors don't warp - there is a drum brake inside - that surface can deform - it isn't a lot but it does do it if you repeatedly engage the parking brake when the rotor is more than 250 degrees, which is well below the melting point

you can tell it's happening if when you go to release the brake it "pops" like it was stuck - eventually that deformation results in balance issues, albeit small

the real risk is moving the car with the brake engaged

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[Monstrous4Banger]

Langley: Youll have to take the rotor off, and caliper, its a drum brake inside the rotor. Things, break or get disconnected in there, it happens. Hopefully, it hasnt scored the inside of the rotor.

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[rxter]

The spring on my was shot at 90K miles. Both pads were cracked and one was missing a chunk. Replaced it when I had the rotors replaced.

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[Scott Collins]

I had a similar event on my '87 944. I had about 90k miles at the time.

I was doing about 45mph and the right rear locked. The report was that one of the springs holding things together failed. It was like an impact. [img]style_emoticons/<#EMO_DIR#>/ohmy.gif[/img] You always imagine a $10,000 repair for stuff like this.

Bent the right rear trailing arm from the sudden force, which required me to get a rebuilt one from 944Ecology. Inside the hub, it was like a food processor just shredded the metal components. I drove the car home, sounding like a running washing machine with steel ball bearings inside. My "fun-o-meter" went way down on this job, which I did myself. [img]style_emoticons/<#EMO_DIR#>/dry.gif[/img] Those trailing arms are heavy. [img]style_emoticons/<#EMO_DIR#>/mad.gif[/img]

Best of luck.

-Scott

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[flash]

holy chain reactions batman!

i think things could only be worse if your rear diff blew because your cigarette lighter shorted, while you were on the phone, changing radio stations, resulting in a sudden short in the heater, causing you to lurch forward during a shift to sort out the problem, meanwhile your clutch blew and you jammed hard on the shifter, stuffing it into reverse

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[Scott Collins]

while you are trying to roll back the odometer to disguise the parking attendants joyride, then it slides off the jack and crashes through the glass and hits the ground after a 25' drop. Bueller!

http://www.youtube.com/watch?v=JRBgoIIhfJM

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[Langley968]

I pulled the right/rear drum off after supper and there was the answer. [img]style_emoticons/<#EMO_DIR#>/mellow.gif[/img] I will post a picture tomorrow of the parts. It was not as bad as I had imagined. It seems that one (or both) of the smaller "Compression Springs" snapped (that's what the PORSCHE Parts List calls it / an on-line parts source calls it a "Pressure Spring" - they seem to hold the brake pads laterally in position). The "Supporting Plate" is completely mangled. The slotted head of the "Adjusting Screw" is almost split wide open. The pads are damaged, but they also show their age, so its good they get replaced. The "Expanding Bow" seams to be OK. The P-Brake cable end is also damaged, so that section will also need to be replaced. I figure that it will cost ~$200 -$250 in parts. I might as well order all new springs for both sides.

I agree with Scott, that from the sound you "imagine a $10,000 repair"! It was a horrible feeling when the grinding started and I lost momentum. It sure was good that I had no "tailgaters" at that moment. [img]style_emoticons/<#EMO_DIR#>/ohmy.gif[/img]

Thanks also to the posted tip about being careful with the hard brake lines. I was able to get the caliper loose and rest it on a block while I pulled the mess out.

<b>QUESTION: Can I safely drive with the guts missing from the right side while the left side is left untouched till the parts arrive? </b>

I must confess that after I put things together and had taken a shower, I just had to get in and drive a few blocks before putting the 968 away. It was a good thing, because I needed some "feel good" time with the car again! I am also hoping to go on the Breakfast Run this Saturday morning and I am not sure if the parts will be here before then OR if I will have time to do the replacement.

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[Monstrous4Banger]

"Compression Springs" snapped (that's what the PORSCHE Parts List calls it / an on-line parts source calls it a "Pressure Spring" - they seem to hold the brake pads laterally in position).

Yep, thats the ones.

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[Scott Collins]

Langley,

I drove around for about 2 weeks while I waited for my replacement trailing arm with new hub and wheel bearings. I had no problems. I just tied up the loose cable that would have activated the parking brake on the right rear and it was fine.

I got all new springs afterward to prevent it from happening again, and had the car for at least another year with no problems. Good luck.

-Scott

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[DaveN]

I'm glad/sad someone has these problems. I was unaware of this hidden Genie waiting to be rubbed. I have it on my list of MUST check items now.

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[flash]

that's exactly why this site exists - i love it when it works like that

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[Langley968]

The end of the P-Brake cable @ the right/passenger side P-Brake drum is broken.
Does that mean that I need to order the "Parking Brake cable - long" (#951 424 072 02)? [img]style_emoticons/<#EMO_DIR#>/dry.gif[/img]

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