1. A Spooky Ghost

    A Spooky Ghost Loyal Comrade

    Have any of you trabbi folks had the rear brakes slowly lock up at speed?

    I thought the car was running different / low on power for the past few days. So for what ever reason, I decided a good run at 70 mph on the interstate would sort things out...

    I kept going slower, and slower- then saw a tremendous amount of smoke out the back. Then I realized it wasn't the engine grenading- but the rear drums almost on fire!

    So there I am, standing on the interstate, under a trabant. Anyway, I noticed the brake lights were on, and the brake pedal was firm, and could not be pushed at all. So a idea hit me,

    I panicklly found a ddr wrench in the trunk, and opened the rear brake line on the master cylinder. It shot out every where, and the brakes were free.

    Without even touching the middle pedal, I proceeded to go 70+ mph to the next exit.

    Wasn't sure anything would happen when I stepped on it, well since I'm typing this- it stopped well enough to get me home.

    So the issue is somewhere near/ or at the master cylinder.

    The car has has within the last 3000km's a full brake system done, new cylinders hoses, pipes, shoes, master cylinder.

    Never had this happen on ANY other car.

    Maybe something was in the line, and blocked it from returning? Or the M/C cap is not venting?
  2. turbofiat124

    turbofiat124 Premium Member Forum Donor

    You don't think your handbrake cables were sticking?

    I had a weird braking issue with my Trabant. One day I pulled out of my driveway and when I hit the brakes, the pedal went to the floor! The next time I hit the brakes, the pedal travel was perfectly fine.

    Needless to say I replaced the master cylinder thinking there was something wrong with it. The Trabant master cylinder has these ball bearings that fit below the ports that goes to the reservoir. I thought these were check valves but they act as "stoppers". Or they limit the pedal travel.

    If you ever take one of these apart. Be sure to install the ram before installing these balls. I'm wondering if there is crud or something inside the MS that caused the rear brakes to stick.

    Also worth noting. If you ever need hose that runs from the reservoir to the master cylinder. I believe it's 9 mm. BMW clutch reservoir blue cloth braided 8 mm hose is not tight enough. I found some clear poly tubing at Lowes that works. It's some weird size. It's either 11/32 or 23/64. There is nothing in Imperial between those two sizes that equals 9 mm perfectly.

    The rear driver's side brake sticks on me from time to time. But I think I know what is causing it. I try not to engage the parking brake unless I absolutely have to, like on a hill. Occasionally I will forget and engage the hand brake while the car is parked in my garage. If the park brake is engaged for more than a week, it can cause that particular brake to stick.

    The fix is to just work the handbrake several times and check to make sure the car will roll afterwards.

    When I redid the brakes on my car, the cables felt sticky. I removed them and sprayed WD-40 into the sleeves and worked the cables to free up any dried grease. Then sprayed some graphite based lubricant I have called Kano Penephite.
  3. A Spooky Ghost

    A Spooky Ghost Loyal Comrade

    The e brake lever was the first thing I checked. The pedal was stuck on... When I cracked open the rear line(on the master cylinder) fluid shot out, and I could roll the car. I'm hoping there was a little piece of something in the line( like red rubber grease that worked its way up there!).

    I'm going to look at the rear shoes, I probably fried them- still have another new spare set. Either way I'm going to bleed each line several times, and look for odd crap out of the fluid. Could have been something simple as a flake of rubber from a wheel cylinder- clogging a port.
  4. trondd

    trondd Loyal Comrade

    Could be a failing rubber hose. They can hold pressure when they swell inside, or be shedding bits into the fluid.
  5. turbofiat124

    turbofiat124 Premium Member Forum Donor

    I forgot to mention something. You said your brake lights were on when this happened. A few years ago I came out to my garage (it was in the middle of summer and my garage was above 95 F) and noticed my brake lights were on. The wiring was getting hot. So they had to have been on for quite some time. I hit the brake pedal and the lights went off but the next day they had kicked on again at some time. I thought it was the heat inside the garage causing the brake fluid to expand in conjunction with a faulty switch.

    I had ordered a spare brake light switch. The new switch I had ordered did the same thing the next day!

    Out of paranoia, I moved the brake light wire to the adjacent fuse. That way the brakes only function when the ignition switch is on.

    I found out that AutoZone sells these brake light switches. They are the same for a VW Type 1, 10 mm thread.

    So I went to AutoZone and bought another a switch. This switch seemed to last a couple of years but noticed one day my brake lights were on once more. Seems like this time it was after driving the car and this time the lights would not go off.

    So I replaced the switch one more time. I think I am on my third switch. To the best of my knowledge this switch is still working. I'm thinking prior to the third switch, I replaced the master cylinder.

    The next switch I plan on trying is one that screws into the master cylinder which breaks the cruise control function on a Ford truck (example 1996 Ford Explorer, 2002 F-150). To the best of my knowledge, it's 10 mm as well.

    I should know this but can't remember right off hand but I think there is a single rear brake hose that feeds both rear wheels. This hose screws into a junction then hard lines runs to each wheel.

    That hose maybe collapsing internally causing the rear brakes to lock up.

    I've had a hoses on my Fiat Spider do this as well as my Chevy van. Usually this just happens to the front hoses since they are always twisting. Can't say I've ever had this happen to a rear hose. The rear hose on my Fairlane was on there for almost 30 years before I replaced it and it was just because it was old. I've replaced the front hoses on my Fiat Spider two or three times but the rear hoses have been on there for 20+ years.
  6. A Spooky Ghost

    A Spooky Ghost Loyal Comrade

    I'm starting to wonder if the 100F temp, plus barreling down the interstate- had anything to do with it. It seemed they were being slowly applied more, and more- the farther I drove. Never hit the pedal during any of this either.

    Will update soon with my results.
  7. A Spooky Ghost

    A Spooky Ghost Loyal Comrade

    Had a look at the rear drums. Both sides look as if nothing bad happened, shoes have no cracks- or excessive wear marks. Maybe a bit glossed over though.

    Now the RR side needs new bearings( was the only ones I didn't replace....). Have some coming Sunday, no way this caused both sides to lock- with the pedal having pressure.

    Even after bleeding the brakes, the pedal feels a bit nothcy. Me thinks it fried the rear shoe adjusters. You can here a clicking in the back wheels now, like the adjusters are moving out, and not holding back the other way.

    I just so happen to have 2 new adjusters from a recent order, but not enough for both sides...

    Also it seems that ignition tone wheel has once again come out of perfect timing( the hole in the middle is worn out), and the trans is leaking from the drain plugs.

    Lastly I imagine the head bolts have once again back out loose a little bit. Replaced two with SAE bolts, and a crap load of washers...

    The spring is still working on the pedal too.

    So my only ideas are:


    On the RR swing arm, the brake hose didn't quite fit right( like it was too long). It is not at the best angle, and maybe it is kinking weirdly- really doesn't explain pedal- with lights- being stuck on though.

    When bleeding this side, fluid shot out- without toughing the pedal. Probably due to the bad brake adjusters letting the spring pressure off.


    Maybe a spring in the mastercylinder bore became stuck, or broke causing it to stick on.

    3: Some junk is in the cylinder ports

    4:I don't think they were all that tightly applied, from the way things look. Just the heat, and friction stopped the car. Maybe they have been dragging a bit already?

    5: Of course the best for last

    It's Haunted! :eek:
  8. A Spooky Ghost

    A Spooky Ghost Loyal Comrade

  9. turbofiat124

    turbofiat124 Premium Member Forum Donor

    I didn't think of this since you said it was just the rear brakes that locked up.

    A friend of mine reported this happening to him with his Fiat Spider Except in his case, he said all four wheels locked up. This happened after messing with the pedal free play.

    When you get a new MS, it comes with instructions on adjusting the free play. He said he adjusted the free play shortly before this happened.

    I've never messed with the free play . The pedal on my Spider stops about 1" from the floor. I figure as long as it doesn't go all the way to the floor, not to worry about it.
  10. A Spooky Ghost

    A Spooky Ghost Loyal Comrade

    Checked the MC rod, it was pressing on it, while at rest. So that explains why the brake lights were on, when it seized up.. I think it broke something inside of it though, more than just a seal.

    Also me e-brake cables are free, but they may be causing a bit of drag.

    Seems a order from Germany is in order. Getting to be a trend.:p
  11. A Spooky Ghost

    A Spooky Ghost Loyal Comrade

    Been a few days since fixing it. So far, so good. No more brake lock ups. On my next parts order, I'll get a M/C rebuild kit. Should be easy- since it was a new unit...

    I did have to sand the drums, and shoe linings a bit after all of this mess. Had quite a nice glaze!

Share This Page