1. turbofiat124

    turbofiat124 Premium Member Forum Donor

    So I get my Trabbi out today for the first time in awhile since I've been caught up with my 2CV. I had to make a panic stop to avoid getting a red light ticket. So about 3 miles later I start smelling hot brake lining. I stopped and sure enough the rear driver's wheel is hot and smells. I fiddled with the parking brake and backed up tapping the brake pedal. I took off and all seems fine now. Is it possible the panic stop over adjusted the self adjuster?
  2. phi

    phi Loyal Comrade

    Sounds like a cylinder was stuck. I wonder how you managed to get it free again. Was there a certain noise when "unlocking" it?

    Take off the drum und try if you can move the brake cylinder there and back some millimeters smoothly.
  3. turbofiat124

    turbofiat124 Premium Member Forum Donor

    Well the brakes are perfectly fine now!

    I was taking my daughter to the playground when this happened. The brakes were even working fine before the panic stop occurred.

    I did use the parking brake while waiting for the red light to change (before the next red light when the panic stop occurred) which took about 5 minutes for the light to change. When I redid my brakes tw0 years ago, the cables seemed gummed up from old grease. I was pulling in and out on the cables while I had them disconnected from the drums.

    I sprayed WD-40 into the sleeves and pulled the the cables in and out until they felt free and I think I sprayed some Penephite (a graphite based grease) into the sleeves for lubricant.

    When I stopped after smelling the burned brakes I fiddled with the parking brake lever then reversed while tapping the brake pedal. I don't know why, this always adjusts the drum brakes American cars and works on our fork trucks at work that grab when they that get out of adjustment because some people never use the brakes! :D

    Maybe when I engaged the hand brake lever while waiting on the light to change, the cable going to that wheel stuck slightly?

    After I got to the park, I felt of the rear wheels and they felt uniform in temperature.

    Two hours later , got back in and I tested the brakes to see if they were sticking by letting out on the clutch on slight inclines and they were free.

    Got home and both rear wheels were fairly cool to the touch like the fronts and the car would roll back and fourth after giving it a little gas to see if the brakes were sticking. The rears on my Trabant always seems to run hotter than the fronts. I guess because they don't have cooling slots?

    My guess is the panic stop somehow caused the shoes to jam on that particular wheel. Or the parking brake had something to do with it.

    All seems fine now!
  4. RogerDerSchrauber

    RogerDerSchrauber Premium Member Forum Donor

    Trabis have self-adjusting brakes, just like American cars of that vintage, with a pawl adjustment that adjusts when you back up and hit the brake.
  5. Wartburg353W

    Wartburg353W Loyal Comrade

    I think the most likely scenario is a rough spot in that wheel cylinder "stuck" the piston when you hit the brakes so hard it moved to a position it hasn't touched in years. Luckily, it came unstuck and it may be ok for a long time as the rear brakes wear pretty slowly in general. On the other side of the coin flip of this story, I bought a Wartburg a couple years ago that had service brakes that worked fine but the parking brake did nothing. So I adjusted the cables a whole bunch and finally the left rear wheel would engage when I pulled the parking brake. Then after I drove it around the block a couple times that brake "stuck" repeatedly on the next short drive. I have not investigated the problem yet because the thing is not roadworthy anyway, but there's your mysterious link to using the parking brake and sticking brakes . . . . (Twilight Zone music).
  6. Keri

    Keri Leader

    Brake adjusters on a Trabant have nothing in common with American type self adjusters!
    Unlike the excessively complicated star wheel / lever system which only works when backing up, Trabant self-adjusters work anytime the brake is used.

    The adjuster had a rod in a holder, which is acted on by an angled lock piece and spring. Each shoe has its own adjuster.
    This works like a holder for a screen door, allowing travel in one direction, and stopping travel in reverse.

    By the way, the manual has a typo.... illustration (1) depicts a rear wheel brake adjuster, (2) is correctly labeled as a front. (4) would more accurately be called a "Lock Plate"

    Trabi Brake Adjuster 2a.png

    The brakes can "drag" if the slot in the shoe is too tight of a fit. It is supposed to have a clearance between the adjuster and shoe so the shoe can retract when the brakes are released.

    The gap shown below must be 0.3-0.45mm. If less, the brakes might drag, heat up and possibly lock up.

    Trabi Brake Adjuster1a.png

    Of course, a sticking wheel cylinder can also cause dragging, as can anything on the parking brake mechanism, on a rear wheel.
    RogerDerSchrauber likes this.
  7. turbofiat124

    turbofiat124 Premium Member Forum Donor

    I hope I am not having trouble issues with the brakes this soon. I just replaced everything but the drums two years ago.

    The driver's side rear brake caliper on my Fiat Spider would stick occasionally after the parking brake was applied. I could apply the hand brake while moving then release then it would be fine for another year.
    The funny is I have not touched the rear brakes in almost 20 years. The last known incident of this happening was about 16 years ago. It hasn't done it since.
  8. aardvark64

    aardvark64 Puttering Along

    It's best not to leave the little darlings parked up for long periods with the hand-brake on 'cos the rear wheel cylinders can seize. Leave it in gear and chock the wheels if you're going to lay up for the winter.

    On a related topic, my brake cylinder sprang a leak earlier this week. There's virtually no braking effect from the pedal and brake fluid widdles into the pocket in the bulkhead when you push the pedal. Seals have gone, the repair kit's on order. That's another job for the week-end (assuming the seals arrive in time). Ho hum.

    Never a dull moment with Trabants.
  9. turbofiat124

    turbofiat124 Premium Member Forum Donor

    If you live in the US, I actually have a seal kit for a wheel cylinder. I'm not sure why I bought it. I ended buying a brake kit and replacing all four wheel cylinders.

    The master cylinder is the trickiest thing I've ever seen to rebuild. I've rebuilt several Fiat/Yugo master cylinders but Trabant master cylinders are not something I want to mess with. One mistake is to not install the detent balls until the plunger is installed first. I think they limit the plunger travel. I thought they were some sort of check valves.

    The other thing is when I tried to install new seals in the plunger they were so tight, I broke a couple of them. Maybe the trick is to heat them up first with a hair dryer to swell them up a bit and/or place the plunger in the freezer to shrink it before installing them.

    I ended up buying a rebuilt master cylinder from Danzer (I think) because they did not require a core charge. All others wanted the old one back. Which is understandable but figured shipping the old one back to Germany would cost more than paying the core charge.
    aardvark64 likes this.
  10. Keri

    Keri Leader

    On the topic of sticking, corroded and leaking brake hydraulics;

    Change fluid regularly, like every year in a humid climate.

    Brand of fluid matters! Just because a fluid meets the DOT specification, does not mean it is equal to all others.
    In general, you get what you pay for.

    One of the factors is the lubricating additives, which extend life of moving parts, especially the seals.
    I have a simple test for these additives..... If the fluid spills on the floor and I almost fall on my rear, it is deemed "slippery enough". Inexpensive fluids are safe to walk on, even on a slippery shop floor.

    Expensive fluids, like "Toyota" branded brake fluid will land you on your rear in no time. This is what I use in my cars, including Comrade Trabi., Toyota DOT 3.

    Cheap fluids, like the "cheapest stuff at the parts store" are perfectly safe to walk on, and might be good for increasing traction on snow.

    Another factor to consider is that Trabant wheel cylinders have no effective outer seals. The plus side is that any accumulated water can dry off quickly when the brakes heat up, the minus side is that water can easily corrode the wheel cylindes and pistons if stored wet. A reasonable solution is to apply red rubber lube or other grease meant for brake hydraulics to the pistons and cylinders when rebuilding them or when installing new ones.
    I recently checked the rear cylinders on Comrade Trabi after 4 years and 84,000km... in the murderously humid Chicago climate.... no sticking of corrosion of the bores, so I re-applied a little more rubber lube.
    RogerDerSchrauber likes this.
  11. aardvark64

    aardvark64 Puttering Along

    Have to 'fess up: I tried to refurbish the master cylinder and couldn't get it to work properly afterwards. Rats!

    So bit the bullet and bought a new one from Trabantwelt. Took a week to arrive and all of 20 minutes to install. Spent the rest of the evening bleeding the brakes. Ho hum. I still have the old cylinder back in bits with a refurb kit if anyone wants to practice?

    Keri likes this.
  12. Keri

    Keri Leader

  13. turbofiat124

    turbofiat124 Premium Member Forum Donor

    I hear you.

    I've rebuilt several Fiat and Yugo master cylinders but did not have much luck with the Trabant master cylinder. The seals were so small, I ended up tearing them when I tried sliding them over the plunger. Even after lubing them with rubber grease. Maybe they were too cold and soaking them in hot water or heating them up with a hair dryer would have made them more pliable.

    Another thing I did not know but the "balls" that fit under the nipples are not check valves (as I thought) but rather "stops". If anyone attempts this, don't install the balls until the plunger is installed. Otherwise when you go to press the brake pedal, it makes an "thud" and most likely damages the plunger.

    There is one vendor that does not require a core charge. I can't remember who it was but I think it was Danzer.
  14. mbeamish

    mbeamish Loyal Comrade

    I've heard a vw beetle master cylinder fits a trabant . It would be interesting to get hold of one and see if it's a myth. VW parts are very cheap and probably easier to get hold of .

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