1. turbofiat124

    turbofiat124 Loyal Comrade

    Can someone grab the axles on your Trabbi and check to see if there is any play whatsoever in your axles? This is the model with the hinge joints (NOT the CV joints). There is a couple of mm of play in both axles and I'm wondering if there should be any. I inspected the hinge pins on mine and they are not worn. I did find some play where the hinges meet. Just wondering if this is OK.

    This thumping noise:

    It's not getting any worse but it's not getting any better. Is easier to hear when the clutch is depressed, taken out of gear or in 4th gear freewheeling and coasting at low speeds. At high speeds, I can barely hear it, I guess because the engine noise is drowning out the thumping sound.

    There is not any unusual drivetrain vibration from the steering wheel.

    I thought this started after I replaced the brake shoes. When I had the drums off to inspect the hinge pins, the scuff marks from the 60 grit sandpaper are still there after a couple of thousand miles . The shoes are not wearing in as I would expect. The friction material is not hard like most brake shoes or pads but a soft rubber material. The same friction material used on the brake drum on Snapper lawnmowers! The car stops OK. The thumping sound does not go away when the brakes are pressed.

    I can spin the front wheels off the ground and it does sound like the drums have high spots in them though. Could this be the source of the thumping sound?

    I'm sort of leaning toward the wheel bearings. When I had the hubs off, if I grab the outer stub and try to move it up and down, the bearings are tight as a drum but when I turn the steering wheel to the left going down the road, the "thumping" sounds seems to go away or is not as loud. Usually this condition indicates a bad wheel bearing.

    My transmission would make this ungodly noise when I pressed in the clutch. I thought it was the release bearing but turned out when I had the freewheel device replaced, the transmission guy said the input shaft bearings were bad. There was no play in them but when spun on my finger sounded like sand was inside them. After installing new input shaft bearings, the noise is no longer there.

    So in other words, the wheel bearings may not have any play in them but could still be bad. I still have the new SKF bearings I planned on installing back in the winter. I should have went ahead and replaced them since this job doesn't seem as bad as I think it will be. The outer hinge joint "floats" inside of the bearings. I figured it was pressed in and would be a devil to remove.

    I hate to just replacing parts until something fixes the problem.

    What do you guys think?
  2. turbofiat124

    turbofiat124 Loyal Comrade

  3. mbeamish

    mbeamish Loyal Comrade

    Are front and rear drums the same maybe swap front to rear temp to eliminate the drums ?
  4. turbofiat124

    turbofiat124 Loyal Comrade

    I think the fronts and rears are the same. But I'm not sure sure it's in the brakes. There is no vibration or pulsating feeling from the brake pedal. There is not any vibration from the steering wheel either. The only feeling is from my feet through the floorboards.

    This noise kind of sounds like it maybe the tires. My Subaru came with a set of Bridgestones from the factory and when below freezing would make a thumping sound. Like those old bias ply tires before radials. For some reason after I rotated the tires (front to back), the noise went ahead.

    I'm not sure of the model name but the tires I'm running are Vredesteins SR145 13s. They "should be" fairly new tires. When I mean "should be new", I bought them from Coker Tire about 4 years ago. I have not checked the date on them. Maybe I should try rotating them and see what happens.

    Could it be possibly these tires are not radials? I just assumed all car tires were radials these days.
  5. mbeamish

    mbeamish Loyal Comrade

    Vredestein are a good quality brand . I suppose it's possible you 'kerbed' one and damaged it ? Maybe put your spare onto the front at both sides and see what happens ( no cost in that)
  6. mbeamish

    mbeamish Loyal Comrade

    Or buckled rim ?
  7. turbofiat124

    turbofiat124 Loyal Comrade

    The rims look straight. I did have the tires taken off and painted them myself before having new ones installed.

    The noise seems to be coming more from the front passenger side than the other side. The engine tends to drown out any noise at high speeds. It's more noticeable at very low speeds (like < 20 mph) while coasting.
  8. Steve

    Steve Loyal Comrade

    I kind of think you may get the same noises as me when I coast with the engine off. I think it's on the front passenger side and think it maybe a worn stub axle joint with the drive shaft. The this is in time with road wheel rotation and it cannot be wheel bearings which would be a rumble sound if worn.
  9. turbofiat124

    turbofiat124 Loyal Comrade

    I only did this on the passenger side, not sure about the driver side since the noise seems to be on the passenger side. But both axles do have some play in them. Just only about a couple of mm.

    I'm wondering if the stub end should be tight within the bearings. If I remember when I had the pins out, the stub end could be pushed out of the hub if it were not for the hinged end that is larger than the ID of the bearings. In other words, once the hub assembly was pulled off the car, the stub end could be pushed out easily the opposite way. Seems like I read or saw in a photo this piece needs to be pressed out of the bearings. However with the pin removed, there was no up and down play in the bearings.

    I do know that the axle play is where the hinges meet. But the pins are not worn. I'm just trying to figure out if this is normal or not.

    If I remember the hinge ends just make contact with one another. There is nothing holding them together. The way to separate the
    axle assembly is to

    remove 36mm nut
    pull the boot back
    remove the circlips on the pins
    disconnect everything connected to the hub assembly pull the hub assembly off
    pull the long axle out of the transmission
    remove the stub end
  10. Steve

    Steve Loyal Comrade

    Well I'm gonna wait a bit longer to see if the noise gets worse. If it does then I will investigate it further. At the moment it doesn't concern me that much and is part of the overall pops, bangs squeaks and groans of a terrible, although cute and quirky, Communist car. Did I mention that after a long run, when I turn the engine off, I sometimes get a great backfire which scares the S**T out of anyone nearby. All part of the fun!!
  11. mati0921

    mati0921 Loyal Comrade

    Same her with the backfire, and sometimes ghostrun. engine still running after i am out the door. gives some wierd looks standing beside the car for a few seconds waiting for the engine to die out... :D
  12. turbofiat124

    turbofiat124 Loyal Comrade

    My only concern was the wheel falling off! Although they are both tight. The thump also sounds like a flat spot in one of the tires.

    One day I was out showing a friend of mine my turbo system on my Fiat Spider when all of a sudden it sounded as if a cat got caught in the fan blade then a thump thump thump. I pulled over and pushed the front wheel with my foot and there was quite a bit of movement. I managed to get the car home without damaging the king pin. Some of the balls in one of the tapered bearings had disintegrated. This same thing happened to the crankshaft bearings on my moped. It seems ball bearings tend to explode sometimes.

    Getting back to the Trabant. This backfiring and run-on maybe due to carbon buildup on the cylinder heads. When I was attempting to set up my electronic ignition, I had the timing advanced way to far. When I went to shut the ignition off, the engine continued to run! I pulled the air cleaner hose off the carburetor and laid my hand over the throat to choke the engine to kill it. My guess was carbon buildup on the cylinder head was acting as a glow plug as the ignition source.

    My riding mower will backfire at times when I shut the engine off and blow a flame out of the muffler. There is a solenoid in the base of the carburetor that goes up through the fuel bowel. It's supposed to shut off the flow of fuel when the ignition is turned off to prevent backfiring. The older engines do not have this. I need to get a new one...

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