88 535i rough ride

Hi, my mechanic has repaired a broken steering box bracket by welding it. This has been done twice and now it is breaking again. What could be causing the repeated breaking?

By the way, the car drives so much smoother with the steering box able to move around. I think the box is moving even with the bracket not broken but sticking so the alignment is off. Then with the bracket broken I don't think it is sticking any more, hence the smooth ride. So what else could be broken, maybe the frame it bolts onto? Does this make any sense?

Reply to
michaelharvey
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Sounds as if the chassis is out of line or the vehicle has been totaled at one time or been in a front end fender bender and not fix correctly.

Reply to
steve-caner

That's correct it has been in a front end collision and some of the frame was welded before I bought the car. I presume the frame is not rigid anymore causing stress on the bracket, right? That sounds like a difficult frame repair, considering the car has a 3 or 4 more years of life.

If that is correct then I think a loose steering box is able to float to compensate for frame movement, but that good effect will end up with another broken bracket. Unfortunately for my mechanic he guarantees his work so he has to keep repairing the bracket, not a happy situation for him. What would you advise him to do? Is it possible to reinforce the frame for a reasonable effort?

Reply to
michaelharvey

The car has NO MORE LIFE it is a TOTALED WRECK and should be 10 miles away from any road or it should be crushed NOW!

It is probably illegal to repair or attempt to repair this car.

Reply to
steve-caner

Not if you can straighten the frame.

Reply to
R. Mark Clayton

The way I experience the car, it is a straight frame because the tire wear is normal. There just seems to be something moving. If it is a broken frame it might be right to be concerned about the safety. I don't know what would happen if the frame suddenly came apart, I wouldn't want to be travelling at high speed. Maybe it could be welded without if it the break could be seen.

Reply to
michaelharvey

Welding actually weakens the area around the weld. That's why the Liberty Ships nearly always broke in half.

It might have to be plated but I still say it's dangerous. Get it down to a chassis/body shop with a Laser aligning jig or a BMW body shop to be checked.

IT'S NOT SAFE

Reply to
steve-caner

And you think riveting stronger?

Reply to
Dave Plowman (News)

What would actually happen if the frame came apart? Would the front tires suddenly splay outwards bringing the chassis down to the road, or would the chassis hold it together for a while where bolted to the frame?

Reply to
michaelharvey

Dave - I didn't say that. there is welding and "WELDING" one is done by divi Jones the work experience school leaver and the other is done by educated professionals with years of experience.

It only need a bit of oxygen to reach the molten metal and the weld is flawed. GAS, MIG & ARC have always been the favorites of crash body shops and gas is the main culprit of porous welds with ARC coming a very close second. MIG is generally better in the hands of a skilled operator but only if there is enough gas pressure and flow rate.

BTW 99.9% of all airplanes are riveted and they are pretty strong they only seem to break up when they hit the ground at speeds over 300 MPH as your car would - don't know many ships that go that fast except space-ships.

Reply to
steve-caner

Ok Bill - wrong example but the QE2 and many other ships of equal size didn't. BTW I did see that prog last year and remember the reinforcement belt.

The truth still stands that the heat generated when welding can and does weaken the surrounding metal. Generally if you look at a broken "welded" joint you will invariably see the weld intact and the metal around it has broken showing the weakness.

Reply to
steve-caner

So those ships were welded by amateurs?

Reply to
Dave Plowman (News)

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Negative. They broke because of the relationship between the length of the ship and the length of the waves at sea. It caused a harmonic motion that weakened the ship at the midship (middle) by lifting the bow (front) out of the water and slamming it down as the wave passed. A period of time doing this caused the metal to fatigue. That's why the Liberty ships were overhauled by adding a steel belt at the midships area. Welding had ZERO to do with it. I saw the History channel episode on Liberty ships, maybe you should, too. This is an excellent thread on mis-information. And if welding caused weaked areas, why is it so prolific throughout metal construction of any kind? Yeah, I thought so. Moving on...

Bill in Omaha '86 535i

Reply to
Bill

Obviously we must have watched different episodes.

Wave lengths vary at sea as does the angle of incidence of the ship, so inevitably every ship will experience waves that will resonate with the ship at some time in their lives.

The real reason Liberty ships sank is as follows: -

  1. Material The steel was cheap and of poor quality, but the particular problem was that the relatively high carbon content meant that the steel became brittle at low temperatures, such as those experienced in the north Atlantic in winter.

  1. Welded without stress relief An all welded ship was a new idea, and it was not realised that once started a crack could propagate through the entire structure. In particular the deck hatches were rectangular with right angle corners and this provided a point of high stress for cracks to start from.

  2. Amateur Welding (well not quite) Workers building the ships were relatively inexperienced (most experienced ship builders had been drafted) in ship building in general and welding in particular. Tight schedules (like building a ship in three days) meant that there was little quality assurance and welds were often weak or defective and / or liable to corrosion. Poor technique also weakened the steel near the weld.

  1. Poor loading In the fog of war the ships were simply loaded willy nilly, resulting in increased stresses in the hull.

The net result was that cracks would start in the corners of the hatches and propagate right around the hull and the ship would split in two. The are plenty of pictures of half liberty ships, and one allegedly split immediately after launch.

That said, after relatively light remedial work (around the hatches) many liberty ships spent decades plying in the tropics (as well as vulnerability to cold they usually also lacked heating for the crew), and IIRC the last one only retired in the 90's.

Early Comet aeroplanes also suffered in this way.

Reply to
R. Mark Clayton

Possible - there was a war on.....................?

Reply to
steve-caner

Didn't the tail crack off or something like that. The other great one was the DC-10 and the cargo door frame cracking and the 3rd engine mounts giving way????

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Reply to
steve-caner

Or was it a Lockheed L-1011 that had the cargo door failure? ...but I think the incident I am referring to was a DC-10. Its happened over France or Germany. The cargo door wasn't closed properly by ground crew. The cargo door blew open at high altitude. The differential pressure between the cargo and passenger compartments buckled the passenger deck. Unfortunately all the control cables ran underneath the passenger deck, causing the crash.

Does a 535 have a frame? or is it unibody

JoshIII Not UK

Reply to
JoshIII

No cracks started in the corners of the square windows and propagated all the way round the fuselage. The metal was too thin as well.

Correct this was diagnosed, but not acted upon by by ?Turkish? Airlines, whose DC10 crached near Paris, when the door came off, hold depresurised and the floor collapsed (sucked) into the hold severing control cables.

This was a crash at Chicago. Bad maintenance practice (fork lift) overstressed mounting bolts, which sheered in service. OTOH the plane should have survived this.

Other 'involuntary retirements' of DC10's include: -

San Diego - instructor allowed trainee to fly a light aircraft into the glide path and collide with DC10.

Mount Erebus (Antartica) - Air New Zealand pilot over ruled navigator and flew below known height of terrain in poor visibility and hit the ground. CFIT

Other notable sillies with Airbus

France - test pilot over-rode automatic at show and failed to avoid forest - CFIT Bangalore - 6 week old plane crashed at airport (pilot error) probably CFIT Strassbourg - co pilot set 10X descent rate; pilot failed to observe altimeter; CFIT Russia - Aeroflot pilot put his eight year old son in charge of controls - spiralled into the ground.

The last won a Darwin Award.

Reply to
R. Mark Clayton

near Paris

The cargo door had a fault, which allowed it to open in flight.

relatively low altitude.

Reply to
R. Mark Clayton

"R. Mark Clayton"

Just the facts: The aircraft suffered an explosive decompression while climbing through 11,000 feet after takeoff from Paris Orly Airport. Due to a design flaw in the locking mechanism of the cargo door, a ground crew member was able to force the locking arm into position, while the door was not, in reality, locked. Climbing into thinner air, the door was unable to remain closed without the lock, and it burst open. The outrush of air caused the cabin floor to collapse and severe all control cables, leading to a loss of control by the flight crew.

Reply to
JoshIII

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