Member
Sooo my trailing arm ripped out
Driving home one day when my trailing arm decided to pop out on me. I am currently in the process of fixing the car.
What are my options to fix this? As the entire bolt/bracket ripped out of the chassis.
IMG_0355.jpg
Member
This is a common problem on our cars. When it happened to me I simply welded the threaded chunks back in where they belong, but there are some aftermarket reinforcement kits available which basically add a plate/bracket to the area and ensure it will never happen again. I would highly recommend that for the drifters out there. Just go to google and type "e36 trailing arm reinforcement kit" to see what it looks like. Either way you will need a welder, and you should put a shield of some sort over the nearby part of the gas tank during the repair process to make sure you don't blow up.
Last edited by BMW1999m3; 06-28-2020 at 07:01 PM.
When you step on the brakes, your life is in your foot's hands.
Member
Well that is pathetic! BMW.
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Balogne Cajones
Eh.. Its not uncommon. Ive actually had 1 or 2 individual boss rip out when i was unbolting control arms. Alls you do is put it back in, weld the snot out of it.. The reinforcment plates can be made out of extra rtab brackets, cut the boss holes out, weld over. Paint over. Win. Move on.
Member
Yikes. Ya ripped all 3 bungs out. If you arent able to drop the gas tank and do all the welding yourself, it probably wouldn't be worth it to keep the car.
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Member
How about panel bond (the automotive stuff). Could one inject a lot just above and let it seep down. Maybe put the bolt in the thread and put light upward pressure with a jack to hold it in place.
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Member
Are you saying you suggest glueing it all back together?Originally Posted by Eric93se
Last edited by samy01; 06-30-2020 at 05:08 AM.
Balogne Cajones
Although the hope is admirable.. Thats not going to resolve or bandaid the problem.
Welding is the only repair method advisable.
(Dropping the gas tank is not nessesary given you take adaguate precations).
Get the car on a lift to do the jobb then youl have plenty of space to utelize. The pocket is far enough away from the tank for safe welding. But you will have to cover the lines, and if it eases your mind, drape someing over the tank as well.
Member
Spyderg0d is right. No matter how strong a glue or epoxy you use, it won't be strong enough to endure the stresses encountered by the suspension over pavement. You will need to weld the bungs back into place. You won't need to drop the gas tank. Just cover the exposed area with a damp cloth or sufficiently thick shield that will block the welding sparks.
When you step on the brakes, your life is in your foot's hands.
Member
Can't believe someone really considered glueing the suspension back together was a real option.
Balogne Cajones
Well.. There are alot of situations where glues can be used when you think "theres no way a glue would work".. Ive seen strut horn sections and bowls glued on. With proper metal adhesives ofcoarse.. . but still. It isnt exactly a completely out of context thing to ask.
Member
Recently a guy here attached sub frame re enforcements with high strength metal 3m panel bond.
It doesn't look like enough surface area to work in this case, that's why I asked if you were to put a lot of it above the crack.
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I only have experience with 3m panelbond which I believe is the most popular. It specifically states that it is for non-structural panels. That said, with proper prep,it is incredibly strong and the sheet metal will typically shear before the bond is broken in a re-wrecked car (I've seen a couple). I wouldn't use it for a rtab pocket repair as it is an awkward area to access and by pouring in from above you can't get a good surface prep, I would also avoid using a product that expressly discourages such application due to liability.
When I welded the new floor pan section into my vert, I used it like a seam sealer and to generally reinforce the welds around thin metal tends to get brittle with welding. It was overkill but when I sold the car, I don't have any doubts about the repair.
It must have been a real eye opener when that pocket let go while driving.
Last edited by gdavid; 07-01-2020 at 07:33 AM.
Member
How can this even happen? There's no rust or anything. It just ripped out? Just like that? Why? I never heard of that happen.
Balogne Cajones
Because the metel is pressed and then welded. It draws on the tensil strength and curvature to maintain its strength in shape instead of shear thickness of metel. Its like comparing old 12 guage panels to modern 22 guage panels. Old cars are strong because they used thick sheets. Todays car panels are strong because of the press form. (But they still bend and crease ALOT easier) So even though its strong shape, it also becomes brittle, especially over time and temp cylces. First tiny cracks form in very small increments. Then over time those cracks expand in length, meet together, then eventually the metal breaks like a piece of porcelain in chunks. This is also why ppl use reinforcment plates instead of just welding beads. It applies to the entire area not just where the cracks specifically happen. Basically, the shape of the pocket is very very good... But they didnt use thick enough metel to meet the load the structure takes over the coarse of 20 years or race car like beatings. Lol.
Member
That's what makes me wonder. OP didn't say he was racing. He just said he was driving home one day.
I can't get my head around this. Driving home, listening to some radio or whatever, BAAAM trailing arm suddenly gone.
And then what happened? It just fell on the ground, scraping along? Did it make the car instable? I mean this could lead to a bad accident if that happens on a highway. I think there was maybe more going on beforehand, maybe an accident damaged this area or something else that weakened this section or the threads.
Balogne Cajones
Its over time. It had cracked slowly over lots of instances.. Then the last time was the one that broke the camels back..
The arm wont fall out and down. If you unbolt a rtab mount. Even up in the air, the end will naturally want to stay in the pocket. So unless you hard brake and the bushings are somewhat bad, the arm shouldnt shove into the ground hard enough to catch.
Member
Oh it was an interesting experience, just trying to get home and then boom lost control.
This is a better idea of the damage.
any ideas on where or how to get the arm back up, when it ripped out of the body it hit the ground. making me unable to weld it back up
Attachment 674287
Last edited by eee36chris; 07-03-2020 at 03:11 AM.
Balogne Cajones
Looks like you need to unbolt everything.. Thats deff going to be bent to shit.. Buy new arm. Buy new everything in there. Lol.
Member
I see you rocking the ground control kit. How'd you like it before all this happens?
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Member
yup thats basically what i have done, new trailing arm, bushings, axle, rear lower control arm , upper control arm, rear sway bar and exhaust. I've got most of it installed i just need to find my self a welder and way to get the bolts back in.
Balogne Cajones
Use the ripped out bosses. Loosen them from the bolts on the control arm pocket mount. Position the broken off melet back in as closely as you can to where it was.. Tack it in place.. Remove bolts. Then you can finish welding it in.. Then... Id suggest getting the rtab pocket reinforcments (probably the best idea is to get ALL chassis reinforcments done while your here) .. They have a stencil of the bolt boss positions in the plate naturally.. So everything will align properly.
The bosses themselves arent the problem.. The problem was the thickness of the sheet steel inbetween them. So as long as you put them back in where they were, and use the reinforcments, it wont happen again.
Driver
As above, do it properly and use these: https://rallyroad.net/collections/e3...reinforcements
'96 M3, S50B32, 6MT
+ good stuff
Member
So if this happens how does a normal weapon hire a welded to fix it? What instructions would I need to give? I’m sure I can find a welder on Craigslist
Balogne Cajones
If i were you. Id buy all the replacement parts yourself. Assemble what you can.. Then have it taken to a shop. It shouldnt be to much to have them weld the pocket in. You can have the upper spring arm pre bolted to the arm, and camber arm on the arm, rtab, axle together.. Then they just have to bolt the axle on, 1 upper arm bolt, 1 camber arm bolt, bolt the rtab in and put the shock in. And the wheel and caliper and rotor ofcoarse.. It really is a simple job that should not require alot of effort or time.
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