Coilover bracket failure

[Bicyclops]

The bracket holding the bottom of the coilover on left front broke putting my nose on the tarmac at 60mph. Looking at the failed bracket, it's obvious that the weld didn't penetrate. The other side isn't a lot better. I ran a bead on the inside corner except where the flange bolt would foul. Hope this holds up better.

Might want to take a look at yours. Really disappointing weld quality.

Ed

20240531_152028[1].jpg

[Hobby Racer]

Wow! Thanks for the heads up. I'll be checking mine today.

[RPGs818SNA]

Thanks for the warning, Ed. Glad you lived through it. When were your brackets made? Mine are painted and on the car. I can look for cracks, but how might I tell if my welds are deep/strong enough?

RPG

[Bicyclops]

Took delivery in May of 2020. I have about 4500 miles on it, mostly twisties, and some of those roads do work the suspension. I got my car tuned on E85 (386 whp yikes!). I hit it pretty hard in second because, well because. The front end got light and when I went to shift it dropped the body onto the street. The shock was dangling behind the A-arm. I'm just glad it happened there and not on the canyon road I was headed to. The shock showed signs of rubbing on the bolt heads so it was already broken, who knows how long.

Hard to see it on the car with the shocks on. I had no clue that it was broken until it dropped. The only weld on them is from the bottom. There's no weld on the inside corner and if there was, it would foul the outboard bolt head. If you have the shock off you might be able to see down the gap in that inside corner using a bright light and maybe a magnifying glass or a borescope. If there was weld penetration it would look like a rough line of weld down in the bottom of the gap. Full penetration would have filled that gap right up to the top. I used acetylene to weld the inside corner avoiding the area of that bolt head. I also put a spot of weld on the ends of the vertical sides where they meet the bottom piece.

I'm coming to the conclusion that I need to put the car up and crawl under it every thousand miles or so to make sure everthing is still there. I have an EZcarlift which will get it up to about 28" that I built the car on. I highly recommend it.

Ed

[J R Jones]

My unfinished 2014 kit had two former owners. The donor is a 2002 Impreza with steel LCAs. I upgraded to 2006 alloy control arms. The original bracket assembly to the LCA was a mess of cross threaded plates and jamb nuts.
I threaded the aluminum LCAs and reworked the clamped surfaces to fit flat with no gaps or interference. If I were fabricating the bracket I would TIG weld it or shape it from one piece of flat stock.
You may be an excellent gas welder, I find TIG to be more precise.
I can not inspect the welds adequately with the bracket bolted in place. There is no weld bead in the fillets.
Make sure that with your alignment and shock eye shimming at the top, that the lower eye does not bind in the bracket bending the ears with suspension travel. I have to shim the upper eyes full aft.
jim

[Bicyclops]

I would love to learn tig but have yet to pop for the equipment. Good point about aligning the shock. It does have some amount of self correction with the ball joints. Bolted up stress is for sure going to be a bad thing.

Ed

[RPGs818SNA]

Another quick question, Ed: Do you have a front sway bar installed? It seems like it would try to keep the frame off the ground if one bracket failed, but it may not be strong enough to do so.

Thanks,
RPG

[Bicyclops]

I do have the sway bar. With the car sitting level it's not under any tension really. Seems like it would take quite a lot to keep one corner off the ground using the torsion of that skinny bar and no preload. The spring on the coilover is the only thing supporting it. Once that is hanging behind the lower A-arm...

If I hadn't goosed it on a straightaway and got the front end light enough to pop the coilover clear, it probably would have happened in a tight corner with a bump in it. As it was, I didn't lose directional control and was able to steer it into a center left turn lane. Triple A said they wouldn't tow a kit car. Oh come on! Probably would have devolved into a ****show if they had showed up. I hitched a ride home to get a jack and some tools in my truck. I saw a harbor fright furniture dolly and threw that in too. I was able to get that under the front end of the main frame after jacking it up and managed to back up about 100 yards and turn it onto a side street, a much better/safer place to work on it. My nephew is building an 818 too and was able to bring me a bracket from his project so I could put it back together and drive home. All in all, it could have been a whole lot worse.

I've got an aluminum scissor jack from a Porsche at the hangar. I think I'm going to start carrying it in the car along with a way to break loose lug nuts in case I get something as silly as a flat tire. Maybe some reflectors and a tow rope too. I guess I should be carrying a first aid kit. I like to have the feeling that I can have some sort of positive impact on my fate when stuff like this happens.

Ed

[Grubester]

What is the thickness of the steel? Shouldn't it have a well-defined weld-prep to promote penetration?

[RPGs818SNA]

I wonder if it would be better to replace the FFR mount with one cut out of 1/4" thick 1.5"x3" mild steel tubing. Would mild steel be strong enough? At least there's no weld to worry about.

RPG

818 front lower shock mount.jpg

[Ajzride]

Steel tubing still has a weld in, although probably only one, so if you are cutting in half one side should be a solid piece that has been bent.

[J R Jones]

The FFR bracket material is ~0.190 which is suitable. 0.250 wall tube has a big inside radius.
EWT and structural tube welds are on the longest side, not in a corner.
The FFR bracket inside width is 0.880.
The 3.0 X 1.5 with 0.250 wall will need a spacer washer.
If you used 0.188 wall 3.0 X 1.5 you would need two ~0.125 washers.

You could press brake bend 0.188 to shape. You would not bend 0.25 into a "U" without a large press and fixturing.
jim

[Bicyclops]

I've got the aluminum A-arms. On one of arms at the side of the bracket, I had to carve a little bit off the arm to get it to sit flat. A wider bracket would be problematic. Maybe it wouldn't be a problem on the steel arms, don't know.

I think (and hope) that my weld reinforced brackets will be sufficiently strong enough. I'll be looking at them regularly.

Ed

[Grubester]

I guess I have to chime in here -- and BTW, my Mk IV kit arrives ~mid-July.
Are FF people aware of this failure? (Note: in the aerospace industry, manned and unmanned rockets are treated with slightly different quality control stds. -- but these cars are manned!)
As a retired engineer and QC Mgr., I can think of a number of req'ts for consistently providing high-integrity weldments.
My impression of FF (I'm new) is that there is an excellent commitment to quality designs and manufacturing, however, consistent "process control" does not happen routinely: it happens by design of processes supported by the work teams' vigilance.
That's simplistic to say, but a satisfying accomplishment to achieve it!
-sg

[Bicyclops]

To follow up, I was looking at my nephew Josh's steel A-arms and they are flat on top so the cut the bracket out of a piece of tube approach would be viable. He has put a bead of weld on the inside using flux core. I proposed that he cut a v-groove in the backside where the original weld is and fill it with gas shield wire to insure full penetration.

On the aluminum arm, one could make a spacer and set a cut tube bracket on that with longer bolts and crank a little out of the coilover. Maybe I'll go that route if I manage to break another bracket and survive.

Ed

[Jo3sh]

Ed, after we talked about this, I tacked my brackets on the inside corner, then ground out the pre-existing weld and rewelded it. On one side of one bracket, anyway - I still have to finish the other three welds.
groundout.jpg
filledin.jpg

[Bicyclops]

At least both pieces of metal are involved with the weld now. Should be strong enough.

Ed

[aquillen]

Thanks for posting this. I have a little project to do now...