Article is from New Zealand
https://www.lvvta.org.nz/documents/i...FS_Failure.pdf


If you have a TCI brand IFS, better go check it out.

 

Thanks for posting that. Some pretty sketchy welds on that particular IRS shock mount.

 

Are these made in the USA? Looks like cheap nasty 'offshore' guff ( to coin a phrase)

 

Thanks for posting. It's a pretty damning verdict not only on quality of manufacturing but design as well. I'm surprised this hasn't attracted more comment.

 

I have this IFS on my TCI chassis under my 40 Ford coupe. I checked the upper coil spring mounts on both sides and the welds look great...inner and outer. As for the NZ write-up, page 7, where do these guys get off on calling the fit up poor? These blokes are obviously not welders. That gap is essential for providing weld penetration at the joint. The IFS failure is well-documented and the photos show that the workmanship was lacking in the weld joint, glad to hear that TCI is onboard with the testing effort. This is the first failure that I have been made aware of with this style IFS, I would like to know more about the vehicle on which this IFS was installed and the circumstances around the failure.

 

The fit was poor if the attempted weld was a fillet. A gap is fine if the intent was a full penetration weld. This seemed to be neither one nor the other. It was a report on a failed component not a lesson in welding. In any case the summary said the weld length and shape was inadequate for the load even if done correctly. Welds should be designed to avoid tension. I'm glad if these guys shine a light on safety problems like this and similar problems with steering columns.

 

I am not a welding expert but my understanding of fillet welds is that they are used when two flat plates are joined together which is not the case here. I can see no drawback in using a full penetration weld in this application so I guess I did not see an issue with the gap. I agree that the welding on this IFS was poor but I am not sure that I agree with the report and some other comments that the design is deficient just because the workmanship on this sample was poor. If, as you say, the weld length/shape was inadequate for the load then I would expect to see a rash of failures. This is why I stated that I would like to know more about the vehicle and the driving circumstances under which this IFS failed. It's one thing to analyze a failed component but it's all together another to fault the design especially when the cause of the failed component is so obvious.
For me this is not just an academic discussion...I own a vehicle with this IFS. Furthermore I personally know of at least 8 others in my immediate area who are running TCI chassis so there is a definite concern for all of us. As I said, this is the first report that I have read about a failure in this IFS. What I would like to see is a destructive test of the mount...put a load on it until it breaks and compare that load against the load that would be found in the normal operation of a motor vehicle.
Good discussion...

 

A full pen weld is ideal. It can be done via a gap or edge preparation. Fillet welds are usually cheaper to do. It is a lesson for us all because when you buy a kit like this at the price they are you expect them to be right. You certainly wouldn't be expecting to have it NDT'd.
Also the relevant tests for this would probably be a fatigue test followed by a static test. I'm sure TCI would have done that but did they leave enough in reserve for the inevitable defects?

 

Only reason I posted the link here was as a heads up for those that have a TCI IFS fitted .
This will not be a big issue here in Australia or New Zealand due to the fact these IFS would only likely be here in imported vehicles .
But it's my understanding these are used a lot in the US .
If you have one fitted , or know of one fitted to a friends car just be safe and take a look at the welds and look for cracks , chances are it's fine .

 

Thanks for the heads-up, here are some pics I found in the TCI installation document. As can be seen in these photos the welds look nothing like those in the LVVTA document. My IFS was fabricated almost 10 years ago and the welds look very similar to these photos from TCI. I would really be interested in learning more about the circumstances around the failed IFS and how the owner came to own the IFS. Those welds do not look like factory welds to me...

 

Charlie, The welds on the last photo don't look good to me, unless it is an optical illusion from the camera angle. There appears to be undercutting on the edges of the welds and the weld across the top of the shock bracket is not adequately filled. The weld looks concave. There is definitely undercutting on the lefthand upper side of the left set screw boss. I would expect welds that look like that from someone that has not been welding long, but not from a manufacturer.
Mark

 

I hear ya Mark...what is going on is there is a 3/16ths step that is being filled on that back edge of the shock bracket. As for the set screw boss, lots of heat with not much metal right there at that corner.
I know that it is easy to nit pick when you have food resolution closeup pics but I am not so concerned about these welds as I am about the crappy job depicted in the NZ writeup. I'm glad you weren't an inspector when I went through certification! Actually I didn't submit for certification but it was included in the program I was enrolled in...I just wanted to improve my TIG skills, didn't need the paper.

 

Charlie, I'm sorry. It was not my intension to be offensive in any way and I am not trying to be offensive with this post either. I just don't like what I see in that photo. I have been doing industrial fabricating and machine work for almost 40 years, over 25 years self employed as a Machine and Welding shop owner/operator. I have had to repair a lot of fatigue failures over the years. I understand what you are saying about heat on the edge of the part next to the boss and the amount of fill at the top of the shock bracket. These areas are only setting this part up for possible fatigue failure. Although it may never fail, proper welding technique would have eliminated these problem areas. It should have never been sent out with those welds.
Mark

 

X2 on that.

B

 

No problem Mark, I do not have the training or life's experiences in welding to have developed a critical eye to spot deficiencies like this. That said, I do hold two degrees in engineering so I am somewhat aware of force vectors and stress points. The set screw boss welding seems a bit overkill to have it welded 360 degrees to begin with...maybe I am missing something here but I don't see a potential fatigue issue due to the small section that is undercut. As for the upper bracket weld, the thickness of the weld bead is equal to the thickness of both sections being joined. Is my criteria for a quality weld in error here?