Technical Alert: Safety Notice Affects '33 Hot Rods and Mk4 Roadsters

[Mad Dog]

We have become aware of a two separate customers who have had fasteners break. The fastener is part of the Hot Rod and Mk4 spindle assembly and it attaches the steering arm to the spindle. This is a serious concern. If you have a Factory Five Mk4 Roadster (complete kit only) or '33 Hot Rod, please stop driving your vehicle and read the following information.

http://www.factoryfive.com/whatsnew/tech/steeringarm/fastnertext_files/image002.jpg

The Factory Five part number is 33610. This is an M12-1.75 x 50mm long button head zinc colored bolt grade 12.9. The fasteners of concern are a silver zinc color and were used starting May 2009.

http://www.factoryfive.com/whatsnew/tech/steeringarm/fastnertext_files/image004.jpg

If you have a Mk4 complete kit or a 33 Hot rod do not drive your car.

Actions we are taking:

1. We will be sending All Mk4 complete kit and 33 Hot rod customers hex head replacement bolts as soon as possible (days, not weeks).

2. While these fasteners are correct for the application, we do not know why they have failed. We have sent samples to an independent testing lab, but are proceeding to replace all fasteners as quickly as possible.

3. We are posting this notice on our website, customer discussions forums, our Facebook page, and sending certified mail notices to customers immediately.

Our number one concern is your safety. If you have any concerns, questions or feel that you don’t understand this message, please e-mail or call FFR’s tech department at 508-291-3443.

UPDATE: Patti in purchasing and I have been working hard to get the new fasteners and instructions ready to send to all of those who may be affected by this tech alert. Everything was sent out on 8/18.

Factory Five Racing, Inc

[BigLeo69]

shouldn't the bolt in question be or have a shoulder on it, and a fine thread would be better, looks like there would be room just for a hex-head and a locking shoulder nut in the grade 8 strength. "86" the nylock (should be of higher grade)

[crash]

Can you tell me what the difference is between "grade 8" and "12.9"?

Only reason I ask is that I always thought that grade 12.9 was as high or higher in strength than a "grade 8".

BTW- My guess on the failure issue is that the bolts are being put in tension, as opposed to shear, when the load is being applied, and if the bolts are over tightened to begin with, then it doesn't take much to push them over the edge. Quite a lot of force can be generated from trying to turn the wheels at times.

[crash]

"ISO metric materials are Class 12.9 (applies to hex socket head cap screws, equivalant to ANSI 'heat treated alloy steel' Rc38-45); Class 10.9 (applies to hex head cap screws, equivalant to Grade 8); Class 8.8 (applies to hex head cap screws, equivalant to Grade 5)For tensile strengths over 180m psi uts, special manufacture in a variety of available materials and conditions are the norm.Jim DisharoonTranSpec Fasteners, Inc."

Yep, looks like the grade 12.9 is actually a higher strength bolt than the grade 8 or 10.9 fasteners. Again, it's my feeling that the spindle design along with possible overtightening is what is leading to this issue.

[crash]

I guess in the bigger picture, since the spindle, or what I commonly call the "upright", isn't symetrical, the question I would pose is why isn't the steering arm part of the main piece? Is this upright used in varying locations where the steering arm is different depending upon location/application?

[bobzffr]

Why would a bolt without a shank ever be used for a steering application. Or any other application where high strength is needed for that matter?

[crash]

Because many times a short bolt is not readily available that includes a shank, maybe?

I will say that when a bolt is used exclusively in tension, that it really makes no difference if there is any shoulder or shank section to the bolt, so in this application, it would make little to no difference.

[Jim Schenck]

Steering arms are seperate pieces so the spindle can be used on the 33 (rear steer) and the MKIV (front steer) This also give the added benefit of more adjustability. Shimming the arm can modify ackerman and bumpsteer, or steering quickness can be altered by machining shorter/longer replacements.

[crash]

Thanks Jim. I figured that that was the reasoning, I just didn't know what the different applications were. :) Hope the new bolts are THE fix.

[geoffav]

Can someone post the specs for the correct replacement bolts for all of the button heads for the 33 front suspension. I want to buy them local.

[Jim Schenck]

Spindle to arm bolts - M12-1.75 x 50mm 4 total
Lower arm short - 1/2-20 x 1.5in. 4 total
Lower arm long - 1/2-20 x 2.0in. 2 total

Use grade 8 (10.9 metric) or higher

Anyone with Cycle fenders on a 33 would not need the spindle to steering arm bolts as they are replaced in that assembly.

[geoffav]

Spindle to arm bolts - M12-1.75 x 50mm 4 total
Lower arm short - 1/2-20 x 1.5in. 4 total
Lower arm long - 1/2-20 x 2.0in. 2 total

Use grade 8 (10.9 metric) or higher


Anyone with Cycle fenders on a 33 would not need the spindle to steering arm bolts as they are replaced in that assembly.


Thanks Jim. I'm an open wheel guy so that's the info I needed. I never received them back in 8/10 and never got a reply from anyone else. I think my address is wrong in FF records but thankfully my MSO is good. If I can't find new hub nuts (without buying hubs) I will probably just reuse the current nuts.

[crash]

If you guys want the ultimate in fasteners, go to aircraft hardware, sometimes referred to as AN hardware. Coast Fabrication offers anything yuo may want. If they don't have it in stock, they can make it!:)

http://www.coastfab.com/hardware.html

[geoffav]

Haha, you're right. The funny thing is I'm around the stuff all day long. I would have more time for the car if I won't hanging around aviation maintenance. Work really gets in the way of the finer things in life. :cool:

[PatriotRider]

Sent out on 8/18?? I have a 33 complete kit (#271), and I got no notice or parts. Is this an old outdated thread? The posts are early this year??

[E-Ticket Ride]

I just happened upon this thread. I believe that depending on when your kit was shipped this may be OBE (overtaken by events) and they have sent you the proper replacement as part of the original shipment. Given the importance of this I would recommend a call to FFR to double check.
JMO - ICBW
CL