Warning Corvair pitman arm failure - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum

Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Suspension - Brakes - Steering
User Name
lost password?   |   register now

LinkBack Thread Tools
  #1 (permalink)  
Old 12-11-2007, 12:20 PM
RPM's Avatar
RPM RPM is offline
World Class ASE tech
Last photo:
Join Date: Nov 2004
Location: Hills of TN
Age: 66
Posts: 705
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
Warning Corvair pitman arm failure

One of the members of the National T Bucket Alliance has had a chrome pitman arm fail. He bought it from Speedway and Speedway has pulled them from the market. If you have one of these pitman arms you need to check it. One of the other members checked his and it was cracked also.


Reply With Quote Quick reply to this message
Sponsored Links
  #2 (permalink)  
Old 12-11-2007, 02:45 PM
302 Z28's Avatar  
Last photo:
Join Date: May 2003
Location: North Texas
Posts: 10,940
Wiki Edits: 0

Thanks: 1
Thanked 120 Times in 101 Posts
Thanks for posting, that is scary.

Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 12-11-2007, 04:02 PM
Registered User

Last journal entry: T'Bird projectr
Last photo:
Join Date: Nov 2007
Location: Delton, MI
Posts: 209
Wiki Edits: 0

Thanks: 0
Thanked 2 Times in 2 Posts
Chroming causes hydrogen embrittlement, suspensiona, steering and other critcal parts shouldn't be chromed. Luckily, I can't afford to chrome ANYTHING!

Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 12-11-2007, 05:19 PM
Dugg's Avatar
My compass doesn't point North
Last photo:
Join Date: Apr 2007
Location: in the hills of Colorado
Posts: 148
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Cheap Chinese Communist Conscripted Child Cruelty Conflicting Capitalism Chrome Corvair Copy Crap?
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 12-11-2007, 06:02 PM
willys36@aol.com's Avatar
Hotrodders.com Moderator
Last wiki edit: How to rebuild a Rochester Quadrajet 4MV carbureto...
Last journal entry: How to change auto shift timing on 200R4
Last photo:
Join Date: May 2002
Location: Bakersfield
Posts: 8,455
Wiki Edits: 21

Thanks: 6
Thanked 45 Times in 33 Posts
I can't figure out how to post in that bulletin board so I will post here. I have a lot of opinions about that failure.

First, hydrogen embrittlement is a well know phenomenon and used to be widely known in the hot rodding community. With the new generation of 'journalists' who are technically uneducated and practice their craft by reprinting manufacturer's installation brochures and pass that off as tech. The hydrogen atom is very small and passes easily through steel. A steel cylinder full of hydrogen will eventually empty itself due to this permeability. Hydrogen generated in the plating process will penetrate steel. If it is mild low carbon steel, there is no problem, the hydrogen will evolve out and there will be no cracks. However in high carbon, heat treated steel, the hydrogen is captured in the grain structure and causes a disruption in the chemistry that exhibits itself in brittleness and tendency to crack. The solution is to bake the parts for about 4 hours at 400F which 'boils' out the hydrogen molecules and restores the ductility of the steel.

That may or may not be a contributing factor to the failure in the steering arm in the picture. Another very likely possibility is inferior material. If those after market arms are cast, that is a huge problem. The steering arm is one of the most highly stressed pieces in the steering system and MUST be forged. That thing definitely looks cast. It broke at the thick section because that is where the stress is highest in the part. That is why they make it thicker! Regardless it needed a stress riser such as a hydrogen crack or a casting flaw to initiate the crack. If you look closely at the picture, the fracture face is white in the right-hand quadrant, showing that it had been cracked there for some time and water deposits had collected. Look more closely and there appears to be a pit on the surface of the rod in the middle of that white spot. If that is a casting pit, that would definitely initiate a crack. I can't believe they made that thing of cast iron, it must at least be cast steel. Regardless, should have been forged.

Finally this gives me a soap box to preach on my quest to get all rodders to beef up their steering systems. Just like MII front ends that are documented on this forum to be catastrophically failing due to bad engineering, this steering arm is obviously another example of the dangers of back-of-the-envelope engineering. The Speedway tech support guy was quoted as saying 'they have sold over 200 of them and never had a problem.' That is scary!! Engineers in Detroit are held to a standard of NO failures in 3 or 4 MILLION units!!!! 2 failures in 200 critical steering units would be a DISASTER in the auto industry. 200 units in a test is woefully inadequate. Be VERY careful in designing your steering system. ALWAY use strut rods in MII front ends, ALWAY use forged pieces where Detroit used forged pieces. If you weld anything in the system make sure you know what you are doing or have it done professionally.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 12-11-2007, 06:49 PM
Dugg's Avatar
My compass doesn't point North
Last photo:
Join Date: Apr 2007
Location: in the hills of Colorado
Posts: 148
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
The link-message said Speedway gets the parts from Total Performance. I think it's the other way around. I believe this has seen further documentation here on the forum. Speedway has a history of using import (Yes Paris, we've seen the CCCCCCC.... Crap post above.)

A cast steering arm! What blatant disregard for human life!

Had this failure resulted in an injury accident or worse, we may have never found out about this. The steering arm breakage would have been considered just part of the damage, not the cause. Legislators would see this as an opportunity to further restrict or ban rods completely.

Where is SEMA on this? Does Speedway belong to SEMA? And, what difference would it make anyway? Does SEMA make evaluations of products? Does SEMA have any authority to restrict or recommend products not be offered? Probably not. I suspect if you pay your membership monies and don't have a man of the cloth chasing a young boy around your SEMA booth, you're products must be OK.

Let's see if Speedway or Total or ?? - the steering arm supplier, steps up to the plate and issues a recall or directive.

Did I ever mention that in airplane drawing class we learned; no weldments, no casting? No Paris, I'm not trying to rub it in. And, yes my dear, I know we're a bunch of rodders who are not trying to land on the Moon.
Reply With Quote Quick reply to this message

Recent Suspension - Brakes - Steering posts with photos

Quick Reply

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Please select your insurance company (Optional)


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Custom Pitman Arm Tribal Suspension - Brakes - Steering 7 07-17-2007 04:24 PM
4" drop pitman arm for 85 chevy 3/4 ton punk1c5040 Suspension - Brakes - Steering 1 01-01-2007 05:04 PM
Header Clearance Issues with Pitman Arm k2mooch Suspension - Brakes - Steering 4 04-26-2005 01:35 PM
pitman arm installation help?? fireforsin Suspension - Brakes - Steering 4 08-11-2004 01:13 PM
bad pitman arm? 69elcaminoss Suspension - Brakes - Steering 8 03-02-2004 12:44 PM

All times are GMT -6. The time now is 08:28 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.