Front End Feels Strange... Wanders

[MrMagoo]

I just got back from a long trip (over 1500 miles) and all was well. About a week later, I have suddenly developed a problem where the car seems to wander, and the steering feels light and uncertain. I checked underneath and I couldn't find anything that was obviously wrong. Any ideas?

[VINCENT RUDI]

Any shaking or extra play in the steering wheel?

[vanoochka]

Does it happen only when you accelerate, or is it constant?

[JUS BIT]

Check and retighten the 4 bolts that hold the steering rack to the frame mount. Also, double check and put a 17mm wrench on the tie rod ends to make sure that they have not gotten loose.

Good luck, James

[Buzz]

Take this very seriously. Sorry if this seems long winded, but the story is necessary to make my point. I feel stupid about the mistake I made but I also realise I am less stupid now than I was before it happened.

After I first rebuilt my Cobra, including installation of a brand new front suspension and rack, there was a very small bit of play in the steering. Apparently the threads on the steering shaft at the steering wheel end were damaged and didn't allow the nut to tighten all the way down on the splined adapter. I always meant to address this but I saw it as more of an annoyance, and fixing it it was a little way down on the priority list. I used to tighten it up every once in a while and at times it seemed like it may have been getting a bit worse but complacency set in and I began to get accustomed to it.

Briefly, one day, I noticed a "squirrely" sensation very similar to what you describe. Afterwards, I checked all the fasteners in the front and rear suspension plus the shock mounts, control arms, steering shaft u-joints, wheel nuts and tire pressures. Nothing was out of spec so, against my better judgement, I concluded that it might have been either my imagination or something to do with the road conditions at the time.

Next day, heading out to dinner with my wife, some friends of my lil' brother pulled up behind us in a gussied-up Supra that they had been trash talking about. We were on a good, quiet, open stretch of road, so I decided to teach them some discipline . The Cobra bellowed and smoked the tires as I pulled away hard and held a good lead before it was time for both of us to start slowing down as we approached an intersection marking entry into a busier traffic area. They loved the rare display of the Cobra's fury and honked, hooted and waved as they exited and carried on.

Immediately after we turned left and accelerated slightly, the steering felt really strange, but went back to normal as we picked up a bit of speed. I slowed again and this time the steering was gone completely at idle speed - TURNING THE WHEEL HAD ALMOST NO EFFECT ON THE CAR'S DIRECTION!! I was barely able to guide the car to the shoulder. At a dead stop, the steering wheel turned freely on the shaft 90 degrees in either direction. The splines in the aluminum steering wheel adapter were almost completely worn flat from the constant vibration and back and forth movement allowed by the loose fit.

Luckily, I had a pair of visegrips in the toolkit that I clamped on to the shaft after removing the steering wheel and I was able to limp us home using them to steer. Even more luckily, the steering hadn't chosen to let go at a time and place and speed that would have had some serious consequences.

The moral of this long diatribe: Do not take ANY loose or vague feeling in in your steering lightly. Being unable to control the direction of my car while it is moving is something I never, ever want to experience again!

[MrMagoo]

Thanks all. I am taking this very seriously. I limped the car over to a service station where they are checking it out now.

The problem is not one that happens at speed, you can see and feel things are not right with low speed maneuvering. There is no significant play or vibration in the steering column. I have fixed those issues early on like many here have. The U-joints in the steering column have a little wear in them, but not enough so as you notice when you turn the wheel. The retaining bolt that holds the steering shaft onto the steering rack was a little bit loose so I tightened it up, but the splines seem ok

On the way over to the service station (only a few miles thankfully) the problems seemed to be getting progressively worse. Now the right wheel looks obviously out of alignment, and it is rubbing against the body (it never used to do that), so the ride height has changed on that side.

I originally suspected the steering rack. and I'm starting to believe that the steering assembly is not the culprit. Now I am thinking a spring or strut failure might be the problem. It's as if the suspension on that side of the car has collapsed. I have read that some here have experienced blown out struts, and maybe this is what it feels like to drive a car in that condition.

[MrMagoo]

Problem discovered. A weld where the lower control arm in the front end connects to the frame is failing. This sort of explains everything... the fact that the problem appeared suddenly, and then progressively got worse to the point where the car got to be undriveable was the joint fatiguing. It's almost but not quite completely cracked.

My guess is that a certain 7-8 mile stretch of I-78 near Philadelphia did not help matters. That was pretty abusive. I was waiting for the shoe to drop after that one, but it took a while to manifest itself. Stay off I-78 guys, it was like driving over railroad ties, go I-84 through Scranton instead!

For you Performance Cars afficionados, both rear (trailing) control arm frame mounts have already cracked and been repaired and reinforced (by me), so this is another area on the frame that can fail. I noticed that a fairly new Backdraft I saw last year had a reinforcing support welded to the tab and frame similar to what I did to prevent the tab from flexing and ultimately cracking, maybe this was learned through trial and error or perhaps they just thought it through from the beginning.The rear mounts failed after only a few thousand miles. I now have 16,000 miles on the car, and the front mounts are Kaput. Those 16,000 miles have been earned the hard way with some fairly heroic efforts on my part keeping the thing on the road during the last 5 summer driving seasons since I bought the car. I've never had the car in a shop, I've fixed everything myself, but since this is the front end, I'm having a frame repair shop handle this one.

This one of course is a bad one. I'm glad it didn't happen suddenly and at speed, or your friendly Magoo would probably not be writing this. It is quite probable that this sort of thing has not occurred on Backdrafts, but I guess you Backdraft guys can file it away on the list of the possibilities if you experience similar symptoms.


Thanks and Good Luck to all!

[Gatorac]

If you can, please post some pictures of the failure point. That will help the rest of us to inspect the area properly.

Backdraft added some reinforcements to the rear mounts on a lot of cars. They came and picked mine up and took it back to Miami with them to do the work.

[MrMagoo]

Jim,

Will do. I'm not sure if I will have access until after it is repaired, but I will try to photograph the point of failure so you BDR guys can see if you have any design similarities.

It makes sense to me that BDR, once they had a customer who experienced the rear mount problem, would take care of this pro-actively. The original design was just bound to fail. It's easy to add the reinforcement, a pain in the rear to fix it once it breaks. I think that speaks well of BDR. By the time mine failed (after around 2500 miles!), Performance Cars was in the process of folding so naturally no help there. I did a count. There are only 6 fellow Venom 427 owners who have posted on this site in the last year!

[Smokingcobra2]

Fuuny thing, had same feeling from car on wednesday, luckly was close to home ( 1 mile)
pulled wheel of could not find anything loose, went to turn car around in drive way to check other wheels and heard a snap- backed in real slow and saw same arm totally snapped off.
joeg

[Gatorac]

Re-reading your post I noticed "A weld where the upper control arm connects to the frame is failing".

Is this on the front? My BDR has no front upper control arm.

[MrMagoo]

Just change that to lower control arm. Sorry for the confusion there. Jim, you may not have the same problem, it's possible that BDR reinforced this or redesigned the mount by the time your car was built. These Venoms are like very early BDR. The basic suspension geometry should still be the same though.

[MrMagoo]

Joe

Thats too weird! Glad you weren't too far from home. There is no "field expedient" repair for this one, you just have to get the flatbed.

I think this proves that this is just a design problem. My guess (my car is still at the shop, I haven't inspected the mount myself yet) is that the mount is an unsupported tab. Over time, the flex just weakens it until it cracks. If you bring it to a welder, save yourself some grief and get supports welded to the trailing arm mount in the back as well. I guarantee they will fail eventually with similar results.

Mines still at the shop, and I'll let you know the scoop when I get it back.

UPDATE: Just called them, they are working away. Hope to have it ready in about a week. They are planning a reinforcement that they are also going to apply to the other side. Interestingly, they also say my tranny mount is cracked. Thats a removable piece, and when I did the tranny swap over the winter, it seemed to be OK. They checked the rear (the part I welded up a few years ago) and they say it's OK.

[Smokingcobra2]

I stopped by and saw Brian at vintage, he has a guy who lives near me who will pick up the car and weld and resupport the area.
It was weird, i had the same symptons as you and glad it broke in my driveway.
Hopefully i will get a call from the guy soon
joe

[Gatorac]

Originally Posted by MrMagoo

Just change that to lower control arm. Sorry for the confusion there. Jim, you may not have the same problem, it's possible that BDR reinforced this or redesigned the mount by the time your car was built. These Venoms are like very early BDR. The basic suspension geometry should still be the same though.

OK. That makes more sense. I thought these 2 cars were similar with a BMW strut suspension. I think I know the tab you speak of. I believe my car has support on 2 sides of the tab. I'd love to see pics of yours to see if mine needs reinforced or not. Whenever you get a chance....

[MrMagoo]

I will, Jim. Sounds like you have the rear covered. If its not a tab butt welded to the frame just sticking out into space, you are fine back there. Front will be interesting, but I'm betting BDR figured this out before chassis 189.

[MrMagoo]

Here is a link to my gallery.... look for "Broken Trailing Arm Mount" to see some major FAIL from 2005. I'll get the front mount failure up ASAP.

http://www.clubcobra.com/photopost/s...=19129&cat=500

[cbreez]

All I have to say is WOW! Thanks for the photos...scary...sorry for your misfortune.

[CobraEd]

I would say that the arm needs to be supported from BOTH SIDES, not just one, or it will always fatigue due to flex. A major design flaw!!!


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[Gatorac]