Broken Power Cylinder (C3), Don't let this happen

[Lee S.]

I thought I would share experience. Yesterday, I suddenly lost all power steering assist while backing into a parking space at a local show. Now, if you have ever driven a big block car that is supposed to have power steering and now doesn't, you quickly find out it is a job for a real man. Unfortunately, I guess I'm not anymore as it was a struggle to get into the parking space and subsequentially drive home. Now to what happened...

If you have power steering on a C3 (probably C2 and others?), you have undoubtably seen the power cylinder underneath the left front area of your car aft of the front wheel/tire. There are two hydraulic hoses attached that are coonected to the control valve at the other end. You can't miss this as it is usually leaking power steering fluid on your garage floor.

This hydraulic cylinder is waht provides power assist to your car. The inboard end is attached to the relay rod with a castle nut and cotter pin. The outboard end is attached to a bracket bolted to the frame with four bolts. This is the source of my problem. Apparently, the inboard attachment ears fractured a long time ago. This now transferred the load to the two remaing bolts on the outboard ears. Eventually, this worked loose and started to pull through the frame. With the bracket and power cylinder mis-aligned, the end of the power cylinder bent to approximately a 20 degree angle. The end of the cylinder finally snapped resulting in loss of power assist.

Symptoms of this prior to snapping, was a steering wheel shimmey in certain conditions. This is very similiar to the shimmey induced by a bad steering dampner. Don't let this happen to you. I'm looking at about $200 in parts. I'm also trying to find someone with mobile welding equipment to come to my house during the week of the Woodward Dream Cruise.

Take a good look at all four mounting ears on this bracket occasionally to ensure they are intact and tight.




http://www.villagephotos.com/pubbrow...elected=980767

[Terry F.]

Re: Broken Power Cylinder (C3), Don't let this hap

I would suspect your problems started when the bracket was installed originally. You may already realize this. Notice the overlap of the two halves of the frame and how they are welded and the way the bracket is made to step down to accept the surface of the frame. I suspect your frame was a little thick at the weld and formed a fulcrum. As the nuts were drawn tight, it probably bent the ears and formed small cracks in the cast iron bracket. Eventually, the repeated stress of steering caused it to snap the ears off completely. I think you have the results.

I would consider reenforcing the frame structure internally somehow. Inspect the quality/integrity of the surrounding metal. Good luck, Terry

[Lee S.]

Re: Broken Power Cylinder (C3), Don't let this hap

Thanks Terry. I agree with your assessment. However, I never considered this to be the root cause. It does make sense. I was concerned about this condition in repairing the area. I do have the new bracket and I'll make certain it does seat on the frame without rocking. As you point out, the bracket can allow for a small amount of mis-alignment.

I have a mobile welding company coming to the house tonight to make the repair. I am at a loss to figure out how to reinforce the frame internally. There is room to get a small piece of steel inside the frame through the reiforcement access hole. The mounting holes for the inboard area are sound. I also purchased new reinforcements.

I'll post results and new photos in a day or so.

Thanks.

[Terry F.]

Re: Broken Power Cylinder (C3), Don't let this hap

If the welder is any good, they may suggest something. I would think there butt is on the line if it breaks again and you get hurt or something worse. It is a tough one. If the steel in the area is sound and not badly rusted internally. I would probably go for it as is. But the cracks should be V'd out so that a deep penetration weld can occure. Then, only in the are that the bracket needs to sit flat on, I would grid it so the bracket will sit flat. If you grind the whole weld flat for cosmetic reasons you may weaken it.

If I was going to reinforce it. I would probably study it and consider sliding a piece of steel inside the area. Make it wide enough to cover the hole area from side to side. You would have to custom make something to step over the way the frame is put together in that area. It could be made in two pieces like the straps and run left to right and attach under the straps that hold the bracket. The wide steel would distribute the force over the entire area more enenly. Something like 3/32 inch thick might do it. Just an idea. Could be inserted through the same hole the other straps insert through. Just be safe. Terry

[Lee S.]

Re: Broken Power Cylinder (C3), Fixed

I just thought I would close out this thread and let everyone know everything went back together with ease and operates fine.

I added a couple new photos to the link showing the completed repair. I am going to post a current link requesting information on the correct finish of the bracket. It was a rusty cast iron NOS when I bought it. A few minutes in the bead blaster had it looking like new.