Bent spindle on front strut?

[PeteKz]

Gents: On my 1973.5 911T; after installing the RSR front bushings, setting the front ride height to 25.5" on both sides (from floor to bottom of fender lip), and setting the toe, I have noticed that it still pulls to the left moderately. So I pulled down my carpenters square, laid one edge on the floor and stood the other edge up alongside the tire to measure the difference in space from the top sidewall to the bottom sidewall. On the left side, I measured about -1.4 degrees of camber, and on the right, -2.1 degrees. So, about 0.7 degrees of difference. To check I laid down behind the rear wheels and sighted down to the front wheels, and the right wheel appears to lean in more than the left.

No problem, I'll just adjust the top plates at the top of the struts. However, when I pulled back the frunk carpet, I saw that the right plate was already adjusted as far out as it could go (close to the fender), and the left side was adjusted as far in as it could go (away from the fender). It appears that the PO had already tried to get the left and right side camber as close as possible, but it still wasn't enough.

Was the front of the car bent or twisted? I didn't notice anything obvious when I pulled it all apart to put in the RSR bushings, but I measured the distance from the floor to the ends of the aluminum crossmember, and they are within 1/16". My garage floor is pretty flat, but it's not perfect, so 1/16" is probably as close as I can measure. I looked around the frunk and under the front clip, and I don't see any buckling of the panels and the hood fits reasonably well with the same gap from front to back on both sides (considering I have fiberglass fenders).

I noodled on it for a day, and thought that maybe the right spindle got bent upward from a hard pothole or curb hit. I then jacked up the car and stuck some blocks of wood between the tire and the upper part of the strut to check the clearance. Sure enough, I had about 3/16" more clearance on the left side than the right side. So it does appear that the right side spindle is bent up a couple degrees.

I know the spindle is pretty stout, so let me ask any of you who have experience with seeing bent spindles, or lots of experience and not seen bent spindles. Is this something you have seen, or is it unheard of?

Thanks.

[icarp]

Pete , it is normal for the strut tube to bend over time and change the camber
Best thing to do is spring for new ones .
sorry for the big $$$ news

Ian

[Arlo911]

I've had the same thing happen, the strut tube bends above the spindle.

[PeteKz]

Thanks for the replies. Good to know it's not something more serious. Also gives me an excuse to "upgrade"!

If I have to replace, should I look for struts from an SC, or Carrera, or something else? Should I look for some with 19mm dropped spindles? Will the brake bracket require that I swap the brake calipers too? (I heard that they have a different pattern than my 1973). Should I consider coil-overs instead?

One thing I won't look forward to is separating the ball joints from the bottoms of the struts. I tried to do that when I installed the RSR bushings and gave up, and removed the ball joints from the A-arms instead.

I love spending more money...

[touringmandan]

Look at the strut tube right where it joins the spindle. Directly above the spindle. You might see cracking in the paint. That's the "tell-tale" of a bent strut tube.

[stownsen914]

If I've read your post correct, I'd want to do some more measuring before assuming parts are damaged. A couple things:
- Don't assume your floor is anyway near flat, or level. It can throw off your measurements. It's very normal for a floor to be unlevel by 1-2 degrees and have some twist. It's hardly noticeable ... except when you are doing an alignment on your car, and suddenly 1 degree is huge.
- 911s are not as symmetrical as you might think. It might contribute to what you are seeing.

Personally my garage floor is slanted by something like 1 degree and also has some twist. When I do alignments I use those cheap thin floor tiles from Home Depot as shims to get the four corners where I want them. I have to shim 3 of the 4 corners to get a level platform for alignments.

It's still possible you have a bent strut, but consider the above.

[tsuter]

I hit a steel construction plate in the street...pretty hard. Then could not align the driver side to spec. Spindle was bent on the driver side strut that ran over the plate. Since both were 30 years old...I replaced both struts... with new Bilstein.

[mepstein]

They are often bent. Usually it’s the right side. A lot of sets I’ve pulled from cars or purchased have been tweaked on the right side.
When I was at DC Auto, they had about 30 left side struts and only a couple right sides. Rob told me 911’s take a hit on the right side about 95% of the time.

[touringmandan]

Most potholes (and curbs) are on the right, so that makes sense.

[PeteKz]

Gents: Thanks for the additional replies. I haven't pulled off the hub yet--I'll probably save it for when I need to do something else at the same time "as long as I already have the hub off" like replacing discs. It's noticeable, but not annoying. Yet.

Stownsen914: Yes, I'm aware that garage floors usually aren't level. If I lay a straight 2x4 across the floor where the front wheels park, it doesn't wobble or have significant gaps under it. I did visually compare side to side, and use a carpenter's square, and I am sure that the camber is greater on the right side than the left. A couple years ago, I flooded the floor with water while washing it, and observed the high and low areas. The floor has a very slight rise from front to back but very little side to side, and more importantly, it's "pretty flat". That's the technical term...
The difference in spaces between the inside of the tire and the strut, left to right, are the stronger indicator that something is off.

tsuter: Interesting that a hit on a steel plate in the road bent yours. Although these things look pretty stout, and as tubes they should have a lot of geometric rigidity, apparently the steel is not high carbon and yields easily. Knowing that, I might try to bend it back a bit. Hell, I have straightened slightly bent motorcycle front fork tubes in a hydraulic press and it worked pretty well. Yeah, new struts would be better, but I'll hold off on that until I decide whether to pop for coil-overs and/or larger brakes.

mepstein: Thanks for the further confirmation. Interesting that the right sides get bent more often. It makes some sense though, because we tend to avoid things right in front of our eyes (from the left driver's seat) than further away, and curbs are usually on the right side of the road.

[Walt Fricke]

Already listed is one sign of a bent strut - the top backside of the spindle forging is pressed tight against the strut's steel tube. Often there is a noticeable kink in the tube. So it really isn't a bent spindle, but rather a bent strut tube.

Another sign is great difficulty (or even impossibility) in pulling the shock insert out. The kink can lock it in place. If you can pull the shock, you may see a horizontal kink in its tube. You might consider doing this (not difficult), though a good visual inspection with the wheel off and the steering wheel turned to full lock each way may let you see if there is a kink - pull both wheels and compare how the struts look on their back sides right above the forging.

Porsche took to reinforcing the joint between strut and spindle - you can weld all the way around, and weld in triangular gussets from the forged collar to the tube.

If mechanically inclined, it may be possible to fix the kink, perhaps by forcing a mandrel down the tube? Or by doing something else.

If you get a replacement (agree that they have become hard to find), you might remove your spindle and save it. You could mate it later if you find a strut where the spindle itself broke (usually right at the outer part where it necks down to the threaded part). Bit of effort with a die grinder to remove the spindle forging, but doable.

[PeteKz]

Walt, thanks. Im going to try to straighten it first. As noted above, I've done that with motorcycle forks. I did it by putting the tube across two V-blocks under a hydraulic press, with some wood to crush and cushion the tubes. If I doin't like how that is working, I can pull out my torch and heat the tube to soften it and anneal it. It's not high carbon steel, or it wouldn't have bent in the first place.

[Walt Fricke]

Let us know how that works. My concern would be that this is a kink in the tube, not a longer radius bend. In a front oil cooler line with something like this, you pressurize the line and heat it until it goes back almost to true round. But that's thin tubing and not steel, and it is only accidentally stressed, and doesn't need to be round to be strong.

But maybe you can compress the stretched metal back to true?

If you do straighten it, consider the factory 2.8 RSR reinforcement approach. Easy to find pictures, but here are some I grabbed as an illustration for gusseting. The last green one has welding which looks like mine. You are doubtless better at it.

[Tyson Schmidt]

The quick check is to compare the gap between the inside edge of the tires and the strut bodies on both sides. If they are different by more than a few mm, then one is bent.

And like others have mentioned, the spindle is pressed on and rosette welded on the back side. When they take a hard hit, the spindle pivots off that rosette weld. You’ll see a witness mark on the underside of the spindle where it meets the tube on the opposite side from the rosette weld.

[PeteKz]

Walt thanks for the pictures. I have a bunch of other stuff on my plate right now, so this will be a "round tuit" project later. I will post back after I give a try at straightening it. Or I may just use this as my excuse to buy KW dropped spindle front struts.

Tyson, yes, I already checked the clearance between the inside of the tire and the strut on both sides. There is about 1/8" to 3/16" more space on the left side than the right. It's bent.

[PeteKz]

Follow up:
As noted, the car had a moderate pull to the left that I have to counter with steering pressure.
This past weekend, I disassembled the right strut and put it in my hydraulic press to bend it back. The tube did not appear to have any kinks at the forging, but by laying a straight ruler against it, I determined that the tube was bent slightly. I bent the tube about one degree, at which point it appeared to be straight.

Then I reassembled the strut, checked the camber again, and found that the right camber was now about negative 3/4 degree (confirming that I reversed 1 degree of bend). At this point I had about 1/2 degree less camber on the right side than the left side, so I took it for a test drive. It still pulled to the left about the same as before. I have not tried to adjust the caster yet, but I don’t think that will make as significant a difference in pulling to the left as the camber.

I also did a rough check of the corner weights on the right front wheel versus left front wheel. I jacked up the car under the engine centerline to get the rear wheels just clear of the floor, then pushed up and down on the front of the car to settle it, and then measured the fender heights, and they were equal. Also, as I jacked up the car, the rear wheels cleared the floor at the same point. So I think the corner weights are close enough that they are not responsible for the pull to the left.

FYI, since I straightened the tube, but the camber is still negative at it's maximum adjustment, I strongly suspect the spindle forging also bent about a couple degrees.

What are your suggestions to get my car driving straight?

[stownsen914]

Good job straightening the strut tube! It is possible the spindle is also bent. As suggested by another post, is there a difference in the distance between the wheel lip and the strut tube when comparing left and right? If a spindle is bent, there will be a difference.

Corner weights and balancing is a very precise task. Your method may tell you that the weights in the front are not grossly off, but keep in mind that a difference of more than 20 lbs is considered significant. I am thinking that your method may not discern a 20 lb difference.

And perhaps more importantly, rear corner weights impact that front too, and your method doesn't consider this. Cross weights (LR to RF, and RR to LF) directly impact one another. It's tough to precisely check this any other way than a proper corner weight check on a leveled surface.

Have you checked your other alignment specs?

[PeteKz]

Yes, my weight method is pretty crude. Will 20 lbs, 50 lbs, or even 100 lbs difference make the car pull to the left?

The rear alignment camber is about 1 degree more negative than specs, but the toe is about zero. I do not get pushing to one side on hard acceleration, or to the other side on hard deceleration, so I don't think the rear suspension is pushing the car to the left. I've driven cars with rear alignment problems, and this does not feel like a rear alignment problem. It very definitely feels like the front. I do get some looseness from the rear as I go over the ruts in the road. As I said, I have RSR bushings that I have not yet installed. Maybe this month.

[stownsen914]

For reference, Porsche's spec for corner balancing is something like 40 lbs difference if I recall correctly. A proper corner balancing job using scales on a level surface should get you under 20.

There are lots of possible causes of unevenness in an older 911 that could lead to a pull. An alignment and corner balancing should catch most of them.

[Walt Fricke]

Hard to imagine this type of forged spindle bending, Much stronger than the tube. It can break where it necks down, but as the fracture grows the camber won't change measurably.

Porsche has/had a jig (see factory manual) to check the strut/spindle.