S7 Front Suspension. Should I Worry?

[dandan62]

Hopefully there are some pics attached of the top mount of my Sierra S7 RH. Where the ball joint screws into the top member it is slightly bent. I bought this last winter and noticed this a couple of months ago. There has been no movement since. I assume it was like that when I bought it. I cant believe it is from a knock as it would take a huge force and all the rest of the suspension looks good. Maybe it was bent that way by the original builder to get the geometry set up? Probably not. Should I worry? Anybody any idea how far that thread goes into the tube? I know...take it off and have a look! I need a special tool to get up to the ball joint nut I think.

Looking ahead, if it is a problem, how easy would it be to repair it or should I look for a replacement. I presume these top wishbones should be a matched pair. Anybody got a couple that are lying around? I may be interested.

 

Cheers all.

[cb750]

Looks to me that it may have had a hit in the past. Looking at the photos I would strongly recommend that you check how much thread on the ball joint is still in place in the wishbone as it looks to be screwed quite a way out.

[richyb66]

As Rob says, compare your ball joint with this one - should be easy to work out how far in it's threaded:

 

http://nw.rhocar.org/parts.htm

[cb750]

Beat me to it! Just looked at a photo and there are about 40 threads (correct terminology?) on the balljoint so you can work out the distance it's screwed in.

 

Rob

[dandan62]

Thats very useful. Comparing with the photo there must be at least 2 1/2 inches of thread in the tube. That gives me some confidence that it is unlikely to snap. There is no evidence of it actually failing yet but I will take it apart at some point. It must be effecting the geometry though but since I don`t push this car anywhere near its limit and the tyres seem to be wearing evenly i`m not too worried.

I would still be interested if anybody has any though!

[Jez Morton]

I would remove the ball joint to check its length, could have been cut down especially if the thread in the tube wasn't long enough. I think a common issue used to be around the welds seem to remember on mine I had to retap the tube they may have been welded after the thread was cut.

[Snapperpaul]

Mine (S3a) is screwed in a lot further than that, in fact I had to buy thinner locknuts to get the camber right.

[Guest 2b cruising]

By the way the paintwork on it is, it looks like a reasonably new injury. A bandage won't let it heal itself though.

If the ball joint is bent, I doubt you being able to screw it out of the bent tube.

If it has been cut you won't have a problem to screw it out.

Check your geometry and if it's ok, (doubt it myself) you can just clean off the flaking paint and re-paint it.

If it has a shortened ball joint, gentle heat to dark cherry the straighten without removing from the car.

If it's long thread you have a more serious job on your hands. You could remove it, heat it to bright cherry and straighten.

I don't mean with a hammer either.

In both cases allow the metal to go back to its natural state and don't cool it with any liquid.

If you want to temper harden, clean the area off after it has cooled as you need a clean surface.

You will need to watch the colour of the metal as you are heating it. When it's warm enough (light brown), then quench with water.

Edited July 26, 2016 by 2b cruising

[cb750]

My 3A is the same as snapperpaul's. I think the pitch of the thread is 1.5mm, if I am correct then looking at the thread count I would say that if the thread is full length then you have about 30mm of thread inside the tube.

[dandan62]

Ok. So I am back to being worried. I will take it out at some stage. I have freshly painted it with the theory that any movement or cracking show show up more easily. I presume just undoing the mushroom clamp it should be removable with the front jacked up? Not sure if the anti roll bar will allow that much movement. As you can probably tell I'm not a great mechanic but willing to learn! Brakes and oil changes and tinkering. But that's why I bought it. New challenges.

[Guest mcramsay]

From a mechanical point of view you need to check how much thread engagement you have. There's no point trying to guess. Measure the exposed threads after the locknut so you can set it at the same length when putting it back in, the bend may be previous damage, it may have been done when building as things didn't fit. Or it may be an early sign of a failure that is about to happen. Pushing the car to its limits or not, if that let go when you were driving it would not be good for anyone.

 

I'm not trying to panic you, and it may all be fine but it it were me I would want to know for sure

[dandan62]

I'm sure you are right. Jib for the weekend then.

[Guest 2b cruising]

With the paint peeling right on the bend I would say it's a fairly recent occurrence.

As said before, if it screws out easily it's most likely the ball joint rod has been butchered. Possibly because the builder could not be bothered cleaning the dwarf.

I have had first hand experience of a GBS bought one having to be re-tapped.

[cb750]

Cleaning the dwarf? Perhaps the previous builder couldn't catch him!

[Guest 2b cruising]

Oooooopsss. Swarf.

Must have just washed my hands and my fingers were all over the place.