So I am in the progress of rebuilding my front suspension and I need a little help figuring out what is normal and what is the signs of a failing part. As of now, I know I will be replacing all ball joints and tie rods but what I am unsure of is the upper and lower A arm Shafts.
I currently have the A arms separated and checked each for lateral movement. the uppers seem fine (move freely with no lateral wiggle) but the passenger lower has about .5cm travel the lower also sings freely unlike the drivers which seems a bit stiff...
Drivers Side:
Passenger Side:
Apologies for the black swirl but It is at the manufacturer request to protect a pretty unique suspension mounting setup.
I just do not know what is right and wrong with the spindles. Any help would be appreciated, trying to save a few $$$ rather than just replacing everything I see.
I replaced spindles, bushings and grease seals when I rebuilt the suspension on my 69. I dont know how to determine if any of the old parts can be reused. When I pulled them apart, no obvious cause for the slop. Sorry cant be of more help.
yea, I have been thinking that as well... but not replacing them would save like $500 so if at all possible, would be nice to know if I can keep the old parts.
Disclaimer...I'm not expert on this....JT and Ross may chime in or correct as they think necessary.
Let's think about it, the spindle is bolted in place and prevented from turning. The bushings are also threaded in place and do not rotate. The load is not even over the entire surface of the spindle/bushing so, if you were not able to inspect the assembly for play before you pulled the a arms off, I'd think the next best way would be to mic the spindles and bushes for roundness and consistency over the wear surface. This based on the assumption that wear, if it occurs will be at the loaded surfaces thereby wearing away metal and creating an out of round situation.
I have no idea how much is too much but it won't take much "slop" at the mating surfaces to make a few mm travel at the opposite end of the a arm. I'd guess that a variation in roundness or diameter of .010" would be enough to think about replacement but that's a wild assed guess.
If the spindles are all round, consistent over the wear surface and from end to end and sized within a few thousandths of each other, I'd assume them to be good. Same is true of the bushings. If any out of round or any part is different than the others, I'd replace it. Would be nice to have the dimensions of new parts in the Wiki as reference.
Dan
SPL311 aka Skooter. Sold. Now wasting away in the SF area.
1990 Nissan 300zx. Sold this one too.
2018 VW Tiguan
It seems that I remember reading here that the bottom spindles take more abuse, and thus wear out faster than the tops. You might entertain just replacing the bottoms if you're trying to hold costs down.
Mike M
Old enough to know better, too old to remember why!
1969 2000 solex mine since 1972, under resurrection. (Finally resurrected as of spring 2019!)
1969 Porsche 911s -worth more, but not as valuable! Gone!
2017 Lotus Evora 400 - Oh my!!
So it's correct the lowers see more load than the tops, but the '"bearing" surface area of the lowers is much larger than the uppers, so its the uppers that wear out first from what I have seen. Dan is also correct that the load is asymmetric. From what I have seen, the rear lower position gets the most abuse, so you can turn around the lower spindle front to back and get twice the life out of it IF it isn't already worn out.
From the perspective of "how much play". Ideally, only you have rotation, with zero lateral play- that is clearly what the designers intended.
1mm of play at the bushing is actually a lot, because that results in much more movement way out a the ball joint. If you can't really detect any lateral motion, you are in good shape.
Be sure to have the arm rotated up into the normal ride position when testing since that is the position that will show the most wear.
Also, because of the metallurgy (The Japanese were pretty good at that) the bushings tend to wear more than the shafts, so I see about ~30% worn lower shafts, ~70% usable- so yes, a pretty good chance that replacing just the offending bushing will greatly help. If you keep them lubed, they hold up fairly well. If they haven't been lubed much in their life, the shaft may be wasted.
The trouble with bushing play in this suspension design is it dorks up ALL your alignment parameters, toe+caster+camber, at once, not just one or two like other suspension designs&components. That can really make the front end feel loosy/imprecise.
So recommendations, if your uppers bushings are tight/i.e just up down motion, can't feel any play..grease them and let them ride. If the lower rear just has a little play either just replace that bushing and test again, or replace the lower bushings and rotate the shaft end-over-end. Good chance things will tighten up quite a lot. If the lower shaft is really torn up, you will need a new or good used lower shaft and two new or unworn lower bushings.
Okay, thanks for all the input! So Since I have had the car, I have basically greased everything with each oil change but before my ownership, it did not seem like the suspension was touched in years. That said, I was able to give everything a good yank and only the passenger lower bushing had any detectable slop, id say about 1mm back and forth. Sounds like I can chance not replacing the shafts unless something looks particularly bad when i take everything apart.
Just to continue this thread... I was able to disassemble my upper passenger a arm (did not seem to be slop) and after cleaning it up a bit, I noticed some corrosion and just not perfect channels in the threads. Pics Below. Is this still usable? The corrosion is apparent in the top of the photo. I think after hearing all the stories about bad suspension, I have gotten paranoid...
That one really doesn't look bad. Minor thread imperfections are really not a concern. If there isn't any play just clean it well, grease it well, turn it around end-to-end and it will probably work fine for years literally- the original Nissan parts are hi quality and go for a long time if greased regularly. (They only wear significantly if not lubricated and driven - they don't go bad from sitting around).
When the upper arms are worn out it is very easy to feel the play just by grabbing the center bar and trying to wiggle it-no wiggle, no reason to replace it.
If your other arm is tight, I would just lube it and be done - or if you really want to go to the effort, repeat the above.
