Passenger Front Side JKS Spring Rubbing Against Frame

Yaseenaltajer

Yaseenaltajer

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Joined
Jul 17, 2021
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16
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UAE
Hey guys,

I recently installed a JKS adjustable trackbar (front and rear), upper adjustable control arms (front and rear), JKS swaybar disconnect links, JKS 3 inch springs, and my car already came with lower adjustable terraflex monster arms. I have 33 inch tyres on my car

I have aligned both my axles, yet still facing an issue with the spring on the front passenger side rubbing against the frame and making a nasty noise. I tried switching the springs, no use. My car rides smoothly and double checked that my axles are aligned, so not sure what the issue could be.

Could it be that control arms on passenger side are slightly longer than the driver side? Appreciate your inputs. Below are photos for your reference.

Passenger side
IMG-20210928-WA0001.jpg

Driver Side
IMG-20210928-WA0000.jpg
 
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Your upper passenger side control arm extended too long possibly? Looks like your differential housing may be pushed/rolled too far over the top causing the spring to bow and crash into the frame…
I wouldn’t be surprised if your upper control arm lengths were not precisely where they need to be at and causing the differential housing to be off more than you realize…
Also, did you set your pinion angle with one upper arm installed and then once it was set put the other arm into place? It’s the only way to keep them from fighting each other and cause binding…
 
Thanks for your response.

I only adjusted the rear pinion angle, didn't attempt to do the front to be honest. I will try to do that next, maybe will solve the problem. Could you share any information/standards related to front pinion angle alignment? what is the rule of thumb, requirement etc... is it same idea as the rear side (i.e. matching angles and that's it?)
 
The concept for the front is the same as the rear except you want your pinion angle the same or slightly elevated. Where as the rear you want it the same or slightly lower…

The first thing you want to do is make sure your lower control arms aren’t set too long and pushing your differential too far forward. Stock length would be 15.75”. That is usually a good starting point. I don’t know your lift specs so I’m not sure what length you’ll end up using…

Once you have the lowers set and the differential square to the frame using your track bar adjustment as well then you can worry about the uppers…

Pull the upper passenger side arm completely out. Now set your pinion angle using the upper driver side arm. Once you have your pinion angle set go ahead and put your upper passenger side arm back in. Adjust it to fit into it’s mounting points and lock it down. Don’t worry about it’s length because it needs to only connect those two points. The pinion angle was already set using the driver side arm…
 
Thanks so much for these details, very helpful. Just FYI, regarding my lift specs, I have a 3inch lift, don't know if this is what you meant or you are looking for something else, do let me know and I can provide it if it helps put things into context.
 
Yaseenaltajer said:
Thanks so much for these details, very helpful. Just FYI, regarding my lift specs, I have a 3inch lift, don't know if this is what you meant or you are looking for something else, do let me know and I can provide it if it helps put things into context.
Click to expand...
Your lift height is what I meant. At 3” of spring lift your front lower control arms will be about 16”…

Just remember on your upper driver side control arm, you only care about pinion angle. The length will be whatever it will be to hold it at that angle. The passenger side upper arm will only be installed after you are done setting angle with the driver side arm. The lengths will be whatever they need to be to connect the two mounting points on each side…
 
sycboi said:
Your upper passenger side control arm extended too long possibly? Looks like your differential housing may be pushed/rolled too far over the top causing the spring to bow and crash into the frame…
I wouldn’t be surprised if your upper control arm lengths were not precisely where they need to be at and causing the differential housing to be off more than you realize…
Also, did you set your pinion angle with one upper arm installed and then once it was set put the other arm into place? It’s the only way to keep them from fighting each other and cause binding…
Click to expand...
Doesn't quite work that way. If you push the right side arm longer, all that does if put the upper arms in a bind. You can't adjust caster individually between the two sides.

His issue is common due to the factory built in cross caster and the fact that the lower perches are not mirror images with side specific reverse wound springs. On the left side, the pigtail is at the back of the spring perch, on the other it is at the front. That makes the springs sit differently relative to how they point vertically when they are loaded.

The axle tubes are assembled with the mounts and everything welded on and then pressed into the diff and welded at the plug welds. A slight bit of cross caster is dialed in at the same time leaning the right side inner C forward at the top a bit.

The best way for him to fix it is to pull the axle back slightly, add some more caster, some of both, or get different springs to try.
 
I was thinking he has his control arms all out of whack and he has the entire housing twisted at an odd angle…
 
Hey guys
Just an update
I checked my lower front arms and they were bang on 16inches long each.
My front pinion angle was around 4 degrees off. I adjusted that by equally shortening the upper arms and rotating the axle backwards. This made my pinion have a 3 degree difference to the shaft and it actually moved my passenger spring so it JUST misses the frame.

Seems to have solved the scraping issue of the spring and i believe my angle is now good, but i have noticed a new slight vibration at around 80-100km/h after this move. My trackbar is around 1.5cm off to one side but I don't think this should have a major effect.

I will go for a good wheel alignment and balancing, and then i will try to center my axle by adjusting my trackbar as mentioned above. I hope this will solve the vibrations.

I do welcome any suggestions and thank you very much for your inputs.
 
Yaseenaltajer said:
My front pinion angle was around 4 degrees off. I adjusted that by equally shortening the upper arms and rotating the axle backwards. This made my pinion have a 3 degree difference to the shaft and it actually moved my passenger spring so it JUST misses the frame.
Click to expand...
I would adjust your front upper arms shorter. I would make your pinion angle 1° up or less to the front driveshaft…
 
mrblaine said:
Doesn't quite work that way. If you push the right side arm longer, all that does if put the upper arms in a bind. You can't adjust caster individually between the two sides.

His issue is common due to the factory built in cross caster and the fact that the lower perches are not mirror images with side specific reverse wound springs. On the left side, the pigtail is at the back of the spring perch, on the other it is at the front. That makes the springs sit differently relative to how they point vertically when they are loaded.

The axle tubes are assembled with the mounts and everything welded on and then pressed into the diff and welded at the plug welds. A slight bit of cross caster is dialed in at the same time leaning the right side inner C forward at the top a bit.

The best way for him to fix it is to pull the axle back slightly, add some more caster, some of both, or get different springs to try.
Click to expand...

Thank you for the elaborate explanation
 
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Another update:

After some extensive research, I have deduced that I had the whole concept wrong. My pinion was intially at 10 degrees and my driveshaft at 6. I reduced the pinion to 9 but that is still 3 degres higehr than the driveshaft, where it seems it should be equal or slightly lower to the driveshaft angle, to account for the car raising a little during acceleration. My upper front arms are too long (set that way by the garage who installed my new suspension). I will adjust them and fix my pinion angle, that should get rid of my vibrations and hopefully explain why my spring was so far up in front!
 
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