LS - 1st and 2nd Gen (1990-2000) Discussion topics related to the 1990 - 2000 Lexus LS400

'91 Front Suspension Knocking

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Old 09-28-10, 05:32 PM
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dkls400
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Default '91 Front Suspension Knocking

The car had a factory air suspension and while it did, there was a knocking sound in the front suspension that sounded like a shot strut mount (a problem i had in another car). Upon converting to regular struts, the sound got even worse. I'm thinking either sway bar end links or upper control arms. Any ideas? Thanks.
Old 09-28-10, 07:44 PM
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JimsGX
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Could be a variety if things... Upper or lower control arms, or upper / lower ball joints... Jack it up or get it up on a lift and check it all out with a pry bar.
Old 09-28-10, 10:29 PM
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dont forget tie-rod ends!
Old 09-29-10, 12:07 AM
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all this, and nobody's mentioned strut rods bushings....
Old 09-29-10, 01:26 PM
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dkls400
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I had it jacked up and checked everything nothing seemed loose and all bushings seemed ok. I ordered sway bar end links and I think I will get the bushings that hold the bar to the frame or w.e. it is bolted to. I will take it from there and see how it is after that. Thanks guys I wish parts for this thing weren't so expensive.
Old 09-29-10, 02:07 PM
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Max Power
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I just received my new upper control arms today. Struts come in tomorrow. Same boat as you. Knocking, except I have gnarly tire wear to go with it.

Good luck!
Old 09-29-10, 04:01 PM
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JimsGX
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Originally Posted by Max Power
I just received my new upper control arms today.
Which UCA's did you buy?
Old 09-30-10, 01:21 AM
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Max Power
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Originally Posted by JimsGX
Which UCA's did you buy?
Arnott. I know, I read your thread, but for the price I figured I might as well give em a shot. If they're no good I can send them back and try something else. I plan on only having the car another year or two anyways at most.

Plus, in Canada we have it bad for parts ($$$$).
Old 09-30-10, 01:58 AM
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Max Power
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And I'm hoping the arms you got that didn't fit properly was just a fluke.

I paid 3000$ for the car last year. There's no way I'm spending half of that amount on upper control arms only.
Old 09-30-10, 01:31 PM
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JimsGX
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Keep your fingers crossed. I'd be interested to know how they fit. I'd appreciate you posting the results. The UCA ball joint nuts need to torque up to 48ftlbs. As you know, the problem I had was that I reached the end of the threads before I could get them to that torque and the cotter pin hole was 1/2 below the castle nut. The two UCA bolts into the frame need to be torqued to 83ft lbs, just so you know...
Old 10-04-10, 02:07 AM
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Yup! thanks for the info. I will know Wednesday. I'll post up my results.

Fingers crossed for sure.
Old 10-18-10, 01:12 AM
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Max Power
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Originally Posted by JimsGX
Keep your fingers crossed. I'd be interested to know how they fit. I'd appreciate you posting the results. The UCA ball joint nuts need to torque up to 48ftlbs. As you know, the problem I had was that I reached the end of the threads before I could get them to that torque and the cotter pin hole was 1/2 below the castle nut. The two UCA bolts into the frame need to be torqued to 83ft lbs, just so you know...
Hey Jim,

So I did the entire install today. Was able to torque the ball joints properly but the castle nut and cotter pin were still not flush. I ended up using a washer on both sides.

Pretty crappy quality for UCA, however, well worth it for me.

I figure I'll make sure to lube the boots once a month or so.
Old 10-19-10, 08:14 PM
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JimsGX
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Thanks for posting your result Max Power. I'd keep a close eye on them. Depending on the inside / opening diameter of the washer you put on the top of the knuckle and if it's seated on the taper, it may loosen over time. In my case, the taper never seated and the shoulder at the end of the taper, which is maybe 5mm larger than the top of the taper is what it seated on.

I ended up finding replacement urethane boots for my original Arnott UCA's and I reinstalled them with the new boots a couple of weeks ago. The urethane boot is much thicker than the original. Here's a pic of the original Arnott UCA with the urethane replacement boot installed on the car.
Attached Thumbnails '91 Front Suspension Knocking-arnott-uca-w-new-urethan-boot.jpg  
Old 10-21-10, 01:48 AM
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Max Power
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Originally Posted by JimsGX
Thanks for posting your result Max Power. I'd keep a close eye on them. Depending on the inside / opening diameter of the washer you put on the top of the knuckle and if it's seated on the taper, it may loosen over time. In my case, the taper never seated and the shoulder at the end of the taper, which is maybe 5mm larger than the top of the taper is what it seated on.

I ended up finding replacement urethane boots for my original Arnott UCA's and I reinstalled them with the new boots a couple of weeks ago. The urethane boot is much thicker than the original. Here's a pic of the original Arnott UCA with the urethane replacement boot installed on the car.
Good call on the thicker boot. Where did you end up finding them?

So far everything is holding on together very well and the drive is so much nicer. My cotter pins are holding and I check both sides pretty much after every drive.

I don't expect they will loosen at all but I guess anything can happen...
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