1991 Ls400 Suspension Nightmares! (Still Best Car I Ever Owned)

[dulobast25]

I have a 1991 lexus ls400 that I purchased from a 2^nd owner home. The car (other than cruise control not working) was in mint shape, with perfect leather interior (even perfect steering wheel leather).

I have had the car just over 2 yrs and I am now at just over 159k miles. I update the wheels and tires and noticed a rubbing in the front that progressively got worse. First I attributed this to the slightly taller and white wheel/tire combo, but the pass side didn’t have the same problem.

Next attributed this slightly higher wear on the driver’s side due to high freeway miles. I still feel this to be the case, but at this point it time to asses all the symptoms.

It was recommended to be my Sears, my (former) lexus mechanic, and my brother that I replace the front struts. I decided to do all (4) I replaced them with Stagg struts. The price was good and the qulity is good.

For the most part the rubbing on the driver’s side was reduced, but still present, and a small improvement in handling, indicating my old struts still had life in them. Since the car had over $110k, I still considered the strut replacement an overall good idea. Since rubbing continued and worsened until it was where it was before the strut replacement. It was recommended by Sears that I replace the front coil springs, so I purchased (2) coil springs from parkplanolexus in Texas. A Sears also measured the car and concluded that the driver’ side was ¼” lower than the pass side, which fell in line with my early suspicions. Over time the front end developed clunking and tapping, and Sears recommended that I replace the lower balljoints. I took it in to my lexus mechanic and redline suspension in el cajon, and they recommended the lower balljoints, and the front strut bushings. (my mechanic concurred). I paid Rose automotive in el cajon, ca, (another mechanic) to replace the front brakes, both lower balljoints, change the oil, and replace the springs. The mechanic recommended that since the drivers side was lower that I just replace the driver’s side and that would help maintain even the stance. It did. He also stated that the pass side height was within factory tolerances, as was the driver’s side. Sears came to the same conclusion.

Installing the spring on only the driver’s side help a lot with the tire rubbing and bottoming out, however it was still occurring, and over time it grew worse until it was what it was before the spring replacement.

80% of the suspension noise was cured with the lower ball joint replacement, but some 20% clunking and tapping remained. I had Sears, and re-inspect the suspension, and they ruled out all but the front strut bar mounts. I had my (lexus) mechanic replace those, but the noise was unchanged. Although all mechanics concurred that there was minimal cracking in the strut bar mounts, the noise remained. I consider this was waste on money, as there was no improvement in handling or stability either.

During this process, I developed and occasional clunk in the rear and my mechanic concluded the rear driver’s drive axle boot was torn and joint contaminated. He replaced the axle and it cured that clunk in the rear. I also had him replace the carrier bushings (front of the rear arms) with asus urethane units, as the rear arms had developed some play in the bushings. The mechanics assured me he lubed them as well, but they now squeak a little. I will likely have zerk fittings installed and have the bushings reinstalled, so they can be re-greased.

Back to the rubbing, bottoming out and tapping, I read forums on clublexus, lextreme, and a few other lexus forums and after decoding all of the experiences, I concluded that I was going to rid my car of this noise once and for all. I ordered strut cushion, and strut spring upper insulator for driver’s side from parkplanolexus, along with a Monroe strut mount and a transmission mount , each from ebay. I took my car to the lexus mechanic this weekend (Saturday) and we pulled the strut off. I lifted the hood and confirmed the cause of the noise as no matter who pushed the car up and down, I was the only once who could hear the tapping noise. It was coming from the top of each strut tower and was louder on the driver’s side. This was then confirmed with the mechanics’ stethoscope. Upon pulling the strut, we notice the strut hole in the mount was slightly rounded, but since I bought a mount, this was no big deal.

Next thing we noticed was the strut assy had been put together in such a way that the lower strut mounting hole wasn’t aligned perfectly with the mount hole and was rotated with forced with vice grip or channel locks. This of course mangled up the strut body and since the strut wasn’t seat correctly, is mis-seated the lower strut eyelet/mount. When we pulled the coil off, the coil wasn’t sting correctly, and the lower coil spring isolator was not even in the correct position allowing metal to metal contact.

This was causing 35% of the tapping noise. I removed the upper insulator and it has (3) hole where the top of the coil spring had worn thru (at bottom end of each of the mounting studs). There is a corresponding thin spot in the insulator that rests in these areas. This was causing the remaining 75% of the tapping noise. The insulator was also compresses when compared with the new one and it was just under ¼” flatter than the new unit. This, when added to the lack of a lower isolator explains why the driver’s side was 1/8” to ¼” shorter/lower than the pass side. This explains part of the bottoming out as well. Lastly, the strut bumper or bumpstop was chewed up at the lower 25%. Basically about ½” was missing. This allowed the strut to bottom out without the bumper contacting anything.

As it turns out, Toyota is mislabeling the strut bumper s for the sc300/400 and ls400. The one labeled “

48331-24030

front suspension, suspension components, bumper

Is actually incorrect and has a center hole too large in diameter to rest on the stop at the top of the strut (and will slide down the strut unlike the correct one)and is too large in diameter in general to sit in the strut mount. In all my search, no companies make this for the 89-94 ls400s aftermarket. The closest unit is the “SB101” from KYB which is for another lexus, but its about 3/8” to ½” to tall. It will still fit but the height will not be OE, without trimming the top of the bumper down ½”.

FYI, if you are changing everything at once, check fit between the strut cushion to strut mount, and strut mount to strut, before dissasembling your car. Since I was sent the wrong part, my car will still a week as the mechanic house (which Is uncomfortable for me). The correct part for 1991 ls400 has (2) slots in the top of the cushion, the 24030 has (4). Before you order confiem if the correct insulator is:

48331-24030,

48331-51010,

or 483311-51030.

I can assure you if it is the 24030 and you have an 89-92 ls, it WILL NOT fit the strut or strut mount.

A web search show that the numbers are incorrect in the Toyota catalog and you must bring your part to match it.

I will be re-assembling the strut this week and provide updates. Wish me luck!

What I can conclude is that my mechanic and rose automotive were partially responsible as I asked both of them if the strut mounts and hardware looked good during strut and spring replacement, and both said they looked ok. Upon disassembly, It is clear that they don’t know what OK means, what bad components look like, or simply didn’t look and were in too much of a hurry to get the car back together. So I think this whole process could have been avoided.

Next on the list of repairs is:

EGR tube replacement

Center support bearing replacement

Engine mount replacement

Transmission mount replacement

Rear carrier bushing removal and reinstallation with zerk fittings.

Drive belt/cap/rotor/plugwire/plugs,timing belt/oilpump/and pulley replacement (mine is original at 159K and has cracks in it!)

I was able to find the cheapest price on either OE and aftermarket parts and will share that list of sources part number and prices as time permits!