OldLs400

So, I read the sticky about the commonly heard "clunk" or "popping" noise in our LS400s. It's apparently the bushing on the front strut rods/bars that goes bad. The clunk happens usually when braking at low speeds, or when turning and braking at low speeds (like when you're parking your car). It also happens under emergency braking sometimes.

I was THIS close to buying new front strut rods/bars to fix the clunk. However, I changed my brake pads the other day.

And guess what? The clunk ALMOST disappeared. No matter how hard I braked that day, I couldn't make the clunk come back.

However, the other day, the clunk came back. It happened just once, under heavy emergency braking. Nonetheless, I have to report, that the clunk isn't happening as much as before.

So, is there a way to test whether the bushing in the front strut rod/bar is bad? I don't want to just be throwing parts at my car and praying that it fixes the issue! I'm just trying to wrap my head around why fresh brake pads would help with a bad bushing?!

bradland

OldLs400

200k miles

bradland

With 200K I think it's safe to say the bushings are toast. Find a shop that will put the car up on a lift and ask them to show you, with a pry bar, how easily your strut rod moves.

OldLs400

I have a few tire irons in the trunk...you think I could just lift it up with my floor jack and test the bushings myself?

Let's say I replace it. Is it easy to DIY in a parking lot?

Let's say I don't replace it. What's the worst that could happen? Excess tire wear? A crash? Noise in the car?

timmy0tool

iTrader: (7)

the pads do shift under braking, and you should have shims installed on the backs of the pads to prevent further noise and creaks.

to test the bushing, grab a bar and pull at the lower arm where the bushing resides.
it is usually best if the car is on the ground, so the bushing is not loaded while in the air (hard to do on the driveway, so an alignment rack is best).
too much side to side deviation or visible tears calls for a replacement.
at that mileage most likely they are on their last leg.

spuds

If they arent bad at that mileage that would be news.If you can,replace.....any time you add fresh suspension rubber you wont regret it in any event.Thats my opinion on car suspensions.Also when you have clunks,you are stressing out other parts,creating further problems IMO.

Good luck Olds.

OldLs400

Is there a DIY guide for the 98? Or is it as simple as unbolt the old and bolt on the new part?

Amish

It's pretty simple. Just unbolt and replace. Make sure to torque correctly and if cotter pins are used that you replace them. I've done this on other cars without issue.

OldLs400

Thanks. I just got the struts in the mail. Just waiting for the Milwaukee mid-torque impact to arrive tonight. I slipped a 1/2" craftsman breaker bar over a suspension bracket bolt yesterday and it didn't touch it. This was after I soaked everything in PB blaster. I slipped my jack handle over the breaker bar and I think I ended up flexing the socket and breaker bar instead of touching the nut.

I ended up soaking the nuts in both PB Blaster and Kroil last night and hopefully, 600 ft-lbs of torque will be enough to zap the bolts.

bradland

It is a fairly simple swap but there are a few details worth mentioning. The index mark on the bushing must be in the downward position when seen from outside the vehicle and IIRC the large bolt going through the bushing itself should be torqued AFTER the car is down on the ground with normal weight/load on the bushing.

OldLs400

Where did you get the FSM for the LS400? I bought the Chilton manual, and that thing has one blurry blow-up of the suspension and absolutely no mention of the strut bar/rod/cushion. I had to squint at the suspension diagram in the Chilton manual to count the number of bolts holding down in the suspension bracket. On the other hand, in your FSM excerpts, how to remove the suspension bracket is clear as day and night!

bradland

OldLs400

Thanks for the PDF. I just got back from trying to do it. I couldn't get it done, unfortunately. My Milwaukee m18 fuel 1/2" impact, rated up to 600 ft-lbs of nut-busting torque, failed to even budge the first suspension bracket bolt I put it against. I had soaked every bolt in copious amounts of both PB blaster AND Kroil, and this car is rust-free. My tool utterly failed me.

I'm going to get the high-torque variant of the Milwaukee with an actual 1200+ ft-lbs rating of nut-busting torque. If that don't work, then I'm taking this to a shop!

sha4000

iTrader: (1)

The bolt is probably seized in the bushing. I had to burn the bushing to get the bolt out.