possible fix for those with rattles in the back end

[Torinalth]

For the solution and way to check skip to the asterisks, the story of how i figured it folows

Well,

I have been plagued with rattles in the back of the car for a good long time now, and because of how it was done (only hapened when the drive line was relaxed, went away when it was accellerating) i thought it was slop in the connections between the transmition, driveshaft, u joint, and differential. Finally today had pin pointed it. I usually work on my car myselg, by myself and so never had a chance to test my theory fully. Anyhow..

So i was changing my rear pads on the brakes, and was taking my sweet time with it as i was trying to fab a lil jig to turn the rear brakes with a socket, instead of having to use needle nose pliers... anyhow, once i was done and started to put the wheels back on (cars rear was still jacked up, i use the E brake to keep the wheels from turning when the back end is up) and when i tightened down the last lug i went back to the first one, and gave it a good yank (incase there was slack from when the others were tightened). when i did (pulling towrads the front of the car) i noticed it made the unmistakable sound that i hear every time i go over bumps.


So since i had moved in with my girlfriend a few months back I got her to come outside and yank on the bar still attached to the lugnut with the bar in a vertical position (yes i use the stock tire iron) while i got under the car. this put force on the axle and impacted the suspension like axle wind up, and here is the loving question kids, what controls axle windup.....


****************

Upper control arms!!!! so yes, my UCAs are horridly sloppy, i get nearly 1/2" play in the bushing on the chasis end. its still secure so i am not worried about it braking.... however i will be ordering my trilink tomorrow so, give it a shot on your car

Jack up the rear end, put it on jack stands(either under the axle or on the frame) use the tire iron to for the axle to spin (clockwise if looking from the passenger side) and rock it back in forth... crawl up under the car and see where the slack is... if its the two angled pieces that look like this __/__\__ then its yer UCAs... i am hoping this will be my big fix (as this has been an astonishing annoyance to me) that makes me happier with my car.

Hope this helps those with back end rattles like me.

Torinalth

 

[agorge]

Great info..keep us posted on the install: difficulites, increased NVH...and of course performance improvements!

 

[Torinalth]

its going to be a while, just got an E-mail saying its on a 2-4 week backorder. but i will.

Torinalth

 

[MidnightBlk98GT]

While we're on the topic, what about the lower control arms?? Any problems there? I'm looking at replacing mine within the next 2 weeks as I have what I like to call 'old car rattle'. To best describe it, it sounds like an 87 crown vic/LTD that rattles when you go over bumps. Any suggestions/ways of checking?

 

[Torinalth]

rotate the axle the other way seriously... rotating clockwise on the passenger side will induce axle windup, thus stressing the UCAs... to test the LCAs, go clockwise on the drivers side, rip the rod back and forth... is ther a lot of give. is there any give? LCAs are not typically an issue as they have stronger bushings, and more arm flex. anyhow, just yank on thhe axle with a tire iron on one of the lugs... see were you are getting flex/bending/movement. also, push on the wheel (pushing into the car) and see if you get much side to side flex.

remember to have the axle jacked into the air and not supported by anything..

Torinalth

 

[MidnightBlk98GT]

Thanks. I'll give it a check this weekend.

 

[CRZYHRSGT]

Very interesting...worth a look-see

 

[GettinThere]

...as I have what I like to call 'old car rattle'. To best describe it, it sounds like an 87 crown vic/LTD that rattles when you go over bumps. Any suggestions/ways of checking?

Jack up the rear and place jackstands under the frame, not the axle. This allows the axle to hang unsupported. Crawl under the car and push the sway bar up and down. This should move the axle, and you probably will locate the sound(s). I found a loose uca bolt this way, solved my 'old car rattle' sound (actually was more of a banging sound).

 

[Torinalth]

ehh, cant quite agree with that... pushing on the swaybar will effectivly be pushing on the LCAs... depending on what you are looking at, you will not get much movement, and will NOT articulate the rear suspension on all fronts. second, you really cant get much pressure on the rear swaybar, especially if you have little clearance for you to get under the car.

do it both ways if you feel the need, but you will get more torque on the axle by using the tire iron on the lug. YMMV

Torinalth

 

[GettinThere]

...do it both ways if you feel the need...

Actually that is probably best, perhaps a more complete way to search for noises. Of course I am not saying your method doesn't work. In fact, I'll try to remember it if, in the future, I need to chase another noise in the back.


I was simply sharing a method that worked very well for me. With the axle unsupported, I could move it up and down surprisingly well by pushing on the swaybar (laying on my back). Immediately after starting this pushing, it was clear exactly where the noise was coming from. I tightened that UCA bolt and haven't had any noises from back there since.

 

[MidnightBlk98GT]

Well, I dun just about jumped up and down on this thing and nothing moved. I'm relieved to find out this info as I don't have to invest the much needed school cash into suspension parts and it makes me rethink that the sound I'm hearing is coming from the original shocks that have 111,000 miles on them. I have new springs and shocks but it will have to wait until next weekend as this one is booked for me. Thanks for all your input and support.

 

[Torinalth]

if you cant do it with the suspension, then its time for the driveline in my opinion

Torinalth