Clunking Sound While Shifting After Installing BMR UCA & Adj. LCA's!

[Nastystang06]

Pinion angle has no effect on gear whine.

I didnt know it was actual gear whine, thought it sounded LIKE gear whine.

I wouldnt know I have never had issues, it was just a thought

 

[Mattr89]

The UCA bolt is typically an issue if you use the stock Upper Mount with an aftermarket UCA; and retain the factory sized bolt. The factory hole in the upper is larger than optimal, and the rigid aftermarket upper will cause noises to become present.

When you install an aftermarket Upper Arm, you will want to install an aftermarket Upper Mount. There are also "anti-clunk" spacers available for this, but I always recommend an actual mount to cure the issue.

Here is the issue 9 times out of 10 when my customers call with a "clunk" issue:

As you can see, the factory upper mount has a large tolerance. Add to that tolerance issue, an aftermarket upper arm that is 200% more rigid....and you develop a clunk that is very irritating.

If someone is experiencing a clunk with our upper arm and upper mount installed...I typically recommend them to check their torque settings, and inspect their bushings.

OP, I think you have the very first versions of our parts. My guess would be that they are very used/worn... Bushing issues and/or sleeve wear may be your issue.

oh ok, i am going to pull the upper mount and look, if that is the case then i will get the spacers. I am going to buy your relocation bolt in brackets soon.

How do i know if the bushings are gone? i didnt grease them when i installed them.

also sometimes when i go over an uneven bump and say my passenger side hits it, but the driver side doenst i get a squeaky smudgy sound then a chunk sound.

If i let off the clutch fast i get a slight clunk and reverse, is it safe to say that if the bolts are tight on the LCA's that they are NOT the cause of the sound?

 

[Mattr89]

if i cant fix this issue, or find the clunking, these are the parts i plan to use.

http://www.americanmuscle.com/adj-upper-control-arms-jnm2005.html

http://www.americanmuscle.com/2005-powdercoated-rear-trailing-arms.html

are these good parts?

The only thing i dont like about an udjustable UCA is it has to be unbolted from the AXLE housing in order to lengthen.

 

[Morris]

I have the bmr mount too so I think the minor clunking I hear in mine is in the drive train.

 

[Mattr89]

i just took off the UCA and come to find out there was very little grease in it. hense the squeak.

i put the grease gun on the fitting and i was able to get 3 full pumps before any grease oozed out the sides!

After 4 pumps i saw some clear grease that was the old stuff coming out, so i kept pumping and then the black grease i was putting in started coming out, in short there was pretty much almost no grease in it, or the LCA's!

I removed the bushings on the UCA and to good news there was no burns, rips, tears, or any damage i could see at all!

So i used valvoline durablend sythetic suspension grease (greyish-black color) and fill them up til they started oozing out the sides, wiped the holes for the bolt, and re-installed.


As far as the clunking sound, there is some play, as in the picture posted above! The bolt fits the BMR UCA perfectly however there is a little loose wiggle around the factory mount.

Looks like i need UMI anti-clunk metal spacers....that should take care of most of it.

 

[Morris]

Glad to hear you found the issue!

 

[Mattr89]

my last concern is, i just got my pinion angle at -3 i believe.... i used the analog gauge and the pinion flange ready 2 degrees to the left of the zero, the driveshaft read 1 degree to the right, that means -3 degrees pinion right?

I have 2 questions, if i add relocation brackets from BMR next week or the week after and i bolt my LCA's to the middle or bottom hole on the brackets will i have to adjust my pinion angle again?

Also i dont believe my LCA's are completely equal length, i believe they are slightly off. what is the negatives of this? Is it a big deal?

 

[BMR Tech]

my last concern is, i just got my pinion angle at -3 i believe.... i used the analog gauge and the pinion flange ready 2 degrees to the left of the zero, the driveshaft read 1 degree to the right, that means -3 degrees pinion right?

-2 + (-1) = -3

I have 2 questions, if i add relocation brackets from BMR next week or the week after and i bolt my LCA's to the middle or bottom hole on the brackets will i have to adjust my pinion angle again?

You will not have to re-adjust pinion angle.

Also i dont believe my LCA's are completely equal length, i believe they are slightly off. what is the negatives of this? Is it a big deal?

Yes it is a big deal. Negatives are too long to list. Just make them equal.

 

[Mattr89]

my last concern is, i just got my pinion angle at -3 i believe.... i used the analog gauge and the pinion flange ready 2 degrees to the left of the zero, the driveshaft read 1 degree to the right, that means -3 degrees pinion right?

-2 + (-1) = -3

I have 2 questions, if i add relocation brackets from BMR next week or the week after and i bolt my LCA's to the middle or bottom hole on the brackets will i have to adjust my pinion angle again?

You will not have to re-adjust pinion angle.

Also i dont believe my LCA's are completely equal length, i believe they are slightly off. what is the negatives of this? Is it a big deal?

Yes it is a big deal. Negatives are too long to list. Just make them equal.

Thanks for the help!

If I back my car onto ramps will my readings still be accurate even tho the rear end is higher?

Also what is the best way to make the arms the same length?


Everything to the right of the 0 on the angle is positive correct? If the 90 degree angle is to the left?

 

[nickk678]

This thread has some great information for LCA's and UCA's which nearly every S197 owner installs at some point. Thanks for all the info,

 

[Mattr89]

I just leveled out both arms by measuring from bolt to bolt, they are dead on. If somehow they are off its by less than a 16th of an inch. LOL

I got -4 degrees pinion flange, and -2.5 degrees driveshaft everytime. Once the driveshaft read -2. Therefore my pinion angle is -1.5.

I had the rear tires on "ramps" suspension fully loaded.

I posted pics below to see if you guys think my pinion is accurate....let me know what you think.


Pictures From Left to right...

Pic#1=on the flange
Pic#2=on the flange closer look
Pic#3=pinion flange "angle"
Pic#4=driveshaft position
Pic#5=drivshaft "angle"

 

[lindertw]

...I had the rear tires on "ramps" suspension fully loaded...

Rear tires on ramps, front tires on ground?

I'm in the process of redoing my rear suspension components, and I'm getting ready to dial-in my pinion angle. With the car on the ground I marked the rear shocks using painters tape, I then put the rear on ramps and checked the tape, it was not at the same point as when it was on the ground. I think you need to have the front and rear up on stands to have the suspension properly loaded. May not make much of a difference, but I admit I don't know what I don't know...

looking at your pics it looks like both numbers are to the left of zero, if I'm reading this correctly and using your numbers:

(driveshaft reading) - (pinion reading) = pinion angle with 2-pc driveshaft

(-2.5deg) - (-4deg) = +1.5deg

Again, just asking for clarification as I'm getting ready to adjust mine, and this makes my head hurt...

 

[Mattr89]

Rear tires on ramps, front tires on ground?

I'm in the process of redoing my rear suspension components, and I'm getting ready to dial-in my pinion angle. With the car on the ground I marked the rear shocks using painters tape, I then put the rear on ramps and checked the tape, it was not at the same point as when it was on the ground. I think you need to have the front and rear up on stands to have the suspension properly loaded.

May not make much of a difference, but I admit I don't know what I don't know...

i dont know if that matters, i check my lines they were so very close...

 

[Mattr89]

clunking issues gone! thanks to umi spacers!!

also got my pinion angle to -1.5, flange now reads -5 and the driveshaft reads -3.5.

 

[devildog1679]

Just installed BMR LCA's, know I have a clunk going from 1-2-3. The thing is that it's only there are low rpm, if I shift in high rpm it's not there. Most have said this is slop. Prior to instal I had a slight clunk. Guess with new poly bushings it's transmitting more NVH.

 

[mfergel]

if i cant fix this issue, or find the clunking, these are the parts i plan to use.

http://www.americanmuscle.com/adj-upper-control-arms-jnm2005.html

http://www.americanmuscle.com/2005-powdercoated-rear-trailing-arms.html

are these good parts?

The only thing i dont like about an udjustable UCA is it has to be unbolted from the AXLE housing in order to lengthen.

I have the J&M lowers that you show there and the non adjustable upper (in addition to the J&M adjustable pan hard bar). I've got clunking big time so I'd say you're going to experience it as well with those items listed.

Question: How hard is it to yank that bolt out and install those bushings? Am I going to want to put the chassis on stands and support the axle with my jack to get it in position? Car is lowered 1/1.5 so I don't have a lot of room under there for the crawler and myself. Hate to take it to a shop to install an $8 part.

 

[skwerl]

There's only so many moving parts back there. With a little patience you can check all of them and find the clunk. I have noises appear once in a while and keep looking until I find them. Last week it was the upper shock mounts (I was told not to overtighten them but I had left them too loose). Prior to that it was one of the bolts on the passenger side LCA relocation bracket working its way loose. The time before that it was the upper control arm. I'm not a perfect mechanic, I cut trees for a living. So I have to double check and triple check everything I do on this car to make sure it's right.

 

[michael.konor]

There's only so many moving parts back there. With a little patience you can check all of them and find the clunk. I have noises appear once in a while and keep looking until I find them.

That's very true and we all have the same thing eventually. I had a clunk only under hard acceleration or braking that sounded like it was coming from the middle-rear of the car.

Turns out that it was one of the self locking nuts on my front A-Arm that backed out 1 turn leaving a small air gap. Took nearly 6 hours of a pattern search, finding little things here, tightening them up and taking it for a test drive to see if it worked before I found what was actually causing it.

If you get lucky, you'll see where it's sliding back and forth.

 

[Mattr89]

(driveshaft reading) - (pinion reading) = pinion angle with 2-pc driveshaft

(-2.5deg) - (-4deg) = +1.5deg

Again, just asking for clarification as I'm getting ready to adjust mine, and this makes my head hurt...

this i believe is incorrect...its the pinion flange minus the driveshaft.

in any case its the difference.

I rechecked my pinion angle however the ramps were slightly higher so both numbers changed a little, but its the DIFFERENCE between the numbers that matter most.

I got the following yesterday.

Pinion Flange = -5 degrees (to the left of the zero)
Driveshaft = -3.5 degrees (to the left of the zero)

1.5 degree. thats with the car on ramps, that means that when i lower it, the driveshaft should read about 0 degrees maybe +1. the pinion shaft would be about -1 degree.

correct me if i am wrong somebody?

 

[BMR Tech]

The proper way to achieve your pinion angle setting is to add the angles.

Here is why: (I will make this extremely easy, or try....)

If you have a 0 degree relation, and your drive shaft angle is -2.....then your pinion angle would need to be +2, correct?

If yours isn't -2.....then let's say it is -4. In order to achieve a 0 degree angle, you would need +4 on the pinion flange.

This means, if the drive shaft angle is down -4, the pinion has to be "up" +4 to achieve a "straight line." Correct?

NOW, being that we know how that works....let's do some math.

-2 + (+2) = 0
-4 + (+4) = 0

If you subtract:

-2 - (+2) = -4
-4 - (+4) = -8

If this is hard to understand, see image:

Now, the goal is to ensure there is roughly a 0 degree relation, when under load. That does not necessarily mean everything has to be aligned straight....it means the ANGLES have to be on the same PLANE, and similar. (Parallel)

See below:

The absolute easiest way to achieve the proper pinion angle setting is to use an electronic/digital angle finder that has the feature to "ZERO" it out.

Place angle finder on driveshaft, zero it out, place angle on pinion....and adjust it to your negative setting. Now of course, you will need to re-check both angles before coming to your final pinion angle.


I hope some of you find this useful.