Topic: Spring wedges

[jfrabat]

Ok, so as some of you know, I was suffering from vibrations ever since I put the alloy shafts in my YJ, and the reason for that was that the drive shaft angle in the front was off resulting from the suspension lift.  I just never felt the effects because the front driveshaft normaly does not rotate on a YJ when driving around in 2WD.  But with the alloy shafts, which did away with the vacuum disconnect, the DS is always rotating, bringing this issue to bear (thanks to those of you that helped me with this issue!).

Now, my RE lift cme with Pro Comp 4* wedges, and when I installed them, most of the vibrations went away immediately, but when I drive 65+, I can still feel a very slight vibration on the steering wheel, so I decided to get rid of the vibes completely by getting the right angle wedge. 

So this is what the angles looked like before I put in the 4* wedge (sorry for the crappy pictures!) measured at the TC and axle (basically, I took out the saft and measured the yokes' angles):

Axle:



TC:



As you can see (more or less; sorry about the focus!), the angles shown are about 2* and 7*, so ideally, I would need a 5* shim (which I could not find), but I did find a 6* shim to try.  Now, the question I have is if anyone remembers how wide is the pin on the suspension, as the 6* shims I bought do not have the hole drilled and I need to drill it (and I dont want to take apart the suspension to find out, becase I need to drive to the drill press, so it is a bit impractical).

Any takers?

Felipe

[Bounty Hunter]

I'd drill a 3/8" hole.

[oldjeep]

You're going to be better off with a 4 degree shim if 5 degrees makes it perfect.  The pinion comes up some under power. 

[jfrabat]

You're going to be better off with a 4 degree shim if 5 degrees makes it perfect.  The pinion comes up some under power. 

Under power, the front springs (keep in mind there are no vibes coming from the rear) should unload, increasing the angle, right?  If so, then the angle needed is going to be greater, meaning a 6* wedge should be better than a 4* wedge.

Also, it is more like 5.5 degrees (from what I can tell in the pics), so 6* is closer than 4*.  And besides, I already got both sizes; if the vibes get worse, I'll simply switch back to 4* and call it good (the vibrations will be reduced anyway once I make thejump to 33" tires, as there will be less tire rotations per minute at the same speed); I just wanted to get it perfect while I can still feel the vibrations...

[oldjeep]

Under power, the front springs (keep in mind there are no vibes coming from the rear) should unload, increasing the angle, right?  If so, then the angle needed is going to be greater, meaning a 6* wedge should be better than a 4* wedge.

Also, it is more like 5.5 degrees (from what I can tell in the pics), so 6* is closer than 4*.  And besides, I already got both sizes; if the vibes get worse, I'll simply switch back to 4* and call it good (the vibrations will be reduced anyway once I make thejump to 33" tires, as there will be less tire rotations per minute at the same speed); I just wanted to get it perfect while I can still feel the vibrations...

Sorry - missed the part about it being the front, so yes 6 degree better than 4 degree.   You might want to check your steering angle after putting the shims in.  I never use shims on the front because it messes up the Caster and steering feel.

[jfrabat]

Sorry - missed the part about it being the front, so yes 6 degree better than 4 degree.   You might want to check your steering angle after putting the shims in.  I never use shims on the front because it messes up the Caster and steering feel.

Well, the 4* shims have not had any negtive effects on driveability, so I doubt 6* will, but I do plan to get it aligned once I finish the install...  I guess i will find out at that time how much out of whack the steering will be.

[FourbangerYJ]

What are the shims made out of? Al or steel?

[Bounty Hunter]

Do you have a 4" kit?  I've never seen the need for shims in the front of a 4" kit.

Do you know where your caster is set at currently?  Keep in mind that you want the pinion angle parallel to the front output shaft, so if you added lift springs and everything else stays the same, there should be no need for shims, period.

[jfrabat]

Do you have a 4" kit?  I've never seen the need for shims in the front of a 4" kit.

Yes, a RE 4" Std kit...

Do you know where your caster is set at currently?  Keep in mind that you want the pinion angle parallel to the front output shaft, so if you added lift springs and everything else stays the same, there should be no need for shims, period.

Shackles are also new (currie shackles to match the rear boomerang shackles), but the angle is most defenetely not the same, as you can see in the pics above (also, the 4* shims significantly reduced the vibrations).  Not sure wha the caster angle is, but everything was within specs when I did the alignment before I put in th shims...

What are the shims made out of? Al or steel?

AL

[FourbangerYJ]

Becarefull with the AL shims, they crack and split over time.

[Bounty Hunter]

Correct me if I'm wrong, but the RE standard 4" kit comes with one set of shims, and they're for the rear (as with most other 4" leaf kits).

I still say the spring pads on the front axle are pretty much horizontal in stock position, and after the 4" lift.  Thus no need for shims.

[Jesse-James]

Aluminum shims suck, no way I'd run them in the front. Mine fell apart completely, just crumbled.

[oldjeep]

Aluminum shims suck, no way I'd run them in the front. Mine fell apart completely, just crumbled.

Agreed, except I wouldn't run any kind of shim in the front unless it was welded to the perch.

[jfrabat]

Correct me if I'm wrong, but the RE standard 4" kit comes with one set of shims, and they're for the rear (as with most other 4" leaf kits).

That is correct.

I still say the spring pads on the front axle are pretty much horizontal in stock position, and after the 4" lift.  Thus no need for shims.

But if you look at the angle pictures once again:

Axle:



TC:



There is a difference of about 5*.  The way I measured this is that I took out the front DS, and place the yokes vertically, and then put the angle finder flat against the flat part of the yoke.  So why is it that I have an odd angle on the front? I have no clue, but the fact is that it is off (as shown in the pics).  So what is the best way to correct this?

Aluminum shims suck, no way I'd run them in the front. Mine fell apart completely, just crumbled.

Becarefull with the AL shims, they crack and split over time.

Now, if aluminum shims are dangerous, I guess I better take out the shims completely and simply weld on new perches, huh?  That should not be so expensive...  Although I gotta take it to someone who will weld them for me (I dont trust the guy that did my rear axle, as he's the same guy who return my Jeep to me with no lugnuts on the rear and who welded the rear off center the first time).

So, if I do weld new perches on, what would be the side effects with regards to caster?

[Bounty Hunter]

Curious, have you measured your caster?

Do the vibes disappear when running without the front driveshaft?