Alignment Needed?

spikesputnik · April 23, 2009

OK, so I'm beinga little lazy here and go by one of the nicer "do it all" tire/ brake/ suspension/ muffler places locally to get a shackle installation estimate. After about 20 minutes, they say that it will be 1.9 hrs labor(looked up on a computer) @$75 per, plus due to the ride angle changing may need a front end alignment afterwards. Total tab with tax $209!!

While I can not change how they do estimates, ie 1.9 hrs vs 1.75 or 2.1, I do question the thinking that the front end will be out of alignment after I'm dropped 2" in the rear. Does that sound likely to y'all?

My left brain says that that is just not enough of a difference to affect the alingment, and that they're just trying to hose me. As far as the 1.9 hrs out of a book, I guess it might take me that long in the driveway, but seriously....

Thoughts???

Grebbler · April 23, 2009

As far as a wheel alignment, if it were a front adjustment I would say, "Yay".

Since it's the back and would equal prolly less than a degree of caster angle in the front on a full box truck I would say NAY if it were mine.

I would think they would be more concerned over the pinion angle as that change would be greater.

Are you providing the parts?

BuckFeverZ · April 23, 2009

I wouldn't get an alignment for rear drop shackles...

spikesputnik · April 24, 2009

Grebbler- yes, I'm providing the shackles. I understand what caster is; what is the pinion angle? Got a diagram?

Any others out there dropped 2" and found an alignment was needed?

Grebbler · April 24, 2009

The pinion angle i refer to if for the rear end to transmission alignment (drive line). You want the angle of the trans to the drive shaft that same as the drive shaft to rear end angle. When they are not equal you can get vibrations and stress the u-joints.

Moving only one end of a leaf pack will change the angle of the rear end pinion. In your case, lowering the rear of the truck by tucking up the rear of the springs will nose your pinion down a bit. It may not even be enough to matter.

I just mention it in case you get some vibes or noise you can't figure out. If it does go out of whack it can be corrected with shims.

A Google search on pinion angles and driveline phasing should yield more info than you ever wanted to know.

Ed

spikesputnik · April 24, 2009

Wow. Never wouldda thunk about drive/tranny stuff, too. Something to ponder...

Zembonez · April 24, 2009

2 inch shackles do not warrant any kind of shims or alignment. If the truck didn't need an alignment prior to installing them, it won't need one after. Some shops are idiots. Some shops just try to sell as much work as people will buy.

takevin · April 24, 2009

i was told by a fellow club member who runs firestone said a alignment was necessary for this, so im guessing no it doesnt? I didnt think so.

J-man67 · April 24, 2009

2 inch shackles do not warrant any kind of shims or alignment. If the truck didn't need an alignment prior to installing them, it won't need one after. Some shops are idiots. Some shops just try to sell as much work as people will buy.

Yup yup!

spikesputnik · April 24, 2009

Oh man. After looking at the shackle hanger/shackle, it appears that the hanger has to be removed to be able to remove the shackle bolts as they would be pulled out from the inboard of the shackle, but the frame is right there! Is this true? However, I only see one bolt attaching the hanger to the frame and what appears to be 4? positioning dowels. Are those dowels or welds? (edit and to answere my question, they're rivets) It also appears that maybe the receiver hitch might need to be unbolted too to gain access to all of the bolts.

My concern here is that this is turning into much bigger deal than just unweighting, unbolting and replacing the shackle- ie probably out of my skill set. Another member mentioned loosening bed bolts for clearance too- yikes! The other concern is that the "bubbas" around here have yet to impress me with any model-specific knowledge.... I need a shop that has done this exact thing on this exact truck.

So, fortunately, I feel good about the lack of alignment issues, not so good about the task at hand or any confidence in it being done right.

Comments?

Zembonez · April 24, 2009

i was told by a fellow club member who runs firestone said a alignment was necessary for this, so im guessing no it doesnt? I didnt think so.

Sadly the brain power in the average tire/brake/shock shop wouldn't light the bulb in a maglite. The swiftest of the swift aren't usually working there.