Installing MOOG rear shims to correct camber and toe

Good questions and insights

Need my car back while waiting for new hubs, so not yet. One of the hubs is almost completely silent; the other IS making some noise so I think I'll replace both. (Interesting: NSK 1 year warranty hubs claim to be OEM. I bought MOOG for the front; they come w/ 3 year warranty...)

The pads have only 20k miles on them, so they're going to stay.

BTW, it was a pain to twist one of the pistons a bit -- not THAT easy to move IMHO. I don't want to futz with it... so next time I will borrow the AutoZone loanable OEMTOOLS Front and Rear Disc Brake Pad Spreader Set.

Absolutely true about the hub/rotor/etc angle! Rotor was rubbing directly on the caliper (Caliper has 12.9mm of space, so it needs to be pretty accurate.)

So, I added shims to the caliper as well. For the moment, I used stainless steel M10 washers, 1.5mm thick. I'm hunting for multi-thickness washers for next time (yes I'll be opening it again.) Northstar makes a nice plastic set -- except no dimensions are given. A perfect solution is available in China... I don't want to wait

(Never heard the term 'puck' before in this context. Had to look that one up! Puck = brake pad )

The dust shield "damage" was an added partial screw hole, with the metal still in place. I just banged it back. No harm. For my second attempt, I was a bit more careful and the shield came through unscratched.

BTW, I did the Techstream Linear Solenoid Valve init/calibration, and Yaw as well. Pretty amazing! AND, brakes working better than in years. I have the sense nobody has done that in all these years.

 

So, initial project is done... kinda. I had Firestone do a new alignment. Part of the result is more or less what I expected. Part is not at all what I hoped for.

I am open to any ideas on what could cause this result!

Before Shims
Left -1.0° Camber, -0.13° Toe
Right -0.6° Camber, -0.99° Toe

Shim Adjustments
Left Camber -0.5°, Toe +0.83° (Left/In marker at 304°)
Right Camber -.88°, Toe +0.57° (Right/In marker at 35°)

Expected Result (add the above numbers)
Left Camber -1.5°, Toe +0.70°
Right Camber -1.48°, Toe -0.42°
Total Toe +0.28° (presumably the imbalance will self even-out.)

Actual Result
Left Camber -1.3°, Toe +0.49°
Right Camber -0.9°, Toe -0.20°
Total Toe +0.29°

• Toe came out a bit better than expected: total is right on as I hoped, and individual sides are a little better (but not self-correcting all the way.)
• Camber is a BIG disappointment. On one side I wanted -.5 adjust, and got -0.3. On the other side, wanted -0.88 and got -0.3

I'm obviously a noob at this. My imagined possible reasons:

• (I don't think anything involving rotating parts can impact the camber? I briefly suspected insufficient cleaning of hub/rotor...)
• Plastic shim got squished or wiggle out of the way
• Alignment system isn't very consistent on camber?

 

Wow, somehow things became confusing for my readers. My apologies!

• This thread is about installing MOOG shims to correct rear camber and toe. I had hoped that was implicit to the conversation No worries about the front.
• The pads do NOT need replacing. They have 20k miles on them. I posted a photo up above. Lots of life remaining.
• Right now I'm using stainless steel washers to shim the caliper angle. But literally all commercial caliper shims out there ARE plastic. Apparently not a big deal, as they simply slide onto one or both caliper bolts. Nothing should be flapping around

As for the (rear alignment) measures:

• Rear camber on both sides is supposed to be -1.5° plus or minus. Yep, about 3 degrees total if adding both sides makes sense.
• Rear toe total is supposed to be + 0.29 so mine is exactly correct.
• The reason I'm hoping the rear toe will "self adjust" is because @josh2008 discussed extensively the need to properly center the rear axle beam -- not that it's loose, but various factors put it out of whack unless you go through a straightening process before alignment. He's an alignment professional and shot a video showing what techs at his shop do. Here's his first comment in that thread: Shim Kit for rear toe adjustment? | PriusChat

As for the whole piston reset... it was hard enough to do a small change on mine without any specialized tool, I decided that next time I might as well borrow the fancy tool that includes compression capability. I'm already borrowing other stuff from AZone for these projects. Why (a) spend real $, (b) on a widget that helps but doesn't actually push the piston.

(@ASRDogman I'm not sure where would lifting/lowering be happening? I'm confused. The MOOG/Northstar alignment shims are simple disks with a small eccentricity (one side thinner than the other) that can tweak rear camber and toe, mounted between the axle and the hub. And the caliper shims are SS washers that go between the caliper and its mount, as part of the mounting bolt system. Both pretty simple.)

 

I'm learning quite a bit about alignment from all y'all, as well as searches to fill in my many gaps of understanding. Thanks! Here is a post that explains the importance of (front?) cross camber and cross caster to road drift, along with other things I didn't know, such as:

• Why SAI (Steering Axis Inclination) is important -- not as an adjustment.
• We have a high SAI (~ 12 degrees) which makes cross camber important for adjusting drift.

Looking at my earliest alignments, I've always had a -0.3 cross camber in back. But now it's positive and yeah I don't like that.

 

What do you think about the perspective in the article I linked above?

 

LOL. I have no dog in that hunt, so won't get between you and other alignment folks.

Sounds like there's some controversy over whether high-SAI cars need camber instead of caster adjustment to fix drift/pull.

@ASRDogman, if you know of any metal shim sources that could/would work for fixing rear prius alignment, I'm all ears. The MOOG shim is way better than the EZ Shim... but it's still plastic.

 

Now I"m quite confused. If this is true, then why...

• Have PriusChat people like Bob Wilson, The Critic and more have successfully corrected rear alignment using these shims and others?
• And why do mfg's make and sell these shims (available at every auto parts supplier from NAPA to AutoZone and more?

If any bump into a rear tire means a $1-2k repair, that's pretty scary.

 

GREAT example, @ASRDogman

Yes, long term want to resolve the root cause. On my engine, HG sealer (in the coolant not oil) gave us the 1600 miles and time we needed to get to the ultimate solution -- a replaced engine. I can't say it caused more damage along the way... 'twas still working fine, no overheating etc by the time we did the engine swap. Yet it's true: I wouldn't trust HG sealer further than necessary.

In this case, stepping back I can see a variety of options... at what point does it change from true fix to band aid? Not sure.

AFAIK, any solution that provides a permanent, strong, stable mounting surface for the hub, caliper, etc at the correct angles, is a good solution.

• OEM original: properly mfg'd solid axle, zero miles, in spec.

After a while, wear and tear gets us out of spec for whatever reason. Possible solutions:

a. Install replacement OEM axle (42101-121071), back to spec
b. Hardface (weld) and grind/tap to build up the surface. Back to spec, stronger than OEM.
c. Body shop bangs it back to correct angles. In spec, but metal tension etc may lead to future spec loss.
d. Do same as (b) using modern industrial adhesive/filler (Loctite EA 3478 (Fixmaster superior metal) is one. Also SikaPower-1277).
e. Install high-strength metal shims permanently to face, calculated to fix angle. More limited life yet same specs.
f. Install low cost shims, held by mounting bolts. Less than perfect on specs, limited lifespan.

Looks like a typical price/performance (and possibly safety) tradeoff.

Price

a. Parts OEM MSRP is US$1924. Available online for $793 incl UPS shipping (thanks, @Mendel Leisk!). Install ~$400?
b. Almost all labor. May get a quote on this, a local auto place loves a particular fabricator here who does this work! Guess: ~~$300-400.
c. No parts. Guess $400 labor.
d. Done professionally, similar to (b). The good adhesives are not available at retail.
e. Haven't found a good source yet.
f. I have a new set on order, including 0.1/0.2/0.5 mm metal for bulding up the caliper mounts. Under $30 total on Amazon.

(I need to install the new hubs anyway, and with my recent experience I'm confident this can go quickly )

Bottom line, I see three viable alternatives out of all that:
1) Spend a little, possibly get a good fix -- option (f). I'm not out a lot. (Spent time learning but for me that's all good. I love to learn!)
2) Pro repair version (b) for maybe $400... I need to get that quote.
3) Replace for ~~$1200 (a).

Up to the car owner what to do. To me those are all viable.

I have one more bit I can contribute but not today (Gotta get other stuff done):

I'm going to make a spreadsheet that calculates the correct angles, and the correct shim thicknesses at each bolt hole on the axle plate. Should not be too hard... and helpful for others.

 

Why it's off so much...

Primarily: hit a curb. Mostly caused front trouble but also glanced off the back.
A little: it's always been a little off, although within spec.
Confusing: I see different numbers from every alignment. Even camber. That part makes no sense to me... other than yeah -- don't expect much from Firestone

So, it does need fixing. And I don't want to put over $1k into it (new axle) if I can fix it for much less.

 

Good info:

A quality shop demonstrates how they do brake jobs.
Main thing I learned: how and why and what they clean intensely in the various bits of a brake job.

Plus: what they do and do not lubricate, and why they open the bleeder valve.

 

OK, I have a new thing confusing to me. Is this normal, or telling me something about (shocks?)

MOOG hubs arrived, plus a new set of shims, and a set of 0.1 / 0.2 / 0.3 / 0.5 mm steel washers. Ready to go at it again, this time with a few more careful measurements and observations.

Right away, I'm seeing something that I've seen before but never really paid attention to...

When I jack up the rear end, the right tire is about an inch further off the ground than the left.

At first, I assumed it's because the jack point is off center - about 2' to right side, 3' to left. BUT

• Axle angle never changes (1.2 degrees down to left)
• Angle at base of R shock does change while L shock hardly changes

Normal, or could this mean the left/right shocks are acting differently? While they are old shocks, they aren't causing tire trouble and neither I nor any service person has suggested an issue.