Installing MOOG rear shims to correct camber and toe

This is my adventure in DIY rear shims for my Gen 3 Prius. First time I've gone in deeper than wheels on the rear end.

I'll fill in blanks later. At the moment I am working on getting the rotor off.

Just learned from another thread: the bolt holes are M8x1.25 ... need a couple of 1" or longer bolts. Hmmm...

I've tried several other methods, and have some penetrating spray working on it (while we watch the Super Bowl - Go 49ers LOL)... but I may need something stronger and those two bolts seem the safest reliable solution.

 

Found a spare M8x1.25 bolt.

I tried lots of other things first:
* PB blaster
* hammer whacks
* my fancy heat gun

Nothing.

That little bolt? Turned it in until it stopped. Another fraction and there was a loud clunk as the connection let go on one side. Did onthe other hole and voilà all done!

It's worth the 50 cents to get this done reliably in seconds

 

Yep! Unfortunately I broke my 14mm 3/8 in sockets... time to go get some 1/2 inch drive extensions.

And yes, @Tombukt2 we live at 7,000 feet in Colorado. Very sunny but also snow, ice and mud.

 

Or my brain turned on. Using a 30 year old junk 3/8 inch socket was just dumb. (I could tell stories about other dumb things I've done with brain off ). And this only minutes after noticing that my 1/2" flex breaker/torque wrench was reading well over 100 ft-lb even on removing a few of the wheel nuts.

I have a set of reasonably good 1/2 in Harbor Freight sockets. Nary a problem to date up to almost 200 ft-lb.

I just did a search and found generic advice on sockets/drive max torque (which obviously depends a lot on quality: 1/4 in = 60 ft-lb max; 3/8 in = 100 ft lb max; 1/2 in anywhere from 150 to 250 or even 500 if incredibly good.

OK, my reality does NOT match your description. What am I misunderstanding?

• The layers involved here: solid axle beam, then thin brake dust shield, then wheel bearing/hub assy, (then rotor but that's off)
• I got out the bolts that hold the hub/bearing to the axle (just spin the hub to the right point and use a good extension.)

BUT there's no way I can reverse the bolts and put them in from the back side!

• For two, the axle beam pipe completely covers the bolt hole
• For the other two, there IS an access hole, but...
  • The top-rear one, yep can get the bolt started. If I had a longer bolt it would be fine. But the bolt head hits the axle tube before I can sink it in far enough.
  • The lower-rear one, the edge of the access hole interferes with the bolt head. No way to even get started.

I can see the value of approaching this. If I could get the specs on those hub bolts maybe I could get/find a longer one and use it- on at least two of the positions to get things started. It's 90119-A0350

My other creative stupidities:
1) No need to loosen the hub right away. I can spin the dust shield a bit, and put pressure on THAT from behind... at least somewhat.

2) Use hub bolts in original position to force hub off of axle beam:

• Reinstall two of the hub bolts part way
• place a 2x4 or whatever between bolt heads and the wheel hub (with lug bolts still there)
• use socket wrench to loosen bolts, forcing wheel hub away from the axle beam mount. (Of course that might simply rip the hub apart as well, costing me even more )

 

I found a MUCH better way. No hammering, no chisels, no prying. I'll explain briefly now, but I need to finish up this job... then will share photos and more!

What you need (about $3 of hardware is all):

• Two big "hex tap bolts" aka Fulll Thread Hex Bolts. You need threads along the entire shaft. More than 3 inches long... I used 4 inch 3/8 x 16
• Two nuts to match (me: 3/8 x 16)
• Two matching washers plus 2-4 thick fender washers -- I used 1/2 fenders, which are about 1 1/2 inch diameter.

For now, just imagine:

• Choose two of the "outer" (away from car body) holes in the hub.
• In each, assemble: hex bolt into the hole. Between the outer hub and the base (actually resting on the brake dust guard) thread... the larger fender washers first (up against backside of hub), then the smaller washer, then a nut.
• Spin the nut as far as it goes toward the hex head, and rest the tip of the bolt against the dust guard, NOT the bearing base.
• Set the up on two opposing sides (it won't be perfect because there are five not six holes... but close enough.

Now, grab one of the nuts with an adjustable wrench, and use an impact wrench on the hex head to turn it in (clockwise).

• First round just tighten it, then tighten the other one
• Then, go back and forth a couple of times only a few turns at a time
• No fuss, no muss. In seconds the bearing/hub will come free!
• (I did punch a hole through the dust shield with one of the bolts. I am not at ALL concerned about that

Now I'm ready to finish up.

 

LOL. Took longer to write than to do

Now I have a new "Ugh." NONE of the shim templates are correct.

In addition, it isn't obvious what the zero (straight up) angle is supposed to be.

• I did some measurements of how much the rear axle shifts from "normal on road" to "hanging w/o wheel"... and get ~5 inches. That appears to translate to a 4 degree adjustment.
• BUT, then what?

The good news: the brake dust shield makes a rather nice template. It's flat where it counts, and it's easy to trace the four bolt holes and center hole for the hub. So I do know the relative angles of the bolt holes (67, 137, 233, 303 -- all +/- 7 for a range of 14 degrees...)

I have a guess at my own template... but before moving forward I sense I should call MOOG tech support in the AM, to see what they have to say.

 

OK, reassembly time at last.

Discovery (yes I was warned in the instructions...) Need a bit of caliper shim to avoid binding, since the caliper is mounted on the solid axle, not the hub. (Thus, it is affected by adding a shim!)... Looks like stainless steel washers will do the trick.

QUESTIONS

• I don't find a spec anywhere for how closely the rotor needs to be centered within the caliper. As long as there's no binding, does it not actually matter? (If true, then I'm imagining the brake shoes simply ride along w/o any issues.)
• Mendel's 2010 brake instructions include some bits that I'm not finding at all, such as anti-squeal springs. Mine has no such thing. Is that truly a nothingburger, or did a service person leave something important out?
• I see the spec for the rotor is 9mm start, 7.5mm replace. Mine are at 7.9mm with reasonably new shoes. AFAIK I have the original rotors, and have gotten 230k miles in 1.1mm of wear (9-7.9). If so, then in theory I can get almost 90k more miles before the rotor must go. Am I thinking right, or am I crazy?
• The repair guide says the brake pad support plates are NOT the same, and should be marked to put them back in the right place. I didn't mark... and can't see any difference. Did I mess up royally?

And now for Brake Pad Questions. I've never looked at brake pads before... and am seeing things that don't make sense to me.

1. One of the two pads has an attached metal spring. Now I see that's for the inside pad. No idea why it is different???
2. I'm a bit confused about how pad thickness is measured. Is it the entire thickness of the pad (not including removable outside bits?
3. My pads appear to have a trapezoidal wear surface, that slowly increases in size as it wears, becoming a more rectangular surface for the last 2/3 of its life. Is that normal? Seems it would change the braking characteristics over time...

 

Got the second wheel, rotor, hub apart in a few minutes. Having the right tools and methods sure helps!

One more question: this hub makes some noises when I turn it. Bad... or let it go? No wobble at all. I'm now comfortable pulling and replacing the hub another time if/when needed.
https://youtube.com/shorts/FUWO3UumIUc

 

All assembled! Thanks for the various reminders. (One brake piston was a proper "X"... the other was offset... and looks slightly dinged as if someone servicing got it wrong at one point )

Everything was acting nice and free... until I finished reassembling. Now, I did NOT do anything special to fully retract the piston. Could that be why (before I do any test drive) it has some brake friction?

Before reconnecting battery, I *did* do the brake pedal pushes and parking brake activations. Yet spinning the wheel is noiiiisy.

I thought I saw the need to do some special actions on first turn-on, but can't find it.

Any ideas?