Rear Alignment with Shim

Well, I can think of two reasons that the front wheel alignment measurements might be off:

1) measurement error in the alignment equipment
2) your front suspension parts have sufficient wear so that the front toe-in shows that much change from one measurement to the next

Regardless, I suggest that you drive the car on the freeway at the maximum speed that you'll be likely to drive the car and see if you have any concerns about its handling and performance. If not, then don't worry.

 

Very informational and interesting post; thanks for sharing!

 

Thank for the write-up and pictures, you make it a lot clearer than the generic online instruction.

What are the shims made of?

 

I think that 1) is the majority of the discrepancy - I had the alignment checked several times before installing the rear shim and there was a couple of tenths of a degree difference in readings even on the same alignment rack. I think that amount depends upon the equipment and upon the skill of the alignment tech.

 

Yes, it is possible that those parts may be worn, but you might want to have a professional mechanic inspect your suspension for wear before you start to replace parts.

When you replace the front struts the camber (at minimum) will be affected so you should have the front wheel alignment checked (for a third time) after that job is done.

 

Definitely replace a leaky shock, the other side also to keep that end of the car equally damped.

Springs often last forever. Unless your car is sagging more than you find acceptable or you just want different spring rates or height, don't waste money on springs.

Patrick's suggestion of having a mechanic check suspension components for wear is a good one, the trick is finding one you can trust.

Your front toe changing (if it isn't a measurement issue) suggests tie rod ends because the other front end measurements didn't change much.

I had a 1983 Camry and a 1991 Accord that didn't need any suspension work in 200k miles and I'm pretty fussy about suspension, I've replaced shocks on a new vehicles.

Thanks again for the shim info.

 

FWIW, your shim manufacturer SPC Alignment - Specialty Products Co. calls out the same p/n for 2010 so you have helped those of us with Gen IIIs too.:thumb:

 

I had to do this exact same thing to my 2005. The company that makes the shims is Specialty Products Company( Specialty Products Corporate Home Page ) the part number is 75800. They have a really nice video and a calculator to figure out exactly what sections to cut out and what numbers need to be aligned.

 

They also list a front camber adjustment bolt for the Gen II Prius. Looks like it gives the full range of adjustment (+/- 1.75 deg) that it takes several Toyota alignment bolts to achieve.

 

http://www.spcalignment.net/instructions/75800-INS_WEB.pdf

Dumb question, the OP says 52 ft lbs of torque, but using the ez shim document above, 52 is for a configuration not for the Prius. For the prius, configuration 3B is to be used which specifies 44 ft lbs.

Does anyone know what the actual toyota spec is? It should be that + 15%.

 

Service Manual says 45 ft lbs (61 Nm) for the bolts holding the hub and backing plate to the axle beam.

 

Thanks. So that really is 52 ft lbs. The PDF I posted above must be wrong.

 

Well this sucks. The shim doesn't fit. I'm using the 75800 red ez shim but it's too small for the diameter of the hub. The hub has a 75 mm diameter but the shim's inner diameter is 72mm so it won't fit over the hub. Did they change the shim specs or is my 2009 prius somehow different? I could trim the inside of the shim a little to make it the correct diameter, but I'm not really sure the shim was intended to be used that way. Is the touring hub different than the the non touring hub? Perhaps that's the difference? Obviously I'll need to call the company that makes tomorrow

 

The template shows the inner diameter at two different sizes. The one it comes with matches the smaller size. It's clear from the template that it's meant to be trimmed even though the instructions don't say so. The OP's photo clearly shows his has been trimmed, so I used a dremel and it took about 5 minutes and now it fits fine.

 

You should shim between the backing plate and the axle beam according to Galaxee (and her DH). I didn't think the diameter was that critical when shimming between the backing plate and beam. I didn't use the SPC shim because it wasn't available yet; I used a custom made aluminum shim.

 

That's correct. Here's what it looks like:



So even though it's not in the instructions, it is on the template and says to trim the inside for the larger diameter axle.




BTW, it's critical to re torque the bolts as the compressibility of the shim will mean the first bolt torqued will no longer be at the correct torque. i.e after torquing all 4 bolts in a cross pattern, the first bolt that was torqued to 52 ft-lbs was only at 43 ft-lbs after the 4th bolt was torqued to 52. It was necessary to re torque several times to get them all even.