521 carrier bearing shims

[Kyle253]

So I lowered my truck with lowering blocks and now have the usual vibrations. I've been doing some research and saw people talking about adding shims. I'm a little unsure on how they work or where exactly they go. If someone has a picture I could see to better understand what they're doing that would be greatly appreciated. Also curious where I can get them, do Napa/Oriellys/Autozone carry them?

[Draker]

If you are talking about the center bearing, just raise it by ~3/4-1" I believe. Use square tubing or whatever.

 

I'm sure someone will have a picture.. I'm not a truck guy

[banzai510(hainz)]

most people try to get the anglerd lowering blocks. Belletech made 2deg onrs I think part number was 6202  3 inch 2 degree.

 

Now if you went more(lower you need to lift the carrier bearing up by putting a spacer in there. Key is how long are your bolts that hold th bearing on.

 

 

I would loosen the bolts and see where it naturally lift up to then add a little then that will be your spacer size.

 

I would know a good part store also incase you need longer bolts and also those are SAE size on the older trucks NOT METRIC .

[wayno]

I thought we were taking about a 520, but now I see it is a 521 that has a carrier, I should have read the title instead of looking at what he had in his avatar.

Try raising the carrier an inch, just put a spacer under the carrier.

[datzenmike]

With the vehicle sitting on it's wheels, if the transmission is level then the differential must also be level.  If the transmission is tilted downwards at the back by 5 degrees then the differential must tilt up 5 degrees at the front. Whatever angle transmission is at, the differential must also be at. This angle relationship will assure that the two angles produced at the bends are identical and vibration is cancelled out.

 

 

 

 

3/4" or 1" is a rough approximation and does not exactly fit how much you have lowered your body. To raise the front of the diff up slip a shim between the leaf and the front of the lowering block, to lower the front of the diff down place the shim at the back. Trial and error to get the diff level equal to the transmission level.

 

 

I lowered my 710 maybe 3" and it hummed really bad. I checked using a protractor and a string with a washer on it as a plumb bob to get the angles. Turns out a 1/8" shim between the leaf spring and the 2" lowering block at the behind the axle tilted the diff down at the front and made it level with the transmission. Problem gone, the difference was night and day different.

 

Vehicle has to be on it's wheels. If you jack it up you raise the body relationship to the axle and the angles change. If you want, have someone sit in the driver's seat to simulate the added weight..

[flatcat19]

Angled 2° shims can be had off the shelf at AutoZone for like $12.

 

If only a 3" or 4" job, 2° is normally enough to cancel out NVH.

 

Without shims I read 1" square tube to raise the carrier works.

3" would take a 1/2" or so.

[Kyle253]

Alright, I've got 4" blocks. I'll take a look and see what I can get. It was working fine at 3" but as soon as I dropped it that extra inch it started vibrating pretty bad. Didn't think it would make that much of a difference.

[Kyle253]

Also just for the future I'd like to but a 1 piece driveline in, do I have to have one made or can I pull one from another vehicle?

[flatcat19]

Have one made after you decide what transmission you will finally end up using.

 

4" blocks...go get a chunk of 1" square pipe. Fab to fit between cross member and carrier.

[Kyle253]

Cool. Got a bunch of scrap tubing at work. Should be easy enough. Thanks for the advice.

[datzenmike]

Measure angles and use shims. Your truck height is unique, what works for one may not for another. At best this is only 'close'.  It may be better, but not perfect.

[Charlie69]

Rule of thumb Is for every 1" in drop add a 1/4" shim to raise the carrier bearing.

 

1" = 1/4"

2" = 1/2"

3" = 3/4"

4" = 1"