Dusterbd13 MegaDork
11/12/18 2:46 p.m.

I have 2 inch lowering blocks on the back of my duster. The pinion angle is WRONG. Like 4+ degrees off.

These are the universal aluminium parts sold at the flaps. Just cheap blocks.

Im wondering if i can angle them at home safely to correct the pinion angle and see if it cures the vibrations ive picked up. 

I do not have machining equipment like a bridgeport or anything  more like a table saw, portaband, belt sander, etc.


Or am i asking for death and destruction?

rdcyclist Reader
11/12/18 2:50 p.m.

Depends on how good you are with the aforementioned tools. Since you've got leaf springs, they'll accommodate some variation between blocks. I'd say go for it. What could go wrong?

Professor_Brap HalfDork
11/12/18 2:50 p.m.

Nothing wrong with using the angled block (wedge looking blocks) to correct pinion angle. 

Dusterbd13 MegaDork
11/12/18 3:06 p.m.

The only commercially available angled blocks seem to be 3-4 inch.

I have some wedges, but am concerned about the amount of engagement with the centering pins.

Still trying to figure out if i can safely do this with my woodworking tools.  I know they will cut aluminium acceptably well, but safely and without kicking back....

Cooter Dork
11/12/18 3:09 p.m.

While cutting them should be very easy, I'd personally prefer to see steel blocks under it.  I have seen many aluminum wedges split and spit out over the years. 

Cooter Dork
11/12/18 3:12 p.m.

In reply to Cooter :

After rereading your post, you really should just take off the spring pads and reweld them on the correct angle. It really isn't rocket science. 

MadScientistMatt PowerDork
11/12/18 3:13 p.m.

Clamp the blocks in a vice and hit them with a belt sander - as long as you don't grind into the centering hole too much, you should be fine.

Dusterbd13 MegaDork
11/12/18 3:50 p.m.

Rewelding the perches has crossed my mind. However, im going to wait until im done screwing around with the leaf packs and mounts. Once i have that all dialed in, ill redo the perches and use steel blocks of appropriate height.

Hadn't thought about just sanding the angle, to be honest. Ill have to draw the line and see how much sanding it would be. 

stafford1500 HalfDork
11/12/18 4:04 p.m.

Call the used race parts places in Mooresville and ask if they have Pinion Shims. Basically thin wedges for the spring pads in an amazing array of sizes (angles). The best way is to grind or sand your blocks down and then you could re-drill the pin hole if it is not deep enough or has some odd fit because of the angle. The Pinion Shim option gives you too many pieces that can fall out if things loosen up. The used race parts places probably also have lowering block to give you new raw material to work with while you keep the Duster on the road.

wheelsmithy SuperDork
11/12/18 4:07 p.m.

My two cents as a final solution is to make a tube steel lowering block/spring pad out of steel. Welded to the axle and all. 


Short term, tape/scribe an accurate line, and use 40 grit sandpaper or the like glued to a table. Should get you there fairly quick after a rough cut. Files are nice, too. 

rdcyclist Reader
11/12/18 4:21 p.m.

Actually, I would convert it to Four Bar and coilovers...

Dusterbd13 MegaDork
11/12/18 4:31 p.m.

In reply to rdcyclist :

3 link crossed my mind....


But leaves are staying.  The car is a fun cruiser. It no longer autocrosses or drag races due to insurance restrictions. 

Dusterbd13 MegaDork
11/12/18 4:34 p.m.

In reply to stafford1500 :

That was the name of the wedges i have!

And exactly my concern with them falling out.

I can get more cheap blocks off ebay if i need to. I THINK the current spring package is close. Needs more drive time to be certain though.....

Robbie UltimaDork
11/12/18 4:44 p.m.

Why can't you hit them with an angle grinder? Chock them into a vice and give em hell.

If you don't have one they are less than $10 at hf. But I would refuse to believe you don't have one...

Dusterbd13 MegaDork
11/12/18 4:46 p.m.
Robbie said:

Why can't you hit them with an angle grinder? Chock them into a vice and give em hell.

If you don't have one they are less than $10 at hf. But I would refuse to believe you don't have one...

I have 4 angle grinders right now. 

I honestly didn't think about them. 

Scribe my line, put in vise, add flap wheel to taste. Right?

Robbie UltimaDork
11/12/18 4:48 p.m.

That's what I'd do. 

Robbie UltimaDork
11/12/18 4:50 p.m.

If they are aluminum it may not be too bad to just use a hack saw.

Scribe line, put it vise so vise teeth are right under line, use hacksaw with blade riding on top of vice teeth to guide.

dean1484 MegaDork
11/12/18 4:51 p.m.
MadScientistMatt said:

Clamp the blocks in a vice and hit them with a belt sander - as long as you don't grind into the centering hole too much, you should be fine.

I have done this. It is easy. Just make sure to wear a mask of some kind so you don’t breath in the aluminum dust.  

Cooter Dork
11/12/18 5:46 p.m.

If you aren't at your final rear suspension setup, then I understand the idea of shims.


Aluminium can be cut pretty easy with a regular hand saw for wood. But I really would want it to be a temporary solution. 

Patrick MegaDork
11/12/18 6:01 p.m.

Gm makes wedges to put under the block.  I have some in new old stock packaging.

also, big belt sander for the current blocks

759NRNG SuperDork
11/12/18 7:21 p.m.


Hey .....check SkinnyG and his square 'build' thread ......he recently went thru a similar process of shimmy n' shake....and came thru with satisfactory results........

Dusterbd13 MegaDork
11/12/18 8:35 p.m.

I need to read that 759 

Pat: didn't know gm offered them factory!

If i can find the angle finder tomorrow, ill start tweaking for a test when the rain ckears out.

GTXVette SuperDork
11/13/18 7:43 a.m.


44Dwarf UberDork
11/13/18 10:30 a.m.

Don't move the perches on the tube you will not have a straight housing afterwards. 

Any truck shop will have the angled shims, but like you said the centering pin depth goes away fast.  I'd use them to dial in the pinion angle then use them as a marking tool for the blocks and scribe the sides of the block then grind or machine the blocks face..

Anyone with a fly cutter and a bridgeport can cut the angle rather quickly if the sides are scribed just holding it in a vice or the angle calculated using a sin plate.

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