Rear spring Question..shims
Thread Starter
Intermediate
Joined: Jul 2010
Posts: 32
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From: north bend washington
Rear spring Question..shims
Well i think i broke my own spring... I think there are four shims or three not sure well i put all of them on top of the spring and installed the spring and that put it further down from the diff. When i lowered it it was puller more arch than the stock position cant believe i did that got in to much of a hurry.
can anyone send me a pic of the stock spring/shim setup i think that there are 2 on top and 2 underneith the spring...thanks
can anyone send me a pic of the stock spring/shim setup i think that there are 2 on top and 2 underneith the spring...thanks
7th Gear
Joined: Aug 2013
Posts: 7
Likes: 0
Churchkey - I am replacing my Z51 rear spring with a softer version. I want to know how many shims to use (all of them from my Z51?).
I see you said that this information varies by suspension setup and should be in the fsm. I have a fsm and it doesn't mention anything in terms of shims vs. suspension package.
Any other ideas?
THanks,
John
I see you said that this information varies by suspension setup and should be in the fsm. I have a fsm and it doesn't mention anything in terms of shims vs. suspension package.
Any other ideas?
THanks,
John
Melting Slicks
Joined: Sep 2008
Posts: 2,376
Likes: 111
From: Cherokee National Forest TN
FSM is @ the shop but have my parts book at home.
84 to 87 lists 4 different shim thickness & lists the suspension package they are used with but not how many. No Z51 listing for 84-87.
84 FE7
84 except FE7
85-87 w/Y07
85-87 w/Y67
88 to 91 also lists 4 different shim sizes however there is no listing as to what suspension package, it just lists 4 different shim thickness.
92 lists 5 sizes for the suspension packages FE1 & FE7
My Y parts manual is for 84 to 92 years.
I will not be able to check the FSM until Tuesday it is @ the shop.
If this were my job I would use the shims that are in the car & change to adjustable hangar bolts. Set the ride height then check/adjust the alignment.
84 to 87 lists 4 different shim thickness & lists the suspension package they are used with but not how many. No Z51 listing for 84-87.
84 FE7
84 except FE7
85-87 w/Y07
85-87 w/Y67
88 to 91 also lists 4 different shim sizes however there is no listing as to what suspension package, it just lists 4 different shim thickness.
92 lists 5 sizes for the suspension packages FE1 & FE7
My Y parts manual is for 84 to 92 years.
I will not be able to check the FSM until Tuesday it is @ the shop.
If this were my job I would use the shims that are in the car & change to adjustable hangar bolts. Set the ride height then check/adjust the alignment.
Last edited by Churchkey; Sep 1, 2013 at 02:44 AM.
7th Gear
Joined: Aug 2013
Posts: 7
Likes: 0
My FSM was purchased with the car in 1984. I wonder if this information was added later because mine just says how to remove and replace the spring. No mention of shims except the picture shows one spring above and below. No difference with suspension set ups.
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Team Owner
Joined: Sep 2003
Posts: 25,362
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I believe the generally accepted practice for replacing the rear spring is to reuse the shims at the same locations as they are presently. So long as they are even both left and right there should be no issues. The shims aren't all the same thickness so don't just assume 2 top and 1 bottom or whatever the count is when you remove them, equal thickness top both sides and equal thickness bottom both sides.
In the FSM they should be covered in 3D - "Spring Anchor Plate" - There are way more possibilities than practical to list.
In the FSM they should be covered in 3D - "Spring Anchor Plate" - There are way more possibilities than practical to list.
Last edited by WVZR-1; Sep 1, 2013 at 07:36 AM.
Team Owner
Joined: Sep 2003
Posts: 25,362
Likes: 2,730
Base car: 14046950 6.11mm
HD car: 14044572 5.21mm
What's actually in your car? Keep in mind that above the spring should also be an insulator. It should be stacked spring, shim, insulator to rear differential cover.
Team Owner
Joined: Sep 2003
Posts: 20,172
Likes: 672
From: Freedom is never more than one generation away from extinction.
St. Jude '03 thru '24
IMHO the shim stack is used to establish ride height.
Specifically, when the factory spring bolt is set with the cotter key/nut.
I moved the entire stack under the spring to assist lowering the rear.
Specifically, when the factory spring bolt is set with the cotter key/nut.
I moved the entire stack under the spring to assist lowering the rear.
7th Gear
Joined: Aug 2013
Posts: 7
Likes: 0
The car is an 84 Z51. In the car now is (from top down):
-An insulator (looks like a shim but a bit smaller)
-2 shims on top
-Spring
-0 shims on bottom
I am installing a base spring (non Z51) to improve the ride. My question is should I keep the shim order exactly the same with a base spring? Or should I move shims around (i.e. one on top and one on bottom) to adjust the height.
I fear that I will put the new (softer) spring in, keep the shims exactly as they are now and have an INCREASE in height.
I'd appreciate the input as always. Thanks.
-An insulator (looks like a shim but a bit smaller)
-2 shims on top
-Spring
-0 shims on bottom
I am installing a base spring (non Z51) to improve the ride. My question is should I keep the shim order exactly the same with a base spring? Or should I move shims around (i.e. one on top and one on bottom) to adjust the height.
I fear that I will put the new (softer) spring in, keep the shims exactly as they are now and have an INCREASE in height.
I'd appreciate the input as always. Thanks.
Melting Slicks
Joined: Sep 2008
Posts: 2,376
Likes: 111
From: Cherokee National Forest TN
If its to high move shims from above the spring to below the spring. Adjusting the height at the differential is linear. A 1/2" change in shim thickness = a 1/2" change in clearance @ the wheel centerline to the body.
Before checking height be sure to roll the car forward/backward to settle the suspension & remove tire scrub.
From post #7 "If this were my job I would use the shims that are in the car & change to adjustable hangar bolts. Set the ride height then check/adjust the alignment. "
Good luck.
Before checking height be sure to roll the car forward/backward to settle the suspension & remove tire scrub.
From post #7 "If this were my job I would use the shims that are in the car & change to adjustable hangar bolts. Set the ride height then check/adjust the alignment. "
Good luck.
Team Owner
Joined: Sep 2003
Posts: 25,362
Likes: 2,730
Impossible to answer - softer doesn't necessarily mean it will do anything to ride height. No one including yourself knows the condition of the spring you're removing. If your desire is to soften the ride it seems you're making a correct move and as "Churchkey" mentioned if the ride height is unsatisfactory "to you" just adjust it with the bolts on the spring ends.
Melting Slicks
Joined: Sep 2008
Posts: 2,376
Likes: 111
From: Cherokee National Forest TN
Other ride quality considerations:
Shocks, Not many options however entry level units (price wise) normally give a softer ride.
Tires: If the tires are old they are hard & non compliant, replace them. I run recommended air pressure for the highway & drop 4# for urban cruising.
Other options:
A pillow on the pilot chair.
A Lexus.
Shocks, Not many options however entry level units (price wise) normally give a softer ride.
Tires: If the tires are old they are hard & non compliant, replace them. I run recommended air pressure for the highway & drop 4# for urban cruising.
Other options:
A pillow on the pilot chair.
A Lexus.
Instructor
Joined: Oct 2006
Posts: 223
Likes: 5
I am no expert...
My rear spring delaminated several years ago on my 85. It was riding on the rubber stops on the left side. I ordered a spring from Ecklers. When I went to install it, the bolts were too short with the oe shims, so I left them out. Still no problems without them.
7th Gear
Joined: Aug 2013
Posts: 7
Likes: 0
I finally had some time to swap out my Z51 spring for a softer base spring (NYR I think). It has a MUCH bigger arc - my Z51 spring is almost flat.
I installed the "2 above, 0 below" shim setup on the new softer base spring and put the brackets back on the RH and LH side and guess what happened....the brackets bottomed out when I tightened the bolts and there was still space left in the spring / shim area.
Basically, the NYR spring I used must have a certain shim count that is required to fill the finite space that the brackets provide. How do I find out what that is? My 1984 factory manual (purchased with the car in 1984) does not call out any differences in shims, etc.
It makes sense, the Z51 spring is much thicker than the base softer spring. When you put the NYR softer spring in place you need extra shims to take up the space. Just need to find out what that is. Anyone have any idea? This must be documented somewhere easy to get. Also, where do I buy shims? I'll look at cc and a couple of others. Thanks in advance.
I installed the "2 above, 0 below" shim setup on the new softer base spring and put the brackets back on the RH and LH side and guess what happened....the brackets bottomed out when I tightened the bolts and there was still space left in the spring / shim area.
Basically, the NYR spring I used must have a certain shim count that is required to fill the finite space that the brackets provide. How do I find out what that is? My 1984 factory manual (purchased with the car in 1984) does not call out any differences in shims, etc.
It makes sense, the Z51 spring is much thicker than the base softer spring. When you put the NYR softer spring in place you need extra shims to take up the space. Just need to find out what that is. Anyone have any idea? This must be documented somewhere easy to get. Also, where do I buy shims? I'll look at cc and a couple of others. Thanks in advance.