Questions regarding rear leaf spring U-Bolt top-plate on a 91 Chevy K1500 Pickup
John2005
I'm hoping I can get some feedback regarding the rear leaf spring U-
Bolt top-plate on a 1991 Chevy K1500 pickup.
I have attached two gif drawings for reference. Here is the download
link for the drawings, only 201.19 KB...
http://ifile.it/fg3beao/U-Bolt%20Drawings.zip
Referring to the drawings, my questions are regarding part # 5
(spacer) of drawing A, or what is called the "top plate" in drawing B.
I purchased the top-plate from the GM dealer and I know it's the right
part because I used the Vin # to order it and I verified the part
number at two different dealers.
When I installed the top-plate, the nut on top of the leaf spring
center-bolt would not go all the way through the hole in the top-
plate. If anything, the hole in the new top-plate looked a little
bigger than the hole in the old top-plate. I went ahead and torqued
the U-bolts to factory specs of 81 foot-pounds and followed the
correct tightening sequence, thinking this would force the nut through
the hole in the U Bolt top-plate (it seemed close enough).
The ends of the top-plate are now clamped tight against the top of the
leaf springs. However, the center of the top-plate is not touching the
top of the leaf springs. The nut on top of the leaf spring center-bolt
was not pushed all the way through the hole in the top-plate. I can
only guess that its' designed this way for some reason but I wanted to
check to make sure. I replaced the drivers side today and I'm
replacing the passenger side tomorrow. I cannot just look at the old
one that is still on the passenger side because there is so much rust
present, I cannot tell if there used to be a space there or not.
According to the factory service manuals I have, there does not appear
to be any other spacer or anything that would "take up" the space.
I did not install the plate upside down, it's installed just as shown
in drawing A and that's how the plate was originally installed as
well.
I would really appreciate any feedback anyone might have on this.
Thanks
John
John2005
Here are download instructions that will help.
File download instructions:
You don't need to register or sign-in with the site to download the
file, just click on the link http://ifile.it/fg3beao/U-Bolt%20Drawings.zip
and after the page loads click "request download ticket" then it will
say "download" where it had said "request download ticket" before.
Then you just click "download" and save the file. The two gif files
are in a zip file that you can open with winzip, winrar, 7-zip, or
similar programs.
Thanks again,
John
John2005
downloading or unzipping anything.
Just click on the links below and the drawings will show up in your
browser. You have to use Internet Explorer or Firefox, for some
reason
the images did not show up in my Opera browser.
http://www.shareimages.com/image.php?32835-pZSel5mjk6Kpk6SZ-drawing_a.gif
http://www.shareimages.com/image.php?32836-pZSel5mjk6Kpk6SZ-drawing_b.gif
John
John2005
the bottom of the top-plate and the top of the leaf spring stack. All
I can think of is that there may have been some rust in there around
the center-bolt nut that made it larger than it was originally. I took
a chisel an hammer to the top surface of the leaf spring stack, and
then wire brushed it, and sprayed on some wax based rust inhibitor and
wax based under coating. It looked pretty clean, but perhaps there was
something there. The wax based undercoating is soft, so that's not a
problem.
If the passenger side goes better tomorrow, I just wonder if I should
take the drivers side back apart and try to re-do it ? I thought I
read once that you should not torque U-bolts and then loosen them and
re-use them, but I'm not sure what it would really hurt ? I would hate
to have to buy another set of U-bolts and nuts if I don't really have
to.
John
PeterD
Personally, I'd remove and reinstall, being careful about locating the
plate, and making sure that things are right. I don't know about
problems reusing the U bolts, maybe someone else can chime in, AFAIK,
they are reusable.
John2005
Doing the passenger side, I found out a little more about what is
going on.
I took the U-bolts off the passenger side and removed the old top-
plate. I cleaned all the rust from around the center-bolt nut very
well and I installed the new top-plate over the nut. What I found is
that even with the ends of the top-plate sitting on the top of the
leaf spring stack, there is still a very small (about 1/6") of space
at the center of the top plate between the top plate and the top of
the leaf spring stack.
I think this is simply because the leaf springs have a very small arc
at the center of the springs (I also checked it with the straight thin
edge of the top plate, and there is a space there). It's not much of
an arc at the center of the spring stack but it appears to be enough
to create a very small space there. It's probably not noticeable on
most vehicles because as soon as you drive down the road you get dust,
debris, and rust in there. You have to clean everything well to see
the space.
On the drivers side, I had about a 1/8" space. I shined a bright light
in the space and found a thin piece of rust in there. I would like to
just loosen the U-bolts back up, take a chisel to the piece of rust,
and then torque everything back down on the drivers side. I had heard
you should not loosen and re-torque U-bolts but I have not even driven
on the U-bolts and I don't really see what it would hurt. It's
probably OK just like it is with the 1/8" space but I like to do
things right.
I looked at an 09 Chevy and found the design is a little different
than on my truck. On the 09, the center-bolt nut is sitting on top of
the top-plate, but on my truck, you cannot even see the center-bolt
nut unless you remove the top plate, all you see are threads sticking
up before the top-plate is removed.
Another thing I noticed when I took a closer look at my original (old)
top-plates is that the hole is hexed shaped. It seems at least
originally, the top plate hole was very close in size to the nut and
it was pressed over the nut a little.
John