Anchor plates for U-bolts that hold rear leaf springs to axle housing (why are left and right sides needed) shocks do not mount to anchor plates

Hi everyone,

This is something I'm just curious about since it does not make sense.

The four U-bolts that hold the rear leaf springs to the axle housing on a 91 Chevy K1500 pickup, work with removable U-bolt anchor plates that go under the axle housing. There is one anchor plate on each side of the vehicle. Each anchor plate works with two U-bolts. The shocks and/or shock-mounts are not connected to the anchor plates (like on some Dodge trucks I've seen), and nothing else is mounted to the anchor plates.

For some reason, there are two different part numbers for the anchor plates, i.e., left and right sides for the drivers and passenger side of the vehicle. However, both parts look identical. I held the parts next to each other, and I looked at the parts comparing all the features and they looked exactly the same. I measured the parts with a tape measure and all the features and hole spacing of both parts measured the same.

Since there are two different part numbers it seems there must be some difference between the parts but I cannot detect the difference by looking and measuring.

Can anyone tell me why left and right side U-bolt anchor plates are necessary for this vehicle ? What is the difference between the left and right side parts ?

Any feedback would be appreciated.

Thanks John

Reply to
John2005
Loading thread data ...

First, are you getting the parts numbers off the parts themselves, or from a dealership parts list?

If it is from the dealer's parts list, then I have no idea.

If it is from the parts themselves, might it be possible that a previous owner had to replace one of these plates, for whatever reason, and that he matched one from a GMC or Chevrolet of a different year, etc, from a junkyard. Even possible that it didnt come from a pickup at all?

Just a wild guess.

Reply to
HLS

I had three different GM dealers look up the parts and they all got the same numbers, using my vehicle VIN number with their computer data base. The U-bolt anchor part numbers are different for the drivers and passengers sides, and on the two new anchor plates that I bought from GM, the part numbers are also stamped into the parts, along with an LH and RH designation.

As far as the original parts on the truck, there are no previous owners. However, any part numbers on the anchors that are installed on the truck rusted off long ago, so there is no way to double check it that way.

It's no big deal and I'm not going to lose sleep over it or anything, I'm just curious why GM would have two different part numbers and stamp the part for a left and right side when the parts appear to be physically identical.

John

Reply to
John2005

If you haven't already installed them, post some photos.

Reply to
Ashton Crusher

I'm thinking you're onto something.

I'm tied up at the moment, so I can't look at my truck (90 K1500) but I bet someone replaced one of the original poster's - I think the shocks are staggered and the mounting plates aren't interchangeable.

As soon as I get a chance I'll go look.

Ray

Reply to
ray

I had a quick peek at my truck (90 K1500) and I don't have an answer for you. You're right, the plates look the same. They're just "square" plates with 4 holes for the U bolts...

If it was my truck, I'd chalk it up to "one of those things" and not worry about it.

Ray

Reply to
ray

There could be a variety of reasons for the different part number and all of them would be paperwork reasons because they are the same part. Maybe the BOM only got updated when the part was revised for one side. Maybe there is some manufacturing book keeping reason that a part number for each side is required, etc and so on. Maybe the guy who was in charge of setting up service part numbers was so used to having the sides different he just did it that way but they both refer back to the same engineering part number. My guess is that the part number difference falls under some internal paperwork issue at GM.

Reply to
Brent P

*same part based on everyone's observations and making a different one would be foolish given the description.
Reply to
Brent P

I'm curious if there was a difference in price.

Reply to
Steve Austin

Thanks for your replies guys.

No difference in price, both sides cost the same amount.

Again, this is not a big deal and not something I'm going to lose sleep over or anything. It was just something that seemed odd to me. The fact that there would be two different part numbers for a left and right side, when both parts appear identical.

I think Brent P. is probably right, it's just an internal paperwork thing. Perhaps other trucks have the shock mounts attached to the anchor plates and require left and right sides. They were probably so used to assigning different part numbers that they just went ahead and assigned two part numbers when only one is necessary. You would still think they would try to avoid situations like this though.

Here's the thing, the GM dealers said that the Left side anchor plate is either on backorder or discontinued (depending on who I talked to). The GM dealer had to put my VIN into the computer and do a nation wide dealer search but was able to get one left side for me.

So, if anyone else needs these parts and the dealer tells you that the left side is discontinued or on backorder, you may want to check to see if you can just use two right sides or whatever the case may be. Even aftermarket suppliers like LMC truck list a left and right side so the same thing would probably apply there as well, and *could* apply to different years, makes, models, etc..

Thanks for checking your 1990 Ray.

John

Reply to
John2005

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.