Rear Leaf Spring Mount Plate...

[Patrick T.]

I'm in the process of replacing the rear leaf spring with a new Eaton 9 leaf spring. I have the old spring off now and have noticed that the 4 1/2" x 7" black attachment plate is not perfectly flat. When I lay it on a flat surface, the plate rocks back and forth about 1/8". It appears that the plate is slightly curved around where the spring attaches to the differential. I'm guessing this has resulted from 45 years of the (4) 5/8" attachment bolts being over torqued.

My question is...is this warped plate a big deal, it's hardly noticeable? Should I replace it now with a new plate or just continue to use this one? Replacing this spring is a real PITA and I only want to do this once. Thanks, PT

[Harry S.]

Re: Rear Leaf Spring Mount Plate...

PT, it's bent because something went wrong in the past. I'd look for a real one not a repop and replace it.

[Joe R.]

Re: Rear Leaf Spring Mount Plate...

Patrick,

Would not hesitate a second to use the original! I would check after the spring is torqued down the distance from the tips of the spring to the floor. They should be the same and not distorted in any way. That check should be done without the trailing arms connected.

JR

[Dick W.]

Re: Rear Leaf Spring Mount Plate...

Patrick, we reused many that were not perfectly flat, and had no problems

[Gene M.]

Re: Rear Leaf Spring Mount Plate...

Patrick,
What Dick said. But if I was doing a complete job for myself and time no object, I would set it in a hydraulic press and make it flat prior to bead blasting it and repainting it. There now you have both ends of the extreme, take your choice.

[Timothy B.]

Re: Rear Leaf Spring Mount Plate...

Patrick,

I would reuse also, just take a few minutes and straighten and don't over torque the bolts.

[Dick W.]

Re: Rear Leaf Spring Mount Plate...

Patrick,
What Dick said. But if I was doing a complete job for myself and time no object, I would set it in a hydraulic press and make it flat prior to bead blasting it and repainting it. There now you have both ends of the extreme, take your choice.

Four pound pent roof hammer and a piece of railroad track works wonders

[Patrick T.]

Re: Rear Leaf Spring Mount Plate...

Thanks to everyone for your comments. I looked at the plate again with a straight edge and the curve is more like 1/16" of an inch instead of 1/8". So I took it down to the Chevy Dealer in town. They have a 10 ton arbor press in the shop. I had the manager place the plate on the press and he pumped it up to about 5 tons in 4 places. That worked like a charm; now the plate is completely flat. Best of all there was no charge! Thanks again for your help.

[Gene M.]

Re: Rear Leaf Spring Mount Plate...

Four pound pent roof hammer and a piece of railroad track works wonders

Sounds easy enough, now where did I put that section of rail road track?.............

[Dick W.]

Re: Rear Leaf Spring Mount Plate...

Sounds easy enough, now where did I put that section of rail road track?.............

I thought everyone had a piece in their shop. Have a piece welded on the welding table.

[John H.]

Re: Rear Leaf Spring Mount Plate...

Thanks to everyone for your comments. I looked at the plate again with a straight edge and the curve is more like 1/16" of an inch instead of 1/8". So I took it down to the Chevy Dealer in town. They have a 10 ton arbor press in the shop. I had the manager place the plate on the press and he pumped it up to about 5 tons in 4 places. That worked like a charm; now the plate is completely flat. Best of all there was no charge! Thanks again for your help.

Patrick -

When you put it back together, don't fully torque those four spring plate bolts until the car is back on wheels with the suspension at normal ride height; you don't want to break the bottom ears off your rear cover or bend the plate again. They didn't put that little tidbit in the Chassis Service Manual until 1971; probably got tired of replacing rear covers under warranty.

[Patrick T.]

Re: Rear Leaf Spring Mount Plate...

Patrick -

When you put it back together, don't fully torque those four spring plate bolts until the car is back on wheels with the suspension at normal ride height; you don't want to break the bottom ears off your rear cover or bend the plate again. They didn't put that little tidbit in the Chassis Service Manual until 1971; probably got tired of replacing rear covers under warranty.

Thanks John, got it!

[Wayne M.]

Re: Rear Leaf Spring Mount Plate...

...When you put it back together, don't fully torque those four spring plate bolts until the car is back on wheels with the suspension at normal ride height; you don't want to break the bottom ears off your rear cover or bend the plate again. They didn't put that little tidbit in the Chassis Service Manual until 1971; probably got tired of replacing rear covers under warranty.

John --- can I assume the same instructions apply prior to removing the rear spring ? ie. back off the four bolts 3 turns or so when the tires are still supporting the full weight of the rear ?

[Timothy B.]

Re: Rear Leaf Spring Mount Plate...

Probably does not hurt Wayne, but I don't think it matters when loosening the bolts.

[Paul J.]

Re: Rear Leaf Spring Mount Plate...

John --- can I assume the same instructions apply prior to removing the rear spring ? ie. back off the four bolts 3 turns or so when the tires are still supporting the full weight of the rear ?

I used to think about that too, but it doesn't matter. Taking the weight off the rear suspension to work on the spring is no different from putting the car on a lift for any other maintenance or repair. If the ears did'nt break when the car was put back on the ground, they're not going to break when taking the weight off. There's probably a better way to explain this but I hope you get what I mean.

Paul