Does this 1967 rear spring / leaf-spring look salvageable? (pictures)

[Scott S.]

Does this 1967 rear spring / leaf-spring look salvageable? It is the standard small-block 9-leaf spring. I have read in the archives here that if there is too much metal lost due to corrosion, it won't be any good, even if I clean up to look like new.

Are there any tricks to determine if this one can be saved, or do the pictures show enough to experienced eyes that I should be looking for a good used replacement?

Thanks,

Scott

[Scott S.]

Re: Does this 1967 rear spring / leaf-spring look salvageable? (pictures)

A few more pictures.

[Timothy B.]

Re: Does this 1967 rear spring / leaf-spring look salvageable? (pictures)

Scott,

Take the center bolt out and look at each leaf. That's where you will find the corrosion..

[Edward J.]

Re: Does this 1967 rear spring / leaf-spring look salvageable? (pictures)

Scott, sometimes the inside part of the spring may have the least corrosoin, the factory primer between the leafs helps keep the rust away. The edges do not mean much, the main leaf is important as it is the main support for the other leafs. sometimes if you have another original you maybe able to make one good one.

I did my 72 spring 3 yrs ago it was original to car and after sand blasting it had some minor pitting car sits level and painting and installing new liners and new cushings.

[Scott S.]

Re: Does this 1967 rear spring / leaf-spring look salvageable? (pictures)

Thanks guys,

I will try to take it apart this evening and post better pictures later tonight.

[David S.]

Re: Does this 1967 rear spring / leaf-spring look salvageable? (pictures)

Scott,

Be very careful taking the center bolt out. Keep the spring compressed in a vise when you remove the bolt. Then slowly take it out. I would recommend media blasting each leaf to get rid of all the rust. Then inspect each leaf for cracks. Be sure to give it a nice coat of paint and put it back together using the spring liners from your favorite Corvette parts company.

Best,
Dave

[Scott S.]

Re: Does this 1967 rear spring / leaf-spring look salvageable? (pictures)

Scott,

Be very careful taking the center bolt out. Keep the spring compressed in a vise when you remove the bolt. Then slowly take it out. I would recommend media blasting each leaf to get rid of all the rust. Then inspect each leaf for cracks. Be sure to give it a nice coat of paint and put it back together using the spring liners from your favorite Corvette parts company.

Best,
Dave

Hi Dave,

Thanks for the warning, it probably would have made removing the bolt easier if it was compressed in a vise, but I didn't think of that until the bolt was almost out, and many of the leaves had already separated from each other gradually, as the bolt tension was released.

I couldn't tell if the nut was stripped or just corroded, so I'm not sure if it had ever been apart before, but a socket wrench wouldn't stay on it. The bolt holding the leaf-spring together was a round-head bolt. Not stripped, just round. I had never seen a round head bolt before, but fortunately, I had a round-head bolt removing tool for just such an occasion.

[David S.]

Re: Does this 1967 rear spring / leaf-spring look salvageable? (pictures)

Scott,

That round head bolt is indeed an original. That is 100% correct. I would strongly recommend either purchasing a new round head bolt or putting a regular bolt through the spring to keep it compressed (when you put it all back together). On those original round head bolts, I have seen several springs that the nut slips on the threads of the original bolts. If you do replace the center bolt with a regular bolt, make sure the head is small enough to fit in the designated spot on the bottom of the rear differential housing.

Best,
Dave

[Scott S.]

Re: Does this 1967 rear spring / leaf-spring look salvageable? (pictures)

Scott,

That round head bolt is indeed an original. That is 100% correct. I would strongly recommend either purchasing a new round head bolt or putting a regular bolt through the spring to keep it compressed (when you put it all back together). On those original round head bolts, I have seen several springs that the nut slips on the threads of the original bolts. If you do replace the center bolt with a regular bolt, make sure the head is small enough to fit in the designated spot on the bottom of the rear differential housing.

Best,
Dave

Thanks Dave. The bolt appears slightly bent, and the threads look questionable, so it should probably be replaced.

LIC has one that appears similar, but has threads the whole length of the shaft, where the original has a smooth shaft with threads only on the last inch. Also, the shaft (not counting the bolt-head) on the LIC example looks about 3 1/2" long, vs. 2 13/16th on the original (3" overall length).

The original has a bolt-head that looks about 3/16th tall, where the LIC bolt looks like a taller bolt-head, which may be a problem. No idea what the bolt-head marking is on the LIC, but my original has a "W".

[Timothy B.]

Re: Does this 1967 rear spring / leaf-spring look salvageable? (pictures)

Scott,

Quanta used to sell a kit with liners, paint and new center bolt. Be very careful to trim the head of the new bolt to match the original, you can poke a hole or crack the rear housing if not trimmed..

[Joe L.]

Re: Does this 1967 rear spring / leaf-spring look salvageable? (pictures)

Thanks Dave. The bolt appears slightly bent, and the threads look questionable, so it should probably be replaced.

LIC has one that appears similar, but has threads the whole length of the shaft, where the original has a smooth shaft with threads only on the last inch. Also, the shaft (not counting the bolt-head) on the LIC example looks about 3 1/2" long, vs. 2 13/16th on the original (3" overall length).

The original has a bolt-head that looks about 3/16th tall, where the LIC bolt looks like a taller bolt-head, which may be a problem. No idea what the bolt-head marking is on the LIC, but my original has a "W".

Scott------

The all-thread bolt causes no functional problems and is fine to use. No one will ever know the difference except the next guy that takes the spring apart.

Most replacement bolts, including those sourced from GM, have the taller head. These MUST be ground down to the height of the original bolt head.

[Rich P.]

Re: Does this 1967 rear spring / leaf-spring look salvageable? (pictures)

25 years ago when no one was reproing these bolts I got a few dozen grade 8 bolts that had the same shoulder and thread length and ground the heads round to fit into the rear. I still have a few.
The reason the threads look a little screwed up on the original bolt is because once it was assembled they would wack the end to distort the thread.....then whamo instant locking bolt! If you take a look at an original spring the end of the bolt should have a flattening of the threads.
Krylon dove grey was always my choice to match the spring color.

Rich

[Scott S.]

Re: Does this 1967 rear spring / leaf-spring look salvageable? (pictures)

Thanks to everyone for the replies and the warnings about the bolt-head not being too tall. I will get the spring media-blasted and then post pictures for analysis.

[Steve L.]

Re: Does this 1967 rear spring / leaf-spring look salvageable? (pictures)

Scott,
Test each leaf separately using a bathroom scale as shown in the picture.

Deflect spring 1 through 5 a distance of 2 inches measured at the center and spring 6, 1 inch (spring #1 being the longest).

The numbers for a repro spring are around 30 lbs for spring #1; 50 lbs for springs 2,3 and 4; 60 lbs for #5 and 70 lbs(@1inch deflection for #6)

Spring 7,8 and 9 are difficult to test at home.

These numbers for repro spring are stiffer, yours are going to be a lot less.

You can do this test before any cleaning.

The picture shows a wheel dolly for the support but anything that is low and rolls should work i.e. skate board. It only takes about 15 minutes to do this.

Any unseen cracks will show very low numbers.

Post your numbers and a picture of your set-up so we can have a look.

[Scott S.]

Re: Does this 1967 rear spring / leaf-spring look salvageable? (pictures)

I think I can manage that, I'll post the results back here.

Thanks,

Scott