Hey Guys , i have purchased a set of lowered hotchkis rear leafs for my 69. It is a mono leaf rear at moment. Does the original spring perches or 'plates' and shox fit up with the change. Ive been told i need the specific multi leaf base plates and longer shox ,
P.s these things cost me $1000 in australia ! hope they feel good !

Thanx , Blacky

Blacky -

From what I recall and from a quick search here using "hotchkis mono", I think you can get away without changing anything other than the springs.

The monoleaf perch welded to the rear axle housing does not have a hole in it to locate the through bolt found on most OE style multileafs, but the Hotchkis springs apparently have less of a protrusion here, and guys have just been using the top rubber isolator pad to deal with it. Most have been leaving the lower isolator pad out to reduce the thickness of the pack, so the lower part of the spring just contacts the original monoleaf anchor plate.

I assume the Hotchkis springs come with new U-bolts to relpace the OE T-bolts, and you may find you need to oval the mounting holes slightly, as some U-bolts have a little more width than the perches/plates.

Because they are drop springs, it seems that most guys are getting away with using the OE length monoleaf shocks with Hotchkis. The way to confirm this is okay on your car is to bolt the springs on (leaving the shocks off), lower it down and torque the front eye mount and shackle bolts to spec, and then jack it back up and see how much "droop" you have (support the rear subframe with stands under the rails near the front spring mounts, and let the jack down to let the axle housing hang as low as it will go). If the droop is the same (or just a little less) than the extended length of the shock, you should be fine. If there's a big difference, you may just want to try a pair of shock extenders (they thread onto the top of the upper bayonet mount, and give about 1.5 inches more travel).

Good luck!

There is a Monroe shock that's about 2" longer than stock and is a direct bolt on replacement if you find that your stock shocks are too short. I posted the part number and all the specs. before but now I can't seem to find the part number or the post. To me using shock extensions when there is a better alternative is just plain "Mickey Mouse"

Found it.. On my 67 I swapped the single leaf springs for multileafs and used the stock bottom plates but swapped the T-bolts for U-bolts. I'm not a believer in shock extenders so I simply went to the shock dimension & mounting pages in a Monroe shock catalog and came up with a stock shock that's a couple inches longer than the original 67 shock and has the same mounting on the ends. It's Monroe part number 32284 for anyone interested. I would imagine that number can be cross referenced to any other brand of shock. For reference the stock shock for a 67 with monoleaf springs (Monroe #32143) is 11.625 compressed length, 19.250 extended length with a travel length of 7.635. The Monroe part number 32284 is 13.875 compressed, 22.750 extended and has a travel of 8.875. That gains you roughly 2 1/2 inches extended which works out well and slightly more travel.

I think the swap would be "best" with the multi-leaf plates and shocks. But I'm too cheap, so I kept my mono stuff.

The Hotchkis springs come with a short "filler leaf" that is suppsoed to be used for taking up space if you have multi leaf perches on your axle tubes. I cut the head off of a 3/8-20 grade 8 bolt and welded a to the leaf and used that filler leaf ON TOP of the springs in replacement of the through bolt. This has the effect of lowering the rear the thickness of the filler leaf - about 1/4" Turned out I wanted even lower, so I added 1/2" aluminum plates between the filler leaf and the spring. The benefit to all of this is that I didn't have to use the poly pads, which I felt were pretty squishy.

http://img.photobucket.com/albums/v61/gort69/DSCN0179.jpg

Once I had everything where I was happy, I added some 1" (maybe 3/4", I forget) square tubing to fill the gap between the spring perches and the shock plates. I drilled holes through the tubing and used U-bolts to hold it all together. No poly pads whatsoever.

http://img.photobucket.com/albums/v61/gort69/DSCN0235.jpg

One of these days I'm going to buy some "real" shocks for it, and when I do I'll buy multi-leaf plates and shocks.

Thanx Guys all very useful info , sounds like a couple of different ways to go about this swap. Do you feel any extra vibration when the poly pads arn't used?

I installed 5/16" carriage bolts in my springs by first grinding off the four points under the heads, then threaded them way long!

I just installed them, tightened them down and then whacked hell outta the heads w/ my trusty 3 pound FT to flatten/seat the heads and retightened and they are fine up top!!

Then I just cut off the threads where I wanted them and peined the bottom nuts so they wouldn't back off.

I am using poly pads tho and I am going to go back onna these days and install some spacers to keep my plates straight.

AND USE at least two "U"-BOLTS, and better yet, four! Throw the little-bitty "T"-bolts in your bolt can!!

pdq67