Installing TRW composite spring???

[74 454]

Have a 74 vette. When I bought it the owner already had a TRW composite spring for it, part #602-101-103-105, with hardware. I'm trying to bolt the center section to the diff cover and the bolts are too short, by probably a 1/2" or more. I have no directions with it. I'm using the heat shield, then the original mounting plate. The bolts measure about a little less than 3 1/2" inches from bottom of bolt head. Do you use all the spacer plates on the spring? It has black tape on both ends and says "assembly tape, don't not remove". Don't know what to do? Help.

 

[milo30]

Since no one has answered if I were you I'd call the manufacturer and they'll give you the info. Maybe even run a search of them online and might have the instructions there.

 

[Bob Chadwick]

x2. I had no problem with mine. Everything bolted up perfectly. Some of the acilliary parts may not be right and they would be the first that could clarify for you.

They have some bolt sizes listed on the Muskegon web site. This might help you.

 

[ElPelon1965]

I just finished installing the same spring on my Vette today. My bolts too were just a little short. I bought some new bolts of the same grade but an inch longer. Because the 'ears' are tapped all the way thru, I had the room if they went a little long. The extra length allowed the spring to go up against the differential easier and allowed the use of flat and lock washers too.

One word of caution that was passed along to me. If you torque the bolts unevenly, you can snap the 'ears' off. Take it slowly, ensuring the pin on top engages the recess at the differential.

Combining the new spring with new shock absorbers and bushings has the car riding a little high. I may have to bottom out the bolts at the trailing arm.

Had quite a bit of trouble removing the spare tire carrier. Also because my exhaust is one piece from the headers back to the muffler, I really had a struggle getting the spring up and in there. Again, the longer bolts helped tremendously.

 

[JW73]

Have a 74 vette. When I bought it the owner already had a TRW composite spring for it, part #602-101-103-105, with hardware. I'm trying to bolt the center section to the diff cover and the bolts are too short, by probably a 1/2" or more. I have no directions with it. I'm using the heat shield, then the original mounting plate. The bolts measure about a little less than 3 1/2" inches from bottom of bolt head. Do you use all the spacer plates on the spring? It has black tape on both ends and says "assembly tape, don't not remove". Don't know what to do? Help.

I have a TRW 602-101-103-105 spring as well on 73 vette. Mine split. I need to get a new spring. Do you know the spring weight for this part number. i/e 320 lbs, 340 lbs, 360 lbs etc. I want to get a new spring with at least the spring weight I had. I have asked TRW and some distributers, but no answer yet.

Thanks for your time, jw73

 

[TMPJoe]

jw73

did you check the ecklers catalog numbers.. a lot of times they just repeat the mfg number with a code in front to identify the mfg

oops that did not work.. thats summitt! ha sorry
IIRC the stock spring is 315 approx

 

[TMPJoe]

74 454

big blocks have the heavy duty diff cover and require a different spring kit as a rule...

 

[JohnZ]

74 454

big blocks have the heavy duty diff cover and require a different spring kit as a rule...

There's no such thing as a factory heavy-duty diff cover - they were all the same. The "heavy-duty diff cover" is an aftermarket invention by Muskegon Brake to address the issue created when people ignore the instructions in the Shop Manual and tighten the four spring retainer plate bolts without the full weight of the car on wheels and break the ears off the factory cover. The Assembly Manual makes it very clear that the suspension is to be compressed to normal ride height before torquing those four bolts, but nobody reads that either.

The only difference between the small-block and big-block diffs was the end of the yokes for the U-joint attachment (U-bolts on SB's, steel caps and bolts on BB's); all other parts are identical.

 

[TMPJoe]

thanks john.. last big block i saw had that other cover

my spring went on without any issues bolts i think were much longer... the adjustable ones are like 7 something