57 convertible rear suspension

[ronniep]

Hey everyone! I put new heater levers in my 56 and have the unit back in. There are 3 wires, 2 brown and 1 gray.However, now I have no light or fan. Using my test light, I have power on the gray and 1 of the two brown. I have checked all fuses
etc. Any help is appreciated... Thanks!!
ronniep

[markm]

If I recall dash lights in 56 are gray and heater power wires are brown. The gray one should only have power when lights are on. The heater should have power to it with key in run position coming in and out if fan is switched on.

[ronniep]

If I recall dash lights in 56 are gray and heater power wires are brown. The gray one should only have power when lights are on. The heater should have power to it with key in run position coming in and out if fan is switched on.


Thanks for your reply. Yes, you are right and I checked the power with the headlights on. I can't understand why I'm having this problem. The light and fan both worked before I took control panel out. It' strange I have power to one brown but not the other???

[markm]

Unplug both and jumper them together and fan should run.

[ronniep]

Unplug both and jumper them together and fan should run.


Thanks Mark! I never thought to try that. That is a good idea.

Ronnie P.

[Bow tie downunder]

Hi Laszlo
I recall you saying that you have converted a convertible chassis to a c4.Do you recall whether it had coilovers or a transverse spring with shocks.I could go either way but can't decide which is best.The price of everything I purchase in America doubles buy the time It arrives in Australia.Its important I get it right .
I have completed the fuel tank similar to yours Hereis a photo

[chevynut]

Very nice work on the tank Mick!

I don't remember what the owner was planning for the convertible frame. We set up the suspensions so either coilovers or regular shocks can be used so we don't reallycare.

In the rear, coilovers don't buy you a whole lot over the stock spring with adjustable shocks. The main advantage to coilovers, imo, is the ease of changing spring rates and adjusting ride height. The stock rear spring setup makes it easy to change ride height, but the spring rates are limited to what GM offered or what's available aftermarket.

What is your real question? Not sure I understand what you want to know.

[Bow tie downunder]

Thanks for your reply
I have recently contacted Newmans car creations to purchase a transverse Spring but they have not replied also Hyperco who wanted to know the weight over the front axle to supply a rear spring.the shock absorber is not a problem.I have researched the factory Spring rates but I don't understand how to work it out .The question is what to buy and from where or would it be possible to put me in contact with the owner of the convertible .Thanks
Mick

[chevynut]

Hi Mick, I don't think the convertible is done but I can PM his contact info to you if you want. Are you missing the spring that came with your suspension? I have several rear springs available, but not sure how to ship. If you have an address in the states I would sell you one for $60 plus shipping which is what I usually get for them.

The springs are all designed to give you pretty much the same ride height. The difference is the spring rate, and to compensate they have a different arc to them, resulting in more or less preload. The lighter rate springs have more arc. All C4 REAR springs interchange. So all you need to do is decide whether you want a softer or stiffer spring, or something in the middle. I have a chart that shows the wheel rates of the springs, and that is what determines the ride quality, stiff or soft. Actually, since they all have the same geometry, the spring rate will give a relative ride quality as well.

[Bow tie downunder]

I have the spring that come with the suspension,but being a Dana 44 I thought it would have the stiffer Spring,I fitted the spring to the suspension and added weight to the rear of the car thinking that at some point the half shafts would be level .I allowed for two adults in the back a full tank of petrol the weight of the trunk and bumper and the convertible top.The half shafts were still way off level.If I it's ok I'd like to contact the owner of the convertible.Thanks for the offer of the springs I'm not sure which way to go .

[chevynut]

Mick, if I were you I'd use the spring you have and not do anything until you have the full weight of the car on the wheels. The Dana 44s didn't have any different spring than the 36's. It was all based on the suspension option....i.e. FE1, Z51, Z07, etc. What year is your rear suspension? What is the code on the end of the spring?

I honestly don't think the 55 convertible builder is going to help you any more than I can. In fact, he'll probably refer you to me ;). I looked up my records on that frame and he has an early rear with Dana 36. Here's a pic:

http://www.trifivechevys.com/attachment.php?attachmentid=6138&stc=1

http://www.trifivechevys.com/attachment.php?attachmentid=6139&stc=1


If you have the stock rear spring, there is no reason it won't work. The only one I'd probably replace is an early ('84) Z51 with code "BMH", since it's very stiff at 500 lb/in or 214 lb/in at the wheel. However, the C4 autocross guys love them so they're easy to sell....at least in the US.

Any other spring will work. The softest ones are the latest ones, like 94-96. The most common spring codes are "NYR/RCA/RHZ" and they are 228 lb/in springs, or 147 lb/in at the wheels. The softest is "RR" which is a 149 lb/in spring, or 103 lb/in at the wheel per the info I have on them. The stiffest late spring is "NYU" with a rate of 327 lb/in or 191 lb/in at the wheels.

Again, all of these should give the SAME ride height, but a stiffer or softer ride. So I'm pretty confident you can get the ride height you need once the full weight is on the car, unless something else is wrong.

[Bow tie downunder]

The code is RHZ 1-6. 11-2-95 . I'll take your advice and wait until it is all together.
Thanks
mick

[chevynut]

RHZ is the base suspension as I mentioned above. I think it will work fine. ;)