Thread: 53 Is back from the Body Shop

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Finally had time to mess around with Rita's brakes again. I bypassed the willwood adjustable proportioning valve to the back brakes and they work perfect. Just sitting there applying the brakes you can hear stuff crunching in the back when you push on the pedal hard, and on the gravel road they almost lock up before the fronts but not quite. I think we're going to call it a win, I don't know why they work perfect without a proportioning valve but I'm fine with it.

Originally Posted by 53 Chevy5

Finally had time to mess around with Rita's brakes again. I bypassed the willwood adjustable proportioning valve to the back brakes and they work perfect. Just sitting there applying the brakes you can hear stuff crunching in the back when you push on the pedal hard, and on the gravel road they almost lock up before the fronts but not quite. I think we're going to call it a win, I don't know why they work perfect without a proportioning valve but I'm fine with it.

On my coupe with the same valve, I have the adjustment all the way backed off. I don't need it at all. Glad to hear you made a big difference and scored a win!

Nice! Always good when you can leave something out and fix a problem!

Need some wiring help here. I've been messing around making a latching relay so if my door is opened a horn will turn on, but I want it to stay on till I hit the kill switch. I can make a latching one easy if I use a power wire to turn it on but my dome light switch runs on a ground and for the life of me I can't get it to latch. Anybody done this sort of setup before ?

Use to standard automotive relays as drawn

Correct me if I'm wrong, but in order for this to work the switch has to be on at all times since it supplies 12v to the horn. Wouldn't it be simpler to eliminate the second relay and use the first to interrupt the ground leaving the horn supplied with 12v at all times as it was designed?

Thanks a bunch, I was messing around with two relays trying to get something like that figured out and nothing quite worked. I was Google searching quite a while too and could find nothing. I really appreciate the help, did you draw that up yourself?

Glad I could help!
It doesn't take me long to draw em. I have lots of symbols in store and cut / paste em together, the rest is just connecting lines.

Ken, you are correct it can be done with a single relay switching the ground. I may have misread his post thinking he wanted to switch positive via a negative input, thus the second relay.
Thank you

Originally Posted by 36 sedan

Ken, you are correct it can be done with a single relay switching the ground. I may have misread his post thinking he wanted to switch positive via a negative input, thus the second relay.
Thank you

I printed your diagram out a couple of times trying to figure out how it worked and it just dawned on me that only one relay was needed, at least the way I understood it. Glad to help and FWIW, the only "latching" relays I've seen were on DC-10s and they were big and used in the generator power system.
I wish there were more questions of this nature as it helps me keep my brain active

The only caveat with single negative latch relay is the horn needs to be switched through the vehicle's horn relay, otherwise the horn's initial current load will be through the door jam switch until the relay latches. The door jam switch may not tolerate the initial current demand of the horn's coil.

I'll revise my original drawing to remove the horn's ground source from the door jam switch and place directly to ground when I get back to my office.

I backtracked and started reading some of the stuff Ken was asking too. The circuit needs to be turned on by The ground wire via the dome light, and I need to cut off the circuit with my hidden toggle switch. It doesn't matter to me whether the toggle switch cuts off positive or negative power, it just needs to turn it off. I did have it where it would latch , but like Ken mentioned, the relay was energized all the time which would be bad. One thing that I see that I will have to do differently is get a horn with a separate ground wire. The one I am using uses the frame of the horn to ground it.

Originally Posted by 53 Chevy5

The one I am using uses the frame of the horn to ground it.

Use my revised drawing for your horn, it switches the positive to the horn. The latch stays on until the power switch is interrupted. The interrupt switch will need to be outside the car or put on a delay, otherwise the opened door will activate it. You can put a delay module on the first relay, this would give you time to set and de-activate without setting the horn off.
https://www.amazon.com/Delay-Relay-M...592299&sr=1-17

I will be using a separate horn than the factory horn. It will be mounted on the bottom of the floorboard right next to the relays I use. I was hoping to hook it up tonight but my BIL grabbed Rita today to look at what's going on with the transmission. We were going to take it to Cruz to the woods by Des Moines Iowa, I was going to be danged if I let that thing sit at a motel parking lot overnight in Des Moines without an alarm, the club, a kill switch, and my concealed carrying permit LOL

revised drawing;