My friend aquired 1 new needle for my Tach for my 92 - sc400, I pulled off the old needle. It looks like it was spring mounted. What is the trick to get the spring back where it should be so that there is the return to 0 tension. Any help or a link would be very much appreciated. Thanks again.
Mike Nielsen Red SC400 with 140,000 miles. And loving it !

 

Not a chance in *you know what* of getting that recoil spring back in correctly if it is even SLIGHTLY deformed, and it probably is.

 

Oh all of a sudden you're this big expert on gauge needles.

-PHiZ

 

i was told they pull right out and reinstall is just plugging them back in. Is that incorrect?

 

he isn't talking about needles, he is talking about springs.

 

Here's a little more insight now that i have had time to phoho a bad spring. This is a perfectly working motor from someone's cluster, but it was sent to me after they pulled the needle off the spring went with it. it is very common for the spring to pull out because it is not glued in, just sat into a plastic hole. The contacts of the needle are holding on to it and it lifs the spring when you lift the needle.

This process is irreversible once the spring is stretched. the spring looks innocent enough, right? it is a SUPER thin metal that has to float dead center in the middle of the air both left to right and up and down. if it get's deformed in any way, it will not return the needle to the zero position, it will also bind up and short out the circut board. This spring is not there to return the motor, it carries the voltage to the needle to illuminate it. However once it is deformed, it resists the motor. These are LIVE voltage springs, if they bind and cross the poles, things start to smoke.

I have rewound the springs on these 100 times, they never go back right, and never work right. If you try and be slick and work on your cluster yourself, be prepared to replace the cluster when it screws up. You gotta know these little things when working on somehting this sensitive. now you need a tach motor.

I have one by the way.
Now, you think to yourself, ok i'm still going to try and get the spring strait even though i know i'll never be able to do it, guess what......... there is more than one spring. there are two! one on top of the black disk and one below it. when the top one stretches, the bottom one crushes. you lose.

Don't mess with these if you don't know what you are doing, that's why you have me

pics of a deformed spring:

 

#2

see those poles sticking up? each one has a different polarity of voltage. when that deformed spring hits them, your lexus will have smoke coming from the dash.

it looks fine while it is sitting still, but what happens when you start the car? the tach needle swings and the spring twists up and gets smaller, rapping around the poles and dead shorting.

 

Brian- Who does your nails?

 

Nippendenso

These are laboror's hands for sure. i work, then wash up. these clusters are usually dusty and dirty. They get naturally shaven down during the day on the board components

 

I actually started probing around my gauges with a small screwdriver ( BAD IDEA) and it popped out that spring.

Thanks to OLT...I got a replacement gauge cluster.

 

Oh yeah, that was you...lol. forgot that i got that motor from you. i remember it involved pulling the needle off, and a screwdriver was in the story somewhere.

anyway, you know better than anyone, these springs are impossible to work with.